/* * 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.database.DataSetObserver; import android.os.Parcel; import android.os.Parcelable; import android.os.SystemClock; import android.view.View; import android.view.ViewGroup; import java.util.ArrayList; import java.util.Collections; /* * Implementation notes: * *

* Terminology: *

  • flPos - Flat list position, the position used by ListView *
  • gPos - Group position, the position of a group among all the groups *
  • cPos - Child position, the position of a child among all the children * in a group */ /** * A {@link BaseAdapter} that provides data/Views in an expandable list (offers * features such as collapsing/expanding groups containing children). By * itself, this adapter has no data and is a connector to a * {@link ExpandableListAdapter} which provides the data. *

    * Internally, this connector translates the flat list position that the * ListAdapter expects to/from group and child positions that the ExpandableListAdapter * expects. */ class ExpandableListConnector extends BaseAdapter implements Filterable { /** * The ExpandableListAdapter to fetch the data/Views for this expandable list */ private ExpandableListAdapter mExpandableListAdapter; /** * List of metadata for the currently expanded groups. The metadata consists * of data essential for efficiently translating between flat list positions * and group/child positions. See {@link GroupMetadata}. */ private ArrayList mExpGroupMetadataList; /** The number of children from all currently expanded groups */ private int mTotalExpChildrenCount; /** The maximum number of allowable expanded groups. Defaults to 'no limit' */ private int mMaxExpGroupCount = Integer.MAX_VALUE; /** Change observer used to have ExpandableListAdapter changes pushed to us */ private final DataSetObserver mDataSetObserver = new MyDataSetObserver(); /** * Constructs the connector */ public ExpandableListConnector(ExpandableListAdapter expandableListAdapter) { mExpGroupMetadataList = new ArrayList(); setExpandableListAdapter(expandableListAdapter); } /** * Point to the {@link ExpandableListAdapter} that will give us data/Views * * @param expandableListAdapter the adapter that supplies us with data/Views */ public void setExpandableListAdapter(ExpandableListAdapter expandableListAdapter) { if (mExpandableListAdapter != null) { mExpandableListAdapter.unregisterDataSetObserver(mDataSetObserver); } mExpandableListAdapter = expandableListAdapter; expandableListAdapter.registerDataSetObserver(mDataSetObserver); } /** * Translates a flat list position to either a) group pos if the specified * flat list position corresponds to a group, or b) child pos if it * corresponds to a child. Performs a binary search on the expanded * groups list to find the flat list pos if it is an exp group, otherwise * finds where the flat list pos fits in between the exp groups. * * @param flPos the flat list position to be translated * @return the group position or child position of the specified flat list * position encompassed in a {@link PositionMetadata} object * that contains additional useful info for insertion, etc. */ PositionMetadata getUnflattenedPos(final int flPos) { /* Keep locally since frequent use */ final ArrayList egml = mExpGroupMetadataList; final int numExpGroups = egml.size(); /* Binary search variables */ int leftExpGroupIndex = 0; int rightExpGroupIndex = numExpGroups - 1; int midExpGroupIndex = 0; GroupMetadata midExpGm; if (numExpGroups == 0) { /* * There aren't any expanded groups (hence no visible children * either), so flPos must be a group and its group pos will be the * same as its flPos */ return PositionMetadata.obtain(flPos, ExpandableListPosition.GROUP, flPos, -1, null, 0); } /* * Binary search over the expanded groups to find either the exact * expanded group (if we're looking for a group) or the group that * contains the child we're looking for. If we are looking for a * collapsed group, we will not have a direct match here, but we will * find the expanded group just before the group we're