path: root/src/github/daneren2005/dsub/view/HeaderGridView.java

/*
 * Copyright (C) 2013 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 github.daneren2005.dsub.view;

import android.annotation.TargetApi;
import android.content.Context;
import android.database.DataSetObservable;
import android.database.DataSetObserver;
import android.os.Build;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.widget.*;

import java.lang.reflect.Field;
import java.util.ArrayList;

/**
 * A {@link GridView} that supports adding header rows in a
 * very similar way to {@link android.widget.ListView}.
 * See {@link HeaderGridView#addHeaderView(View, Object, boolean)}
 * See {@link HeaderGridView#addFooterView(View, Object, boolean)}
 */
public class HeaderGridView extends GridView {
	private static final String TAG = HeaderGridView.class.getSimpleName();
	public static boolean DEBUG = false;

	/**
	 * A class that represents a fixed view in a list, for example a header at the top
	 * or a footer at the bottom.
	 */
	private static class FixedViewInfo {
		/**
		 * The view to add to the grid
		 */
		public View view;
		public ViewGroup viewContainer;
		/**
		 * The data backing the view. This is returned from {@link ListAdapter#getItem(int)}.
		 */
		public Object data;
		/**
		 * <code>true</code> if the fixed view should be selectable in the grid
		 */
		public boolean isSelectable;
	}

	private int mNumColumns = AUTO_FIT;
	private View mViewForMeasureRowHeight = null;
	private int mRowHeight = -1;
	private static final String LOG_TAG = HeaderGridView.class.getSimpleName();

	private ArrayList<FixedViewInfo> mHeaderViewInfos = new ArrayList<FixedViewInfo>();
	private ArrayList<FixedViewInfo> mFooterViewInfos = new ArrayList<FixedViewInfo>();

	private void initHeaderGridView() {
	}

	public HeaderGridView(Context context) {
		super(context);
		initHeaderGridView();
	}

	public HeaderGridView(Context context, AttributeSet attrs) {
		super(context, attrs);
		initHeaderGridView();
	}

	public HeaderGridView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		initHeaderGridView();
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		ListAdapter adapter = getAdapter();
		if (adapter != null && adapter instanceof HeaderViewGridAdapter) {
			((HeaderViewGridAdapter) adapter).setNumColumns(getNumColumnsCompatible());
			((HeaderViewGridAdapter) adapter).setRowHeight(getRowHeight());
		}
	}

	@Override
	public void setClipChildren(boolean clipChildren) {
		// Ignore, since the header rows depend on not being clipped
	}

	/**
	 * Do not call this method unless you know how it works.
	 *
	 * @param clipChildren
	 */
	public void setClipChildrenSupper(boolean clipChildren) {
		super.setClipChildren(false);
	}

	/**
	 * Add a fixed view to appear at the top of the grid. If addHeaderView is
	 * called more than once, the views will appear in the order they were
	 * added. Views added using this call can take focus if they want.
	 * <p/>
	 * NOTE: Call this before calling setAdapter. This is so HeaderGridView can wrap
	 * the supplied cursor with one that will also account for header views.
	 *
	 * @param v The view to add.
	 */
	public void addHeaderView(View v) {
		addHeaderView(v, null, true);
	}

	/**
	 * Add a fixed view to appear at the top of the grid. If addHeaderView is
	 * called more than once, the views will appear in the order they were
	 * added. Views added using this call can take focus if they want.
	 * <p/>
	 * NOTE: Call this before calling setAdapter. This is so HeaderGridView can wrap
	 * the supplied cursor with one that will also account for header views.
	 *
	 * @param v            The view to add.
	 * @param data         Data to associate with this view
	 * @param isSelectable whether the item is selectable
	 */
	public void addHeaderView(View v, Object data, boolean isSelectable) {
		ListAdapter adapter = getAdapter();
		if (adapter != null && !(adapter instanceof HeaderViewGridAdapter)) {
			throw new IllegalStateException(
					"Cannot add header view to grid -- setAdapter has already been called.");
		}

		ViewGroup.LayoutParams lyp = v.getLayoutParams();

