Android example source code file (ListView.java)
The ListView.java Android example source code/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.widget;
import com.android.internal.R;
import com.google.android.collect.Lists;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.AttributeSet;
import android.util.LongSparseArray;
import android.util.SparseBooleanArray;
import android.view.FocusFinder;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SoundEffectConstants;
import android.view.View;
import android.view.ViewDebug;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.accessibility.AccessibilityEvent;
import java.util.ArrayList;
/*
* Implementation Notes:
*
* Some terminology:
*
* index - index of the items that are currently visible
* position - index of the items in the cursor
*/
/**
* A view that shows items in a vertically scrolling list. The items
* come from the {@link ListAdapter} associated with this view.
*
* @attr ref android.R.styleable#ListView_entries
* @attr ref android.R.styleable#ListView_divider
* @attr ref android.R.styleable#ListView_dividerHeight
* @attr ref android.R.styleable#ListView_choiceMode
* @attr ref android.R.styleable#ListView_headerDividersEnabled
* @attr ref android.R.styleable#ListView_footerDividersEnabled
*/
public class ListView extends AbsListView {
/**
* Used to indicate a no preference for a position type.
*/
static final int NO_POSITION = -1;
/**
* Normal list that does not indicate choices
*/
public static final int CHOICE_MODE_NONE = 0;
/**
* The list allows up to one choice
*/
public static final int CHOICE_MODE_SINGLE = 1;
/**
* The list allows multiple choices
*/
public static final int CHOICE_MODE_MULTIPLE = 2;
/**
* When arrow scrolling, ListView will never scroll more than this factor
* times the height of the list.
*/
private static final float MAX_SCROLL_FACTOR = 0.33f;
/**
* When arrow scrolling, need a certain amount of pixels to preview next
* items. This is usually the fading edge, but if that is small enough,
* we want to make sure we preview at least this many pixels.
*/
private static final int MIN_SCROLL_PREVIEW_PIXELS = 2;
/**
* A class that represents a fixed view in a list, for example a header at the top
* or a footer at the bottom.
*/
public class FixedViewInfo {
/** The view to add to the list */
public View view;
/** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */
public Object data;
/** <code>true if the fixed view should be selectable in the list */
public boolean isSelectable;
}
private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList();
private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList();
Drawable mDivider;
int mDividerHeight;
private boolean mIsCacheColorOpaque;
private boolean mDividerIsOpaque;
private boolean mClipDivider;
private boolean mHeaderDividersEnabled;
private boolean mFooterDividersEnabled;
private boolean mAreAllItemsSelectable = true;
private boolean mItemsCanFocus = false;
private int mChoiceMode = CHOICE_MODE_NONE;
private SparseBooleanArray mCheckStates;
private LongSparseArray<Boolean> mCheckedIdStates;
// used for temporary calculations.
private final Rect mTempRect = new Rect();
private Paint mDividerPaint;
// the single allocated result per list view; kinda cheesey but avoids
// allocating these thingies too often.
private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult();
// Keeps focused children visible through resizes
private FocusSelector mFocusSelector;
public ListView(Context context) {
this(context, null);
}
public ListView(Context context, AttributeSet attrs) {
this(context, attrs, com.android.internal.R.attr.listViewStyle);
}
public ListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
TypedArray a = context.obtainStyledAttributes(attrs,
com.android.internal.R.styleable.ListView, defStyle, 0);
CharSequence[] entries = a.getTextArray(
com.android.internal.R.styleable.ListView_entries);
if (entries != null) {
setAdapter(new ArrayAdapter<CharSequence>(context,
com.android.internal.R.layout.simple_list_item_1, entries));
}
final Drawable d = a.getDrawable(com.android.internal.R.styleable.ListView_divider);
if (d != null) {
// If a divider is specified use its intrinsic height for divider height
setDivider(d);
}
// Use the height specified, zero being the default
final int dividerHeight = a.getDimensionPixelSize(
com.android.internal.R.styleable.ListView_dividerHeight, 0);
if (dividerHeight != 0) {
setDividerHeight(dividerHeight);
}
setChoiceMode(a.getInt(R.styleable.ListView_choiceMode, CHOICE_MODE_NONE));
mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true);
mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true);
a.recycle();
}
/**
* @return The maximum amount a list view will scroll in response to
* an arrow event.
*/
public int getMaxScrollAmount() {
return (int) (MAX_SCROLL_FACTOR * (mBottom - mTop));
}
/**
* Make sure views are touching the top or bottom edge, as appropriate for
* our gravity
*/
private void adjustViewsUpOrDown() {
final int childCount = getChildCount();
int delta;
if (childCount > 0) {
View child;
if (!mStackFromBottom) {
// Uh-oh -- we came up short. Slide all views up to make them
// align with the top
child = getChildAt(0);
delta = child.getTop() - mListPadding.top;
if (mFirstPosition != 0) {
// It's OK to have some space above the first item if it is
// part of the vertical spacing
delta -= mDividerHeight;
}
if (delta < 0) {
// We only are looking to see if we are too low, not too high
delta = 0;
}
} else {
// we are too high, slide all views down to align with bottom
child = getChildAt(childCount - 1);
delta = child.getBottom() - (getHeight() - mListPadding.bottom);
if (mFirstPosition + childCount < mItemCount) {
// It's OK to have some space below the last item if it is
// part of the vertical spacing
delta += mDividerHeight;
}
if (delta > 0) {
delta = 0;
}
}
if (delta != 0) {
offsetChildrenTopAndBottom(-delta);
}
}
}
/**
* Add a fixed view to appear at the top of the list. If addHeaderView is
* called more than once, the views will appear in the order they were
* added. Views added using this call can take focus if they want.
* <p>
* NOTE: Call this before calling setAdapter. This is so ListView can wrap
* the supplied cursor with one that will also account for header and footer
* views.
*
* @param v The view to add.
* @param data Data to associate with this view
* @param isSelectable whether the item is selectable
*/
public void addHeaderView(View v, Object data, boolean isSelectable) {
if (mAdapter != null) {
throw new IllegalStateException(
"Cannot add header view to list -- setAdapter has already been called.");
}
FixedViewInfo info = new FixedViewInfo();
info.view = v;
info.data = data;
info.isSelectable = isSelectable;
mHeaderViewInfos.add(info);
}
/**
* Add a fixed view to appear at the top of the list. If addHeaderView is
* called more than once, the views will appear in the order they were
* added. Views added using this call can take focus if they want.
* <p>
* NOTE: Call this before calling setAdapter. This is so ListView can wrap
* the supplied cursor with one that will also account for header and footer
* views.
*
* @param v The view to add.
*/
public void addHeaderView(View v) {
addHeaderView(v, null, true);
}
@Override
public int getHeaderViewsCount() {
return mHeaderViewInfos.size();
}
/**
* Removes a previously-added header view.
*
* @param v The view to remove
* @return true if the view was removed, false if the view was not a header
* view
*/
public boolean removeHeaderView(View v) {
if (mHeaderViewInfos.size() > 0) {
boolean result = false;
if (((HeaderViewListAdapter) mAdapter).removeHeader(v)) {
mDataSetObserver.onChanged();
result = true;
}
removeFixedViewInfo(v, mHeaderViewInfos);
return result;
}
return false;
}
private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) {
int len = where.size();
for (int i = 0; i < len; ++i) {
FixedViewInfo info = where.get(i);
if (info.view == v) {
where.remove(i);
break;
}
}
}
/**
* Add a fixed view to appear at the bottom of the list. If addFooterView is
* called more than once, the views will appear in the order they were
* added. Views added using this call can take focus if they want.
* <p>
* NOTE: Call this before calling setAdapter. This is so ListView can wrap
* the supplied cursor with one that will also account for header and footer
* views.
*
* @param v The view to add.
* @param data Data to associate with this view
* @param isSelectable true if the footer view can be selected
*/
public void addFooterView(View v, Object data, boolean isSelectable) {
FixedViewInfo info = new FixedViewInfo();
info.view = v;
info.data = data;
info.isSelectable = isSelectable;
mFooterViewInfos.add(info);
// in the case of re-adding a footer view, or adding one later on,
// we need to notify the observer
if (mDataSetObserver != null) {
mDataSetObserver.onChanged();
}
}
/**
* Add a fixed view to appear at the bottom of the list. If addFooterView is called more
* than once, the views will appear in the order they were added. Views added using
* this call can take focus if they want.
* <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied
* cursor with one that will also account for header and footer views.
*
*
* @param v The view to add.
*/
public void addFooterView(View v) {
addFooterView(v, null, true);
}
@Override
public int getFooterViewsCount() {
return mFooterViewInfos.size();
}
/**
* Removes a previously-added footer view.
*
* @param v The view to remove
* @return
* true if the view was removed, false if the view was not a footer view
*/
public boolean removeFooterView(View v) {
if (mFooterViewInfos.size() > 0) {
boolean result = false;
if (((HeaderViewListAdapter) mAdapter).removeFooter(v)) {
mDataSetObserver.onChanged();
result = true;
}
removeFixedViewInfo(v, mFooterViewInfos);
return result;
}
return false;
}
/**
* Returns the adapter currently in use in this ListView. The returned adapter
* might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but
* might be a {@link WrapperListAdapter}.
*
* @return The adapter currently used to display data in this ListView.
*
* @see #setAdapter(ListAdapter)
*/
@Override
public ListAdapter getAdapter() {
return mAdapter;
}
/**
* Sets the data behind this ListView.
*
* The adapter passed to this method may be wrapped by a {@link WrapperListAdapter},
* depending on the ListView features currently in use. For instance, adding
* headers and/or footers will cause the adapter to be wrapped.
*
* @param adapter The ListAdapter which is responsible for maintaining the
* data backing this list and for producing a view to represent an
* item in that data set.
*
* @see #getAdapter()
*/
@Override
public void setAdapter(ListAdapter adapter) {
if (null != mAdapter) {
mAdapter.unregisterDataSetObserver(mDataSetObserver);
}
resetList();
mRecycler.clear();
if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) {
mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter);
} else {
mAdapter = adapter;
}
mOldSelectedPosition = INVALID_POSITION;
mOldSelectedRowId = INVALID_ROW_ID;
if (mAdapter != null) {
mAreAllItemsSelectable = mAdapter.areAllItemsEnabled();
mOldItemCount = mItemCount;
mItemCount = mAdapter.getCount();
checkFocus();
mDataSetObserver = new AdapterDataSetObserver();
mAdapter.registerDataSetObserver(mDataSetObserver);
mRecycler.setViewTypeCount(mAdapter.getViewTypeCount());
int position;
if (mStackFromBottom) {
position = lookForSelectablePosition(mItemCount - 1, false);
} else {
position = lookForSelectablePosition(0, true);
}
setSelectedPositionInt(position);
setNextSelectedPositionInt(position);
if (mItemCount == 0) {
// Nothing selected
checkSelectionChanged();
}
if (mChoiceMode != CHOICE_MODE_NONE &&
mAdapter.hasStableIds() &&
mCheckedIdStates == null) {
mCheckedIdStates = new LongSparseArray<Boolean>();
}
} else {
mAreAllItemsSelectable = true;
checkFocus();
// Nothing selected
checkSelectionChanged();
}
if (mCheckStates != null) {
mCheckStates.clear();
}
if (mCheckedIdStates != null) {
mCheckedIdStates.clear();
}
requestLayout();
}
/**
* The list is empty. Clear everything out.