searching for (so * then we can calculate the group position of the group we're searching * for). If there isn't an expanded group prior to the group being * searched for, then the group being searched for's group position is * the same as the flat list position (since there are no children before * it, and all groups before it are collapsed). */ while (leftExpGroupIndex <= rightExpGroupIndex) { midExpGroupIndex = (rightExpGroupIndex - leftExpGroupIndex) / 2 + leftExpGroupIndex; midExpGm = egml.get(midExpGroupIndex); if (flPos > midExpGm.lastChildFlPos) { /* * The flat list position is after the current middle group's * last child's flat list position, so search right */ leftExpGroupIndex = midExpGroupIndex + 1; } else if (flPos < midExpGm.flPos) { /* * The flat list position is before the current middle group's * flat list position, so search left */ rightExpGroupIndex = midExpGroupIndex - 1; } else if (flPos == midExpGm.flPos) { /* * The flat list position is this middle group's flat list * position, so we've found an exact hit */ return PositionMetadata.obtain(flPos, ExpandableListPosition.GROUP, midExpGm.gPos, -1, midExpGm, midExpGroupIndex); } else if (flPos <= midExpGm.lastChildFlPos /* && flPos > midGm.flPos as deduced from previous * conditions */) { /* The flat list position is a child of the middle group */ /* * Subtract the first child's flat list position from the * specified flat list pos to get the child's position within * the group */ final int childPos = flPos - (midExpGm.flPos + 1); return PositionMetadata.obtain(flPos, ExpandableListPosition.CHILD, midExpGm.gPos, childPos, midExpGm, midExpGroupIndex); } } /* * If we've reached here, it means the flat list position must be a * group that is not expanded, since otherwise we would have hit it * in the above search. */ /** * If we are to expand this group later, where would it go in the * mExpGroupMetadataList ? */ int insertPosition = 0; /** What is its group position in the list of all groups? */ int groupPos = 0; /* * To figure out exact insertion and prior group positions, we need to * determine how we broke out of the binary search. We backtrack * to see this. */ if (leftExpGroupIndex > midExpGroupIndex) { /* * This would occur in the first conditional, so the flat list * insertion position is after the left group. Also, the * leftGroupPos is one more than it should be (since that broke out * of our binary search), so we decrement it. */ final GroupMetadata leftExpGm = egml.get(leftExpGroupIndex-1); insertPosition = leftExpGroupIndex; /* * Sums the number of groups between the prior exp group and this * one, and then adds it to the prior group's group pos */ groupPos = (flPos - leftExpGm.lastChildFlPos) + leftExpGm.gPos; } else if (rightExpGroupIndex < midExpGroupIndex) { /* * This would occur in the second conditional, so the flat list * insertion position is before the right group. Also, the * rightGroupPos is one less than it should be, so increment it. */ final GroupMetadata rightExpGm = egml.get(++rightExpGroupIndex); insertPosition = rightExpGroupIndex; /* * Subtracts this group's flat list pos from the group after's flat * list position to find out how many groups are in between the two * groups. Then, subtracts that number from the group after's group * pos to get this group's pos. */ groupPos = rightExpGm.gPos - (rightExpGm.flPos - flPos); } else { // TODO: clean exit throw new RuntimeException("Unknown state"); } return PositionMetadata.obtain(flPos, ExpandableListPosition.GROUP, groupPos, -1, null, insertPosition); } /** * Translates either a group pos or a child pos (+ group it belongs to) to a * flat list position. If searching for a child and its group is not expanded, this will * return null since the child isn't being shown in the ListView, and hence it has no * position. * * @param pos a {@link ExpandableListPosition} representing either a group position * or child position * @return the flat list position encompassed in a {@link PositionMetadata} * object that contains additional useful info for