Android example source code file (GridView.java)
The GridView.java Android example source code/*
* Copyright (C) 2007 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 android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.SoundEffectConstants;
import android.view.animation.GridLayoutAnimationController;
/**
* A view that shows items in two-dimensional scrolling grid. The items in the
* grid come from the {@link ListAdapter} associated with this view.
*/
public class GridView extends AbsListView {
public static final int NO_STRETCH = 0;
public static final int STRETCH_SPACING = 1;
public static final int STRETCH_COLUMN_WIDTH = 2;
public static final int STRETCH_SPACING_UNIFORM = 3;
public static final int AUTO_FIT = -1;
private int mNumColumns = AUTO_FIT;
private int mHorizontalSpacing = 0;
private int mRequestedHorizontalSpacing;
private int mVerticalSpacing = 0;
private int mStretchMode = STRETCH_COLUMN_WIDTH;
private int mColumnWidth;
private int mRequestedColumnWidth;
private int mRequestedNumColumns;
private View mReferenceView = null;
private View mReferenceViewInSelectedRow = null;
private int mGravity = Gravity.LEFT;
private final Rect mTempRect = new Rect();
public GridView(Context context) {
super(context);
}
public GridView(Context context, AttributeSet attrs) {
this(context, attrs, com.android.internal.R.attr.gridViewStyle);
}
public GridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
TypedArray a = context.obtainStyledAttributes(attrs,
com.android.internal.R.styleable.GridView, defStyle, 0);
int hSpacing = a.getDimensionPixelOffset(
com.android.internal.R.styleable.GridView_horizontalSpacing, 0);
setHorizontalSpacing(hSpacing);
int vSpacing = a.getDimensionPixelOffset(
com.android.internal.R.styleable.GridView_verticalSpacing, 0);
setVerticalSpacing(vSpacing);
int index = a.getInt(com.android.internal.R.styleable.GridView_stretchMode, STRETCH_COLUMN_WIDTH);
if (index >= 0) {
setStretchMode(index);
}
int columnWidth = a.getDimensionPixelOffset(com.android.internal.R.styleable.GridView_columnWidth, -1);
if (columnWidth > 0) {
setColumnWidth(columnWidth);
}
int numColumns = a.getInt(com.android.internal.R.styleable.GridView_numColumns, 1);
setNumColumns(numColumns);
index = a.getInt(com.android.internal.R.styleable.GridView_gravity, -1);
if (index >= 0) {
setGravity(index);
}
a.recycle();
}
@Override
public ListAdapter getAdapter() {
return mAdapter;
}
/**
* Sets the data behind this GridView.
*
* @param adapter the adapter providing the grid's data
*/
@Override
public void setAdapter(ListAdapter adapter) {
if (null != mAdapter) {
mAdapter.unregisterDataSetObserver(mDataSetObserver);
}
resetList();
mRecycler.clear();
mAdapter = adapter;
mOldSelectedPosition = INVALID_POSITION;
mOldSelectedRowId = INVALID_ROW_ID;
if (mAdapter != null) {
mOldItemCount = mItemCount;
mItemCount = mAdapter.getCount();
mDataChanged = true;
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);
checkSelectionChanged();
} else {
checkFocus();
// Nothing selected
checkSelectionChanged();
}
requestLayout();
}
@Override
int lookForSelectablePosition(int position, boolean lookDown) {
final ListAdapter adapter = mAdapter;
if (adapter == null || isInTouchMode()) {
return INVALID_POSITION;
}
if (position < 0 || position >= mItemCount) {
return INVALID_POSITION;
}
return position;
}
/**
* {@inheritDoc}
*/
@Override
void fillGap(boolean down) {
final int numColumns = mNumColumns;
final int verticalSpacing = mVerticalSpacing;
final int count = getChildCount();
if (down) {
final int startOffset = count > 0 ?
getChildAt(count - 1).getBottom() + verticalSpacing : getListPaddingTop();
int position = mFirstPosition + count;
if (mStackFromBottom) {
position += numColumns - 1;
}
fillDown(position, startOffset);
correctTooHigh(numColumns, verticalSpacing, getChildCount());
} else {
final int startOffset = count > 0 ?
getChildAt(0).getTop() - verticalSpacing : getHeight() - getListPaddingBottom();
int position = mFirstPosition;
if (!mStackFromBottom) {
position -= numColumns;
} else {
position--;
}
fillUp(position, startOffset);
correctTooLow(numColumns, verticalSpacing, 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;
final int end = (mBottom - mTop) - mListPadding.bottom;
while (nextTop < end && pos < mItemCount) {
View temp = makeRow(pos, nextTop, true);
if (temp != null) {
selectedView = temp;
}
// mReferenceView will change with each call to makeRow()
// do not cache in a local variable outside of this loop
nextTop = mReferenceView.getBottom() + mVerticalSpacing;
pos += mNumColumns;
}
return selectedView;
}
private View makeRow(int startPos, int y, boolean flow) {
final int columnWidth = mColumnWidth;
final int horizontalSpacing = mHorizontalSpacing;
int last;
int nextLeft = mListPadding.left +
((mStretchMode == STRETCH_SPACING_UNIFORM) ? horizontalSpacing : 0);
if (!mStackFromBottom) {
last = Math.min(startPos + mNumColumns, mItemCount);
} else {
last = startPos + 1;
startPos = Math.max(0, startPos - mNumColumns + 1);
if (last - startPos < mNumColumns) {
nextLeft += (mNumColumns - (last - startPos)) * (columnWidth + horizontalSpacing);
}
}
View selectedView = null;
final boolean hasFocus = shouldShowSelector();
final boolean inClick = touchModeDrawsInPressedState();
final int selectedPosition = mSelectedPosition;
View child = null;
for (int pos = startPos; pos < last; pos++) {
// is this the selected item?
