v17/leanback/src/android/support/v17/leanback/widget/ListRowPresenter.java - platform/frameworks/support.git - Git at Google

 /*
  * Copyright (C) 2014 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.support.v17.leanback.widget;

 import android.content.Context;
 import android.content.res.TypedArray;
 import android.support.v17.leanback.R;
 import android.support.v17.leanback.graphics.ColorOverlayDimmer;
 import android.util.Log;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewGroup.LayoutParams;

 import java.util.HashMap;

 /**
  * ListRowPresenter renders {@link ListRow} using a
  * {@link HorizontalGridView} hosted in a {@link ListRowView}.
  *
  * <h3>Hover card</h3>
  * Optionally, {@link #setHoverCardPresenterSelector(PresenterSelector)} can be used to
  * display a view for the currently focused list item below the rendered
  * list. This view is known as a hover card.
  *
  * <h3>Selection animation</h3>
  * ListRowPresenter disables {@link RowPresenter}'s default dimming effect and draw
  * a dim overlay on top of each individual child items.  Subclass may override and disable
  * {@link #isUsingDefaultListSelectEffect()} and write its own dim effect in
  * {@link #onSelectLevelChanged(RowPresenter.ViewHolder)}.
  *
  * <h3>Shadow</h3>
  * ListRowPresenter applies a default shadow to child of each view.  Call
  * {@link #setShadowEnabled(boolean)} to disable shadow.  Subclass may override and return
  * false in {@link #isUsingDefaultShadow()} and replace with its own shadow implementation.
  */
 public class ListRowPresenter extends RowPresenter {

     private static final String TAG = "ListRowPresenter";
     private static final boolean DEBUG = false;

     private static final int DEFAULT_RECYCLED_POOL_SIZE = 24;

     public static class ViewHolder extends RowPresenter.ViewHolder {
         final ListRowPresenter mListRowPresenter;
         final HorizontalGridView mGridView;
         ItemBridgeAdapter mItemBridgeAdapter;
         final HorizontalHoverCardSwitcher mHoverCardViewSwitcher = new HorizontalHoverCardSwitcher();
         final int mPaddingTop;
         final int mPaddingBottom;
         final int mPaddingLeft;
         final int mPaddingRight;

         public ViewHolder(View rootView, HorizontalGridView gridView, ListRowPresenter p) {
             super(rootView);
             mGridView = gridView;
             mListRowPresenter = p;
             mPaddingTop = mGridView.getPaddingTop();
             mPaddingBottom = mGridView.getPaddingBottom();
             mPaddingLeft = mGridView.getPaddingLeft();
             mPaddingRight = mGridView.getPaddingRight();
         }

         public final ListRowPresenter getListRowPresenter() {
             return mListRowPresenter;
         }

         public final HorizontalGridView getGridView() {
             return mGridView;
         }

         public final ItemBridgeAdapter getBridgeAdapter() {
             return mItemBridgeAdapter;
         }
     }

     class ListRowPresenterItemBridgeAdapter extends ItemBridgeAdapter {
         ListRowPresenter.ViewHolder mRowViewHolder;

         ListRowPresenterItemBridgeAdapter(ListRowPresenter.ViewHolder rowViewHolder) {
             mRowViewHolder = rowViewHolder;
         }

         @Override
         public void onBind(final ItemBridgeAdapter.ViewHolder viewHolder) {
             // Only when having an OnItemClickListner, we will attach the OnClickListener.
             if (getOnItemClickedListener() != null || getOnItemViewClickedListener() != null) {
                 viewHolder.mHolder.view.setOnClickListener(new View.OnClickListener() {
                     @Override
                     public void onClick(View v) {
                         ItemBridgeAdapter.ViewHolder ibh = (ItemBridgeAdapter.ViewHolder)
                                 mRowViewHolder.mGridView.getChildViewHolder(viewHolder.itemView);
                         if (getOnItemClickedListener() != null) {
                             getOnItemClickedListener().onItemClicked(ibh.mItem,
                                     (ListRow) mRowViewHolder.mRow);
                         }
                         if (getOnItemViewClickedListener() != null) {
                             getOnItemViewClickedListener().onItemClicked(viewHolder.mHolder,
                                     ibh.mItem, mRowViewHolder, (ListRow) mRowViewHolder.mRow);
                         }
                     }
                 });
             }
         }

         @Override
         public void onUnbind(ItemBridgeAdapter.ViewHolder viewHolder) {
             if (getOnItemClickedListener() != null || getOnItemViewClickedListener() != null) {
                 viewHolder.mHolder.view.setOnClickListener(null);
             }
         }

         @Override
         public void onAttachedToWindow(ItemBridgeAdapter.ViewHolder viewHolder) {
             if (viewHolder.itemView instanceof ShadowOverlayContainer) {
                 int dimmedColor = mRowViewHolder.mColorDimmer.getPaint().getColor();
                 ((ShadowOverlayContainer) viewHolder.itemView).setOverlayColor(dimmedColor);
             }
             mRowViewHolder.syncActivatedStatus(viewHolder.itemView);
         }