insertion, etc., or null. */ PositionMetadata getFlattenedPos(final ExpandableListPosition pos) { final ArrayList egml = mExpGroupMetadataList; final int numExpGroups = egml.size(); /* Binary search variables */ int leftExpGroupIndex = 0; int rightExpGroupIndex = numExpGroups - 1; int midExpGroupIndex = 0; GroupMetadata midExpGm; if (numExpGroups == 0) { /* * There aren't any expanded groups, so flPos must be a group and * its flPos will be the same as its group pos. The * insert position is 0 (since the list is empty). */ return PositionMetadata.obtain(pos.groupPos, pos.type, pos.groupPos, pos.childPos, null, 0); } /* * Binary search over the expanded groups to find either the exact * expanded group (if we're looking for a group) or the group that * contains the child we're looking for. */ while (leftExpGroupIndex <= rightExpGroupIndex) { midExpGroupIndex = (rightExpGroupIndex - leftExpGroupIndex)/2 + leftExpGroupIndex; midExpGm = egml.get(midExpGroupIndex); if (pos.groupPos > midExpGm.gPos) { /* * It's after the current middle group, so search right */ leftExpGroupIndex = midExpGroupIndex + 1; } else if (pos.groupPos < midExpGm.gPos) { /* * It's before the current middle group, so search left */ rightExpGroupIndex = midExpGroupIndex - 1; } else if (pos.groupPos == midExpGm.gPos) { /* * It's this middle group, exact hit */ if (pos.type == ExpandableListPosition.GROUP) { /* If it's a group, give them this matched group's flPos */ return PositionMetadata.obtain(midExpGm.flPos, pos.type, pos.groupPos, pos.childPos, midExpGm, midExpGroupIndex); } else if (pos.type == ExpandableListPosition.CHILD) { /* If it's a child, calculate the flat list pos */ return PositionMetadata.obtain(midExpGm.flPos + pos.childPos + 1, pos.type, pos.groupPos, pos.childPos, midExpGm, midExpGroupIndex); } else { return null; } } } /* * If we've reached here, it means there was no match in the expanded * groups, so it must be a collapsed group that they're search for */ if (pos.type != ExpandableListPosition.GROUP) { /* If it isn't a group, return null */ return null; } /* * To figure out exact insertion and prior group positions, we need to * determine how we broke out of the binary search. We backtrack to see * this. */ if (leftExpGroupIndex > midExpGroupIndex) { /* * This would occur in the first conditional, so the flat list * insertion position is after the left group. * * The leftGroupPos is one more than it should be (from the binary * search loop) so we subtract 1 to get the actual left group. Since * the insertion point is AFTER the left group, we keep this +1 * value as the insertion point */ final GroupMetadata leftExpGm = egml.get(leftExpGroupIndex-1); final int flPos = leftExpGm.lastChildFlPos + (pos.groupPos - leftExpGm.gPos); return PositionMetadata.obtain(flPos, pos.type, pos.groupPos, pos.childPos, null, leftExpGroupIndex); } else if (rightExpGroupIndex < midExpGroupIndex) { /* * This would occur in the second conditional, so the flat list * insertion position is before the right group. Also, the * rightGroupPos is one less than it should be (from binary search * loop), so we increment to it. */ final GroupMetadata rightExpGm = egml.get(++rightExpGroupIndex); final int flPos = rightExpGm.flPos - (rightExpGm.gPos - pos.groupPos); return PositionMetadata.obtain(flPos, pos.type, pos.groupPos, pos.childPos, null, rightExpGroupIndex); } else { return null; } } @Override public boolean areAllItemsEnabled() { return mExpandableListAdapter.areAllItemsEnabled(); } @Override public boolean isEnabled(int flatListPos) { final PositionMetadata metadata = getUnflattenedPos(flatListPos); final ExpandableListPosition pos = metadata.position; boolean retValue; if (pos.type == ExpandableListPosition.CHILD) { retValue = mExpandableListAdapter.isChildSelectable(pos.groupPos, pos.childPos); } else { // Groups are always selectable retValue = true; } metadata.recycle(); return retValue; } public int getCount() { /* * Total count for the list view is the number groups plus the * number of children from currently expanded