*/
@Override
void resetList() {
// The parent's resetList() will remove all views from the layout so we need to
// cleanup the state of our footers and headers
clearRecycledState(mHeaderViewInfos);
clearRecycledState(mFooterViewInfos);
super.resetList();
mLayoutMode = LAYOUT_NORMAL;
}
private void clearRecycledState(ArrayList<FixedViewInfo> infos) {
if (infos != null) {
final int count = infos.size();
for (int i = 0; i < count; i++) {
final View child = infos.get(i).view;
final LayoutParams p = (LayoutParams) child.getLayoutParams();
if (p != null) {
p.recycledHeaderFooter = false;
}
}
}
}
/**
* @return Whether the list needs to show the top fading edge
*/
private boolean showingTopFadingEdge() {
final int listTop = mScrollY + mListPadding.top;
return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop);
}
/**
* @return Whether the list needs to show the bottom fading edge
*/
private boolean showingBottomFadingEdge() {
final int childCount = getChildCount();
final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom();
final int lastVisiblePosition = mFirstPosition + childCount - 1;
final int listBottom = mScrollY + getHeight() - mListPadding.bottom;
return (lastVisiblePosition < mItemCount - 1)
|| (bottomOfBottomChild < listBottom);
}
@Override
public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) {
int rectTopWithinChild = rect.top;
// offset so rect is in coordinates of the this view
rect.offset(child.getLeft(), child.getTop());
rect.offset(-child.getScrollX(), -child.getScrollY());
final int height = getHeight();
int listUnfadedTop = getScrollY();
int listUnfadedBottom = listUnfadedTop + height;
final int fadingEdge = getVerticalFadingEdgeLength();
if (showingTopFadingEdge()) {
// leave room for top fading edge as long as rect isn't at very top
if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) {
listUnfadedTop += fadingEdge;
}
}
int childCount = getChildCount();
int bottomOfBottomChild = getChildAt(childCount - 1).getBottom();
if (showingBottomFadingEdge()) {
// leave room for bottom fading edge as long as rect isn't at very bottom
if ((mSelectedPosition < mItemCount - 1)
|| (rect.bottom < (bottomOfBottomChild - fadingEdge))) {
listUnfadedBottom -= fadingEdge;
}
}
int scrollYDelta = 0;
if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) {
// need to MOVE DOWN to get it in view: move down just enough so
// that the entire rectangle is in view (or at least the first
// screen size chunk).
if (rect.height() > height) {
// just enough to get screen size chunk on
scrollYDelta += (rect.top - listUnfadedTop);
} else {
// get entire rect at bottom of screen
scrollYDelta += (rect.bottom - listUnfadedBottom);
}
// make sure we aren't scrolling beyond the end of our children
int distanceToBottom = bottomOfBottomChild - listUnfadedBottom;
scrollYDelta = Math.min(scrollYDelta, distanceToBottom);
} else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) {
// need to MOVE UP to get it in view: move up just enough so that
// entire rectangle is in view (or at least the first screen
// size chunk of it).
if (rect.height() > height) {
// screen size chunk
scrollYDelta -= (listUnfadedBottom - rect.bottom);
} else {
// entire rect at top
scrollYDelta -= (listUnfadedTop - rect.top);
}
// make sure we aren't scrolling any further than the top our children
int top = getChildAt(0).getTop();
int deltaToTop = top - listUnfadedTop;
scrollYDelta = Math.max(scrollYDelta, deltaToTop);
}
final boolean scroll = scrollYDelta != 0;
if (scroll) {
scrollListItemsBy(-scrollYDelta);
positionSelector(child);
mSelectedTop = child.getTop();
invalidate();
}
return scroll;
}
/**
* {@inheritDoc}
*/
@Override
void fillGap(boolean down) {
final int count = getChildCount();
if (down) {
final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight :
getListPaddingTop();
fillDown(mFirstPosition + count, startOffset);
correctTooHigh(getChildCount());
} else {
final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight :
getHeight() - getListPaddingBottom();
fillUp(mFirstPosition - 1, startOffset);
correctTooLow(getChildCount());
}
}
/**
* Fills the list from pos down to the end of the list view.
*
* @param pos The first position to put in the list
*
* @param nextTop The location where the top of the item associated with pos
* should be drawn
*
* @return The view that is currently selected, if it happens to be in the
* range that we draw.
*/
private View fillDown(int pos, int nextTop) {
View selectedView = null;
int end = (mBottom - mTop) - mListPadding.bottom;
while (nextTop < end && pos < mItemCount) {
// is this the selected item?
boolean selected = pos == mSelectedPosition;
View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected);
nextTop = child.getBottom() + mDividerHeight;
if (selected) {
selectedView = child;
}
pos++;
}
return selectedView;
}
/**
* Fills the list from pos up to the top of the list view.
*
* @param pos The first position to put in the list
*
* @param nextBottom The location where the bottom of the item associated
* with pos should be drawn
*
* @return The view that is currently selected
*/
private View fillUp(int pos, int nextBottom) {
View selectedView = null;
int end = mListPadding.top;
while (nextBottom > end && pos >= 0) {
// is this the selected item?
boolean selected = pos == mSelectedPosition;
View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected);
nextBottom = child.getTop() - mDividerHeight;
if (selected) {
selectedView = child;
}
pos--;
}
mFirstPosition = pos + 1;
return selectedView;
}
/**
* Fills the list from top to bottom, starting with mFirstPosition
*
* @param nextTop The location where the top of the first item should be
* drawn
*
* @return The view that is currently selected
*/
private View fillFromTop(int nextTop) {
mFirstPosition = Math.min(mFirstPosition, mSelectedPosition);
mFirstPosition = Math.min(mFirstPosition, mItemCount - 1);
if (mFirstPosition < 0) {
mFirstPosition = 0;
}
return fillDown(mFirstPosition, nextTop);
}
/**
* Put mSelectedPosition in the middle of the screen and then build up and
* down from there. This method forces mSelectedPosition to the center.
*
* @param childrenTop Top of the area in which children can be drawn, as
* measured in pixels
* @param childrenBottom Bottom of the area in which children can be drawn,
* as measured in pixels
* @return Currently selected view
*/
private View fillFromMiddle(int childrenTop, int childrenBottom) {
int height = childrenBottom - childrenTop;
int position = reconcileSelectedPosition();
View sel = makeAndAddView(position, childrenTop, true,
mListPadding.left, true);
mFirstPosition = position;
int selHeight = sel.getMeasuredHeight();
if (selHeight <= height) {
sel.offsetTopAndBottom((height - selHeight) / 2);
}
fillAboveAndBelow(sel, position);
if (!mStackFromBottom) {
correctTooHigh(getChildCount());
} else {
correctTooLow(getChildCount());
}
return sel;
}
/**
* Once the selected view as been placed, fill up the visible area above and
* below it.
*
* @param sel The selected view
* @param position The position corresponding to sel
*/
private void fillAboveAndBelow(View sel, int position) {
final int dividerHeight = mDividerHeight;
if (!mStackFromBottom) {
fillUp(position - 1, sel.getTop() - dividerHeight);
adjustViewsUpOrDown();
fillDown(position + 1, sel.getBottom() + dividerHeight);
} else {
fillDown(position + 1, sel.getBottom() + dividerHeight);
adjustViewsUpOrDown();
fillUp(position - 1, sel.getTop() - dividerHeight);
}
}
/**
* Fills the grid based on positioning the new selection at a specific
* location. The selection may be moved so that it does not intersect the
* faded edges. The grid is then filled upwards and downwards from there.
*
* @param selectedTop Where the selected item should be
* @param childrenTop Where to start drawing children
* @param childrenBottom Last pixel where children can be drawn
* @return The view that currently has selection
*/
private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) {
int fadingEdgeLength = getVerticalFadingEdgeLength();
final int selectedPosition = mSelectedPosition;
View sel;
final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength,
selectedPosition);
final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength,
selectedPosition);
sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true);
// Some of the newly selected item extends below the bottom of the list
if (sel.getBottom() > bottomSelectionPixel) {
// Find space available above the selection into which we can scroll
// upwards
final int spaceAbove = sel.getTop() - topSelectionPixel;
// Find space required to bring the bottom of the selected item
// fully into view
final int spaceBelow = sel.getBottom() - bottomSelectionPixel;
final int offset = Math.min(spaceAbove, spaceBelow);
// Now offset the selected item to get it into view
sel.offsetTopAndBottom(-offset);
} else if (sel.getTop() < topSelectionPixel) {
// Find space required to bring the top of the selected item fully
// into view
final int spaceAbove = topSelectionPixel - sel.getTop();
// Find space available below the selection into which we can scroll
// downwards
final int spaceBelow = bottomSelectionPixel - sel.getBottom();
final int offset = Math.min(spaceAbove, spaceBelow);
// Offset the selected item to get it into view
sel.offsetTopAndBottom(offset);
}
// Fill in views above and below
fillAboveAndBelow(sel, selectedPosition);
if (!mStackFromBottom) {
correctTooHigh(getChildCount());
} else {
correctTooLow(getChildCount());
}
return sel;
}
/**
* Calculate the bottom-most pixel we can draw the selection into
*
* @param childrenBottom Bottom pixel were children can be drawn
* @param fadingEdgeLength Length of the fading edge in pixels, if present
* @param selectedPosition The position that will be selected
* @return The bottom-most pixel we can draw the selection into
*/
private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength,
int selectedPosition) {
int bottomSelectionPixel = childrenBottom;
if (selectedPosition != mItemCount - 1) {
bottomSelectionPixel -= fadingEdgeLength;
}
return bottomSelectionPixel;
}
/**
* Calculate the top-most pixel we can draw the selection into
*
* @param childrenTop Top pixel were children can be drawn
* @param fadingEdgeLength Length of the fading edge in pixels, if present
* @param selectedPosition The position that will be selected
* @return The top-most pixel we can draw the selection into
*/
private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) {
// first pixel we can draw the selection into
int topSelectionPixel = childrenTop;
if (selectedPosition > 0) {
topSelectionPixel += fadingEdgeLength;
}
return topSelectionPixel;
}
/**
* Fills the list based on positioning the new selection relative to the old
* selection. The new selection will be placed at, above, or below the
* location of the new selection depending on how the selection is moving.
* The selection will then be pinned to the visible part of the screen,
* excluding the edges that are faded. The list is then filled upwards and
* downwards from there.
*
* @param oldSel The old selected view. Useful for trying to put the new
* selection in the same place
* @param newSel The view that is to become selected. Useful for trying to
* put the new selection in the same place
* @param delta Which way we are moving
* @param childrenTop Where to start drawing children
* @param childrenBottom Last pixel where children can be drawn
* @return The view that currently has selection
*/
private View moveSelection(View oldSel, View newSel, int delta, int childrenTop,
int childrenBottom) {
int fadingEdgeLength = getVerticalFadingEdgeLength();
final int selectedPosition = mSelectedPosition;
View sel;
final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength,
selectedPosition);
final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength,
selectedPosition);
if (delta > 0) {
/*
* Case 1: Scrolling down.
*/
/*
* Before After
* | | | |
* +-------+ +-------+
* | A | | A |
* | 1 | => +-------+
* +-------+ | B |
* | B | | 2 |
* +-------+ +-------+
* | | | |
*
* Try to keep the top of the previously selected item where it was.
* oldSel = A
* sel = B
*/
// Put oldSel (A) where it belongs
oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true,
mListPadding.left, false);
final int dividerHeight = mDividerHeight;
// Now put the new selection (B) below that
sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true,
mListPadding.left, true);
// Some of the newly selected item extends below the bottom of the list
if (sel.getBottom() > bottomSelectionPixel) {
// Find space available above the selection into which we can scroll upwards
int spaceAbove = sel.getTop() - topSelectionPixel;
// Find space required to bring the bottom of the selected item fully into view
int spaceBelow = sel.getBottom() - bottomSelectionPixel;
// Don't scroll more than half the height of the list
int halfVerticalSpace = (childrenBottom - childrenTop) / 2;
int offset = Math.min(spaceAbove, spaceBelow);
offset = Math.min(offset, halfVerticalSpace);
// We placed oldSel, so offset that item
oldSel.offsetTopAndBottom(-offset);
// Now offset the selected item to get it into view
sel.offsetTopAndBottom(-offset);
}
// Fill in views above and below
if (!mStackFromBottom) {
fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight);
adjustViewsUpOrDown();
fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight);
} else {
fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight);
adjustViewsUpOrDown();
fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight);
}
} else if (delta < 0) {
/*
* Case 2: Scrolling up.
