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Android example source code file (ExpandableListView.java)

This example Android source code file (ExpandableListView.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, child_indicator_inherit, drawable, drawing, empty_state_set, expandablelistcontextmenuinfo, expandablelistposition, expandablelistview, graphics, override, packed_position_mask_type, packed_position_shift_group, packed_position_value_null, paint, parcelable, positionmetadata, rect, savedstate, ui, view

The ExpandableListView.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 android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
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.view.ContextMenu;
import android.view.SoundEffectConstants;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.ExpandableListConnector.PositionMetadata;

import java.util.ArrayList;

/**
 * A view that shows items in a vertically scrolling two-level list. This
 * differs from the {@link ListView} by allowing two levels: groups which can
 * individually be expanded to show its children. The items come from the
 * {@link ExpandableListAdapter} associated with this view.
 * <p>
 * Expandable lists are able to show an indicator beside each item to display
 * the item's current state (the states are usually one of expanded group,
 * collapsed group, child, or last child). Use
 * {@link #setChildIndicator(Drawable)} or {@link #setGroupIndicator(Drawable)}
 * (or the corresponding XML attributes) to set these indicators (see the docs
 * for each method to see additional state that each Drawable can have). The
 * default style for an {@link ExpandableListView} provides indicators which
 * will be shown next to Views given to the {@link ExpandableListView}. The
 * layouts android.R.layout.simple_expandable_list_item_1 and
 * android.R.layout.simple_expandable_list_item_2 (which should be used with
 * {@link SimpleCursorTreeAdapter}) contain the preferred position information
 * for indicators.
 * <p>
 * The context menu information set by an {@link ExpandableListView} will be a
 * {@link ExpandableListContextMenuInfo} object with
 * {@link ExpandableListContextMenuInfo#packedPosition} being a packed position
 * that can be used with {@link #getPackedPositionType(long)} and the other
 * similar methods.
 * <p>
 * <em>Note: You cannot use the value wrap_content
 * for the <code>android:layout_height attribute of a
 * ExpandableListView in XML if the parent's size is also not strictly specified
 * (for example, if the parent were ScrollView you could not specify
 * wrap_content since it also can be any length. However, you can use
 * wrap_content if the ExpandableListView parent has a specific size, such as
 * 100 pixels.
 * 
 * @attr ref android.R.styleable#ExpandableListView_groupIndicator
 * @attr ref android.R.styleable#ExpandableListView_indicatorLeft
 * @attr ref android.R.styleable#ExpandableListView_indicatorRight
 * @attr ref android.R.styleable#ExpandableListView_childIndicator
 * @attr ref android.R.styleable#ExpandableListView_childIndicatorLeft
 * @attr ref android.R.styleable#ExpandableListView_childIndicatorRight
 * @attr ref android.R.styleable#ExpandableListView_childDivider
 */
public class ExpandableListView extends ListView {

    /**
     * The packed position represents a group.
     */
    public static final int PACKED_POSITION_TYPE_GROUP = 0;
    
    /**
     * The packed position represents a child.
     */
    public static final int PACKED_POSITION_TYPE_CHILD = 1;

    /**
     * The packed position represents a neither/null/no preference.
     */
    public static final int PACKED_POSITION_TYPE_NULL = 2;
    
    /**
     * The value for a packed position that represents neither/null/no
     * preference. This value is not otherwise possible since a group type
     * (first bit 0) should not have a child position filled.
     */
    public static final long PACKED_POSITION_VALUE_NULL = 0x00000000FFFFFFFFL;
    
    /** The mask (in packed position representation) for the child */
    private static final long PACKED_POSITION_MASK_CHILD = 0x00000000FFFFFFFFL;

    /** The mask (in packed position representation) for the group */
    private static final long PACKED_POSITION_MASK_GROUP = 0x7FFFFFFF00000000L;

    /** The mask (in packed position representation) for the type */
    private static final long PACKED_POSITION_MASK_TYPE  = 0x8000000000000000L;

    /** The shift amount (in packed position representation) for the group */
    private static final long PACKED_POSITION_SHIFT_GROUP = 32;

    /** The shift amount (in packed position representation) for the type */
    private static final long PACKED_POSITION_SHIFT_TYPE  = 63;

    /** The mask (in integer child position representation) for the child */
    private static final long PACKED_POSITION_INT_MASK_CHILD = 0xFFFFFFFF;

    /** The mask (in integer group position representation) for the group */
    private static final long PACKED_POSITION_INT_MASK_GROUP = 0x7FFFFFFF;
    
    /** Serves as the glue/translator between a ListView and an ExpandableListView */
    private ExpandableListConnector mConnector;
    
    /** Gives us Views through group+child positions */ 
    private ExpandableListAdapter mAdapter;
    
    /** Left bound for drawing the indicator. */
    private int mIndicatorLeft;

    /** Right bound for drawing the indicator. */
    private int mIndicatorRight;