groups (a value we keep * cached in this class) */ return mExpandableListAdapter.getGroupCount() + mTotalExpChildrenCount; } public Object getItem(int flatListPos) { final PositionMetadata posMetadata = getUnflattenedPos(flatListPos); Object retValue; if (posMetadata.position.type == ExpandableListPosition.GROUP) { retValue = mExpandableListAdapter .getGroup(posMetadata.position.groupPos); } else if (posMetadata.position.type == ExpandableListPosition.CHILD) { retValue = mExpandableListAdapter.getChild(posMetadata.position.groupPos, posMetadata.position.childPos); } else { // TODO: clean exit throw new RuntimeException("Flat list position is of unknown type"); } posMetadata.recycle(); return retValue; } public long getItemId(int flatListPos) { final PositionMetadata posMetadata = getUnflattenedPos(flatListPos); final long groupId = mExpandableListAdapter.getGroupId(posMetadata.position.groupPos); long retValue; if (posMetadata.position.type == ExpandableListPosition.GROUP) { retValue = mExpandableListAdapter.getCombinedGroupId(groupId); } else if (posMetadata.position.type == ExpandableListPosition.CHILD) { final long childId = mExpandableListAdapter.getChildId(posMetadata.position.groupPos, posMetadata.position.childPos); retValue = mExpandableListAdapter.getCombinedChildId(groupId, childId); } else { // TODO: clean exit throw new RuntimeException("Flat list position is of unknown type"); } posMetadata.recycle(); return retValue; } public View getView(int flatListPos, View convertView, ViewGroup parent) { final PositionMetadata posMetadata = getUnflattenedPos(flatListPos); View retValue; if (posMetadata.position.type == ExpandableListPosition.GROUP) { retValue = mExpandableListAdapter.getGroupView(posMetadata.position.groupPos, posMetadata.isExpanded(), convertView, parent); } else if (posMetadata.position.type == ExpandableListPosition.CHILD) { final boolean isLastChild = posMetadata.groupMetadata.lastChildFlPos == flatListPos; retValue = mExpandableListAdapter.getChildView(posMetadata.position.groupPos, posMetadata.position.childPos, isLastChild, convertView, parent); } else { // TODO: clean exit throw new RuntimeException("Flat list position is of unknown type"); } posMetadata.recycle(); return retValue; } @Override public int getItemViewType(int flatListPos) { final PositionMetadata metadata = getUnflattenedPos(flatListPos); final ExpandableListPosition pos = metadata.position; int retValue; if (mExpandableListAdapter instanceof HeterogeneousExpandableList) { HeterogeneousExpandableList adapter = (HeterogeneousExpandableList) mExpandableListAdapter; if (pos.type == ExpandableListPosition.GROUP) { retValue = adapter.getGroupType(pos.groupPos); } else { final int childType = adapter.getChildType(pos.groupPos, pos.childPos); retValue = adapter.getGroupTypeCount() + childType; } } else { if (pos.type == ExpandableListPosition.GROUP) { retValue = 0; } else { retValue = 1; } } metadata.recycle(); return retValue; } @Override public int getViewTypeCount() { if (mExpandableListAdapter instanceof HeterogeneousExpandableList) { HeterogeneousExpandableList adapter = (HeterogeneousExpandableList) mExpandableListAdapter; return adapter.getGroupTypeCount() + adapter.getChildTypeCount(); } else { return 2; } } @Override public boolean hasStableIds() { return mExpandableListAdapter.hasStableIds(); } /** * Traverses the expanded group metadata list and fills in the flat list * positions. * * @param forceChildrenCountRefresh Forces refreshing of the children count * for all expanded groups. * @param syncGroupPositions Whether to search for the group positions * based on the group IDs. This should only be needed when calling * this from an onChanged callback. */ @SuppressWarnings("unchecked") private void refreshExpGroupMetadataList(boolean forceChildrenCountRefresh, boolean syncGroupPositions) { final ArrayList egml = mExpGroupMetadataList; int egmlSize = egml.size(); int curFlPos = 0; /* Update child count as we go through */ mTotalExpChildrenCount = 0; if (syncGroupPositions) { // We need to check