*/
/*
* Before After
* | | | |
* +-------+ +-------+
* | A | | A |
* +-------+ => | 1 |
* | B | +-------+
* | 2 | | B |
* +-------+ +-------+
* | | | |
*
* Try to keep the top of the item about to become selected where it was.
* newSel = A
* olSel = B
*/
if (newSel != null) {
// Try to position the top of newSel (A) where it was before it was selected
sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left,
true);
} else {
// If (A) was not on screen and so did not have a view, position
// it above the oldSel (B)
sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left,
true);
}
// Some of the newly selected item extends above the top of the list
if (sel.getTop() < topSelectionPixel) {
// Find space required to bring the top of the selected item fully into view
int spaceAbove = topSelectionPixel - sel.getTop();
// Find space available below the selection into which we can scroll downwards
int spaceBelow = bottomSelectionPixel - sel.getBottom();
// Don't scroll more than half the height of the list
int halfVerticalSpace = (childrenBottom - childrenTop) / 2;
int offset = Math.min(spaceAbove, spaceBelow);
offset = Math.min(offset, halfVerticalSpace);
// Offset the selected item to get it into view
sel.offsetTopAndBottom(offset);
}
// Fill in views above and below
fillAboveAndBelow(sel, selectedPosition);
} else {
int oldTop = oldSel.getTop();
/*
* Case 3: Staying still
*/
sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true);
// We're staying still...
if (oldTop < childrenTop) {
// ... but the top of the old selection was off screen.
// (This can happen if the data changes size out from under us)
int newBottom = sel.getBottom();
if (newBottom < childrenTop + 20) {
// Not enough visible -- bring it onscreen
sel.offsetTopAndBottom(childrenTop - sel.getTop());
}
}
// Fill in views above and below
fillAboveAndBelow(sel, selectedPosition);
}
return sel;
}
private class FocusSelector implements Runnable {
private int mPosition;
private int mPositionTop;
public FocusSelector setup(int position, int top) {
mPosition = position;
mPositionTop = top;
return this;
}
public void run() {
setSelectionFromTop(mPosition, mPositionTop);
}
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
if (getChildCount() > 0) {
View focusedChild = getFocusedChild();
if (focusedChild != null) {
final int childPosition = mFirstPosition + indexOfChild(focusedChild);
final int childBottom = focusedChild.getBottom();
final int offset = Math.max(0, childBottom - (h - mPaddingTop));
final int top = focusedChild.getTop() - offset;
if (mFocusSelector == null) {
mFocusSelector = new FocusSelector();
}
post(mFocusSelector.setup(childPosition, top));
}
}
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// Sets up mListPadding
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
int childWidth = 0;
int childHeight = 0;
mItemCount = mAdapter == null ? 0 : mAdapter.getCount();
if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED ||
heightMode == MeasureSpec.UNSPECIFIED)) {
final View child = obtainView(0, mIsScrap);
measureScrapChild(child, 0, widthMeasureSpec);
childWidth = child.getMeasuredWidth();
childHeight = child.getMeasuredHeight();
if (recycleOnMeasure() && mRecycler.shouldRecycleViewType(
((LayoutParams) child.getLayoutParams()).viewType)) {
mRecycler.addScrapView(child);
}
}
if (widthMode == MeasureSpec.UNSPECIFIED) {
widthSize = mListPadding.left + mListPadding.right + childWidth +
getVerticalScrollbarWidth();
}
if (heightMode == MeasureSpec.UNSPECIFIED) {
heightSize = mListPadding.top + mListPadding.bottom + childHeight +
getVerticalFadingEdgeLength() * 2;
}
if (heightMode == MeasureSpec.AT_MOST) {
// TODO: after first layout we should maybe start at the first visible position, not 0
heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1);
}
setMeasuredDimension(widthSize, heightSize);
mWidthMeasureSpec = widthMeasureSpec;
}
private void measureScrapChild(View child, int position, int widthMeasureSpec) {
LayoutParams p = (LayoutParams) child.getLayoutParams();
if (p == null) {
p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT, 0);
child.setLayoutParams(p);
}
p.viewType = mAdapter.getItemViewType(position);
p.forceAdd = true;
int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec,
mListPadding.left + mListPadding.right, p.width);
int lpHeight = p.height;
int childHeightSpec;
if (lpHeight > 0) {
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY);
} else {
childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
child.measure(childWidthSpec, childHeightSpec);
}
/**
* @return True to recycle the views used to measure this ListView in
* UNSPECIFIED/AT_MOST modes, false otherwise.
* @hide
*/
@ViewDebug.ExportedProperty
protected boolean recycleOnMeasure() {
return true;
}
/**
* Measures the height of the given range of children (inclusive) and
* returns the height with this ListView's padding and divider heights
* included. If maxHeight is provided, the measuring will stop when the
* current height reaches maxHeight.
*
* @param widthMeasureSpec The width measure spec to be given to a child's
* {@link View#measure(int, int)}.
* @param startPosition The position of the first child to be shown.
* @param endPosition The (inclusive) position of the last child to be
* shown. Specify {@link #NO_POSITION} if the last child should be
* the last available child from the adapter.
* @param maxHeight The maximum height that will be returned (if all the
* children don't fit in this value, this value will be
* returned).
* @param disallowPartialChildPosition In general, whether the returned
* height should only contain entire children. This is more
* powerful--it is the first inclusive position at which partial
* children will not be allowed. Example: it looks nice to have
* at least 3 completely visible children, and in portrait this
* will most likely fit; but in landscape there could be times
* when even 2 children can not be completely shown, so a value
* of 2 (remember, inclusive) would be good (assuming
* startPosition is 0).
* @return The height of this ListView with the given children.
*/
final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition,
final int maxHeight, int disallowPartialChildPosition) {
final ListAdapter adapter = mAdapter;
if (adapter == null) {
return mListPadding.top + mListPadding.bottom;
}
// Include the padding of the list
int returnedHeight = mListPadding.top + mListPadding.bottom;
final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0;
// The previous height value that was less than maxHeight and contained
// no partial children
int prevHeightWithoutPartialChild = 0;
int i;
View child;
// mItemCount - 1 since endPosition parameter is inclusive
endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition;
final AbsListView.RecycleBin recycleBin = mRecycler;
final boolean recyle = recycleOnMeasure();
final boolean[] isScrap = mIsScrap;
for (i = startPosition; i <= endPosition; ++i) {
child = obtainView(i, isScrap);
measureScrapChild(child, i, widthMeasureSpec);
if (i > 0) {
// Count the divider for all but one child
returnedHeight += dividerHeight;
}
// Recycle the view before we possibly return from the method
if (recyle && recycleBin.shouldRecycleViewType(
((LayoutParams) child.getLayoutParams()).viewType)) {
recycleBin.addScrapView(child);
}
returnedHeight += child.getMeasuredHeight();
if (returnedHeight >= maxHeight) {
// We went over, figure out which height to return. If returnedHeight > maxHeight,
// then the i'th position did not fit completely.
return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1)
&& (i > disallowPartialChildPosition) // We've past the min pos
&& (prevHeightWithoutPartialChild > 0) // We have a prev height
&& (returnedHeight != maxHeight) // i'th child did not fit completely
? prevHeightWithoutPartialChild
: maxHeight;
}
if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) {
prevHeightWithoutPartialChild = returnedHeight;
}
}
// At this point, we went through the range of children, and they each
// completely fit, so return the returnedHeight
return returnedHeight;
}
@Override
int findMotionRow(int y) {
int childCount = getChildCount();
if (childCount > 0) {
if (!mStackFromBottom) {
for (int i = 0; i < childCount; i++) {
View v = getChildAt(i);
if (y <= v.getBottom()) {
return mFirstPosition + i;
}
}
} else {
for (int i = childCount - 1; i >= 0; i--) {
View v = getChildAt(i);
if (y >= v.getTop()) {
return mFirstPosition + i;
}
}
}
}
return INVALID_POSITION;
}
/**
* Put a specific item at a specific location on the screen and then build
* up and down from there.
*
* @param position The reference view to use as the starting point
* @param top Pixel offset from the top of this view to the top of the
* reference view.
*
* @return The selected view, or null if the selected view is outside the
* visible area.
*/
private View fillSpecific(int position, int top) {
boolean tempIsSelected = position == mSelectedPosition;
View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected);
// Possibly changed again in fillUp if we add rows above this one.
mFirstPosition = position;
View above;
View below;
final int dividerHeight = mDividerHeight;
if (!mStackFromBottom) {
above = fillUp(position - 1, temp.getTop() - dividerHeight);
// This will correct for the top of the first view not touching the top of the list
adjustViewsUpOrDown();
below = fillDown(position + 1, temp.getBottom() + dividerHeight);
int childCount = getChildCount();
if (childCount > 0) {
correctTooHigh(childCount);
}
} else {
below = fillDown(position + 1, temp.getBottom() + dividerHeight);
// This will correct for the bottom of the last view not touching the bottom of the list
adjustViewsUpOrDown();
above = fillUp(position - 1, temp.getTop() - dividerHeight);
int childCount = getChildCount();
if (childCount > 0) {
correctTooLow(childCount);
}
}
if (tempIsSelected) {
return temp;
} else if (above != null) {
return above;
} else {
return below;
}
}
/**
* Check if we have dragged the bottom of the list too high (we have pushed the
* top element off the top of the screen when we did not need to). Correct by sliding
* everything back down.
*
* @param childCount Number of children
*/
private void correctTooHigh(int childCount) {
// First see if the last item is visible. If it is not, it is OK for the
// top of the list to be pushed up.
int lastPosition = mFirstPosition + childCount - 1;
if (lastPosition == mItemCount - 1 && childCount > 0) {
// Get the last child ...
final View lastChild = getChildAt(childCount - 1);
// ... and its bottom edge
final int lastBottom = lastChild.getBottom();
// This is bottom of our drawable area
final int end = (mBottom - mTop) - mListPadding.bottom;
// This is how far the bottom edge of the last view is from the bottom of the
// drawable area
int bottomOffset = end - lastBottom;
View firstChild = getChildAt(0);
final int firstTop = firstChild.getTop();
// Make sure we are 1) Too high, and 2) Either there are more rows above the
// first row or the first row is scrolled off the top of the drawable area
if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) {
if (mFirstPosition == 0) {
// Don't pull the top too far down
bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop);
}
// Move everything down
offsetChildrenTopAndBottom(bottomOffset);
if (mFirstPosition > 0) {
// Fill the gap that was opened above mFirstPosition with more rows, if
// possible
fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight);
// Close up the remaining gap
adjustViewsUpOrDown();
}
}
}
}
/**
* Check if we have dragged the bottom of the list too low (we have pushed the
* bottom element off the bottom of the screen when we did not need to). Correct by sliding
* everything back up.