    /**
     * Left bound for drawing the indicator of a child. Value of
     * {@link #CHILD_INDICATOR_INHERIT} means use mIndicatorLeft.
     */
    private int mChildIndicatorLeft;

    /**
     * Right bound for drawing the indicator of a child. Value of
     * {@link #CHILD_INDICATOR_INHERIT} means use mIndicatorRight.
     */
    private int mChildIndicatorRight;

    /**
     * Denotes when a child indicator should inherit this bound from the generic
     * indicator bounds
     */
    public static final int CHILD_INDICATOR_INHERIT = -1;
    
    /** The indicator drawn next to a group. */
    private Drawable mGroupIndicator;

    /** The indicator drawn next to a child. */
    private Drawable mChildIndicator;

    private static final int[] EMPTY_STATE_SET = {};

    /** State indicating the group is expanded. */
    private static final int[] GROUP_EXPANDED_STATE_SET =
            {R.attr.state_expanded};

    /** State indicating the group is empty (has no children). */
    private static final int[] GROUP_EMPTY_STATE_SET =
            {R.attr.state_empty};

    /** State indicating the group is expanded and empty (has no children). */
    private static final int[] GROUP_EXPANDED_EMPTY_STATE_SET =
            {R.attr.state_expanded, R.attr.state_empty};

    /** States for the group where the 0th bit is expanded and 1st bit is empty. */
    private static final int[][] GROUP_STATE_SETS = {
         EMPTY_STATE_SET, // 00
         GROUP_EXPANDED_STATE_SET, // 01
         GROUP_EMPTY_STATE_SET, // 10
         GROUP_EXPANDED_EMPTY_STATE_SET // 11
    };

    /** State indicating the child is the last within its group. */
    private static final int[] CHILD_LAST_STATE_SET =
            {R.attr.state_last};
    
    /** Drawable to be used as a divider when it is adjacent to any children */
    private Drawable mChildDivider;
    private boolean mClipChildDivider;

    // Bounds of the indicator to be drawn
    private final Rect mIndicatorRect = new Rect();

    public ExpandableListView(Context context) {
        this(context, null);
    }

    public ExpandableListView(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.expandableListViewStyle);
    }

    public ExpandableListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        TypedArray a =
            context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.ExpandableListView, defStyle,
                    0);

        mGroupIndicator = a
                .getDrawable(com.android.internal.R.styleable.ExpandableListView_groupIndicator);
        mChildIndicator = a
                .getDrawable(com.android.internal.R.styleable.ExpandableListView_childIndicator);
        mIndicatorLeft = a
                .getDimensionPixelSize(com.android.internal.R.styleable.ExpandableListView_indicatorLeft, 0);
        mIndicatorRight = a
                .getDimensionPixelSize(com.android.internal.R.styleable.ExpandableListView_indicatorRight, 0);
        mChildIndicatorLeft = a.getDimensionPixelSize(
                com.android.internal.R.styleable.ExpandableListView_childIndicatorLeft, CHILD_INDICATOR_INHERIT);
        mChildIndicatorRight = a.getDimensionPixelSize(
                com.android.internal.R.styleable.ExpandableListView_childIndicatorRight, CHILD_INDICATOR_INHERIT);
        mChildDivider = a.getDrawable(com.android.internal.R.styleable.ExpandableListView_childDivider);
        
        a.recycle();
    }
    
    
    @Override
    protected void dispatchDraw(Canvas canvas) {
        // Draw children, etc.
        super.dispatchDraw(canvas);

        // If we have any indicators to draw, we do it here
        if ((mChildIndicator == null) && (mGroupIndicator == null)) {
            return;
        }

        int saveCount = 0;
        final boolean clipToPadding = (mGroupFlags & CLIP_TO_PADDING_MASK) == CLIP_TO_PADDING_MASK;
        if (clipToPadding) {
            saveCount = canvas.save();
            final int scrollX = mScrollX;
            final int scrollY = mScrollY;
            canvas.clipRect(scrollX + mPaddingLeft, scrollY + mPaddingTop,
                    scrollX + mRight - mLeft - mPaddingRight,
                    scrollY + mBottom - mTop - mPaddingBottom);
        }

        final int headerViewsCount = getHeaderViewsCount();
        
        final int lastChildFlPos = mItemCount - getFooterViewsCount() - headerViewsCount - 1;

        final int myB = mBottom; 
        
        PositionMetadata pos;
        View item;
        Drawable indicator; 
        int t, b;
        
        // Start at a value that is neither child nor group
        int lastItemType = ~(ExpandableListPosition.CHILD | ExpandableListPosition.GROUP);

        final Rect indicatorRect = mIndicatorRect;

        // The "child" mentioned in the following two lines is this
        // View's child, not referring to an expandable list's
        // notion of a child (as opposed to a group)
        final int childCount = getChildCount(); 
        for (int i = 0, childFlPos = mFirstPosition - headerViewsCount; i < childCount;
             i++, childFlPos++) {

            if (childFlPos < 0) {
                // This child is header
                continue;
            } else if (childFlPos > lastChildFlPos) {
                // This child is footer, so are all subsequent children
                break;
            }
            
            item = getChildAt(i);
            t = item.getTop();
            b = item.getBottom();
            