		FixedViewInfo info = new FixedViewInfo();
		FrameLayout fl = new FullWidthFixedViewLayout(getContext());

		if (lyp != null) {
			v.setLayoutParams(new FrameLayout.LayoutParams(lyp.width, lyp.height));
			fl.setLayoutParams(new AbsListView.LayoutParams(lyp.width, lyp.height));
		}
		fl.addView(v);
		info.view = v;
		info.viewContainer = fl;
		info.data = data;
		info.isSelectable = isSelectable;
		mHeaderViewInfos.add(info);
		// in the case of re-adding a header view, or adding one later on,
		// we need to notify the observer
		if (adapter != null) {
			((HeaderViewGridAdapter) adapter).notifyDataSetChanged();
		}
	}

	public void addFooterView(View v) {
		addFooterView(v, null, true);
	}

	public void addFooterView(View v, Object data, boolean isSelectable) {
		ListAdapter mAdapter = getAdapter();
		if (mAdapter != null && !(mAdapter instanceof HeaderViewGridAdapter)) {
			throw new IllegalStateException(
					"Cannot add header view to grid -- setAdapter has already been called.");
		}

		ViewGroup.LayoutParams lyp = v.getLayoutParams();

		FixedViewInfo info = new FixedViewInfo();
		FrameLayout fl = new FullWidthFixedViewLayout(getContext());

		if (lyp != null) {
			v.setLayoutParams(new FrameLayout.LayoutParams(lyp.width, lyp.height));
			fl.setLayoutParams(new AbsListView.LayoutParams(lyp.width, lyp.height));
		}
		fl.addView(v);
		info.view = v;
		info.viewContainer = fl;
		info.data = data;
		info.isSelectable = isSelectable;
		mFooterViewInfos.add(info);

		if (mAdapter != null) {
			((HeaderViewGridAdapter) mAdapter).notifyDataSetChanged();
		}
	}

	public int getHeaderViewCount() {
		return mHeaderViewInfos.size();
	}

	public int getFooterViewCount() {
		return mFooterViewInfos.size();
	}

	/**
	 * Removes a previously-added header view.
	 *
	 * @param v The view to remove
	 * @return true if the view was removed, false if the view was not a header
	 * view
	 */
	public boolean removeHeaderView(View v) {
		if (mHeaderViewInfos.size() > 0) {
			boolean result = false;
			ListAdapter adapter = getAdapter();
			if (adapter != null && ((HeaderViewGridAdapter) adapter).removeHeader(v)) {
				result = true;
			}
			removeFixedViewInfo(v, mHeaderViewInfos);
			return result;
		}
		return false;
	}

	/**
	 * Removes a previously-added footer view.
	 *
	 * @param v The view to remove
	 * @return true if the view was removed, false if the view was not a header
	 * view
	 */
	public boolean removeFooterView(View v) {
		if (mFooterViewInfos.size() > 0) {
			boolean result = false;
			ListAdapter adapter = getAdapter();
			if (adapter != null && ((HeaderViewGridAdapter) adapter).removeFooter(v)) {
				result = true;
			}
			removeFixedViewInfo(v, mFooterViewInfos);
			return result;
		}
		return false;
	}

	private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) {
		int len = where.size();
		for (int i = 0; i < len; ++i) {
			FixedViewInfo info = where.get(i);
			if (info.view == v) {
				where.remove(i);
				break;
			}
		}
	}

	@TargetApi(11)
	private int getNumColumnsCompatible() {
		if (Build.VERSION.SDK_INT >= 11) {
			return super.getNumColumns();
		} else {
			try {
				Field numColumns = getClass().getSuperclass().getDeclaredField("mNumColumns");
				numColumns.setAccessible(true);
				return numColumns.getInt(this);
			} catch (Exception e) {
				if (mNumColumns != -1) {
					return mNumColumns;
				}
				throw new RuntimeException("Can not determine the mNumColumns for this API platform, please call setNumColumns to set it.");
			}
		}
	}

	@TargetApi(16)
	private int getColumnWidthCompatible() {
		if (Build.VERSION.SDK_INT >= 16) {
			return super.getColumnWidth();
		} else {
			try {
				Field numColumns = getClass().getSuperclass().getDeclaredField("mColumnWidth");
				numColumns.setAccessible(true);
				return numColumns.getInt(this);
			} catch (NoSuchFieldException e) {
				throw new RuntimeException(e);
			} catch (IllegalAccessException e) {
				throw new RuntimeException(e);
			}
		}
	}