*
* @param childCount Number of children
*/
private void correctTooLow(int childCount) {
// First see if the first item is visible. If it is not, it is OK for the
// bottom of the list to be pushed down.
if (mFirstPosition == 0 && childCount > 0) {
// Get the first child ...
final View firstChild = getChildAt(0);
// ... and its top edge
final int firstTop = firstChild.getTop();
// This is top of our drawable area
final int start = mListPadding.top;
// This is bottom of our drawable area
final int end = (mBottom - mTop) - mListPadding.bottom;
// This is how far the top edge of the first view is from the top of the
// drawable area
int topOffset = firstTop - start;
View lastChild = getChildAt(childCount - 1);
final int lastBottom = lastChild.getBottom();
int lastPosition = mFirstPosition + childCount - 1;
// Make sure we are 1) Too low, and 2) Either there are more rows below the
// last row or the last row is scrolled off the bottom of the drawable area
if (topOffset > 0) {
if (lastPosition < mItemCount - 1 || lastBottom > end) {
if (lastPosition == mItemCount - 1) {
// Don't pull the bottom too far up
topOffset = Math.min(topOffset, lastBottom - end);
}
// Move everything up
offsetChildrenTopAndBottom(-topOffset);
if (lastPosition < mItemCount - 1) {
// Fill the gap that was opened below the last position with more rows, if
// possible
fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight);
// Close up the remaining gap
adjustViewsUpOrDown();
}
} else if (lastPosition == mItemCount - 1) {
adjustViewsUpOrDown();
}
}
}
}
@Override
protected void layoutChildren() {
final boolean blockLayoutRequests = mBlockLayoutRequests;
if (!blockLayoutRequests) {
mBlockLayoutRequests = true;
} else {
return;
}
try {
super.layoutChildren();
invalidate();
if (mAdapter == null) {
resetList();
invokeOnItemScrollListener();
return;
}
int childrenTop = mListPadding.top;
int childrenBottom = mBottom - mTop - mListPadding.bottom;
int childCount = getChildCount();
int index = 0;
int delta = 0;
View sel;
View oldSel = null;
View oldFirst = null;
View newSel = null;
View focusLayoutRestoreView = null;
// Remember stuff we will need down below
switch (mLayoutMode) {
case LAYOUT_SET_SELECTION:
index = mNextSelectedPosition - mFirstPosition;
if (index >= 0 && index < childCount) {
newSel = getChildAt(index);
}
break;
case LAYOUT_FORCE_TOP:
case LAYOUT_FORCE_BOTTOM:
case LAYOUT_SPECIFIC:
case LAYOUT_SYNC:
break;
case LAYOUT_MOVE_SELECTION:
default:
// Remember the previously selected view
index = mSelectedPosition - mFirstPosition;
if (index >= 0 && index < childCount) {
oldSel = getChildAt(index);
}
// Remember the previous first child
oldFirst = getChildAt(0);
if (mNextSelectedPosition >= 0) {
delta = mNextSelectedPosition - mSelectedPosition;
}
// Caution: newSel might be null
newSel = getChildAt(index + delta);
}
boolean dataChanged = mDataChanged;
if (dataChanged) {
handleDataChanged();
}
// Handle the empty set by removing all views that are visible
// and calling it a day
if (mItemCount == 0) {
resetList();
invokeOnItemScrollListener();
return;
} else if (mItemCount != mAdapter.getCount()) {
throw new IllegalStateException("The content of the adapter has changed but "
+ "ListView did not receive a notification. Make sure the content of "
+ "your adapter is not modified from a background thread, but only "
+ "from the UI thread. [in ListView(" + getId() + ", " + getClass()
+ ") with Adapter(" + mAdapter.getClass() + ")]");
}
setSelectedPositionInt(mNextSelectedPosition);
// Pull all children into the RecycleBin.
// These views will be reused if possible
final int firstPosition = mFirstPosition;
final RecycleBin recycleBin = mRecycler;
// reset the focus restoration
View focusLayoutRestoreDirectChild = null;
// Don't put header or footer views into the Recycler. Those are
// already cached in mHeaderViews;
if (dataChanged) {
for (int i = 0; i < childCount; i++) {
recycleBin.addScrapView(getChildAt(i));
if (ViewDebug.TRACE_RECYCLER) {
ViewDebug.trace(getChildAt(i),
ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, i);
}
}
} else {
recycleBin.fillActiveViews(childCount, firstPosition);
}
// take focus back to us temporarily to avoid the eventual
// call to clear focus when removing the focused child below
// from messing things up when ViewRoot assigns focus back
// to someone else
final View focusedChild = getFocusedChild();
if (focusedChild != null) {
// TODO: in some cases focusedChild.getParent() == null
// we can remember the focused view to restore after relayout if the
// data hasn't changed, or if the focused position is a header or footer
if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) {
focusLayoutRestoreDirectChild = focusedChild;
// remember the specific view that had focus
focusLayoutRestoreView = findFocus();
if (focusLayoutRestoreView != null) {
// tell it we are going to mess with it
focusLayoutRestoreView.onStartTemporaryDetach();
}
}
requestFocus();
}
// Clear out old views
detachAllViewsFromParent();
switch (mLayoutMode) {
case LAYOUT_SET_SELECTION:
if (newSel != null) {
sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom);
} else {
sel = fillFromMiddle(childrenTop, childrenBottom);
}
break;
case LAYOUT_SYNC:
sel = fillSpecific(mSyncPosition, mSpecificTop);
break;
case LAYOUT_FORCE_BOTTOM:
sel = fillUp(mItemCount - 1, childrenBottom);
adjustViewsUpOrDown();
break;
case LAYOUT_FORCE_TOP:
mFirstPosition = 0;
sel = fillFromTop(childrenTop);
adjustViewsUpOrDown();
break;
case LAYOUT_SPECIFIC:
sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop);
break;
case LAYOUT_MOVE_SELECTION:
sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom);
break;
default:
if (childCount == 0) {
if (!mStackFromBottom) {
final int position = lookForSelectablePosition(0, true);
setSelectedPositionInt(position);
sel = fillFromTop(childrenTop);
} else {
final int position = lookForSelectablePosition(mItemCount - 1, false);
setSelectedPositionInt(position);
sel = fillUp(mItemCount - 1, childrenBottom);
}
} else {
if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) {
sel = fillSpecific(mSelectedPosition,
oldSel == null ? childrenTop : oldSel.getTop());
} else if (mFirstPosition < mItemCount) {
sel = fillSpecific(mFirstPosition,
oldFirst == null ? childrenTop : oldFirst.getTop());
} else {
sel = fillSpecific(0, childrenTop);
}
}
break;
}
// Flush any cached views that did not get reused above
recycleBin.scrapActiveViews();
if (sel != null) {
// the current selected item should get focus if items
// are focusable
if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) {
final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild &&
focusLayoutRestoreView.requestFocus()) || sel.requestFocus();
if (!focusWasTaken) {
// selected item didn't take focus, fine, but still want
// to make sure something else outside of the selected view
// has focus
final View focused = getFocusedChild();
if (focused != null) {
focused.clearFocus();
}
positionSelector(sel);
} else {
sel.setSelected(false);
mSelectorRect.setEmpty();
}
} else {
positionSelector(sel);
}
mSelectedTop = sel.getTop();
} else {
if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) {
View child = getChildAt(mMotionPosition - mFirstPosition);
if (child != null) positionSelector(child);
} else {
mSelectedTop = 0;
mSelectorRect.setEmpty();
}
// even if there is not selected position, we may need to restore
// focus (i.e. something focusable in touch mode)
if (hasFocus() && focusLayoutRestoreView != null) {
focusLayoutRestoreView.requestFocus();
}
}
// tell focus view we are done mucking with it, if it is still in
// our view hierarchy.
if (focusLayoutRestoreView != null
&& focusLayoutRestoreView.getWindowToken() != null) {
focusLayoutRestoreView.onFinishTemporaryDetach();
}
mLayoutMode = LAYOUT_NORMAL;
mDataChanged = false;
mNeedSync = false;
setNextSelectedPositionInt(mSelectedPosition);
updateScrollIndicators();
if (mItemCount > 0) {
checkSelectionChanged();
}
invokeOnItemScrollListener();
} finally {
if (!blockLayoutRequests) {
mBlockLayoutRequests = false;
}
}
}
/**
* @param child a direct child of this list.
* @return Whether child is a header or footer view.
*/
private boolean isDirectChildHeaderOrFooter(View child) {
final ArrayList<FixedViewInfo> headers = mHeaderViewInfos;
final int numHeaders = headers.size();
for (int i = 0; i < numHeaders; i++) {
if (child == headers.get(i).view) {
return true;
}
}
final ArrayList<FixedViewInfo> footers = mFooterViewInfos;
final int numFooters = footers.size();
for (int i = 0; i < numFooters; i++) {
if (child == footers.get(i).view) {
return true;
}
}
return false;
}
/**
* Obtain the view and add it to our list of children. The view can be made
* fresh, converted from an unused view, or used as is if it was in the
* recycle bin.
*
* @param position Logical position in the list
* @param y Top or bottom edge of the view to add
* @param flow If flow is true, align top edge to y. If false, align bottom
* edge to y.
* @param childrenLeft Left edge where children should be positioned
* @param selected Is this position selected?
* @return View that was added
*/
private View makeAndAddView(int position, int y, boolean flow, int childrenLeft,
boolean selected) {
View child;
if (!mDataChanged) {
// Try to use an exsiting view for this position
child = mRecycler.getActiveView(position);
if (child != null) {
if (ViewDebug.TRACE_RECYCLER) {
ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP,
position, getChildCount());
}
// Found it -- we're using an existing child
// This just needs to be positioned
setupChild(child, position, y, flow, childrenLeft, selected, true);
return child;
}
}
// Make a new view for this position, or convert an unused view if possible
child = obtainView(position, mIsScrap);
// This needs to be positioned and measured
setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]);
return child;
}
/**
* Add a view as a child and make sure it is measured (if necessary) and
* positioned properly.
*
* @param child The view to add
* @param position The position of this child
* @param y The y position relative to which this view will be positioned
* @param flowDown If true, align top edge to y. If false, align bottom
* edge to y.
* @param childrenLeft Left edge where children should be positioned
* @param selected Is this position selected?
* @param recycled Has this view been pulled from the recycle bin? If so it
* does not need to be remeasured.
*/
private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft,
boolean selected, boolean recycled) {
final boolean isSelected = selected && shouldShowSelector();
final boolean updateChildSelected = isSelected != child.isSelected();
final int mode = mTouchMode;
final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL &&
mMotionPosition == position;
final boolean updateChildPressed = isPressed != child.isPressed();
final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested();
// Respect layout params that are already in the view. Otherwise make some up...
// noinspection unchecked
AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams();
if (p == null) {
p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT, 0);
}
p.viewType = mAdapter.getItemViewType(position);
if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter &&
p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) {
attachViewToParent(child, flowDown ? -1 : 0, p);
} else {
p.forceAdd = false;
if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) {
p.recycledHeaderFooter = true;
}
addViewInLayout(child, flowDown ? -1 : 0, p, true);
}
if (updateChildSelected) {
child.setSelected(isSelected);
}
if (updateChildPressed) {
child.setPressed(isPressed);
}
if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) {
if (child instanceof Checkable) {
((Checkable) child).setChecked(mCheckStates.get(position));
}
}
if (needToMeasure) {
int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec,
mListPadding.left + mListPadding.right, p.width);
int lpHeight = p.height;
int childHeightSpec;
if (lpHeight > 0) {
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY);
} else {
childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
child.measure(childWidthSpec, childHeightSpec);
} else {
cleanupLayoutState(child);
}
final int w = child.getMeasuredWidth();
final int h = child.getMeasuredHeight();
final int childTop = flowDown ? y : y - h;
if (needToMeasure) {
final int childRight = childrenLeft + w;
final int childBottom = childTop + h;
child.layout(childrenLeft, childTop, childRight, childBottom);
} else {
child.offsetLeftAndRight(childrenLeft - child.getLeft());
child.offsetTopAndBottom(childTop - child.getTop());
}
if (mCachingStarted && !child.isDrawingCacheEnabled()) {
child.setDrawingCacheEnabled(true);
}
}
@Override
protected boolean canAnimate() {
return super.canAnimate() && mItemCount > 0;
}
/**
* Sets the currently selected item. If in touch mode, the item will not be selected
* but it will still be positioned appropriately. If the specified selection position
* is less than 0, then the item at position 0 will be selected.
*
* @param position Index (starting at 0) of the data item to be selected.
*/
@Override
public void setSelection(int position) {
setSelectionFromTop(position, 0);
}
/**
* Sets the selected item and positions the selection y pixels from the top edge
* of the ListView. (If in touch mode, the item will not be selected but it will
* still be positioned appropriately.)
*
* @param position Index (starting at 0) of the data item to be selected.
* @param y The distance from the top edge of the ListView (plus padding) that the
* item will be positioned.