            // This item isn't on the screen
            if ((b < 0) || (t > myB)) continue;

            // Get more expandable list-related info for this item
            pos = mConnector.getUnflattenedPos(childFlPos);

            // If this item type and the previous item type are different, then we need to change
            // the left & right bounds
            if (pos.position.type != lastItemType) {
                if (pos.position.type == ExpandableListPosition.CHILD) {
                    indicatorRect.left = (mChildIndicatorLeft == CHILD_INDICATOR_INHERIT) ?
                            mIndicatorLeft : mChildIndicatorLeft;
                    indicatorRect.right = (mChildIndicatorRight == CHILD_INDICATOR_INHERIT) ?
                            mIndicatorRight : mChildIndicatorRight;
                } else {
                    indicatorRect.left = mIndicatorLeft;
                    indicatorRect.right = mIndicatorRight;
                }
                
                lastItemType = pos.position.type; 
            }

            if (indicatorRect.left != indicatorRect.right) {
                // Use item's full height + the divider height
                if (mStackFromBottom) {
                    // See ListView#dispatchDraw
                    indicatorRect.top = t;// - mDividerHeight;
                    indicatorRect.bottom = b;
                } else {
                    indicatorRect.top = t;
                    indicatorRect.bottom = b;// + mDividerHeight;
                }
                
                // Get the indicator (with its state set to the item's state)
                indicator = getIndicator(pos);
                if (indicator != null) {
                    // Draw the indicator
                    indicator.setBounds(indicatorRect);
                    indicator.draw(canvas);
                }
            }
            
            pos.recycle();
        }

        if (clipToPadding) {
            canvas.restoreToCount(saveCount);
        }
    }

    /**
     * Gets the indicator for the item at the given position. If the indicator
     * is stateful, the state will be given to the indicator.
     * 
     * @param pos The flat list position of the item whose indicator
     *            should be returned.
     * @return The indicator in the proper state.
     */
    private Drawable getIndicator(PositionMetadata pos) {
        Drawable indicator;
        
        if (pos.position.type == ExpandableListPosition.GROUP) {
            indicator = mGroupIndicator;
            
            if (indicator != null && indicator.isStateful()) {
                // Empty check based on availability of data.  If the groupMetadata isn't null,
                // we do a check on it. Otherwise, the group is collapsed so we consider it
                // empty for performance reasons.
                boolean isEmpty = (pos.groupMetadata == null) ||
                        (pos.groupMetadata.lastChildFlPos == pos.groupMetadata.flPos);
                
                final int stateSetIndex =
                    (pos.isExpanded() ? 1 : 0) | // Expanded?
                    (isEmpty ? 2 : 0); // Empty?
                indicator.setState(GROUP_STATE_SETS[stateSetIndex]);
            }
        } else {
            indicator = mChildIndicator;
            
            if (indicator != null && indicator.isStateful()) {
                // No need for a state sets array for the child since it only has two states
                final int stateSet[] = pos.position.flatListPos == pos.groupMetadata.lastChildFlPos
                        ? CHILD_LAST_STATE_SET
                        : EMPTY_STATE_SET;
                indicator.setState(stateSet);
            }
        }
        
        return indicator;
    }
    
    /**
     * Sets the drawable that will be drawn adjacent to every child in the list. This will
     * be drawn using the same height as the normal divider ({@link #setDivider(Drawable)}) or
     * if it does not have an intrinsic height, the height set by {@link #setDividerHeight(int)}.
     * 
     * @param childDivider The drawable to use.
     */
    public void setChildDivider(Drawable childDivider) {
        mChildDivider = childDivider;
        mClipChildDivider = childDivider != null && childDivider instanceof ColorDrawable;
    }

    @Override
    void drawDivider(Canvas canvas, Rect bounds, int childIndex) {
        int flatListPosition = childIndex + mFirstPosition;
        
        // Only proceed as possible child if the divider isn't above all items (if it is above
        // all items, then the item below it has to be a group)
        if (flatListPosition >= 0) {
            final int adjustedPosition = getFlatPositionForConnector(flatListPosition);
            PositionMetadata pos = mConnector.getUnflattenedPos(adjustedPosition);
            // If this item is a child, or it is a non-empty group that is expanded
            if ((pos.position.type == ExpandableListPosition.CHILD) || (pos.isExpanded() &&
                    pos.groupMetadata.lastChildFlPos != pos.groupMetadata.flPos)) {
                // These are the cases where we draw the child divider
                final Drawable divider = mChildDivider;
                final boolean clip = mClipChildDivider;
                if (!clip) {
                    divider.setBounds(bounds);
                } else {
                    canvas.save();
                    canvas.clipRect(bounds);
                }
                divider.draw(canvas);
                if (clip) {
                    canvas.restore();
                }
                pos.recycle();
                return;
            }
            pos.recycle();
        }
        