         @Override
         public void onAddPresenter(Presenter presenter, int type) {
             mRowViewHolder.getGridView().getRecycledViewPool().setMaxRecycledViews(
                     type, getRecycledPoolSize(presenter));
         }
     }

     private int mRowHeight;
     private int mExpandedRowHeight;
     private PresenterSelector mHoverCardPresenterSelector;
     private int mZoomFactor;
     private boolean mShadowEnabled = true;
     private int mBrowseRowsFadingEdgeLength = -1;
     private boolean mRoundedCornersEnabled = true;
     private HashMap<Presenter, Integer> mRecycledPoolSize = new HashMap<Presenter, Integer>();

     private static int sSelectedRowTopPadding;
     private static int sExpandedSelectedRowTopPadding;
     private static int sExpandedRowNoHovercardBottomPadding;

     /**
      * Constructs a ListRowPresenter with defaults.
      * Uses {@link FocusHighlight#ZOOM_FACTOR_MEDIUM} for focus zooming.
      */
     public ListRowPresenter() {
         this(FocusHighlight.ZOOM_FACTOR_MEDIUM);
     }

     /**
      * Constructs a ListRowPresenter with the given parameters.
      *
      * @param zoomFactor Controls the zoom factor used when an item view is focused. One of
      *         {@link FocusHighlight#ZOOM_FACTOR_NONE},
      *         {@link FocusHighlight#ZOOM_FACTOR_SMALL},
      *         {@link FocusHighlight#ZOOM_FACTOR_XSMALL},
      *         {@link FocusHighlight#ZOOM_FACTOR_MEDIUM},
      *         {@link FocusHighlight#ZOOM_FACTOR_LARGE}
      */
     public ListRowPresenter(int zoomFactor) {
         if (!FocusHighlightHelper.isValidZoomIndex(zoomFactor)) {
             throw new IllegalArgumentException("Unhandled zoom factor");
         }
         mZoomFactor = zoomFactor;
     }

     /**
      * Sets the row height for rows created by this Presenter. Rows
      * created before calling this method will not be updated.
      *
      * @param rowHeight Row height in pixels, or WRAP_CONTENT, or 0
      * to use the default height.
      */
     public void setRowHeight(int rowHeight) {
         mRowHeight = rowHeight;
     }

     /**
      * Returns the row height for list rows created by this Presenter.
      */
     public int getRowHeight() {
         return mRowHeight;
     }

     /**
      * Sets the expanded row height for rows created by this Presenter.
      * If not set, expanded rows have the same height as unexpanded
      * rows.
      *
      * @param rowHeight The row height in to use when the row is expanded,
      *        in pixels, or WRAP_CONTENT, or 0 to use the default.
      */
     public void setExpandedRowHeight(int rowHeight) {
         mExpandedRowHeight = rowHeight;
     }

     /**
      * Returns the expanded row height for rows created by this Presenter.
      */
     public int getExpandedRowHeight() {
         return mExpandedRowHeight != 0 ? mExpandedRowHeight : mRowHeight;
     }

     /**
      * Returns the zoom factor used for focus highlighting.
      */
     public final int getZoomFactor() {
         return mZoomFactor;
     }

     private ItemBridgeAdapter.Wrapper mCardWrapper = new ItemBridgeAdapter.Wrapper() {
         @Override
         public View createWrapper(View root) {
             ShadowOverlayContainer wrapper = new ShadowOverlayContainer(root.getContext());
             wrapper.setLayoutParams(
                     new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
             wrapper.initialize(needsDefaultShadow(),
                     needsDefaultListSelectEffect(),
                     areChildRoundedCornersEnabled());
             return wrapper;
         }
         @Override
         public void wrap(View wrapper, View wrapped) {
             ((ShadowOverlayContainer) wrapper).wrap(wrapped);
         }
     };

     @Override
     protected void initializeRowViewHolder(RowPresenter.ViewHolder holder) {
         super.initializeRowViewHolder(holder);
         final ViewHolder rowViewHolder = (ViewHolder) holder;
         rowViewHolder.mItemBridgeAdapter = new ListRowPresenterItemBridgeAdapter(rowViewHolder);
         if (needsDefaultListSelectEffect() || needsDefaultShadow()
                 || areChildRoundedCornersEnabled()) {
             rowViewHolder.mItemBridgeAdapter.setWrapper(mCardWrapper);
         }
         if (needsDefaultListSelectEffect()) {
             ShadowOverlayContainer.prepareParentForShadow(rowViewHolder.mGridView);
         }
         FocusHighlightHelper.setupBrowseItemFocusHighlight(rowViewHolder.mItemBridgeAdapter,
                 mZoomFactor, false);
         rowViewHolder.mGridView.setFocusDrawingOrderEnabled(!isUsingZOrder());
         rowViewHolder.mGridView.setOnChildSelectedListener(
                 new OnChildSelectedListener() {
             @Override
             public void onChildSelected(ViewGroup parent, View view, int position, long id) {
                 selectChildView(rowViewHolder, view);
             }
         });
     }

     final boolean needsDefaultListSelectEffect() {
         return isUsingDefaultListSelectEffect() && getSelectEffectEnabled();
     }