boolean selected = pos == selectedPosition;
// does the list view have focus or contain focus
final int where = flow ? -1 : pos - startPos;
child = makeAndAddView(pos, y, flow, nextLeft, selected, where);
nextLeft += columnWidth;
if (pos < last - 1) {
nextLeft += horizontalSpacing;
}
if (selected && (hasFocus || inClick)) {
selectedView = child;
}
}
mReferenceView = child;
if (selectedView != null) {
mReferenceViewInSelectedRow = mReferenceView;
}
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;
final int end = mListPadding.top;
while (nextBottom > end && pos >= 0) {
View temp = makeRow(pos, nextBottom, false);
if (temp != null) {
selectedView = temp;
}
nextBottom = mReferenceView.getTop() - mVerticalSpacing;
mFirstPosition = pos;
pos -= mNumColumns;
}
if (mStackFromBottom) {
mFirstPosition = Math.max(0, 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;
}
mFirstPosition -= mFirstPosition % mNumColumns;
return fillDown(mFirstPosition, nextTop);
}
private View fillFromBottom(int lastPosition, int nextBottom) {
lastPosition = Math.max(lastPosition, mSelectedPosition);
lastPosition = Math.min(lastPosition, mItemCount - 1);
final int invertedPosition = mItemCount - 1 - lastPosition;
lastPosition = mItemCount - 1 - (invertedPosition - (invertedPosition % mNumColumns));
return fillUp(lastPosition, nextBottom);
}
private View fillSelection(int childrenTop, int childrenBottom) {
final int selectedPosition = reconcileSelectedPosition();
final int numColumns = mNumColumns;
final int verticalSpacing = mVerticalSpacing;
int rowStart;
int rowEnd = -1;
if (!mStackFromBottom) {
rowStart = selectedPosition - (selectedPosition % numColumns);
} else {
final int invertedSelection = mItemCount - 1 - selectedPosition;
rowEnd = mItemCount - 1 - (invertedSelection - (invertedSelection % numColumns));
rowStart = Math.max(0, rowEnd - numColumns + 1);
}
final int fadingEdgeLength = getVerticalFadingEdgeLength();
final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, rowStart);
final View sel = makeRow(mStackFromBottom ? rowEnd : rowStart, topSelectionPixel, true);
mFirstPosition = rowStart;
final View referenceView = mReferenceView;
if (!mStackFromBottom) {
fillDown(rowStart + numColumns, referenceView.getBottom() + verticalSpacing);
pinToBottom(childrenBottom);
fillUp(rowStart - numColumns, referenceView.getTop() - verticalSpacing);
adjustViewsUpOrDown();
} else {
final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom,
fadingEdgeLength, numColumns, rowStart);
final int offset = bottomSelectionPixel - referenceView.getBottom();
offsetChildrenTopAndBottom(offset);
fillUp(rowStart - 1, referenceView.getTop() - verticalSpacing);
pinToTop(childrenTop);
fillDown(rowEnd + numColumns, referenceView.getBottom() + verticalSpacing);
adjustViewsUpOrDown();
}
return sel;
}
private void pinToTop(int childrenTop) {
if (mFirstPosition == 0) {
final int top = getChildAt(0).getTop();
final int offset = childrenTop - top;
if (offset < 0) {
offsetChildrenTopAndBottom(offset);
}
}
}
private void pinToBottom(int childrenBottom) {
final int count = getChildCount();
if (mFirstPosition + count == mItemCount) {
final int bottom = getChildAt(count - 1).getBottom();
final int offset = childrenBottom - bottom;
if (offset > 0) {
offsetChildrenTopAndBottom(offset);
}
}
}
@Override
int findMotionRow(int y) {
final int childCount = getChildCount();
if (childCount > 0) {
final int numColumns = mNumColumns;
if (!mStackFromBottom) {
for (int i = 0; i < childCount; i += numColumns) {
if (y <= getChildAt(i).getBottom()) {
return mFirstPosition + i;
}
}
} else {
for (int i = childCount - 1; i >= 0; i -= numColumns) {
if (y >= getChildAt(i).getTop()) {
return mFirstPosition + i;
}
}
}
}
return INVALID_POSITION;
}
/**
* Layout during a scroll that results from tracking motion events. Places
* the mMotionPosition view at the offset specified by mMotionViewTop, and
* then build surrounding views from there.
*
* @param position the position at which to start filling
* @param top the top of the view at that position
* @return The selected view, or null if the selected view is outside the
* visible area.