	@Override
	protected void onDetachedFromWindow() {
		super.onDetachedFromWindow();
		mViewForMeasureRowHeight = null;
	}

	public void invalidateRowHeight() {
		mRowHeight = -1;
	}

	public int getHeaderHeight(int row) {
		if (row >= 0) {
			return mHeaderViewInfos.get(row).view.getMeasuredHeight();
		}

		return 0;
	}

	public int getRowHeight() {
		if (mRowHeight > 0) {
			return mRowHeight;
		}
		ListAdapter adapter = getAdapter();
		int numColumns = getNumColumnsCompatible();

		// adapter has not been set or has no views in it;
		if (adapter == null || adapter.getCount() <= numColumns * (mHeaderViewInfos.size() + mFooterViewInfos.size()) || numColumns == -1) {
			return -1;
		}
		int mColumnWidth = getColumnWidthCompatible();
		View view = getAdapter().getView(numColumns * mHeaderViewInfos.size(), mViewForMeasureRowHeight, this);
		AbsListView.LayoutParams p = (AbsListView.LayoutParams) view.getLayoutParams();
		if (p == null) {
			p = new AbsListView.LayoutParams(-1, -2, 0);
			view.setLayoutParams(p);
		}
		int childHeightSpec = getChildMeasureSpec(
				MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), 0, p.height);
		int childWidthSpec = getChildMeasureSpec(
				MeasureSpec.makeMeasureSpec(mColumnWidth, MeasureSpec.EXACTLY), 0, p.width);
		view.measure(childWidthSpec, childHeightSpec);
		mViewForMeasureRowHeight = view;
		mRowHeight = view.getMeasuredHeight();
		return mRowHeight;
	}

	@TargetApi(11)
	public void tryToScrollToBottomSmoothly() {
		int lastPos = getAdapter().getCount() - 1;
		if (Build.VERSION.SDK_INT >= 11) {
			smoothScrollToPositionFromTop(lastPos, 0);
		} else {
			setSelection(lastPos);
		}
	}

	@TargetApi(11)
	public void tryToScrollToBottomSmoothly(int duration) {
		int lastPos = getAdapter().getCount() - 1;
		if (Build.VERSION.SDK_INT >= 11) {
			smoothScrollToPositionFromTop(lastPos, 0, duration);
		} else {
			setSelection(lastPos);
		}
	}

	@Override
	public void setAdapter(ListAdapter adapter) {
		if (mHeaderViewInfos.size() > 0 || mFooterViewInfos.size() > 0) {
			HeaderViewGridAdapter headerViewGridAdapter = new HeaderViewGridAdapter(mHeaderViewInfos, mFooterViewInfos, adapter);
			int numColumns = getNumColumnsCompatible();
			if (numColumns > 1) {
				headerViewGridAdapter.setNumColumns(numColumns);
			}
			headerViewGridAdapter.setRowHeight(getRowHeight());
			super.setAdapter(headerViewGridAdapter);
		} else {
			super.setAdapter(adapter);
		}
	}

	/**
	 * full width
	 */
	private class FullWidthFixedViewLayout extends FrameLayout {

		public FullWidthFixedViewLayout(Context context) {
			super(context);
		}

		@Override
		protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
			int realLeft = HeaderGridView.this.getPaddingLeft() + getPaddingLeft();
			// Try to make where it should be, from left, full width
			if (realLeft != left) {
				offsetLeftAndRight(realLeft - left);
			}
			super.onLayout(changed, left, top, right, bottom);
		}

		@Override
		protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
			int targetWidth = HeaderGridView.this.getMeasuredWidth()
					- HeaderGridView.this.getPaddingLeft()
					- HeaderGridView.this.getPaddingRight();
			widthMeasureSpec = MeasureSpec.makeMeasureSpec(targetWidth,
					MeasureSpec.getMode(widthMeasureSpec));
			super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		}
	}