*/
public void setSelectionFromTop(int position, int y) {
if (mAdapter == null) {
return;
}
if (!isInTouchMode()) {
position = lookForSelectablePosition(position, true);
if (position >= 0) {
setNextSelectedPositionInt(position);
}
} else {
mResurrectToPosition = position;
}
if (position >= 0) {
mLayoutMode = LAYOUT_SPECIFIC;
mSpecificTop = mListPadding.top + y;
if (mNeedSync) {
mSyncPosition = position;
mSyncRowId = mAdapter.getItemId(position);
}
requestLayout();
}
}
/**
* Makes the item at the supplied position selected.
*
* @param position the position of the item to select
*/
@Override
void setSelectionInt(int position) {
setNextSelectedPositionInt(position);
boolean awakeScrollbars = false;
final int selectedPosition = mSelectedPosition;
if (selectedPosition >= 0) {
if (position == selectedPosition - 1) {
awakeScrollbars = true;
} else if (position == selectedPosition + 1) {
awakeScrollbars = true;
}
}
layoutChildren();
if (awakeScrollbars) {
awakenScrollBars();
}
}
/**
* Find a position that can be selected (i.e., is not a separator).
*
* @param position The starting position to look at.
* @param lookDown Whether to look down for other positions.
* @return The next selectable position starting at position and then searching either up or
* down. Returns {@link #INVALID_POSITION} if nothing can be found.
*/
@Override
int lookForSelectablePosition(int position, boolean lookDown) {
final ListAdapter adapter = mAdapter;
if (adapter == null || isInTouchMode()) {
return INVALID_POSITION;
}
final int count = adapter.getCount();
if (!mAreAllItemsSelectable) {
if (lookDown) {
position = Math.max(0, position);
while (position < count && !adapter.isEnabled(position)) {
position++;
}
} else {
position = Math.min(position, count - 1);
while (position >= 0 && !adapter.isEnabled(position)) {
position--;
}
}
if (position < 0 || position >= count) {
return INVALID_POSITION;
}
return position;
} else {
if (position < 0 || position >= count) {
return INVALID_POSITION;
}
return position;
}
}
@Override
public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
boolean populated = super.dispatchPopulateAccessibilityEvent(event);
// If the item count is less than 15 then subtract disabled items from the count and
// position. Otherwise ignore disabled items.
if (!populated) {
int itemCount = 0;
int currentItemIndex = getSelectedItemPosition();
ListAdapter adapter = getAdapter();
if (adapter != null) {
final int count = adapter.getCount();
if (count < 15) {
for (int i = 0; i < count; i++) {
if (adapter.isEnabled(i)) {
itemCount++;
} else if (i <= currentItemIndex) {
currentItemIndex--;
}
}
} else {
itemCount = count;
}
}
event.setItemCount(itemCount);
event.setCurrentItemIndex(currentItemIndex);
}
return populated;
}
/**
* setSelectionAfterHeaderView set the selection to be the first list item
* after the header views.
*/
public void setSelectionAfterHeaderView() {
final int count = mHeaderViewInfos.size();
if (count > 0) {
mNextSelectedPosition = 0;
return;
}
if (mAdapter != null) {
setSelection(count);
} else {
mNextSelectedPosition = count;
mLayoutMode = LAYOUT_SET_SELECTION;
}
}
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
// Dispatch in the normal way
boolean handled = super.dispatchKeyEvent(event);
if (!handled) {
// If we didn't handle it...
View focused = getFocusedChild();
if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) {
// ... and our focused child didn't handle it
// ... give it to ourselves so we can scroll if necessary
handled = onKeyDown(event.getKeyCode(), event);
}
}
return handled;
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
return commonKey(keyCode, 1, event);
}
@Override
public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) {
return commonKey(keyCode, repeatCount, event);
}
@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
return commonKey(keyCode, 1, event);
}
private boolean commonKey(int keyCode, int count, KeyEvent event) {
if (mAdapter == null) {
return false;
}
if (mDataChanged) {
layoutChildren();
}
boolean handled = false;
int action = event.getAction();
if (action != KeyEvent.ACTION_UP) {
if (mSelectedPosition < 0) {
switch (keyCode) {
case KeyEvent.KEYCODE_DPAD_UP:
case KeyEvent.KEYCODE_DPAD_DOWN:
case KeyEvent.KEYCODE_DPAD_CENTER:
case KeyEvent.KEYCODE_ENTER:
case KeyEvent.KEYCODE_SPACE:
if (resurrectSelection()) {
return true;
}
}
}
switch (keyCode) {
case KeyEvent.KEYCODE_DPAD_UP:
if (!event.isAltPressed()) {
while (count > 0) {
handled = arrowScroll(FOCUS_UP);
count--;
}
} else {
handled = fullScroll(FOCUS_UP);
}
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
if (!event.isAltPressed()) {
while (count > 0) {
handled = arrowScroll(FOCUS_DOWN);
count--;
}
} else {
handled = fullScroll(FOCUS_DOWN);
}
break;
case KeyEvent.KEYCODE_DPAD_LEFT:
handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT);
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT);
break;
case KeyEvent.KEYCODE_DPAD_CENTER:
case KeyEvent.KEYCODE_ENTER:
if (mItemCount > 0 && event.getRepeatCount() == 0) {
keyPressed();
}
handled = true;
break;
case KeyEvent.KEYCODE_SPACE:
if (mPopup == null || !mPopup.isShowing()) {
if (!event.isShiftPressed()) {
pageScroll(FOCUS_DOWN);
} else {
pageScroll(FOCUS_UP);
}
handled = true;
}
break;
}
}
if (!handled) {
handled = sendToTextFilter(keyCode, count, event);
}
if (handled) {
return true;
} else {
switch (action) {
case KeyEvent.ACTION_DOWN:
return super.onKeyDown(keyCode, event);
case KeyEvent.ACTION_UP:
return super.onKeyUp(keyCode, event);
case KeyEvent.ACTION_MULTIPLE:
return super.onKeyMultiple(keyCode, count, event);
default: // shouldn't happen
return false;
}
}
}
/**
* Scrolls up or down by the number of items currently present on screen.
*
* @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN}
* @return whether selection was moved
*/
boolean pageScroll(int direction) {
int nextPage = -1;
boolean down = false;
if (direction == FOCUS_UP) {
nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1);
} else if (direction == FOCUS_DOWN) {
nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1);
down = true;
}
if (nextPage >= 0) {
int position = lookForSelectablePosition(nextPage, down);
if (position >= 0) {
mLayoutMode = LAYOUT_SPECIFIC;
mSpecificTop = mPaddingTop + getVerticalFadingEdgeLength();
if (down && position > mItemCount - getChildCount()) {
mLayoutMode = LAYOUT_FORCE_BOTTOM;
}
if (!down && position < getChildCount()) {
mLayoutMode = LAYOUT_FORCE_TOP;
}
setSelectionInt(position);
invokeOnItemScrollListener();
if (!awakenScrollBars()) {
invalidate();
}
return true;
}
}
return false;
}
/**
* Go to the last or first item if possible (not worrying about panning across or navigating
* within the internal focus of the currently selected item.)
*
* @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN}
*
* @return whether selection was moved
*/
boolean fullScroll(int direction) {
boolean moved = false;
if (direction == FOCUS_UP) {
if (mSelectedPosition != 0) {
int position = lookForSelectablePosition(0, true);
if (position >= 0) {
mLayoutMode = LAYOUT_FORCE_TOP;
setSelectionInt(position);
invokeOnItemScrollListener();
}
moved = true;
}
} else if (direction == FOCUS_DOWN) {
if (mSelectedPosition < mItemCount - 1) {
int position = lookForSelectablePosition(mItemCount - 1, true);
if (position >= 0) {
mLayoutMode = LAYOUT_FORCE_BOTTOM;
setSelectionInt(position);
invokeOnItemScrollListener();
}
moved = true;
}
}
if (moved && !awakenScrollBars()) {
awakenScrollBars();
invalidate();
}
return moved;
}
/**
* To avoid horizontal focus searches changing the selected item, we
* manually focus search within the selected item (as applicable), and
* prevent focus from jumping to something within another item.
* @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT}
* @return Whether this consumes the key event.
*/
private boolean handleHorizontalFocusWithinListItem(int direction) {
if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) {
throw new IllegalArgumentException("direction must be one of"
+ " {View.FOCUS_LEFT, View.FOCUS_RIGHT}");
}
final int numChildren = getChildCount();
if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) {
final View selectedView = getSelectedView();
if (selectedView != null && selectedView.hasFocus() &&
selectedView instanceof ViewGroup) {
final View currentFocus = selectedView.findFocus();
final View nextFocus = FocusFinder.getInstance().findNextFocus(
(ViewGroup) selectedView, currentFocus, direction);
if (nextFocus != null) {
// do the math to get interesting rect in next focus' coordinates
currentFocus.getFocusedRect(mTempRect);
offsetDescendantRectToMyCoords(currentFocus, mTempRect);
offsetRectIntoDescendantCoords(nextFocus, mTempRect);
if (nextFocus.requestFocus(direction, mTempRect)) {
return true;
}
}
// we are blocking the key from being handled (by returning true)
// if the global result is going to be some other view within this
// list. this is to acheive the overall goal of having
// horizontal d-pad navigation remain in the current item.
final View globalNextFocus = FocusFinder.getInstance().findNextFocus(
(ViewGroup) getRootView(), currentFocus, direction);
if (globalNextFocus != null) {
return isViewAncestorOf(globalNextFocus, this);
}
}
}
return false;
}
/**
* Scrolls to the next or previous item if possible.
*
* @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN}
*
* @return whether selection was moved
*/
boolean arrowScroll(int direction) {
try {
mInLayout = true;
final boolean handled = arrowScrollImpl(direction);
if (handled) {
playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction));
}
return handled;
} finally {
mInLayout = false;
}
}
/**
* Handle an arrow scroll going up or down. Take into account whether items are selectable,
* whether there are focusable items etc.
*
* @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}.
* @return Whether any scrolling, selection or focus change occured.
*/
private boolean arrowScrollImpl(int direction) {
if (getChildCount() <= 0) {
return false;
}
View selectedView = getSelectedView();
int nextSelectedPosition = lookForSelectablePositionOnScreen(direction);
int amountToScroll = amountToScroll(direction, nextSelectedPosition);
// if we are moving focus, we may OVERRIDE the default behavior
final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null;
if (focusResult != null) {
nextSelectedPosition = focusResult.getSelectedPosition();
amountToScroll = focusResult.getAmountToScroll();
}
boolean needToRedraw = focusResult != null;
if (nextSelectedPosition != INVALID_POSITION) {
handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null);
setSelectedPositionInt(nextSelectedPosition);
setNextSelectedPositionInt(nextSelectedPosition);
selectedView = getSelectedView();
if (mItemsCanFocus && focusResult == null) {
// there was no new view found to take focus, make sure we
// don't leave focus with the old selection
final View focused = getFocusedChild();
if (focused != null) {
focused.clearFocus();
}
}
needToRedraw = true;
checkSelectionChanged();
}
if (amountToScroll > 0) {
scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll);
needToRedraw = true;
}
// if we didn't find a new focusable, make sure any existing focused
// item that was panned off screen gives up focus.
if (mItemsCanFocus && (focusResult == null)
&& selectedView != null && selectedView.hasFocus()) {
final View focused = selectedView.findFocus();
if (distanceToView(focused) > 0) {
focused.clearFocus();
}
}
// if the current selection is panned off, we need to remove the selection
if (nextSelectedPosition == INVALID_POSITION && selectedView != null
&& !isViewAncestorOf(selectedView, this)) {
selectedView = null;
hideSelector();
// but we don't want to set the ressurect position (that would make subsequent
// unhandled key events bring back the item we just scrolled off!)
mResurrectToPosition = INVALID_POSITION;
}
if (needToRedraw) {
if (selectedView != null) {
positionSelector(selectedView);
mSelectedTop = selectedView.getTop();
}
if (!awakenScrollBars()) {
invalidate();
}
invokeOnItemScrollListener();
return true;
}
return false;
}
/**
* When selection changes, it is possible that the previously selected or the
* next selected item will change its size. If so, we need to offset some folks,
* and re-layout the items as appropriate.
