Add artist headers to grids as well

3 files changed, 803 insertions, 7 deletions

diff --git a/res/layout/grid_view.xml b/res/layout/grid_view.xml
index 40674c8d..7690d975 100644
--- a/res/layout/grid_view.xml
+++ b/res/layout/grid_view.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>

-<GridView xmlns:android="http://schemas.android.com/apk/res/android"

+<github.daneren2005.dsub.view.HeaderGridView xmlns:android="http://schemas.android.com/apk/res/android"

 	android:id="@+id/gridview"

 	android:layout_width="fill_parent"

 	android:layout_height="0dip"

diff --git a/src/github/daneren2005/dsub/fragments/SelectDirectoryFragment.java b/src/github/daneren2005/dsub/fragments/SelectDirectoryFragment.java
index 9cb8c582..b19caced 100644
--- a/src/github/daneren2005/dsub/fragments/SelectDirectoryFragment.java
+++ b/src/github/daneren2005/dsub/fragments/SelectDirectoryFragment.java
@@ -54,6 +54,8 @@ import github.daneren2005.dsub.util.TabBackgroundTask;
 import github.daneren2005.dsub.util.UserUtil;

 import github.daneren2005.dsub.util.Util;

 import github.daneren2005.dsub.view.AlbumListAdapter;

+import github.daneren2005.dsub.view.HeaderGridView;

+

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.HashSet;

@@ -687,10 +689,13 @@ public class SelectDirectoryFragment extends SubsonicFragment implements Adapter
     private void finishLoading() {

 		// Show header if not album list type and not root and not artist

 		// For Subsonic 5.1+ display a header for artists with getArtistInfo data if it exists

+		View header = null;

 		if(albumListType == null && !"root".equals(id) && (!artist || (ServerInfo.checkServerVersion(context, "1.11") && artistInfo != null))) {

-			View header = createHeader();

-			if(header != null && entryList != null) {

+			header = createHeader();

+			// Only add header to entry list if we aren't going recreate album grid as root anyways

+			if(header != null && entryList != null && (!addAlbumHeader || entries.size() > 0)) {

 				entryList.addHeaderView(header, null, false);

+				header = null;

 			}

 		}

 

@@ -706,6 +711,12 @@ public class SelectDirectoryFragment extends SubsonicFragment implements Adapter
 				

 				setupScrollList(albumList);

 				setupAlbumList();

+

+				// This should only not be null for a artist with only albums

+				if(header != null) {

+					HeaderGridView headerGridView = (HeaderGridView) albumList;

+					headerGridView.addHeaderView(header);

+				}

 			}

 			addAlbumHeader = false;

 		}

@@ -1390,13 +1401,13 @@ public class SelectDirectoryFragment extends SubsonicFragment implements Adapter
 

 		TextView songCountView = (TextView) header.findViewById(R.id.select_album_song_count);

 		TextView songLengthView = (TextView) header.findViewById(R.id.select_album_song_length);

-		if(podcastDescription == null) {

+		if(podcastDescription != null || artistInfo != null) {

+			songCountView.setVisibility(View.GONE);

+			songLengthView.setVisibility(View.GONE);

+		} else {

 			String s = context.getResources().getQuantityString(R.plurals.select_album_n_songs, songCount, songCount);

 			songCountView.setText(s.toUpperCase());

 			songLengthView.setText(Util.formatDuration(totalDuration));

-		} else {

-			songCountView.setVisibility(View.GONE);

-			songLengthView.setVisibility(View.GONE);

 		}

 	}

 	private void setupButtonEvents(View header) {

diff --git a/src/github/daneren2005/dsub/view/HeaderGridView.java b/src/github/daneren2005/dsub/view/HeaderGridView.java
new file mode 100644
index 00000000..cd57dc0e
--- /dev/null
+++ b/src/github/daneren2005/dsub/view/HeaderGridView.java
@@ -0,0 +1,785 @@
+/*
+ * 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 {
+
+	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 = "grid-view-with-header-and-footer";
+
+	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 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())) {
+			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 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();
+		}
+	}
+}