	@Override
	public void setNumColumns(int numColumns) {
		super.setNumColumns(numColumns);
		mNumColumns = numColumns;
		ListAdapter adapter = getAdapter();
		if (adapter != null && adapter instanceof HeaderViewGridAdapter) {
			((HeaderViewGridAdapter) adapter).setNumColumns(numColumns);
		}
	}

	/**
	 * ListAdapter used when a HeaderGridView has header views. This ListAdapter
	 * wraps another one and also keeps track of the header views and their
	 * associated data objects.
	 * <p>This is intended as a base class; you will probably not need to
	 * use this class directly in your own code.
	 */
	private static class HeaderViewGridAdapter extends BaseAdapter implements WrapperListAdapter, Filterable {
		// This is used to notify the container of updates relating to number of columns
		// or headers changing, which changes the number of placeholders needed
		private final DataSetObservable mDataSetObservable = new DataSetObservable();
		private final ListAdapter mAdapter;
		static final ArrayList<FixedViewInfo> EMPTY_INFO_LIST =
				new ArrayList<FixedViewInfo>();

		// This ArrayList is assumed to NOT be null.
		ArrayList<FixedViewInfo> mHeaderViewInfos;
		ArrayList<FixedViewInfo> mFooterViewInfos;
		private int mNumColumns = 1;
		private int mRowHeight = -1;
		boolean mAreAllFixedViewsSelectable;
		private final boolean mIsFilterable;
		private boolean mCachePlaceHoldView = true;
		// From Recycle Bin or calling getView, this a question...
		private boolean mCacheFirstHeaderView = false;

		public HeaderViewGridAdapter(ArrayList<FixedViewInfo> headerViewInfos, ArrayList<FixedViewInfo> footViewInfos, ListAdapter adapter) {
			mAdapter = adapter;
			mIsFilterable = adapter instanceof Filterable;
			if (headerViewInfos == null) {
				mHeaderViewInfos = EMPTY_INFO_LIST;
			} else {
				mHeaderViewInfos = headerViewInfos;
			}

			if (footViewInfos == null) {
				mFooterViewInfos = EMPTY_INFO_LIST;
			} else {
				mFooterViewInfos = footViewInfos;
			}
			mAreAllFixedViewsSelectable = areAllListInfosSelectable(mHeaderViewInfos)
					&& areAllListInfosSelectable(mFooterViewInfos);
		}

		public void setNumColumns(int numColumns) {
			if (numColumns < 1) {
				return;
			}
			if (mNumColumns != numColumns) {
				mNumColumns = numColumns;
				notifyDataSetChanged();
			}
		}

		public void setRowHeight(int height) {
			mRowHeight = height;
		}

		public int getHeadersCount() {
			return mHeaderViewInfos.size();
		}

		public int getFootersCount() {
			return mFooterViewInfos.size();
		}

		@Override
		public boolean isEmpty() {
			return (mAdapter == null || mAdapter.isEmpty()) && getHeadersCount() == 0 && getFootersCount() == 0;
		}

		private boolean areAllListInfosSelectable(ArrayList<FixedViewInfo> infos) {
			if (infos != null) {
				for (FixedViewInfo info : infos) {
					if (!info.isSelectable) {
						return false;
					}
				}
			}
			return true;
		}

		public boolean removeHeader(View v) {
			for (int i = 0; i < mHeaderViewInfos.size(); i++) {
				FixedViewInfo info = mHeaderViewInfos.get(i);
				if (info.view == v) {
					mHeaderViewInfos.remove(i);
					mAreAllFixedViewsSelectable =
							areAllListInfosSelectable(mHeaderViewInfos) && areAllListInfosSelectable(mFooterViewInfos);
					mDataSetObservable.notifyChanged();
					return true;
				}
			}
			return false;
		}

		public boolean removeFooter(View v) {
			for (int i = 0; i < mFooterViewInfos.size(); i++) {
				FixedViewInfo info = mFooterViewInfos.get(i);
				if (info.view == v) {
					mFooterViewInfos.remove(i);
					mAreAllFixedViewsSelectable =
							areAllListInfosSelectable(mHeaderViewInfos) && areAllListInfosSelectable(mFooterViewInfos);
					mDataSetObservable.notifyChanged();
					return true;
				}
			}
			return false;
		}