*/
private View fillSpecific(int position, int top) {
final int numColumns = mNumColumns;
int motionRowStart;
int motionRowEnd = -1;
if (!mStackFromBottom) {
motionRowStart = position - (position % numColumns);
} else {
final int invertedSelection = mItemCount - 1 - position;
motionRowEnd = mItemCount - 1 - (invertedSelection - (invertedSelection % numColumns));
motionRowStart = Math.max(0, motionRowEnd - numColumns + 1);
}
final View temp = makeRow(mStackFromBottom ? motionRowEnd : motionRowStart, top, true);
// Possibly changed again in fillUp if we add rows above this one.
mFirstPosition = motionRowStart;
final View referenceView = mReferenceView;
// We didn't have anything to layout, bail out
if (referenceView == null) {
return null;
}
final int verticalSpacing = mVerticalSpacing;
View above;
View below;
if (!mStackFromBottom) {
above = fillUp(motionRowStart - numColumns, referenceView.getTop() - verticalSpacing);
adjustViewsUpOrDown();
below = fillDown(motionRowStart + numColumns, referenceView.getBottom() + verticalSpacing);
// Check if we have dragged the bottom of the grid too high
final int childCount = getChildCount();
if (childCount > 0) {
correctTooHigh(numColumns, verticalSpacing, childCount);
}
} else {
below = fillDown(motionRowEnd + numColumns, referenceView.getBottom() + verticalSpacing);
adjustViewsUpOrDown();
above = fillUp(motionRowStart - 1, referenceView.getTop() - verticalSpacing);
// Check if we have dragged the bottom of the grid too high
final int childCount = getChildCount();
if (childCount > 0) {
correctTooLow(numColumns, verticalSpacing, childCount);
}
}
if (temp != null) {
return temp;
} else if (above != null) {
return above;
} else {
return below;
}
}
private void correctTooHigh(int numColumns, int verticalSpacing, int childCount) {
// First see if the last item is visible
final 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;
final 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 - (mStackFromBottom ? 1 : numColumns),
firstChild.getTop() - verticalSpacing);
// Close up the remaining gap
adjustViewsUpOrDown();
}
}
}
}
private void correctTooLow(int numColumns, int verticalSpacing, int childCount) {
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;
final View lastChild = getChildAt(childCount - 1);
final int lastBottom = lastChild.getBottom();
final 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 && (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 + (!mStackFromBottom ? 1 : numColumns),
lastChild.getBottom() + verticalSpacing);
// Close up the remaining gap
adjustViewsUpOrDown();
}
}
}
}
/**
* 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) {
final int fadingEdgeLength = getVerticalFadingEdgeLength();
final int selectedPosition = mSelectedPosition;
final int numColumns = mNumColumns;
final int verticalSpacing = mVerticalSpacing;
int rowStart;
int rowEnd = -1;
if (!mStackFromBottom) {
rowStart = selectedPosition - (selectedPosition % numColumns);
} else {
int invertedSelection = mItemCount - 1 - selectedPosition;
rowEnd = mItemCount - 1 - (invertedSelection - (invertedSelection % numColumns));
rowStart = Math.max(0, rowEnd - numColumns + 1);
}
View sel;
View referenceView;
int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, rowStart);
int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength,
numColumns, rowStart);
sel = makeRow(mStackFromBottom ? rowEnd : rowStart, selectedTop, true);
// Possibly changed again in fillUp if we add rows above this one.
mFirstPosition = rowStart;
referenceView = mReferenceView;
adjustForTopFadingEdge(referenceView, topSelectionPixel, bottomSelectionPixel);
adjustForBottomFadingEdge(referenceView, topSelectionPixel, bottomSelectionPixel);
if (!mStackFromBottom) {
fillUp(rowStart - numColumns, referenceView.getTop() - verticalSpacing);
adjustViewsUpOrDown();
fillDown(rowStart + numColumns, referenceView.getBottom() + verticalSpacing);
} else {
fillDown(rowEnd + numColumns, referenceView.getBottom() + verticalSpacing);
adjustViewsUpOrDown();
fillUp(rowStart - 1, referenceView.getTop() - verticalSpacing);
}
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 numColumns Number of columns in the grid
* @param rowStart The start of the row that will contain the selection
* @return The bottom-most pixel we can draw the selection into
*/
private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength,
int numColumns, int rowStart) {
// Last pixel we can draw the selection into
int bottomSelectionPixel = childrenBottom;
if (rowStart + numColumns - 1 < 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 rowStart The start of the row that will contain the selection
* @return The top-most pixel we can draw the selection into
*/
private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int rowStart) {
// first pixel we can draw the selection into
int topSelectionPixel = childrenTop;
if (rowStart > 0) {
topSelectionPixel += fadingEdgeLength;
}
return topSelectionPixel;
}
/**
* Move all views upwards so the selected row does not interesect the bottom
* fading edge (if necessary).
*
* @param childInSelectedRow A child in the row that contains the selection
* @param topSelectionPixel The topmost pixel we can draw the selection into
* @param bottomSelectionPixel The bottommost pixel we can draw the
* selection into
*/
private void adjustForBottomFadingEdge(View childInSelectedRow,
int topSelectionPixel, int bottomSelectionPixel) {
// Some of the newly selected item extends below the bottom of the
// list
if (childInSelectedRow.getBottom() > bottomSelectionPixel) {
// Find space available above the selection into which we can
// scroll upwards
int spaceAbove = childInSelectedRow.getTop() - topSelectionPixel;
// Find space required to bring the bottom of the selected item
// fully into view
int spaceBelow = childInSelectedRow.getBottom() - bottomSelectionPixel;
int offset = Math.min(spaceAbove, spaceBelow);
// Now offset the selected item to get it into view
offsetChildrenTopAndBottom(-offset);
}
}
/**
* Move all views upwards so the selected row does not interesect the top
* fading edge (if necessary).