*
* @param selectedView The currently selected view (before changing selection).
* should be <code>null if there was no previous selection.
* @param direction Either {@link android.view.View#FOCUS_UP} or
* {@link android.view.View#FOCUS_DOWN}.
* @param newSelectedPosition The position of the next selection.
* @param newFocusAssigned whether new focus was assigned. This matters because
* when something has focus, we don't want to show selection (ugh).
*/
private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition,
boolean newFocusAssigned) {
if (newSelectedPosition == INVALID_POSITION) {
throw new IllegalArgumentException("newSelectedPosition needs to be valid");
}
// whether or not we are moving down or up, we want to preserve the
// top of whatever view is on top:
// - moving down: the view that had selection
// - moving up: the view that is getting selection
View topView;
View bottomView;
int topViewIndex, bottomViewIndex;
boolean topSelected = false;
final int selectedIndex = mSelectedPosition - mFirstPosition;
final int nextSelectedIndex = newSelectedPosition - mFirstPosition;
if (direction == View.FOCUS_UP) {
topViewIndex = nextSelectedIndex;
bottomViewIndex = selectedIndex;
topView = getChildAt(topViewIndex);
bottomView = selectedView;
topSelected = true;
} else {
topViewIndex = selectedIndex;
bottomViewIndex = nextSelectedIndex;
topView = selectedView;
bottomView = getChildAt(bottomViewIndex);
}
final int numChildren = getChildCount();
// start with top view: is it changing size?
if (topView != null) {
topView.setSelected(!newFocusAssigned && topSelected);
measureAndAdjustDown(topView, topViewIndex, numChildren);
}
// is the bottom view changing size?
if (bottomView != null) {
bottomView.setSelected(!newFocusAssigned && !topSelected);
measureAndAdjustDown(bottomView, bottomViewIndex, numChildren);
}
}
/**
* Re-measure a child, and if its height changes, lay it out preserving its
* top, and adjust the children below it appropriately.
* @param child The child
* @param childIndex The view group index of the child.
* @param numChildren The number of children in the view group.
*/
private void measureAndAdjustDown(View child, int childIndex, int numChildren) {
int oldHeight = child.getHeight();
measureItem(child);
if (child.getMeasuredHeight() != oldHeight) {
// lay out the view, preserving its top
relayoutMeasuredItem(child);
// adjust views below appropriately
final int heightDelta = child.getMeasuredHeight() - oldHeight;
for (int i = childIndex + 1; i < numChildren; i++) {
getChildAt(i).offsetTopAndBottom(heightDelta);
}
}
}
/**
* Measure a particular list child.
* TODO: unify with setUpChild.
* @param child The child.
*/
private void measureItem(View child) {
ViewGroup.LayoutParams p = child.getLayoutParams();
if (p == null) {
p = new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
}
int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec,
mListPadding.left + mListPadding.right, p.width);
int lpHeight = p.height;
int childHeightSpec;
if (lpHeight > 0) {
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY);
} else {
childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
child.measure(childWidthSpec, childHeightSpec);
}
/**
* Layout a child that has been measured, preserving its top position.
* TODO: unify with setUpChild.
* @param child The child.
*/
private void relayoutMeasuredItem(View child) {
final int w = child.getMeasuredWidth();
final int h = child.getMeasuredHeight();
final int childLeft = mListPadding.left;
final int childRight = childLeft + w;
final int childTop = child.getTop();
final int childBottom = childTop + h;
child.layout(childLeft, childTop, childRight, childBottom);
}
/**
* @return The amount to preview next items when arrow srolling.
*/
private int getArrowScrollPreviewLength() {
return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength());
}
/**
* Determine how much we need to scroll in order to get the next selected view
* visible, with a fading edge showing below as applicable. The amount is
* capped at {@link #getMaxScrollAmount()} .
*
* @param direction either {@link android.view.View#FOCUS_UP} or
* {@link android.view.View#FOCUS_DOWN}.
* @param nextSelectedPosition The position of the next selection, or
* {@link #INVALID_POSITION} if there is no next selectable position
* @return The amount to scroll. Note: this is always positive! Direction
* needs to be taken into account when actually scrolling.
*/
private int amountToScroll(int direction, int nextSelectedPosition) {
final int listBottom = getHeight() - mListPadding.bottom;
final int listTop = mListPadding.top;
final int numChildren = getChildCount();
if (direction == View.FOCUS_DOWN) {
int indexToMakeVisible = numChildren - 1;
if (nextSelectedPosition != INVALID_POSITION) {
indexToMakeVisible = nextSelectedPosition - mFirstPosition;
}
final int positionToMakeVisible = mFirstPosition + indexToMakeVisible;
final View viewToMakeVisible = getChildAt(indexToMakeVisible);
int goalBottom = listBottom;
if (positionToMakeVisible < mItemCount - 1) {
goalBottom -= getArrowScrollPreviewLength();
}
if (viewToMakeVisible.getBottom() <= goalBottom) {
// item is fully visible.
return 0;
}
if (nextSelectedPosition != INVALID_POSITION
&& (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) {
// item already has enough of it visible, changing selection is good enough
return 0;
}
int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom);
if ((mFirstPosition + numChildren) == mItemCount) {
// last is last in list -> make sure we don't scroll past it
final int max = getChildAt(numChildren - 1).getBottom() - listBottom;
amountToScroll = Math.min(amountToScroll, max);
}
return Math.min(amountToScroll, getMaxScrollAmount());
} else {
int indexToMakeVisible = 0;
if (nextSelectedPosition != INVALID_POSITION) {
indexToMakeVisible = nextSelectedPosition - mFirstPosition;
}
final int positionToMakeVisible = mFirstPosition + indexToMakeVisible;
final View viewToMakeVisible = getChildAt(indexToMakeVisible);
int goalTop = listTop;
if (positionToMakeVisible > 0) {
goalTop += getArrowScrollPreviewLength();
}
if (viewToMakeVisible.getTop() >= goalTop) {
// item is fully visible.
return 0;
}
if (nextSelectedPosition != INVALID_POSITION &&
(viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) {
// item already has enough of it visible, changing selection is good enough
return 0;
}
int amountToScroll = (goalTop - viewToMakeVisible.getTop());
if (mFirstPosition == 0) {
// first is first in list -> make sure we don't scroll past it
final int max = listTop - getChildAt(0).getTop();
amountToScroll = Math.min(amountToScroll, max);
}
return Math.min(amountToScroll, getMaxScrollAmount());
}
}
/**
* Holds results of focus aware arrow scrolling.
*/
static private class ArrowScrollFocusResult {
private int mSelectedPosition;
private int mAmountToScroll;
/**
* How {@link android.widget.ListView#arrowScrollFocused} returns its values.
*/
void populate(int selectedPosition, int amountToScroll) {
mSelectedPosition = selectedPosition;
mAmountToScroll = amountToScroll;
}
public int getSelectedPosition() {
return mSelectedPosition;
}
public int getAmountToScroll() {
return mAmountToScroll;
}
}
/**
* @param direction either {@link android.view.View#FOCUS_UP} or
* {@link android.view.View#FOCUS_DOWN}.
* @return The position of the next selectable position of the views that
* are currently visible, taking into account the fact that there might
* be no selection. Returns {@link #INVALID_POSITION} if there is no
* selectable view on screen in the given direction.
*/
private int lookForSelectablePositionOnScreen(int direction) {
final int firstPosition = mFirstPosition;
if (direction == View.FOCUS_DOWN) {
int startPos = (mSelectedPosition != INVALID_POSITION) ?
mSelectedPosition + 1 :
firstPosition;
if (startPos >= mAdapter.getCount()) {
return INVALID_POSITION;
}
if (startPos < firstPosition) {
startPos = firstPosition;
}
final int lastVisiblePos = getLastVisiblePosition();
final ListAdapter adapter = getAdapter();
for (int pos = startPos; pos <= lastVisiblePos; pos++) {
if (adapter.isEnabled(pos)
&& getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) {
return pos;
}
}
} else {
int last = firstPosition + getChildCount() - 1;
int startPos = (mSelectedPosition != INVALID_POSITION) ?
mSelectedPosition - 1 :
firstPosition + getChildCount() - 1;
if (startPos < 0) {
return INVALID_POSITION;
}
if (startPos > last) {
startPos = last;
}
final ListAdapter adapter = getAdapter();
for (int pos = startPos; pos >= firstPosition; pos--) {
if (adapter.isEnabled(pos)
&& getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) {
return pos;
}
}
}
return INVALID_POSITION;
}
/**
* Do an arrow scroll based on focus searching. If a new view is
* given focus, return the selection delta and amount to scroll via
* an {@link ArrowScrollFocusResult}, otherwise, return null.
*
* @param direction either {@link android.view.View#FOCUS_UP} or
* {@link android.view.View#FOCUS_DOWN}.
* @return The result if focus has changed, or <code>null.
*/
private ArrowScrollFocusResult arrowScrollFocused(final int direction) {
final View selectedView = getSelectedView();
View newFocus;
if (selectedView != null && selectedView.hasFocus()) {
View oldFocus = selectedView.findFocus();
newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction);
} else {
if (direction == View.FOCUS_DOWN) {
final boolean topFadingEdgeShowing = (mFirstPosition > 0);
final int listTop = mListPadding.top +
(topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0);
final int ySearchPoint =
(selectedView != null && selectedView.getTop() > listTop) ?
selectedView.getTop() :
listTop;
mTempRect.set(0, ySearchPoint, 0, ySearchPoint);
} else {
final boolean bottomFadingEdgeShowing =
(mFirstPosition + getChildCount() - 1) < mItemCount;
final int listBottom = getHeight() - mListPadding.bottom -
(bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0);
final int ySearchPoint =
(selectedView != null && selectedView.getBottom() < listBottom) ?
selectedView.getBottom() :
listBottom;
mTempRect.set(0, ySearchPoint, 0, ySearchPoint);
}
newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction);
}
if (newFocus != null) {
final int positionOfNewFocus = positionOfNewFocus(newFocus);
// if the focus change is in a different new position, make sure
// we aren't jumping over another selectable position
if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) {
final int selectablePosition = lookForSelectablePositionOnScreen(direction);
if (selectablePosition != INVALID_POSITION &&
((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) ||
(direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) {
return null;
}
}
int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus);
final int maxScrollAmount = getMaxScrollAmount();
if (focusScroll < maxScrollAmount) {
// not moving too far, safe to give next view focus
newFocus.requestFocus(direction);
mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll);
return mArrowScrollFocusResult;
} else if (distanceToView(newFocus) < maxScrollAmount){
// Case to consider:
// too far to get entire next focusable on screen, but by going
// max scroll amount, we are getting it at least partially in view,
// so give it focus and scroll the max ammount.
newFocus.requestFocus(direction);
mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount);
return mArrowScrollFocusResult;
}
}
return null;
}
/**
* @param newFocus The view that would have focus.
* @return the position that contains newFocus
*/
private int positionOfNewFocus(View newFocus) {
final int numChildren = getChildCount();
for (int i = 0; i < numChildren; i++) {
final View child = getChildAt(i);
if (isViewAncestorOf(newFocus, child)) {
return mFirstPosition + i;
}
}
throw new IllegalArgumentException("newFocus is not a child of any of the"
+ " children of the list!");
}
/**
* Return true if child is an ancestor of parent, (or equal to the parent).
*/
private boolean isViewAncestorOf(View child, View parent) {
if (child == parent) {
return true;
}
final ViewParent theParent = child.getParent();
return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent);
}
/**
* Determine how much we need to scroll in order to get newFocus in view.