        // Otherwise draw the default divider
        super.drawDivider(canvas, bounds, flatListPosition);
    }

    /**
     * This overloaded method should not be used, instead use
     * {@link #setAdapter(ExpandableListAdapter)}.
     * <p>
     * {@inheritDoc}
     */
    @Override
    public void setAdapter(ListAdapter adapter) {
        throw new RuntimeException(
                "For ExpandableListView, use setAdapter(ExpandableListAdapter) instead of " +
                "setAdapter(ListAdapter)");
    }

    /**
     * This method should not be used, use {@link #getExpandableListAdapter()}.
     */
    @Override
    public ListAdapter getAdapter() {
        /*
         * The developer should never really call this method on an
         * ExpandableListView, so it would be nice to throw a RuntimeException,
         * but AdapterView calls this
         */
        return super.getAdapter();
    }

    /**
     * Register a callback to be invoked when an item has been clicked and the
     * caller prefers to receive a ListView-style position instead of a group
     * and/or child position. In most cases, the caller should use
     * {@link #setOnGroupClickListener} and/or {@link #setOnChildClickListener}.
     * <p />
     * {@inheritDoc}
     */
    @Override
    public void setOnItemClickListener(OnItemClickListener l) {
        super.setOnItemClickListener(l);
    }

    /**
     * Sets the adapter that provides data to this view.
     * @param adapter The adapter that provides data to this view.
     */
    public void setAdapter(ExpandableListAdapter adapter) {
        // Set member variable
        mAdapter = adapter;
        
        if (adapter != null) {
            // Create the connector
            mConnector = new ExpandableListConnector(adapter);
        } else {
            mConnector = null;
        }
        
        // Link the ListView (superclass) to the expandable list data through the connector
        super.setAdapter(mConnector);
    }
    
    /**
     * Gets the adapter that provides data to this view.
     * @return The adapter that provides data to this view.
     */
    public ExpandableListAdapter getExpandableListAdapter() {
        return mAdapter;
    }
    
    /**
     * @param position An absolute (including header and footer) flat list position.
     * @return true if the position corresponds to a header or a footer item.
     */
    private boolean isHeaderOrFooterPosition(int position) {
        final int footerViewsStart = mItemCount - getFooterViewsCount();
        return (position < getHeaderViewsCount() || position >= footerViewsStart);
    }

    /**
     * Converts an absolute item flat position into a group/child flat position, shifting according
     * to the number of header items.
     * 
     * @param flatListPosition The absolute flat position
     * @return A group/child flat position as expected by the connector.
     */
    private int getFlatPositionForConnector(int flatListPosition) {
        return flatListPosition - getHeaderViewsCount();
    }

    /**
     * Converts a group/child flat position into an absolute flat position, that takes into account
     * the possible headers.
     * 
     * @param flatListPosition The child/group flat position
     * @return An absolute flat position.
     */
    private int getAbsoluteFlatPosition(int flatListPosition) {
        return flatListPosition + getHeaderViewsCount();
    }

    @Override
    public boolean performItemClick(View v, int position, long id) {
        // Ignore clicks in header/footers
        if (isHeaderOrFooterPosition(position)) {
            // Clicked on a header/footer, so ignore pass it on to super
            return super.performItemClick(v, position, id);
        }
        
        // Internally handle the item click
        final int adjustedPosition = getFlatPositionForConnector(position);
        return handleItemClick(v, adjustedPosition, id);
    }
    
    /**
     * This will either expand/collapse groups (if a group was clicked) or pass
     * on the click to the proper child (if a child was clicked)
     * 
     * @param position The flat list position. This has already been factored to
     *            remove the header/footer.
     * @param id The ListAdapter ID, not the group or child ID.
     */
    boolean handleItemClick(View v, int position, long id) {
        final PositionMetadata posMetadata = mConnector.getUnflattenedPos(position);
        
        id = getChildOrGroupId(posMetadata.position);
        
        boolean returnValue;
        if (posMetadata.position.type == ExpandableListPosition.GROUP) {
            /* It's a group, so handle collapsing/expanding */

            /* It's a group click, so pass on event */
            if (mOnGroupClickListener != null) {
                if (mOnGroupClickListener.onGroupClick(this, v,
                        posMetadata.position.groupPos, id)) {
                    posMetadata.recycle();
                    return true;
                }
            }

            if (posMetadata.isExpanded()) {
                /* Collapse it */
                mConnector.collapseGroup(posMetadata);

                playSoundEffect(SoundEffectConstants.CLICK);

                if (mOnGroupCollapseListener != null) {
                    mOnGroupCollapseListener.onGroupCollapse(posMetadata.position.groupPos);
                }
            } else {
                /* Expand it */
                mConnector.expandGroup(posMetadata);

                playSoundEffect(SoundEffectConstants.CLICK);

                if (mOnGroupExpandListener != null) {
                    mOnGroupExpandListener.onGroupExpand(posMetadata.position.groupPos);
                }
                