*
* @param childInSelectedRow A child in the row that contains the selection
* @param topSelectionPixel The topmost pixel we can draw the selection into
* @param bottomSelectionPixel The bottommost pixel we can draw the
* selection into
*/
private void adjustForTopFadingEdge(View childInSelectedRow,
int topSelectionPixel, int bottomSelectionPixel) {
// Some of the newly selected item extends above the top of the list
if (childInSelectedRow.getTop() < topSelectionPixel) {
// Find space required to bring the top of the selected item
// fully into view
int spaceAbove = topSelectionPixel - childInSelectedRow.getTop();
// Find space available below the selection into which we can
// scroll downwards
int spaceBelow = bottomSelectionPixel - childInSelectedRow.getBottom();
int offset = Math.min(spaceAbove, spaceBelow);
// Now offset the selected item to get it into view
offsetChildrenTopAndBottom(offset);
}
}
/**
* Fills the grid 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 grid is then filled upwards and
* downwards from there.
*
* @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(int delta, int childrenTop, int childrenBottom) {
final int fadingEdgeLength = getVerticalFadingEdgeLength();
final int selectedPosition = mSelectedPosition;
final int numColumns = mNumColumns;
final int verticalSpacing = mVerticalSpacing;
int oldRowStart;
int rowStart;
int rowEnd = -1;
if (!mStackFromBottom) {
oldRowStart = (selectedPosition - delta) - ((selectedPosition - delta) % numColumns);
rowStart = selectedPosition - (selectedPosition % numColumns);
} else {
int invertedSelection = mItemCount - 1 - selectedPosition;
rowEnd = mItemCount - 1 - (invertedSelection - (invertedSelection % numColumns));
rowStart = Math.max(0, rowEnd - numColumns + 1);
invertedSelection = mItemCount - 1 - (selectedPosition - delta);
oldRowStart = mItemCount - 1 - (invertedSelection - (invertedSelection % numColumns));
oldRowStart = Math.max(0, oldRowStart - numColumns + 1);
}
final int rowDelta = rowStart - oldRowStart;
final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, rowStart);
final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength,
numColumns, rowStart);
// Possibly changed again in fillUp if we add rows above this one.
mFirstPosition = rowStart;
View sel;
View referenceView;
if (rowDelta > 0) {
/*
* Case 1: Scrolling down.
*/
final int oldBottom = mReferenceViewInSelectedRow == null ? 0 :
mReferenceViewInSelectedRow.getBottom();
sel = makeRow(mStackFromBottom ? rowEnd : rowStart, oldBottom + verticalSpacing, true);
referenceView = mReferenceView;
adjustForBottomFadingEdge(referenceView, topSelectionPixel, bottomSelectionPixel);
} else if (rowDelta < 0) {
/*
* Case 2: Scrolling up.
*/
final int oldTop = mReferenceViewInSelectedRow == null ?
0 : mReferenceViewInSelectedRow .getTop();
sel = makeRow(mStackFromBottom ? rowEnd : rowStart, oldTop - verticalSpacing, false);
referenceView = mReferenceView;
adjustForTopFadingEdge(referenceView, topSelectionPixel, bottomSelectionPixel);
} else {
/*
* Keep selection where it was
*/
final int oldTop = mReferenceViewInSelectedRow == null ?
0 : mReferenceViewInSelectedRow .getTop();
sel = makeRow(mStackFromBottom ? rowEnd : rowStart, oldTop, true);
referenceView = mReferenceView;
}
if (!mStackFromBottom) {
fillUp(rowStart - numColumns, referenceView.getTop() - verticalSpacing);
adjustViewsUpOrDown();
fillDown(rowStart + numColumns, referenceView.getBottom() + verticalSpacing);
} else {
fillDown(rowEnd + numColumns, referenceView.getBottom() + verticalSpacing);
adjustViewsUpOrDown();
fillUp(rowStart - 1, referenceView.getTop() - verticalSpacing);
}
return sel;
}
private void determineColumns(int availableSpace) {
final int requestedHorizontalSpacing = mRequestedHorizontalSpacing;
final int stretchMode = mStretchMode;
final int requestedColumnWidth = mRequestedColumnWidth;
if (mRequestedNumColumns == AUTO_FIT) {
if (requestedColumnWidth > 0) {
// Client told us to pick the number of columns
mNumColumns = (availableSpace + requestedHorizontalSpacing) /
(requestedColumnWidth + requestedHorizontalSpacing);
} else {
// Just make up a number if we don't have enough info
mNumColumns = 2;
}
} else {
// We picked the columns
mNumColumns = mRequestedNumColumns;
}
if (mNumColumns <= 0) {
mNumColumns = 1;
}
switch (stretchMode) {
case NO_STRETCH:
// Nobody stretches
mColumnWidth = requestedColumnWidth;
mHorizontalSpacing = requestedHorizontalSpacing;
break;
default:
int spaceLeftOver = availableSpace - (mNumColumns * requestedColumnWidth) -
((mNumColumns - 1) * requestedHorizontalSpacing);
switch (stretchMode) {
case STRETCH_COLUMN_WIDTH:
// Stretch the columns
mColumnWidth = requestedColumnWidth + spaceLeftOver / mNumColumns;
mHorizontalSpacing = requestedHorizontalSpacing;
break;
case STRETCH_SPACING:
// Stretch the spacing between columns
mColumnWidth = requestedColumnWidth;
if (mNumColumns > 1) {
mHorizontalSpacing = requestedHorizontalSpacing +
spaceLeftOver / (mNumColumns - 1);
} else {
mHorizontalSpacing = requestedHorizontalSpacing + spaceLeftOver;
}
break;
case STRETCH_SPACING_UNIFORM:
// Stretch the spacing between columns
mColumnWidth = requestedColumnWidth;
if (mNumColumns > 1) {
mHorizontalSpacing = requestedHorizontalSpacing +
spaceLeftOver / (mNumColumns + 1);
} else {
mHorizontalSpacing = requestedHorizontalSpacing + spaceLeftOver;
}
break;
}
break;
}
}
@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);
if (widthMode == MeasureSpec.UNSPECIFIED) {
if (mColumnWidth > 0) {
widthSize = mColumnWidth + mListPadding.left + mListPadding.right;
} else {
widthSize = mListPadding.left + mListPadding.right;
}
widthSize += getVerticalScrollbarWidth();
}
int childWidth = widthSize - mListPadding.left - mListPadding.right;
determineColumns(childWidth);
int childHeight = 0;
mItemCount = mAdapter == null ? 0 : mAdapter.getCount();
final int count = mItemCount;
if (count > 0) {
final View child = obtainView(0, mIsScrap);
AbsListView.LayoutParams p = (AbsListView.LayoutParams)child.getLayoutParams();
if (p == null) {
p = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT, 0);
child.setLayoutParams(p);
}
p.viewType = mAdapter.getItemViewType(0);
p.forceAdd = true;
int childHeightSpec = getChildMeasureSpec(
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 0, p.height);
int childWidthSpec = getChildMeasureSpec(
MeasureSpec.makeMeasureSpec(mColumnWidth, MeasureSpec.EXACTLY), 0, p.width);
child.measure(childWidthSpec, childHeightSpec);
childHeight = child.getMeasuredHeight();
if (mRecycler.shouldRecycleViewType(p.viewType)) {
mRecycler.addScrapView(child);
}
}
if (heightMode == MeasureSpec.UNSPECIFIED) {
heightSize = mListPadding.top + mListPadding.bottom + childHeight +
getVerticalFadingEdgeLength() * 2;
}
if (heightMode == MeasureSpec.AT_MOST) {
int ourSize = mListPadding.top + mListPadding.bottom;
final int numColumns = mNumColumns;
for (int i = 0; i < count; i += numColumns) {
ourSize += childHeight;
if (i + numColumns < count) {
ourSize += mVerticalSpacing;
}
if (ourSize >= heightSize) {
ourSize = heightSize;
break;
}
}
heightSize = ourSize;
}
setMeasuredDimension(widthSize, heightSize);
mWidthMeasureSpec = widthMeasureSpec;
}
@Override
protected void attachLayoutAnimationParameters(View child,
ViewGroup.LayoutParams params, int index, int count) {
GridLayoutAnimationController.AnimationParameters animationParams =
(GridLayoutAnimationController.AnimationParameters) params.layoutAnimationParameters;
if (animationParams == null) {
animationParams = new GridLayoutAnimationController.AnimationParameters();
params.layoutAnimationParameters = animationParams;
}
animationParams.count = count;
animationParams.index = index;
animationParams.columnsCount = mNumColumns;
animationParams.rowsCount = count / mNumColumns;
if (!mStackFromBottom) {
animationParams.column = index % mNumColumns;
animationParams.row = index / mNumColumns;
} else {
final int invertedIndex = count - 1 - index;
animationParams.column = mNumColumns - 1 - (invertedIndex % mNumColumns);
animationParams.row = animationParams.rowsCount - 1 - invertedIndex / mNumColumns;
}
}
@Override
protected void layoutChildren() {
final boolean blockLayoutRequests = mBlockLayoutRequests;
if (!blockLayoutRequests) {
mBlockLayoutRequests = true;
}
try {
super.layoutChildren();
invalidate();
if (mAdapter == null) {
resetList();
invokeOnItemScrollListener();
return;
}
final int childrenTop = mListPadding.top;
final int childrenBottom = mBottom - mTop - mListPadding.bottom;
int childCount = getChildCount();
int index;
int delta = 0;
View sel;
View oldSel = null;
View oldFirst = null;
View newSel = 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:
if (mNextSelectedPosition >= 0) {
delta = mNextSelectedPosition - mSelectedPosition;
}
break;
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);
}
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;
}
setSelectedPositionInt(mNextSelectedPosition);
// Pull all children into the RecycleBin.