* @param direction either {@link android.view.View#FOCUS_UP} or
* {@link android.view.View#FOCUS_DOWN}.
* @param newFocus The view that would take focus.
* @param positionOfNewFocus The position of the list item containing newFocus
* @return The amount to scroll. Note: this is always positive! Direction
* needs to be taken into account when actually scrolling.
*/
private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) {
int amountToScroll = 0;
newFocus.getDrawingRect(mTempRect);
offsetDescendantRectToMyCoords(newFocus, mTempRect);
if (direction == View.FOCUS_UP) {
if (mTempRect.top < mListPadding.top) {
amountToScroll = mListPadding.top - mTempRect.top;
if (positionOfNewFocus > 0) {
amountToScroll += getArrowScrollPreviewLength();
}
}
} else {
final int listBottom = getHeight() - mListPadding.bottom;
if (mTempRect.bottom > listBottom) {
amountToScroll = mTempRect.bottom - listBottom;
if (positionOfNewFocus < mItemCount - 1) {
amountToScroll += getArrowScrollPreviewLength();
}
}
}
return amountToScroll;
}
/**
* Determine the distance to the nearest edge of a view in a particular
* direction.
*
* @param descendant A descendant of this list.
* @return The distance, or 0 if the nearest edge is already on screen.
*/
private int distanceToView(View descendant) {
int distance = 0;
descendant.getDrawingRect(mTempRect);
offsetDescendantRectToMyCoords(descendant, mTempRect);
final int listBottom = mBottom - mTop - mListPadding.bottom;
if (mTempRect.bottom < mListPadding.top) {
distance = mListPadding.top - mTempRect.bottom;
} else if (mTempRect.top > listBottom) {
distance = mTempRect.top - listBottom;
}
return distance;
}
/**
* Scroll the children by amount, adding a view at the end and removing
* views that fall off as necessary.
*
* @param amount The amount (positive or negative) to scroll.
*/
private void scrollListItemsBy(int amount) {
offsetChildrenTopAndBottom(amount);
final int listBottom = getHeight() - mListPadding.bottom;
final int listTop = mListPadding.top;
final AbsListView.RecycleBin recycleBin = mRecycler;
if (amount < 0) {
// shifted items up
// may need to pan views into the bottom space
int numChildren = getChildCount();
View last = getChildAt(numChildren - 1);
while (last.getBottom() < listBottom) {
final int lastVisiblePosition = mFirstPosition + numChildren - 1;
if (lastVisiblePosition < mItemCount - 1) {
last = addViewBelow(last, lastVisiblePosition);
numChildren++;
} else {
break;
}
}
// may have brought in the last child of the list that is skinnier
// than the fading edge, thereby leaving space at the end. need
// to shift back
if (last.getBottom() < listBottom) {
offsetChildrenTopAndBottom(listBottom - last.getBottom());
}
// top views may be panned off screen
View first = getChildAt(0);
while (first.getBottom() < listTop) {
AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams();
if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) {
detachViewFromParent(first);
recycleBin.addScrapView(first);
} else {
removeViewInLayout(first);
}
first = getChildAt(0);
mFirstPosition++;
}
} else {
// shifted items down
View first = getChildAt(0);
// may need to pan views into top
while ((first.getTop() > listTop) && (mFirstPosition > 0)) {
first = addViewAbove(first, mFirstPosition);
mFirstPosition--;
}
// may have brought the very first child of the list in too far and
// need to shift it back
if (first.getTop() > listTop) {
offsetChildrenTopAndBottom(listTop - first.getTop());
}
int lastIndex = getChildCount() - 1;
View last = getChildAt(lastIndex);
// bottom view may be panned off screen
while (last.getTop() > listBottom) {
AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams();
if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) {
detachViewFromParent(last);
recycleBin.addScrapView(last);
} else {
removeViewInLayout(last);
}
last = getChildAt(--lastIndex);
}
}
}
private View addViewAbove(View theView, int position) {
int abovePosition = position - 1;
View view = obtainView(abovePosition, mIsScrap);
int edgeOfNewChild = theView.getTop() - mDividerHeight;
setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left,
false, mIsScrap[0]);
return view;
}
private View addViewBelow(View theView, int position) {
int belowPosition = position + 1;
View view = obtainView(belowPosition, mIsScrap);
int edgeOfNewChild = theView.getBottom() + mDividerHeight;
setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left,
false, mIsScrap[0]);
return view;
}
/**
* Indicates that the views created by the ListAdapter can contain focusable
* items.
*
* @param itemsCanFocus true if items can get focus, false otherwise
*/
public void setItemsCanFocus(boolean itemsCanFocus) {
mItemsCanFocus = itemsCanFocus;
if (!itemsCanFocus) {
setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
}
}
/**
* @return Whether the views created by the ListAdapter can contain focusable
* items.
*/
public boolean getItemsCanFocus() {
return mItemsCanFocus;
}
/**
* @hide Pending API council approval.
*/
@Override
public boolean isOpaque() {
return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque &&
hasOpaqueScrollbars()) || super.isOpaque();
}
@Override
public void setCacheColorHint(int color) {
final boolean opaque = (color >>> 24) == 0xFF;
mIsCacheColorOpaque = opaque;
if (opaque) {
if (mDividerPaint == null) {
mDividerPaint = new Paint();
}
mDividerPaint.setColor(color);
}
super.setCacheColorHint(color);
}
@Override
protected void dispatchDraw(Canvas canvas) {
// Draw the dividers
final int dividerHeight = mDividerHeight;
final boolean drawDividers = dividerHeight > 0 && mDivider != null;
if (drawDividers) {
// Only modify the top and bottom in the loop, we set the left and right here
final Rect bounds = mTempRect;
bounds.left = mPaddingLeft;
bounds.right = mRight - mLeft - mPaddingRight;
final int count = getChildCount();
final int headerCount = mHeaderViewInfos.size();
final int itemCount = mItemCount;
final int footerLimit = itemCount - mFooterViewInfos.size() - 1;
final boolean headerDividers = mHeaderDividersEnabled;
final boolean footerDividers = mFooterDividersEnabled;
final int first = mFirstPosition;
final boolean areAllItemsSelectable = mAreAllItemsSelectable;
final ListAdapter adapter = mAdapter;
// If the list is opaque *and* the background is not, we want to
// fill a rect where the dividers would be for non-selectable items
// If the list is opaque and the background is also opaque, we don't
// need to draw anything since the background will do it for us
final boolean fillForMissingDividers = drawDividers && isOpaque() && !super.isOpaque();
if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) {
mDividerPaint = new Paint();
mDividerPaint.setColor(getCacheColorHint());
}
final Paint paint = mDividerPaint;
final int listBottom = mBottom - mTop - mListPadding.bottom + mScrollY;
if (!mStackFromBottom) {
int bottom = 0;
final int scrollY = mScrollY;
for (int i = 0; i < count; i++) {
if ((headerDividers || first + i >= headerCount) &&
(footerDividers || first + i < footerLimit)) {
View child = getChildAt(i);
bottom = child.getBottom();
// Don't draw dividers next to items that are not enabled
if (drawDividers) {
if ((areAllItemsSelectable ||
(adapter.isEnabled(first + i) && (i == count - 1 ||
adapter.isEnabled(first + i + 1))))) {
bounds.top = bottom;
bounds.bottom = bottom + dividerHeight;
drawDivider(canvas, bounds, i);
} else if (fillForMissingDividers) {
bounds.top = bottom;
bounds.bottom = bottom + dividerHeight;
canvas.drawRect(bounds, paint);
}
}
}
}
} else {
int top;
int listTop = mListPadding.top;
final int scrollY = mScrollY;
for (int i = 0; i < count; i++) {
if ((headerDividers || first + i >= headerCount) &&
(footerDividers || first + i < footerLimit)) {
View child = getChildAt(i);
top = child.getTop();
// Don't draw dividers next to items that are not enabled
if (drawDividers && top > listTop) {
if ((areAllItemsSelectable ||
(adapter.isEnabled(first + i) && (i == count - 1 ||
adapter.isEnabled(first + i + 1))))) {
bounds.top = top - dividerHeight;
bounds.bottom = top;
// Give the method the child ABOVE the divider, so we
// subtract one from our child
// position. Give -1 when there is no child above the
// divider.
drawDivider(canvas, bounds, i - 1);
} else if (fillForMissingDividers) {
bounds.top = top - dividerHeight;
bounds.bottom = top;
canvas.drawRect(bounds, paint);
}
}
}
}
if (count > 0 && scrollY > 0 && drawDividers) {
bounds.top = listBottom;
bounds.bottom = listBottom + dividerHeight;
drawDivider(canvas, bounds, -1);
}
}
}
// Draw the indicators (these should be drawn above the dividers) and children
super.dispatchDraw(canvas);
}
/**
* Draws a divider for the given child in the given bounds.
*
* @param canvas The canvas to draw to.
* @param bounds The bounds of the divider.
* @param childIndex The index of child (of the View) above the divider.
* This will be -1 if there is no child above the divider to be
* drawn.
*/
void drawDivider(Canvas canvas, Rect bounds, int childIndex) {
// This widget draws the same divider for all children
final Drawable divider = mDivider;
final boolean clipDivider = mClipDivider;
if (!clipDivider) {
divider.setBounds(bounds);
} else {
canvas.save();
canvas.clipRect(bounds);
}
divider.draw(canvas);
if (clipDivider) {
canvas.restore();
}
}
/**
* Returns the drawable that will be drawn between each item in the list.
*
* @return the current drawable drawn between list elements
*/
public Drawable getDivider() {
return mDivider;
}
/**
* Sets the drawable that will be drawn between each item in the list. If the drawable does
* not have an intrinsic height, you should also call {@link #setDividerHeight(int)}
*
* @param divider The drawable to use.
*/
public void setDivider(Drawable divider) {
if (divider != null) {
mDividerHeight = divider.getIntrinsicHeight();
mClipDivider = divider instanceof ColorDrawable;
} else {
mDividerHeight = 0;
mClipDivider = false;
}
mDivider = divider;
mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE;
requestLayoutIfNecessary();
}
/**
* @return Returns the height of the divider that will be drawn between each item in the list.
*/
public int getDividerHeight() {
return mDividerHeight;
}
/**
* Sets the height of the divider that will be drawn between each item in the list. Calling
* this will override the intrinsic height as set by {@link #setDivider(Drawable)}
*
* @param height The new height of the divider in pixels.
*/
public void setDividerHeight(int height) {
mDividerHeight = height;
requestLayoutIfNecessary();
}
/**
* Enables or disables the drawing of the divider for header views.
*
* @param headerDividersEnabled True to draw the headers, false otherwise.
*
* @see #setFooterDividersEnabled(boolean)
* @see #addHeaderView(android.view.View)
*/
public void setHeaderDividersEnabled(boolean headerDividersEnabled) {
mHeaderDividersEnabled = headerDividersEnabled;
invalidate();
}
/**
* Enables or disables the drawing of the divider for footer views.
*
* @param footerDividersEnabled True to draw the footers, false otherwise.
*
* @see #setHeaderDividersEnabled(boolean)
* @see #addFooterView(android.view.View)
*/
public void setFooterDividersEnabled(boolean footerDividersEnabled) {
mFooterDividersEnabled = footerDividersEnabled;
invalidate();
}
@Override
protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) {
super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);
int closetChildIndex = -1;
if (gainFocus && previouslyFocusedRect != null) {
previouslyFocusedRect.offset(mScrollX, mScrollY);
final ListAdapter adapter = mAdapter;
// Don't cache the result of getChildCount or mFirstPosition here,
// it could change in layoutChildren.
if (adapter.getCount() < getChildCount() + mFirstPosition) {
mLayoutMode = LAYOUT_NORMAL;
layoutChildren();
}
// figure out which item should be selected based on previously
// focused rect
Rect otherRect = mTempRect;
int minDistance = Integer.MAX_VALUE;
final int childCount = getChildCount();
final int firstPosition = mFirstPosition;
for (int i = 0; i < childCount; i++) {
// only consider selectable views
if (!adapter.isEnabled(firstPosition + i)) {
continue;
}
View other = getChildAt(i);
other.getDrawingRect(otherRect);
offsetDescendantRectToMyCoords(other, otherRect);
int distance = getDistance(previouslyFocusedRect, otherRect, direction);
if (distance < minDistance) {
minDistance = distance;
closetChildIndex = i;
}
}
}
if (closetChildIndex >= 0) {
setSelection(closetChildIndex + mFirstPosition);
} else {
requestLayout();
}
}
/*
* (non-Javadoc)
*
* Children specified in XML are assumed to be header views. After we have
* parsed them move them out of the children list and into mHeaderViews.