whether any groups have moved positions boolean positionsChanged = false; for (int i = egmlSize - 1; i >= 0; i--) { GroupMetadata curGm = egml.get(i); int newGPos = findGroupPosition(curGm.gId, curGm.gPos); if (newGPos != curGm.gPos) { if (newGPos == AdapterView.INVALID_POSITION) { // Doh, just remove it from the list of expanded groups egml.remove(i); egmlSize--; } curGm.gPos = newGPos; if (!positionsChanged) positionsChanged = true; } } if (positionsChanged) { // At least one group changed positions, so re-sort Collections.sort(egml); } } int gChildrenCount; int lastGPos = 0; for (int i = 0; i < egmlSize; i++) { /* Store in local variable since we'll access freq */ GroupMetadata curGm = egml.get(i); /* * Get the number of children, try to refrain from calling * another class's method unless we have to (so do a subtraction) */ if ((curGm.lastChildFlPos == GroupMetadata.REFRESH) || forceChildrenCountRefresh) { gChildrenCount = mExpandableListAdapter.getChildrenCount(curGm.gPos); } else { /* Num children for this group is its last child's fl pos minus * the group's fl pos */ gChildrenCount = curGm.lastChildFlPos - curGm.flPos; } /* Update */ mTotalExpChildrenCount += gChildrenCount; /* * This skips the collapsed groups and increments the flat list * position (for subsequent exp groups) by accounting for the collapsed * groups */ curFlPos += (curGm.gPos - lastGPos); lastGPos = curGm.gPos; /* Update the flat list positions, and the current flat list pos */ curGm.flPos = curFlPos; curFlPos += gChildrenCount; curGm.lastChildFlPos = curFlPos; } } /** * Collapse a group in the grouped list view * * @param groupPos position of the group to collapse */ boolean collapseGroup(int groupPos) { ExpandableListPosition elGroupPos = ExpandableListPosition.obtain( ExpandableListPosition.GROUP, groupPos, -1, -1); PositionMetadata pm = getFlattenedPos(elGroupPos); elGroupPos.recycle(); if (pm == null) return false; boolean retValue = collapseGroup(pm); pm.recycle(); return retValue; } boolean collapseGroup(PositionMetadata posMetadata) { /* * Collapsing requires removal from mExpGroupMetadataList */ /* * If it is null, it must be already collapsed. This group metadata * object should have been set from the search that returned the * position metadata object. */ if (posMetadata.groupMetadata == null) return false; // Remove the group from the list of expanded groups mExpGroupMetadataList.remove(posMetadata.groupMetadata); // Refresh the metadata refreshExpGroupMetadataList(false, false); // Notify of change notifyDataSetChanged(); // Give the callback mExpandableListAdapter.onGroupCollapsed(posMetadata.groupMetadata.gPos); return true; } /** * Expand a group in the grouped list view * @param groupPos the group to be expanded */ boolean expandGroup(int groupPos) { ExpandableListPosition elGroupPos = ExpandableListPosition.obtain( ExpandableListPosition.GROUP, groupPos, -1, -1); PositionMetadata pm = getFlattenedPos(elGroupPos); elGroupPos.recycle(); boolean retValue = expandGroup(pm); pm.recycle(); return retValue; } boolean expandGroup(PositionMetadata posMetadata) { /* * Expanding requires insertion into the mExpGroupMetadataList */ if (posMetadata.position.groupPos < 0) { // TODO clean exit throw new RuntimeException("Need group"); } if (mMaxExpGroupCount == 0) return false; // Check to see if it's already expanded if (posMetadata.groupMetadata != null) return false; /* Restrict number of expanded groups to mMaxExpGroupCount */ if (mExpGroupMetadataList.size() >= mMaxExpGroupCount) { /* Collapse a group */ // TODO: Collapse something not on the screen instead of the first one? // TODO: Could write overloaded function to take GroupMetadata to collapse GroupMetadata collapsedGm = mExpGroupMetadataList.get(0); int collapsedIndex = mExpGroupMetadataList.indexOf(collapsedGm); collapseGroup(collapsedGm.gPos); /* Decrement index if it is after the group we removed */ if (posMetadata.groupInsertIndex > collapsedIndex) { posMetadata.groupInsertIndex--; } } GroupMetadata expandedGm = GroupMetadata.obtain( GroupMetadata.REFRESH, GroupMetadata.REFRESH, posMetadata.position.groupPos, mExpandableListAdapter.getGroupId(posMetadata.position.groupPos)); mExpGroupMetadataList.add(posMetadata.groupInsertIndex, expandedGm); // Refresh the metadata refreshExpGroupMetadataList(false, false); // Notify of change notifyDataSetChanged(); // Give the callback mExpandableListAdapter.onGroupExpanded(expandedGm.gPos); 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) { GroupMetadata groupMetadata; for (int i = mExpGroupMetadataList.size() - 1; i >= 0; i--) { groupMetadata = mExpGroupMetadataList.get(i); if (groupMetadata.gPos == groupPosition) { return true; } } return false; } /** * Set the maximum number of groups that can be expanded at any given time */ public void setMaxExpGroupCount(int maxExpGroupCount) { mMaxExpGroupCount = maxExpGroupCount; } ExpandableListAdapter getAdapter() { return mExpandableListAdapter; } public Filter getFilter() { ExpandableListAdapter adapter = getAdapter(); if (adapter instanceof Filterable) { return ((Filterable) adapter).getFilter(); } else { return null; } } ArrayList getExpandedGroupMetadataList() { return mExpGroupMetadataList; } void setExpandedGroupMetadataList(ArrayList expandedGroupMetadataList) { if ((expandedGroupMetadataList == null) || (mExpandableListAdapter == null)) { return; } // Make sure our current data set is big enough for the previously // expanded groups, if not, ignore this request int numGroups = mExpandableListAdapter.getGroupCount(); for (int i = expandedGroupMetadataList.size() - 1; i >= 0; i--) { if (expandedGroupMetadataList.get(i).gPos >= numGroups) { // Doh, for some reason the client doesn't have some of the groups return; } } mExpGroupMetadataList = expandedGroupMetadataList; refreshExpGroupMetadataList(true, false); } @Override public boolean isEmpty() { ExpandableListAdapter adapter = getAdapter(); return adapter != null ? adapter.isEmpty() : true; } /** * Searches the expandable list adapter for a group position matching the * given group ID. The search starts at the given seed position and then * alternates between moving up and moving down until 1) we find the right * position, or 2) we run out of time, or 3) we have looked at every * position * * @return Position of the row that matches the given row ID, or * {@link AdapterView#INVALID_POSITION} if it can't be found * @see AdapterView#findSyncPosition() */ int findGroupPosition(long groupIdToMatch, int seedGroupPosition) { int count = mExpandableListAdapter.getGroupCount(); if (count == 0) { return AdapterView.INVALID_POSITION; } // If there isn't a selection don't hunt for it if (groupIdToMatch == AdapterView.INVALID_ROW_ID) { return AdapterView.INVALID_POSITION; } // Pin seed to reasonable values seedGroupPosition = Math.max(0, seedGroupPosition); seedGroupPosition = Math.min(count - 1, seedGroupPosition); long endTime = SystemClock.uptimeMillis() + AdapterView.SYNC_MAX_DURATION_MILLIS; long rowId; // first position scanned so far int first = seedGroupPosition; // last position scanned so far int last = seedGroupPosition; // True if we should move down on the next iteration boolean next = false; // True when we have looked at the first item in the data boolean hitFirst; // True when we have looked at the last item in the data boolean hitLast; // Get the item ID locally (instead of getItemIdAtPosition), so // we need the adapter ExpandableListAdapter adapter = getAdapter(); if (adapter == null) { return AdapterView.INVALID_POSITION; } while (SystemClock.uptimeMillis() <= endTime) { rowId = adapter.getGroupId(seedGroupPosition); if (rowId == groupIdToMatch) { // Found it! return seedGroupPosition; } hitLast = last == count - 1; hitFirst = first == 0; if (hitLast && hitFirst) { // Looked at everything break; } if (hitFirst || (next && !hitLast)) { // Either we hit the top, or we are trying to move down last++; seedGroupPosition = last; // Try going up next time next = false; } else if (hitLast || (!next && !hitFirst)) { // Either we hit the bottom, or we are trying to move up