                final int groupPos = posMetadata.position.groupPos;
                final int groupFlatPos = posMetadata.position.flatListPos;

                final int shiftedGroupPosition = groupFlatPos + getHeaderViewsCount(); 
                smoothScrollToPosition(shiftedGroupPosition + mAdapter.getChildrenCount(groupPos),
                        shiftedGroupPosition);
            }

            returnValue = true;
        } else {
            /* It's a child, so pass on event */
            if (mOnChildClickListener != null) {
                playSoundEffect(SoundEffectConstants.CLICK);
                return mOnChildClickListener.onChildClick(this, v, posMetadata.position.groupPos,
                        posMetadata.position.childPos, id);
            }

            returnValue = false;
        }

        posMetadata.recycle();

        return returnValue;
    }

    /**
     * Expand a group in the grouped list view
     *
     * @param groupPos the group to be expanded
     * @return True if the group was expanded, false otherwise (if the group
     *         was already expanded, this will return false)
     */
    public boolean expandGroup(int groupPos) {
        boolean retValue = mConnector.expandGroup(groupPos);

        if (mOnGroupExpandListener != null) {
            mOnGroupExpandListener.onGroupExpand(groupPos);
        }
        
        return retValue;
    }
    
    /**
     * Collapse a group in the grouped list view
     * 
     * @param groupPos position of the group to collapse
     * @return True if the group was collapsed, false otherwise (if the group
     *         was already collapsed, this will return false)
     */
    public boolean collapseGroup(int groupPos) {
        boolean retValue = mConnector.collapseGroup(groupPos);
        
        if (mOnGroupCollapseListener != null) {
            mOnGroupCollapseListener.onGroupCollapse(groupPos);
        }

        return retValue;
    }

    /** Used for being notified when a group is collapsed */
    public interface OnGroupCollapseListener {
        /**
         * Callback method to be invoked when a group in this expandable list has
         * been collapsed.
         * 
         * @param groupPosition The group position that was collapsed
         */
        void onGroupCollapse(int groupPosition);
    }
    
    private OnGroupCollapseListener mOnGroupCollapseListener;
    
    public void setOnGroupCollapseListener(
            OnGroupCollapseListener onGroupCollapseListener) {
        mOnGroupCollapseListener = onGroupCollapseListener;
    }

    /** Used for being notified when a group is expanded */
    public interface OnGroupExpandListener {
        /**
         * Callback method to be invoked when a group in this expandable list has
         * been expanded.
         * 
         * @param groupPosition The group position that was expanded
         */
        void onGroupExpand(int groupPosition);
    }
    
    private OnGroupExpandListener mOnGroupExpandListener;
    
    public void setOnGroupExpandListener(
            OnGroupExpandListener onGroupExpandListener) {
        mOnGroupExpandListener = onGroupExpandListener;
    }

    /**
     * Interface definition for a callback to be invoked when a group in this
     * expandable list has been clicked.
     */
    public interface OnGroupClickListener {
        /**
         * Callback method to be invoked when a group in this expandable list has
         * been clicked.
         * 
         * @param parent The ExpandableListConnector where the click happened
         * @param v The view within the expandable list/ListView that was clicked
         * @param groupPosition The group position that was clicked
         * @param id The row id of the group that was clicked
         * @return True if the click was handled
         */
        boolean onGroupClick(ExpandableListView parent, View v, int groupPosition,
                long id);
    }
    
    private OnGroupClickListener mOnGroupClickListener;

    public void setOnGroupClickListener(OnGroupClickListener onGroupClickListener) {
        mOnGroupClickListener = onGroupClickListener;
    }
    
    /**
     * Interface definition for a callback to be invoked when a child in this
     * expandable list has been clicked.
     */
    public interface OnChildClickListener {
        /**
         * Callback method to be invoked when a child in this expandable list has
         * been clicked.
         * 
         * @param parent The ExpandableListView where the click happened
         * @param v The view within the expandable list/ListView that was clicked
         * @param groupPosition The group position that contains the child that
         *        was clicked
         * @param childPosition The child position within the group
         * @param id The row id of the child that was clicked
         * @return True if the click was handled
         */
        boolean onChildClick(ExpandableListView parent, View v, int groupPosition,
                int childPosition, long id);
    }
    
    private OnChildClickListener mOnChildClickListener;

    public void setOnChildClickListener(OnChildClickListener onChildClickListener) {
        mOnChildClickListener = onChildClickListener;
    }
    