// These views will be reused if possible
final int firstPosition = mFirstPosition;
final RecycleBin recycleBin = mRecycler;
if (dataChanged) {
for (int i = 0; i < childCount; i++) {
recycleBin.addScrapView(getChildAt(i));
}
} else {
recycleBin.fillActiveViews(childCount, firstPosition);
}
// Clear out old views
//removeAllViewsInLayout();
detachAllViewsFromParent();
switch (mLayoutMode) {
case LAYOUT_SET_SELECTION:
if (newSel != null) {
sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom);
} else {
sel = fillSelection(childrenTop, childrenBottom);
}
break;
case LAYOUT_FORCE_TOP:
mFirstPosition = 0;
sel = fillFromTop(childrenTop);
adjustViewsUpOrDown();
break;
case LAYOUT_FORCE_BOTTOM:
sel = fillUp(mItemCount - 1, childrenBottom);
adjustViewsUpOrDown();
break;
case LAYOUT_SPECIFIC:
sel = fillSpecific(mSelectedPosition, mSpecificTop);
break;
case LAYOUT_SYNC:
sel = fillSpecific(mSyncPosition, mSpecificTop);
break;
case LAYOUT_MOVE_SELECTION:
// Move the selection relative to its old position
sel = moveSelection(delta, childrenTop, childrenBottom);
break;
default:
if (childCount == 0) {
if (!mStackFromBottom) {
setSelectedPositionInt(mAdapter == null || isInTouchMode() ?
INVALID_POSITION : 0);
sel = fillFromTop(childrenTop);
} else {
final int last = mItemCount - 1;
setSelectedPositionInt(mAdapter == null || isInTouchMode() ?
INVALID_POSITION : last);
sel = fillFromBottom(last, 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) {
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();
}
mLayoutMode = LAYOUT_NORMAL;
mDataChanged = false;
mNeedSync = false;
setNextSelectedPositionInt(mSelectedPosition);
updateScrollIndicators();
if (mItemCount > 0) {
checkSelectionChanged();
}
invokeOnItemScrollListener();
} finally {
if (!blockLayoutRequests) {
mBlockLayoutRequests = 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 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 where to add new item in the list
* @return View that was added
*/
private View makeAndAddView(int position, int y, boolean flow, int childrenLeft,
boolean selected, int where) {
View child;
if (!mDataChanged) {
// Try to use an existing view for this position
child = mRecycler.getActiveView(position);
if (child != null) {
// Found it -- we're using an existing child
// This just needs to be positioned
setupChild(child, position, y, flow, childrenLeft, selected, true, where);
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], where);
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 the view
* @param y The y position relative to which this view will be positioned
* @param flow 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.
* @param where Where to add the item in the list
*
*/
private void setupChild(View child, int position, int y, boolean flow, int childrenLeft,
boolean selected, boolean recycled, int where) {
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();
boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested();
// Respect layout params that are already in the view. Otherwise make
// some up...
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) {
attachViewToParent(child, where, p);
} else {
p.forceAdd = false;
addViewInLayout(child, where, p, true);
}
if (updateChildSelected) {
child.setSelected(isSelected);
if (isSelected) {
requestFocus();
}
}
if (updateChildPressed) {
child.setPressed(isPressed);
}
if (needToMeasure) {
int childHeightSpec = ViewGroup.getChildMeasureSpec(
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 0, p.height);
int childWidthSpec = ViewGroup.getChildMeasureSpec(
MeasureSpec.makeMeasureSpec(mColumnWidth, MeasureSpec.EXACTLY), 0, p.width);
child.measure(childWidthSpec, childHeightSpec);
} else {
cleanupLayoutState(child);
}
final int w = child.getMeasuredWidth();
final int h = child.getMeasuredHeight();
int childLeft;
final int childTop = flow ? y : y - h;
switch (mGravity & Gravity.HORIZONTAL_GRAVITY_MASK) {
case Gravity.LEFT:
childLeft = childrenLeft;
break;
case Gravity.CENTER_HORIZONTAL:
childLeft = childrenLeft + ((mColumnWidth - w) / 2);
break;
case Gravity.RIGHT:
childLeft = childrenLeft + mColumnWidth - w;
break;
default:
childLeft = childrenLeft;
break;
}
if (needToMeasure) {
final int childRight = childLeft + w;
final int childBottom = childTop + h;
child.layout(childLeft, childTop, childRight, childBottom);
} else {
child.offsetLeftAndRight(childLeft - child.getLeft());
child.offsetTopAndBottom(childTop - child.getTop());
}
if (mCachingStarted) {
child.setDrawingCacheEnabled(true);
}
}
/**
* Sets the currently selected item
*
* @param position Index (starting at 0) of the data item to be selected.
*
* If in touch mode, the item will not be selected but it will still be positioned
* appropriately.
*/
@Override
public void setSelection(int position) {
if (!isInTouchMode()) {
setNextSelectedPositionInt(position);
} else {
mResurrectToPosition = position;
}
mLayoutMode = LAYOUT_SET_SELECTION;
requestLayout();
}
/**
* Makes the item at the supplied position selected.