		@Override
		public int getCount() {
			if (mAdapter != null) {
				return (getFootersCount() + getHeadersCount()) * mNumColumns + getAdapterAndPlaceHolderCount();
			} else {
				return (getFootersCount() + getHeadersCount()) * mNumColumns;
			}
		}

		@Override
		public boolean areAllItemsEnabled() {
			if (mAdapter != null) {
				return mAreAllFixedViewsSelectable && mAdapter.areAllItemsEnabled();
			} else {
				return true;
			}
		}

		private int getAdapterAndPlaceHolderCount() {
			final int adapterCount = (int) (Math.ceil(1f * mAdapter.getCount() / mNumColumns) * mNumColumns);
			return adapterCount;
		}

		@Override
		public boolean isEnabled(int position) {
			// Header (negative positions will throw an IndexOutOfBoundsException)
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			if (position < numHeadersAndPlaceholders) {
				return position % mNumColumns == 0
						&& mHeaderViewInfos.get(position / mNumColumns).isSelectable;
			}

			// Adapter
			final int adjPosition = position - numHeadersAndPlaceholders;
			int adapterCount = 0;
			if (mAdapter != null) {
				adapterCount = getAdapterAndPlaceHolderCount();
				if (adjPosition < adapterCount) {
					return adjPosition < mAdapter.getCount() && mAdapter.isEnabled(adjPosition);
				}
			}

			// Footer (off-limits positions will throw an IndexOutOfBoundsException)
			final int footerPosition = adjPosition - adapterCount;
			return footerPosition % mNumColumns == 0
					&& mFooterViewInfos.get(footerPosition / mNumColumns).isSelectable;
		}

		@Override
		public Object getItem(int position) {
			// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			if (position < numHeadersAndPlaceholders) {
				if (position % mNumColumns == 0) {
					return mHeaderViewInfos.get(position / mNumColumns).data;
				}
				return null;
			}

			// Adapter
			final int adjPosition = position - numHeadersAndPlaceholders;
			int adapterCount = 0;
			if (mAdapter != null) {
				adapterCount = getAdapterAndPlaceHolderCount();
				if (adjPosition < adapterCount) {
					if (adjPosition < mAdapter.getCount()) {
						return mAdapter.getItem(adjPosition);
					} else {
						return null;
					}
				}
			}

			// Footer (off-limits positions will throw an IndexOutOfBoundsException)
			final int footerPosition = adjPosition - adapterCount;
			if (footerPosition % mNumColumns == 0) {
				return mFooterViewInfos.get(footerPosition).data;
			} else {
				return null;
			}
		}

		@Override
		public long getItemId(int position) {
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			if (mAdapter != null && position >= numHeadersAndPlaceholders) {
				int adjPosition = position - numHeadersAndPlaceholders;
				int adapterCount = mAdapter.getCount();
				if (adjPosition < adapterCount) {
					return mAdapter.getItemId(adjPosition);
				}
			}
			return -1;
		}

		@Override
		public boolean hasStableIds() {
			if (mAdapter != null) {
				return mAdapter.hasStableIds();
			}
			return false;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			if (DEBUG) {
				Log.d(LOG_TAG, String.format("getView: %s, reused: %s", position, convertView == null));
			}
			// Header (negative positions will throw an ArrayIndexOutOfBoundsException)
			int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			if (position < numHeadersAndPlaceholders) {
				View headerViewContainer = mHeaderViewInfos
						.get(position / mNumColumns).viewContainer;
				if (position % mNumColumns == 0) {
					return headerViewContainer;
				} else {
					if (convertView == null) {
						convertView = new View(parent.getContext());
					}
					// We need to do this because GridView uses the height of the last item
					// in a row to determine the height for the entire row.
					convertView.setVisibility(View.INVISIBLE);
					convertView.setMinimumHeight(headerViewContainer.getHeight());
					return convertView;
				}
			}
			// Adapter
			final int adjPosition = position - numHeadersAndPlaceholders;
			int adapterCount = 0;
			if (mAdapter != null) {
				adapterCount = getAdapterAndPlaceHolderCount();
				if (adjPosition < adapterCount) {
					if (adjPosition < mAdapter.getCount()) {
						View view = mAdapter.getView(adjPosition, convertView, parent);
						return view;
					} else {
						if (convertView == null) {
							convertView = new View(parent.getContext());
						}
						convertView.setVisibility(View.INVISIBLE);
						convertView.setMinimumHeight(mRowHeight);
						return convertView;
					}
				}
			}
			// Footer
			final int footerPosition = adjPosition - adapterCount;
			if (footerPosition < getCount()) {
				View footViewContainer = mFooterViewInfos
						.get(footerPosition / mNumColumns).viewContainer;
				if (position % mNumColumns == 0) {
					return footViewContainer;
				} else {
					if (convertView == null) {
						convertView = new View(parent.getContext());
					}
					// We need to do this because GridView uses the height of the last item
					// in a row to determine the height for the entire row.
					convertView.setVisibility(View.INVISIBLE);
					convertView.setMinimumHeight(footViewContainer.getHeight());
					return convertView;
				}
			}
			throw new ArrayIndexOutOfBoundsException(position);
		}