first--; seedGroupPosition = first; // Try going down next time next = true; } } return AdapterView.INVALID_POSITION; } protected class MyDataSetObserver extends DataSetObserver { @Override public void onChanged() { refreshExpGroupMetadataList(true, true); notifyDataSetChanged(); } @Override public void onInvalidated() { refreshExpGroupMetadataList(true, true); notifyDataSetInvalidated(); } } /** * Metadata about an expanded group to help convert from a flat list * position to either a) group position for groups, or b) child position for * children */ static class GroupMetadata implements Parcelable, Comparable { final static int REFRESH = -1; /** This group's flat list position */ int flPos; /* firstChildFlPos isn't needed since it's (flPos + 1) */ /** * This group's last child's flat list position, so basically * the range of this group in the flat list */ int lastChildFlPos; /** * This group's group position */ int gPos; /** * This group's id */ long gId; private GroupMetadata() { } static GroupMetadata obtain(int flPos, int lastChildFlPos, int gPos, long gId) { GroupMetadata gm = new GroupMetadata(); gm.flPos = flPos; gm.lastChildFlPos = lastChildFlPos; gm.gPos = gPos; gm.gId = gId; return gm; } public int compareTo(GroupMetadata another) { if (another == null) { throw new IllegalArgumentException(); } return gPos - another.gPos; } public int describeContents() { return 0; } public void writeToParcel(Parcel dest, int flags) { dest.writeInt(flPos); dest.writeInt(lastChildFlPos); dest.writeInt(gPos); dest.writeLong(gId); } public static final Parcelable.Creator CREATOR = new Parcelable.Creator() { public GroupMetadata createFromParcel(Parcel in) { GroupMetadata gm = GroupMetadata.obtain( in.readInt(), in.readInt(), in.readInt(), in.readLong()); return gm; } public GroupMetadata[] newArray(int size) { return new GroupMetadata[size]; } }; } /** * Data type that contains an expandable list position (can refer to either a group * or child) and some extra information regarding referred item (such as * where to insert into the flat list, etc.) */ static public class PositionMetadata { private static final int MAX_POOL_SIZE = 5; private static ArrayList sPool = new ArrayList(MAX_POOL_SIZE); /** Data type to hold the position and its type (child/group) */ public ExpandableListPosition position; /** * Link back to the expanded GroupMetadata for this group. Useful for * removing the group from the list of expanded groups inside the * connector when we collapse the group, and also as a check to see if * the group was expanded or collapsed (this will be null if the group * is collapsed since we don't keep that group's metadata) */ public GroupMetadata groupMetadata; /** * For groups that are collapsed, we use this as the index (in * mExpGroupMetadataList) to insert this group when we are expanding * this group. */ public int groupInsertIndex; private void resetState() { if (position != null) { position.recycle(); position = null; } groupMetadata = null; groupInsertIndex = 0; } /** * Use {@link #obtain(int, int, int, int, GroupMetadata, int)} */ private PositionMetadata() { } static PositionMetadata obtain(int flatListPos, int type, int groupPos, int childPos, GroupMetadata groupMetadata, int groupInsertIndex) { PositionMetadata pm = getRecycledOrCreate(); pm.position = ExpandableListPosition.obtain(type, groupPos, childPos, flatListPos); pm.groupMetadata = groupMetadata; pm.groupInsertIndex = groupInsertIndex; return pm; } private static PositionMetadata getRecycledOrCreate() { PositionMetadata pm; synchronized (sPool) { if (sPool.size() > 0) { pm = sPool.remove(0); } else { return new PositionMetadata(); } } pm.resetState(); return pm; } public void recycle() { resetState(); synchronized (sPool) { if (sPool.size() < MAX_POOL_SIZE) { sPool.add(this); } } } /** * Checks whether the group referred to in this object is expanded, * or not (at the time this object was created) * * @return whether the group at groupPos is expanded or not */ public boolean isExpanded() { return groupMetadata != null; } } }