*
* @param position the position of the new selection
*/
@Override
void setSelectionInt(int position) {
int previousSelectedPosition = mNextSelectedPosition;
setNextSelectedPositionInt(position);
layoutChildren();
final int next = mStackFromBottom ? mItemCount - 1 - mNextSelectedPosition :
mNextSelectedPosition;
final int previous = mStackFromBottom ? mItemCount - 1
- previousSelectedPosition : previousSelectedPosition;
final int nextRow = next / mNumColumns;
final int previousRow = previous / mNumColumns;
if (nextRow != previousRow) {
awakenScrollBars();
}
}
@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_LEFT:
case KeyEvent.KEYCODE_DPAD_RIGHT:
case KeyEvent.KEYCODE_DPAD_CENTER:
case KeyEvent.KEYCODE_SPACE:
case KeyEvent.KEYCODE_ENTER:
resurrectSelection();
return true;
}
}
switch (keyCode) {
case KeyEvent.KEYCODE_DPAD_LEFT:
handled = arrowScroll(FOCUS_LEFT);
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
handled = arrowScroll(FOCUS_RIGHT);
break;
case KeyEvent.KEYCODE_DPAD_UP:
if (!event.isAltPressed()) {
handled = arrowScroll(FOCUS_UP);
} else {
handled = fullScroll(FOCUS_UP);
}
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
if (!event.isAltPressed()) {
handled = arrowScroll(FOCUS_DOWN);
} else {
handled = fullScroll(FOCUS_DOWN);
}
break;
case KeyEvent.KEYCODE_DPAD_CENTER:
case KeyEvent.KEYCODE_ENTER: {
if (getChildCount() > 0 && event.getRepeatCount() == 0) {
keyPressed();
}
return true;
}
case KeyEvent.KEYCODE_SPACE:
if (mPopup == null || !mPopup.isShowing()) {
if (!event.isShiftPressed()) {
handled = pageScroll(FOCUS_DOWN);
} else {
handled = pageScroll(FOCUS_UP);
}
}
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:
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;
if (direction == FOCUS_UP) {
nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1);
} else if (direction == FOCUS_DOWN) {
nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1);
}
if (nextPage >= 0) {
setSelectionInt(nextPage);
invokeOnItemScrollListener();
awakenScrollBars();
return true;
}
return false;
}
/**
* Go to the last or first item if possible.
*
* @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) {
mLayoutMode = LAYOUT_SET_SELECTION;
setSelectionInt(0);
invokeOnItemScrollListener();
moved = true;
} else if (direction == FOCUS_DOWN) {
mLayoutMode = LAYOUT_SET_SELECTION;
setSelectionInt(mItemCount - 1);
invokeOnItemScrollListener();
moved = true;
}
if (moved) {
awakenScrollBars();
}
return moved;
}
/**
* Scrolls to the next or previous item, horizontally or vertically.
*
* @param direction either {@link View#FOCUS_LEFT}, {@link View#FOCUS_RIGHT},
* {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN}
*
* @return whether selection was moved
*/
boolean arrowScroll(int direction) {
final int selectedPosition = mSelectedPosition;
final int numColumns = mNumColumns;
int startOfRowPos;
int endOfRowPos;
boolean moved = false;
if (!mStackFromBottom) {
startOfRowPos = (selectedPosition / numColumns) * numColumns;
endOfRowPos = Math.min(startOfRowPos + numColumns - 1, mItemCount - 1);
} else {
final int invertedSelection = mItemCount - 1 - selectedPosition;
endOfRowPos = mItemCount - 1 - (invertedSelection / numColumns) * numColumns;
startOfRowPos = Math.max(0, endOfRowPos - numColumns + 1);
}
switch (direction) {
case FOCUS_UP:
if (startOfRowPos > 0) {
mLayoutMode = LAYOUT_MOVE_SELECTION;
setSelectionInt(Math.max(0, selectedPosition - numColumns));
moved = true;
}
break;
case FOCUS_DOWN:
if (endOfRowPos < mItemCount - 1) {
mLayoutMode = LAYOUT_MOVE_SELECTION;
setSelectionInt(Math.min(selectedPosition + numColumns, mItemCount - 1));
moved = true;
}
break;
case FOCUS_LEFT:
if (selectedPosition > startOfRowPos) {
mLayoutMode = LAYOUT_MOVE_SELECTION;
setSelectionInt(Math.max(0, selectedPosition - 1));
moved = true;
}
break;
case FOCUS_RIGHT:
if (selectedPosition < endOfRowPos) {
mLayoutMode = LAYOUT_MOVE_SELECTION;
setSelectionInt(Math.min(selectedPosition + 1, mItemCount - 1));
moved = true;
}
break;
}
if (moved) {
playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction));
invokeOnItemScrollListener();
}
if (moved) {
awakenScrollBars();
}
return moved;
}
@Override
protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) {
super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);
int closestChildIndex = -1;
if (gainFocus && previouslyFocusedRect != null) {
previouslyFocusedRect.offset(mScrollX, mScrollY);
// figure out which item should be selected based on previously
// focused rect
Rect otherRect = mTempRect;
int minDistance = Integer.MAX_VALUE;
final int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
// only consider view's on appropriate edge of grid
if (!isCandidateSelection(i, direction)) {
continue;
}
final View other = getChildAt(i);
other.getDrawingRect(otherRect);
offsetDescendantRectToMyCoords(other, otherRect);
int distance = getDistance(previouslyFocusedRect, otherRect, direction);
if (distance < minDistance) {
minDistance = distance;
closestChildIndex = i;
}
}
}
if (closestChildIndex >= 0) {
setSelection(closestChildIndex + mFirstPosition);
} else {
requestLayout();
}
}
/**
* Is childIndex a candidate for next focus given the direction the focus
* change is coming from?
* @param childIndex The index to check.
* @param direction The direction, one of
* {FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, FOCUS_RIGHT}
* @return Whether childIndex is a candidate.