		@Override
		public int getItemViewType(int position) {

			final int numHeadersAndPlaceholders = getHeadersCount() * mNumColumns;
			final int adapterViewTypeStart = mAdapter == null ? 0 : mAdapter.getViewTypeCount() - 1;
			int type = AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER;
			if (mCachePlaceHoldView) {
				// Header
				if (position < numHeadersAndPlaceholders) {
					if (position == 0) {
						if (mCacheFirstHeaderView) {
							type = adapterViewTypeStart + mHeaderViewInfos.size() + mFooterViewInfos.size() + 1 + 1;
						}
					}
					if (position % mNumColumns != 0) {
						type = adapterViewTypeStart + (position / mNumColumns + 1);
					}
				}
			}

			// Adapter
			final int adjPosition = position - numHeadersAndPlaceholders;
			int adapterCount = 0;
			if (mAdapter != null) {
				adapterCount = getAdapterAndPlaceHolderCount();
				if (adjPosition >= 0 && adjPosition < adapterCount) {
					if (adjPosition < mAdapter.getCount()) {
						type = mAdapter.getItemViewType(adjPosition);
					} else {
						if (mCachePlaceHoldView) {
							type = adapterViewTypeStart + mHeaderViewInfos.size() + 1;
						}
					}
				}
			}

			if (mCachePlaceHoldView) {
				// Footer
				final int footerPosition = adjPosition - adapterCount;
				if (footerPosition >= 0 && footerPosition < getCount() && (footerPosition % mNumColumns) != 0) {
					type = adapterViewTypeStart + mHeaderViewInfos.size() + 1 + (footerPosition / mNumColumns + 1);
				}
			}
			if (DEBUG) {
				Log.d(LOG_TAG, String.format("getItemViewType: pos: %s, result: %s", position, type, mCachePlaceHoldView, mCacheFirstHeaderView));
			}
			return type;
		}

		/**
		 * content view, content view holder, header[0], header and footer placeholder(s)
		 *
		 * @return
		 */
		@Override
		public int getViewTypeCount() {
			int count = mAdapter == null ? 1 : mAdapter.getViewTypeCount();
			if (mCachePlaceHoldView) {
				int offset = mHeaderViewInfos.size() + 1 + mFooterViewInfos.size();
				if (mCacheFirstHeaderView) {
					offset += 1;
				}
				count += offset;
			}
			if (DEBUG) {
				Log.d(LOG_TAG, String.format("getViewTypeCount: %s", count));
			}
			return count;
		}

		@Override
		public void registerDataSetObserver(DataSetObserver observer) {
			mDataSetObservable.registerObserver(observer);
			if (mAdapter != null) {
				mAdapter.registerDataSetObserver(observer);
			}
		}

		@Override
		public void unregisterDataSetObserver(DataSetObserver observer) {
			mDataSetObservable.unregisterObserver(observer);
			if (mAdapter != null) {
				mAdapter.unregisterDataSetObserver(observer);
			}
		}

		@Override
		public Filter getFilter() {
			if (mIsFilterable) {
				return ((Filterable) mAdapter).getFilter();
			}
			return null;
		}

		@Override
		public ListAdapter getWrappedAdapter() {
			return mAdapter;
		}

		public void notifyDataSetChanged() {
			mDataSetObservable.notifyChanged();
		}
	}
}