*/
@Override
protected void onFinishInflate() {
super.onFinishInflate();
int count = getChildCount();
if (count > 0) {
for (int i = 0; i < count; ++i) {
addHeaderView(getChildAt(i));
}
removeAllViews();
}
}
/* (non-Javadoc)
* @see android.view.View#findViewById(int)
* First look in our children, then in any header and footer views that may be scrolled off.
*/
@Override
protected View findViewTraversal(int id) {
View v;
v = super.findViewTraversal(id);
if (v == null) {
v = findViewInHeadersOrFooters(mHeaderViewInfos, id);
if (v != null) {
return v;
}
v = findViewInHeadersOrFooters(mFooterViewInfos, id);
if (v != null) {
return v;
}
}
return v;
}
/* (non-Javadoc)
*
* Look in the passed in list of headers or footers for the view.
*/
View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) {
if (where != null) {
int len = where.size();
View v;
for (int i = 0; i < len; i++) {
v = where.get(i).view;
if (!v.isRootNamespace()) {
v = v.findViewById(id);
if (v != null) {
return v;
}
}
}
}
return null;
}
/* (non-Javadoc)
* @see android.view.View#findViewWithTag(String)
* First look in our children, then in any header and footer views that may be scrolled off.
*/
@Override
protected View findViewWithTagTraversal(Object tag) {
View v;
v = super.findViewWithTagTraversal(tag);
if (v == null) {
v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag);
if (v != null) {
return v;
}
v = findViewTagInHeadersOrFooters(mFooterViewInfos, tag);
if (v != null) {
return v;
}
}
return v;
}
/* (non-Javadoc)
*
* Look in the passed in list of headers or footers for the view with the tag.
*/
View findViewTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) {
if (where != null) {
int len = where.size();
View v;
for (int i = 0; i < len; i++) {
v = where.get(i).view;
if (!v.isRootNamespace()) {
v = v.findViewWithTag(tag);
if (v != null) {
return v;
}
}
}
}
return null;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) {
// Don't handle edge touches immediately -- they may actually belong to one of our
// descendants.
return false;
}
return super.onTouchEvent(ev);
}
/**
* @see #setChoiceMode(int)
*
* @return The current choice mode
*/
public int getChoiceMode() {
return mChoiceMode;
}
/**
* Defines the choice behavior for the List. By default, Lists do not have any choice behavior
* ({@link #CHOICE_MODE_NONE}). By setting the choiceMode to {@link #CHOICE_MODE_SINGLE}, the
* List allows up to one item to be in a chosen state. By setting the choiceMode to
* {@link #CHOICE_MODE_MULTIPLE}, the list allows any number of items to be chosen.
*
* @param choiceMode One of {@link #CHOICE_MODE_NONE}, {@link #CHOICE_MODE_SINGLE}, or
* {@link #CHOICE_MODE_MULTIPLE}
*/
public void setChoiceMode(int choiceMode) {
mChoiceMode = choiceMode;
if (mChoiceMode != CHOICE_MODE_NONE) {
if (mCheckStates == null) {
mCheckStates = new SparseBooleanArray();
}
if (mCheckedIdStates == null && mAdapter != null && mAdapter.hasStableIds()) {
mCheckedIdStates = new LongSparseArray<Boolean>();
}
}
}
@Override
public boolean performItemClick(View view, int position, long id) {
boolean handled = false;
if (mChoiceMode != CHOICE_MODE_NONE) {
handled = true;
if (mChoiceMode == CHOICE_MODE_MULTIPLE) {
boolean newValue = !mCheckStates.get(position, false);
mCheckStates.put(position, newValue);
if (mCheckedIdStates != null && mAdapter.hasStableIds()) {
if (newValue) {
mCheckedIdStates.put(mAdapter.getItemId(position), Boolean.TRUE);
} else {
mCheckedIdStates.delete(mAdapter.getItemId(position));
}
}
} else {
boolean newValue = !mCheckStates.get(position, false);
if (newValue) {
mCheckStates.clear();
mCheckStates.put(position, true);
if (mCheckedIdStates != null && mAdapter.hasStableIds()) {
mCheckedIdStates.clear();
mCheckedIdStates.put(mAdapter.getItemId(position), Boolean.TRUE);
}
}
}
mDataChanged = true;
rememberSyncState();
requestLayout();
}
handled |= super.performItemClick(view, position, id);
return handled;
}
/**
* Sets the checked state of the specified position. The is only valid if
* the choice mode has been set to {@link #CHOICE_MODE_SINGLE} or
* {@link #CHOICE_MODE_MULTIPLE}.
*
* @param position The item whose checked state is to be checked
* @param value The new checked state for the item
*/
public void setItemChecked(int position, boolean value) {
if (mChoiceMode == CHOICE_MODE_NONE) {
return;
}
if (mChoiceMode == CHOICE_MODE_MULTIPLE) {
mCheckStates.put(position, value);
if (mCheckedIdStates != null && mAdapter.hasStableIds()) {
if (value) {
mCheckedIdStates.put(mAdapter.getItemId(position), Boolean.TRUE);
} else {
mCheckedIdStates.delete(mAdapter.getItemId(position));
}
}
} else {
boolean updateIds = mCheckedIdStates != null && mAdapter.hasStableIds();
// Clear all values if we're checking something, or unchecking the currently
// selected item
if (value || isItemChecked(position)) {
mCheckStates.clear();
if (updateIds) {
mCheckedIdStates.clear();
}
}
// this may end up selecting the value we just cleared but this way
// we ensure length of mCheckStates is 1, a fact getCheckedItemPosition relies on
if (value) {
mCheckStates.put(position, true);
if (updateIds) {
mCheckedIdStates.put(mAdapter.getItemId(position), Boolean.TRUE);
}
}
}
// Do not generate a data change while we are in the layout phase
if (!mInLayout && !mBlockLayoutRequests) {
mDataChanged = true;
rememberSyncState();
requestLayout();
}
}
/**
* Returns the checked state of the specified position. The result is only
* valid if the choice mode has been set to {@link #CHOICE_MODE_SINGLE}
* or {@link #CHOICE_MODE_MULTIPLE}.
*
* @param position The item whose checked state to return
* @return The item's checked state or <code>false if choice mode
* is invalid
*
* @see #setChoiceMode(int)
*/
public boolean isItemChecked(int position) {
if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) {
return mCheckStates.get(position);
}
return false;
}
/**
* Returns the currently checked item. The result is only valid if the choice
* mode has been set to {@link #CHOICE_MODE_SINGLE}.
*
* @return The position of the currently checked item or
* {@link #INVALID_POSITION} if nothing is selected
*
* @see #setChoiceMode(int)
*/
public int getCheckedItemPosition() {
if (mChoiceMode == CHOICE_MODE_SINGLE && mCheckStates != null && mCheckStates.size() == 1) {
return mCheckStates.keyAt(0);
}
return INVALID_POSITION;
}
/**
* Returns the set of checked items in the list. The result is only valid if
* the choice mode has not been set to {@link #CHOICE_MODE_NONE}.
*
* @return A SparseBooleanArray which will return true for each call to
* get(int position) where position is a position in the list,
* or <code>null if the choice mode is set to
* {@link #CHOICE_MODE_NONE}.
*/
public SparseBooleanArray getCheckedItemPositions() {
if (mChoiceMode != CHOICE_MODE_NONE) {
return mCheckStates;
}
return null;
}
/**
* Returns the set of checked items ids. The result is only valid if the
* choice mode has not been set to {@link #CHOICE_MODE_NONE}.
*
* @return A new array which contains the id of each checked item in the
* list.
*
* @deprecated Use {@link #getCheckedItemIds()} instead.
*/
public long[] getCheckItemIds() {
// Use new behavior that correctly handles stable ID mapping.
if (mAdapter != null && mAdapter.hasStableIds()) {
return getCheckedItemIds();
}
// Old behavior was buggy, but would sort of work for adapters without stable IDs.
// Fall back to it to support legacy apps.
if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) {
final SparseBooleanArray states = mCheckStates;
final int count = states.size();
final long[] ids = new long[count];
final ListAdapter adapter = mAdapter;
int checkedCount = 0;
for (int i = 0; i < count; i++) {
if (states.valueAt(i)) {
ids[checkedCount++] = adapter.getItemId(states.keyAt(i));
}
}
// Trim array if needed. mCheckStates may contain false values
// resulting in checkedCount being smaller than count.
if (checkedCount == count) {
return ids;
} else {
final long[] result = new long[checkedCount];
System.arraycopy(ids, 0, result, 0, checkedCount);
return result;
}
}
return new long[0];
}
/**
* Returns the set of checked items ids. The result is only valid if the
* choice mode has not been set to {@link #CHOICE_MODE_NONE} and the adapter
* has stable IDs. ({@link ListAdapter#hasStableIds()} == {@code true})
*
* @return A new array which contains the id of each checked item in the
* list.
*/
public long[] getCheckedItemIds() {
if (mChoiceMode == CHOICE_MODE_NONE || mCheckedIdStates == null || mAdapter == null) {
return new long[0];
}
final LongSparseArray<Boolean> idStates = mCheckedIdStates;
final int count = idStates.size();
final long[] ids = new long[count];
for (int i = 0; i < count; i++) {
ids[i] = idStates.keyAt(i);
}
return ids;
}
/**
* Clear any choices previously set
*/
public void clearChoices() {
if (mCheckStates != null) {
mCheckStates.clear();
}
if (mCheckedIdStates != null) {
mCheckedIdStates.clear();
}
}
static class SavedState extends BaseSavedState {
SparseBooleanArray checkState;
LongSparseArray<Boolean> checkIdState;
/**
* Constructor called from {@link ListView#onSaveInstanceState()}
*/
SavedState(Parcelable superState, SparseBooleanArray checkState,
LongSparseArray<Boolean> checkIdState) {
super(superState);
this.checkState = checkState;
this.checkIdState = checkIdState;
}
/**
* Constructor called from {@link #CREATOR}
*/
private SavedState(Parcel in) {
super(in);
checkState = in.readSparseBooleanArray();
long[] idState = in.createLongArray();
if (idState.length > 0) {
checkIdState = new LongSparseArray<Boolean>();
checkIdState.setValues(idState, Boolean.TRUE);
}
}
@Override
public void writeToParcel(Parcel out, int flags) {
super.writeToParcel(out, flags);
out.writeSparseBooleanArray(checkState);
out.writeLongArray(checkIdState != null ? checkIdState.getKeys() : new long[0]);
}
@Override
public String toString() {
return "ListView.SavedState{"
+ Integer.toHexString(System.identityHashCode(this))
+ " checkState=" + checkState + "}";
}
public static final Parcelable.Creator<SavedState> CREATOR
= new Parcelable.Creator<SavedState>() {
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
@Override
public Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
return new SavedState(superState, mCheckStates, mCheckedIdStates);
}
@Override
public void onRestoreInstanceState(Parcelable state) {
SavedState ss = (SavedState) state;
super.onRestoreInstanceState(ss.getSuperState());
if (ss.checkState != null) {
mCheckStates = ss.checkState;
}
if (ss.checkIdState != null) {
mCheckedIdStates = ss.checkIdState;
}
}
}
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