*/
private boolean isCandidateSelection(int childIndex, int direction) {
final int count = getChildCount();
final int invertedIndex = count - 1 - childIndex;
int rowStart;
int rowEnd;
if (!mStackFromBottom) {
rowStart = childIndex - (childIndex % mNumColumns);
rowEnd = Math.max(rowStart + mNumColumns - 1, count);
} else {
rowEnd = count - 1 - (invertedIndex - (invertedIndex % mNumColumns));
rowStart = Math.max(0, rowEnd - mNumColumns + 1);
}
switch (direction) {
case View.FOCUS_RIGHT:
// coming from left, selection is only valid if it is on left
// edge
return childIndex == rowStart;
case View.FOCUS_DOWN:
// coming from top; only valid if in top row
return rowStart == 0;
case View.FOCUS_LEFT:
// coming from right, must be on right edge
return childIndex == rowEnd;
case View.FOCUS_UP:
// coming from bottom, need to be in last row
return rowEnd == count - 1;
default:
throw new IllegalArgumentException("direction must be one of "
+ "{FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, FOCUS_RIGHT}.");
}
}
/**
* Describes how the child views are horizontally aligned. Defaults to Gravity.LEFT
*
* @param gravity the gravity to apply to this grid's children
*
* @attr ref android.R.styleable#GridView_gravity
*/
public void setGravity(int gravity) {
if (mGravity != gravity) {
mGravity = gravity;
requestLayoutIfNecessary();
}
}
/**
* Set the amount of horizontal (x) spacing to place between each item
* in the grid.
*
* @param horizontalSpacing The amount of horizontal space between items,
* in pixels.
*
* @attr ref android.R.styleable#GridView_horizontalSpacing
*/
public void setHorizontalSpacing(int horizontalSpacing) {
if (horizontalSpacing != mRequestedHorizontalSpacing) {
mRequestedHorizontalSpacing = horizontalSpacing;
requestLayoutIfNecessary();
}
}
/**
* Set the amount of vertical (y) spacing to place between each item
* in the grid.
*
* @param verticalSpacing The amount of vertical space between items,
* in pixels.
*
* @attr ref android.R.styleable#GridView_verticalSpacing
*/
public void setVerticalSpacing(int verticalSpacing) {
if (verticalSpacing != mVerticalSpacing) {
mVerticalSpacing = verticalSpacing;
requestLayoutIfNecessary();
}
}
/**
* Control how items are stretched to fill their space.
*
* @param stretchMode Either {@link #NO_STRETCH},
* {@link #STRETCH_SPACING}, {@link #STRETCH_SPACING_UNIFORM}, or {@link #STRETCH_COLUMN_WIDTH}.
*
* @attr ref android.R.styleable#GridView_stretchMode
*/
public void setStretchMode(int stretchMode) {
if (stretchMode != mStretchMode) {
mStretchMode = stretchMode;
requestLayoutIfNecessary();
}
}
public int getStretchMode() {
return mStretchMode;
}
/**
* Set the width of columns in the grid.
*
* @param columnWidth The column width, in pixels.
*
* @attr ref android.R.styleable#GridView_columnWidth
*/
public void setColumnWidth(int columnWidth) {
if (columnWidth != mRequestedColumnWidth) {
mRequestedColumnWidth = columnWidth;
requestLayoutIfNecessary();
}
}
/**
* Set the number of columns in the grid
*
* @param numColumns The desired number of columns.
*
* @attr ref android.R.styleable#GridView_numColumns
*/
public void setNumColumns(int numColumns) {
if (numColumns != mRequestedNumColumns) {
mRequestedNumColumns = numColumns;
requestLayoutIfNecessary();
}
}
/**
* Make sure views are touching the top or bottom edge, as appropriate for
* our gravity
*/
private void adjustViewsUpOrDown() {
final int childCount = getChildCount();
if (childCount > 0) {
int delta;
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 -= mVerticalSpacing;
}
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 += mVerticalSpacing;
}
if (delta > 0) {
// We only are looking to see if we are too high, not too low
delta = 0;
}
}
if (delta != 0) {
offsetChildrenTopAndBottom(-delta);
}
}
}
@Override
protected int computeVerticalScrollExtent() {
final int count = getChildCount();
if (count > 0) {
final int numColumns = mNumColumns;
final int rowCount = (count + numColumns - 1) / numColumns;
int extent = rowCount * 100;
View view = getChildAt(0);
final int top = view.getTop();
int height = view.getHeight();
if (height > 0) {
extent += (top * 100) / height;
}
view = getChildAt(count - 1);
final int bottom = view.getBottom();
height = view.getHeight();
if (height > 0) {
extent -= ((bottom - getHeight()) * 100) / height;
}
return extent;
}
return 0;
}
@Override
protected int computeVerticalScrollOffset() {
if (mFirstPosition >= 0 && getChildCount() > 0) {
final View view = getChildAt(0);
final int top = view.getTop();
int height = view.getHeight();
if (height > 0) {
final int numColumns = mNumColumns;
final int whichRow = mFirstPosition / numColumns;
final int rowCount = (mItemCount + numColumns - 1) / numColumns;
return Math.max(whichRow * 100 - (top * 100) / height +
(int) ((float) mScrollY / getHeight() * rowCount * 100), 0);
}
}
return 0;
}
@Override
protected int computeVerticalScrollRange() {
// TODO: Account for vertical spacing too
final int numColumns = mNumColumns;
final int rowCount = (mItemCount + numColumns - 1) / numColumns;
return Math.max(rowCount * 100, 0);
}
}
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