    /**
     * Converts a flat list position (the raw position of an item (child or group)
     * in the list) to an group and/or child position (represented in a
     * packed position). This is useful in situations where the caller needs to
     * use the underlying {@link ListView}'s methods. Use
     * {@link ExpandableListView#getPackedPositionType} ,
     * {@link ExpandableListView#getPackedPositionChild},
     * {@link ExpandableListView#getPackedPositionGroup} to unpack.
     * 
     * @param flatListPosition The flat list position to be converted.
     * @return The group and/or child position for the given flat list position
     *         in packed position representation. #PACKED_POSITION_VALUE_NULL if
     *         the position corresponds to a header or a footer item.
     */
    public long getExpandableListPosition(int flatListPosition) {
        if (isHeaderOrFooterPosition(flatListPosition)) {
            return PACKED_POSITION_VALUE_NULL;
        }

        final int adjustedPosition = getFlatPositionForConnector(flatListPosition);
        PositionMetadata pm = mConnector.getUnflattenedPos(adjustedPosition);
        long packedPos = pm.position.getPackedPosition();
        pm.recycle();
        return packedPos;
    }
    
    /**
     * Converts a group and/or child position to a flat list position. This is
     * useful in situations where the caller needs to use the underlying
     * {@link ListView}'s methods.
     * 
     * @param packedPosition The group and/or child positions to be converted in
     *            packed position representation. Use
     *            {@link #getPackedPositionForChild(int, int)} or
     *            {@link #getPackedPositionForGroup(int)}.
     * @return The flat list position for the given child or group.
     */
    public int getFlatListPosition(long packedPosition) {
        PositionMetadata pm = mConnector.getFlattenedPos(ExpandableListPosition
                .obtainPosition(packedPosition));
        final int flatListPosition = pm.position.flatListPos;
        pm.recycle();
        return getAbsoluteFlatPosition(flatListPosition);
    }

    /**
     * Gets the position of the currently selected group or child (along with
     * its type). Can return {@link #PACKED_POSITION_VALUE_NULL} if no selection.
     * 
     * @return A packed position containing the currently selected group or
     *         child's position and type. #PACKED_POSITION_VALUE_NULL if no selection
     *         or if selection is on a header or a footer item.
     */
    public long getSelectedPosition() {
        final int selectedPos = getSelectedItemPosition();

        // The case where there is no selection (selectedPos == -1) is also handled here.
        return getExpandableListPosition(selectedPos);
    }
    
    /**
     * Gets the ID of the currently selected group or child. Can return -1 if no
     * selection.
     * 
     * @return The ID of the currently selected group or child. -1 if no
     *         selection.
     */
    public long getSelectedId() {
        long packedPos = getSelectedPosition();
        if (packedPos == PACKED_POSITION_VALUE_NULL) return -1;

        int groupPos = getPackedPositionGroup(packedPos);
        
        if (getPackedPositionType(packedPos) == PACKED_POSITION_TYPE_GROUP) {
            // It's a group
            return mAdapter.getGroupId(groupPos);
        } else {
            // It's a child
            return mAdapter.getChildId(groupPos, getPackedPositionChild(packedPos));
        }
    }
    
    /**
     * Sets the selection to the specified group.
     * @param groupPosition The position of the group that should be selected.
     */
    public void setSelectedGroup(int groupPosition) {
        ExpandableListPosition elGroupPos = ExpandableListPosition
                .obtainGroupPosition(groupPosition);
        PositionMetadata pm = mConnector.getFlattenedPos(elGroupPos);
        elGroupPos.recycle();
        final int absoluteFlatPosition = getAbsoluteFlatPosition(pm.position.flatListPos);
        super.setSelection(absoluteFlatPosition);
        pm.recycle();
    }
    
    /**
     * Sets the selection to the specified child. If the child is in a collapsed
     * group, the group will only be expanded and child subsequently selected if
     * shouldExpandGroup is set to true, otherwise the method will return false.
     * 
     * @param groupPosition The position of the group that contains the child.
     * @param childPosition The position of the child within the group.
     * @param shouldExpandGroup Whether the child's group should be expanded if
     *            it is collapsed.
     * @return Whether the selection was successfully set on the child.
     */
    public boolean setSelectedChild(int groupPosition, int childPosition, boolean shouldExpandGroup) {
        ExpandableListPosition elChildPos = ExpandableListPosition.obtainChildPosition(
                groupPosition, childPosition); 
        PositionMetadata flatChildPos = mConnector.getFlattenedPos(elChildPos);
        
        if (flatChildPos == null) {
            // The child's group isn't expanded
            
            // Shouldn't expand the group, so return false for we didn't set the selection
            if (!shouldExpandGroup) return false; 

            expandGroup(groupPosition);
            
            flatChildPos = mConnector.getFlattenedPos(elChildPos);
            
            // Sanity check
            if (flatChildPos == null) {
                throw new IllegalStateException("Could not find child");
            }
        }
        
        int absoluteFlatPosition = getAbsoluteFlatPosition(flatChildPos.position.flatListPos);
        super.setSelection(absoluteFlatPosition);
        
        elChildPos.recycle();
        flatChildPos.recycle();
        
        return true;
    }

    /**
     * Whether the given group is currently expanded.
     * 
     * @param groupPosition The group to check.
     * @return Whether the group is currently expanded.
     */
    public boolean isGroupExpanded(int groupPosition) {
        return mConnector.isGroupExpanded(groupPosition);
    }
    
    /**
     * Gets the type of a packed position. See
     * {@link #getPackedPositionForChild(int, int)}.
     * 
     * @param packedPosition The packed position for which to return the type.
     * @return The type of the position contained within the packed position,
     *         either {@link #PACKED_POSITION_TYPE_CHILD}, {@link #PACKED_POSITION_TYPE_GROUP}, or
     *         {@link #PACKED_POSITION_TYPE_NULL}.
     */
    public static int getPackedPositionType(long packedPosition) {
        if (packedPosition == PACKED_POSITION_VALUE_NULL) {
            return PACKED_POSITION_TYPE_NULL;
        }
        
        return (packedPosition & PACKED_POSITION_MASK_TYPE) == PACKED_POSITION_MASK_TYPE
                ? PACKED_POSITION_TYPE_CHILD
                : PACKED_POSITION_TYPE_GROUP;
    }

    /**
     * Gets the group position from a packed position. See
     * {@link #getPackedPositionForChild(int, int)}.
     * 
     * @param packedPosition The packed position from which the group position
     *            will be returned.
     * @return The group position portion of the packed position. If this does
     *         not contain a group, returns -1.
     */
    public static int getPackedPositionGroup(long packedPosition) {
        // Null
        if (packedPosition == PACKED_POSITION_VALUE_NULL) return -1;
        
        return (int) ((packedPosition & PACKED_POSITION_MASK_GROUP) >> PACKED_POSITION_SHIFT_GROUP);
    }

    /**
     * Gets the child position from a packed position that is of
     * {@link #PACKED_POSITION_TYPE_CHILD} type (use {@link #getPackedPositionType(long)}).
     * To get the group that this child belongs to, use
     * {@link #getPackedPositionGroup(long)}. See
     * {@link #getPackedPositionForChild(int, int)}.
     * 
     * @param packedPosition The packed position from which the child position
     *            will be returned.
     * @return The child position portion of the packed position. If this does
     *         not contain a child, returns -1.
     */
    public static int getPackedPositionChild(long packedPosition) {
        // Null
        if (packedPosition == PACKED_POSITION_VALUE_NULL) return -1;
        
        // Group since a group type clears this bit
        if ((packedPosition & PACKED_POSITION_MASK_TYPE) != PACKED_POSITION_MASK_TYPE) return -1;

        return (int) (packedPosition & PACKED_POSITION_MASK_CHILD);
    }

    /**
     * Returns the packed position representation of a child's position.
     * <p>
     * In general, a packed position should be used in
     * situations where the position given to/returned from an
     * {@link ExpandableListAdapter} or {@link ExpandableListView} method can
     * either be a child or group. The two positions are packed into a single
     * long which can be unpacked using
     * {@link #getPackedPositionChild(long)},
     * {@link #getPackedPositionGroup(long)}, and
     * {@link #getPackedPositionType(long)}.
     * 
     * @param groupPosition The child's parent group's position.
     * @param childPosition The child position within the group.
     * @return The packed position representation of the child (and parent group).
     */
    public static long getPackedPositionForChild(int groupPosition, int childPosition) {
        return (((long)PACKED_POSITION_TYPE_CHILD) << PACKED_POSITION_SHIFT_TYPE)
                | ((((long)groupPosition) & PACKED_POSITION_INT_MASK_GROUP)
                        << PACKED_POSITION_SHIFT_GROUP)
                | (childPosition & PACKED_POSITION_INT_MASK_CHILD);  
    }

    /**
     * Returns the packed position representation of a group's position. See
     * {@link #getPackedPositionForChild(int, int)}.
     * 
     * @param groupPosition The child's parent group's position.
     * @return The packed position representation of the group.
     */
    public static long getPackedPositionForGroup(int groupPosition) {
        // No need to OR a type in because PACKED_POSITION_GROUP == 0
        return ((((long)groupPosition) & PACKED_POSITION_INT_MASK_GROUP)
                        << PACKED_POSITION_SHIFT_GROUP); 
    }

    @Override
    ContextMenuInfo createContextMenuInfo(View view, int flatListPosition, long id) {
        if (isHeaderOrFooterPosition(flatListPosition)) {
            // Return normal info for header/footer view context menus
            return new AdapterContextMenuInfo(view, flatListPosition, id);
        }

        final int adjustedPosition = getFlatPositionForConnector(flatListPosition);
        PositionMetadata pm = mConnector.getUnflattenedPos(adjustedPosition);
        ExpandableListPosition pos = pm.position;
        pm.recycle();
        
        id = getChildOrGroupId(pos);
        long packedPosition = pos.getPackedPosition();
        pos.recycle();
        
        return new ExpandableListContextMenuInfo(view, packedPosition, id);
    }

    /**
     * Gets the ID of the group or child at the given <code>position.
     * This is useful since there is no ListAdapter ID -> ExpandableListAdapter
     * ID conversion mechanism (in some cases, it isn't possible).
     * 
     * @param position The position of the child or group whose ID should be
     *            returned.
     */
    private long getChildOrGroupId(ExpandableListPosition position) {
        if (position.type == ExpandableListPosition.CHILD) {
            return mAdapter.getChildId(position.groupPos, position.childPos);
        } else {
            return mAdapter.getGroupId(position.groupPos);
        }
    }
    
    /**
     * Sets the indicator to be drawn next to a child.
     * 
     * @param childIndicator The drawable to be used as an indicator. If the
     *            child is the last child for a group, the state
     *            {@link android.R.attr#state_last} will be set.
     */
    public void setChildIndicator(Drawable childIndicator) {
        mChildIndicator = childIndicator;
    }
    
    /**
     * Sets the drawing bounds for the child indicator. For either, you can
     * specify {@link #CHILD_INDICATOR_INHERIT} to use inherit from the general
     * indicator's bounds.
     *
     * @see #setIndicatorBounds(int, int)
     * @param left The left position (relative to the left bounds of this View)
     *            to start drawing the indicator.
     * @param right The right position (relative to the left bounds of this
     *            View) to end the drawing of the indicator.
     */
    public void setChildIndicatorBounds(int left, int right) {
        mChildIndicatorLeft = left;
        mChildIndicatorRight = right;
    }
    
    /**
     * Sets the indicator to be drawn next to a group.
     * 
     * @param groupIndicator The drawable to be used as an indicator. If the
     *            group is empty, the state {@link android.R.attr#state_empty} will be
     *            set. If the group is expanded, the state
     *            {@link android.R.attr#state_expanded} will be set.
     */
    public void setGroupIndicator(Drawable groupIndicator) {
        mGroupIndicator = groupIndicator;
    }
    
    /**
     * Sets the drawing bounds for the indicators (at minimum, the group indicator
     * is affected by this; the child indicator is affected by this if the
     * child indicator bounds are set to inherit).
     * 
     * @see #setChildIndicatorBounds(int, int) 
     * @param left The left position (relative to the left bounds of this View)
     *            to start drawing the indicator.
     * @param right The right position (relative to the left bounds of this
     *            View) to end the drawing of the indicator.
     */
    public void setIndicatorBounds(int left, int right) {
        mIndicatorLeft = left;
        mIndicatorRight = right;
    }
    
    /**
     * Extra menu information specific to an {@link ExpandableListView} provided
     * to the
     * {@link android.view.View.OnCreateContextMenuListener#onCreateContextMenu(ContextMenu, View, ContextMenuInfo) }
     * callback when a context menu is brought up for this AdapterView.
     */
    public static class ExpandableListContextMenuInfo implements ContextMenu.ContextMenuInfo {
        
        public ExpandableListContextMenuInfo(View targetView, long packedPosition, long id) {
            this.targetView = targetView;
            this.packedPosition = packedPosition;
            this.id = id;
        }
        
        /**
         * The view for which the context menu is being displayed. This
         * will be one of the children Views of this {@link ExpandableListView}.
         */
        public View targetView;

        /**
         * The packed position in the list represented by the adapter for which
         * the context menu is being displayed. Use the methods
         * {@link ExpandableListView#getPackedPositionType},
         * {@link ExpandableListView#getPackedPositionChild}, and
         * {@link ExpandableListView#getPackedPositionGroup} to unpack this.
         */
        public long packedPosition;

        /**
         * The ID of the item (group or child) for which the context menu is
         * being displayed.
         */
        public long id;
    }
    
    static class SavedState extends BaseSavedState {
        ArrayList<ExpandableListConnector.GroupMetadata> expandedGroupMetadataList;
        
        /**
         * Constructor called from {@link ExpandableListView#onSaveInstanceState()}
         */
        SavedState(
                Parcelable superState,
                ArrayList<ExpandableListConnector.GroupMetadata> expandedGroupMetadataList) {
            super(superState);
            this.expandedGroupMetadataList = expandedGroupMetadataList;
        }

        /**
         * Constructor called from {@link #CREATOR}
         */
        private SavedState(Parcel in) {
            super(in);
            expandedGroupMetadataList = new ArrayList<ExpandableListConnector.GroupMetadata>();
            in.readList(expandedGroupMetadataList, ExpandableListConnector.class.getClassLoader());
        }

        @Override
        public void writeToParcel(Parcel out, int flags) {
            super.writeToParcel(out, flags);
            out.writeList(expandedGroupMetadataList);
        }

        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,
                mConnector != null ? mConnector.getExpandedGroupMetadataList() : null);
    }

    @Override
    public void onRestoreInstanceState(Parcelable state) {
        if (!(state instanceof SavedState)) {
            super.onRestoreInstanceState(state);
            return;
        }

        SavedState ss = (SavedState) state;
        super.onRestoreInstanceState(ss.getSuperState());
        
        if (mConnector != null && ss.expandedGroupMetadataList != null) {
            mConnector.setExpandedGroupMetadataList(ss.expandedGroupMetadataList);
        }
    }

}

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