     /**
      * Sets the recycled pool size for the given presenter.
      */
     public void setRecycledPoolSize(Presenter presenter, int size) {
         mRecycledPoolSize.put(presenter, size);
     }

     /**
      * Returns the recycled pool size for the given presenter.
      */
     public int getRecycledPoolSize(Presenter presenter) {
         return mRecycledPoolSize.containsKey(presenter) ? mRecycledPoolSize.get(presenter) :
                 DEFAULT_RECYCLED_POOL_SIZE;
     }

     /**
      * Set {@link PresenterSelector} used for showing a select object in a hover card.
      */
     public final void setHoverCardPresenterSelector(PresenterSelector selector) {
         mHoverCardPresenterSelector = selector;
     }

     /**
      * Get {@link PresenterSelector} used for showing a select object in a hover card.
      */
     public final PresenterSelector getHoverCardPresenterSelector() {
         return mHoverCardPresenterSelector;
     }

     /*
      * Perform operations when a child of horizontal grid view is selected.
      */
     private void selectChildView(ViewHolder rowViewHolder, View view) {
         if (view != null) {
             if (rowViewHolder.mExpanded && rowViewHolder.mSelected) {
                 ItemBridgeAdapter.ViewHolder ibh = (ItemBridgeAdapter.ViewHolder)
                         rowViewHolder.mGridView.getChildViewHolder(view);

                 if (mHoverCardPresenterSelector != null) {
                     rowViewHolder.mHoverCardViewSwitcher.select(rowViewHolder.mGridView, view,
                             ibh.mItem);
                 }
                 if (getOnItemViewSelectedListener() != null) {
                     getOnItemViewSelectedListener().onItemSelected(ibh.mHolder, ibh.mItem,
                             rowViewHolder, rowViewHolder.mRow);
                 }
                 if (getOnItemSelectedListener() != null) {
                     getOnItemSelectedListener().onItemSelected(ibh.mItem, rowViewHolder.mRow);
                 }
             }
         } else {
             if (mHoverCardPresenterSelector != null) {
                 rowViewHolder.mHoverCardViewSwitcher.unselect();
             }
             if (getOnItemViewSelectedListener() != null) {
                 getOnItemViewSelectedListener().onItemSelected(null, null,
                         rowViewHolder, rowViewHolder.mRow);
             }
             if (getOnItemSelectedListener() != null) {
                 getOnItemSelectedListener().onItemSelected(null, rowViewHolder.mRow);
             }
         }
     }

     private static void initStatics(Context context) {
         if (sSelectedRowTopPadding == 0) {
             sSelectedRowTopPadding = context.getResources().getDimensionPixelSize(
                     R.dimen.lb_browse_selected_row_top_padding);
             sExpandedSelectedRowTopPadding = context.getResources().getDimensionPixelSize(
                     R.dimen.lb_browse_expanded_selected_row_top_padding);
             sExpandedRowNoHovercardBottomPadding = context.getResources().getDimensionPixelSize(
                     R.dimen.lb_browse_expanded_row_no_hovercard_bottom_padding);
         }
     }

     private int getSpaceUnderBaseline(ListRowPresenter.ViewHolder vh) {
         RowHeaderPresenter.ViewHolder headerViewHolder = vh.getHeaderViewHolder();
         if (headerViewHolder != null) {
             if (getHeaderPresenter() != null) {
                 return getHeaderPresenter().getSpaceUnderBaseline(headerViewHolder);
             }
             return headerViewHolder.view.getPaddingBottom();
         }
         return 0;
     }

     private void setVerticalPadding(ListRowPresenter.ViewHolder vh) {
         int paddingTop, paddingBottom;
         // Note: sufficient bottom padding needed for card shadows.
         if (vh.isExpanded()) {
             int headerSpaceUnderBaseline = getSpaceUnderBaseline(vh);
             if (DEBUG) Log.v(TAG, "headerSpaceUnderBaseline " + headerSpaceUnderBaseline);
             paddingTop = (vh.isSelected() ? sExpandedSelectedRowTopPadding : vh.mPaddingTop) -
                     headerSpaceUnderBaseline;
             paddingBottom = mHoverCardPresenterSelector == null ?
                     sExpandedRowNoHovercardBottomPadding : vh.mPaddingBottom;
         } else if (vh.isSelected()) {
             paddingTop = sSelectedRowTopPadding - vh.mPaddingBottom;
             paddingBottom = sSelectedRowTopPadding;
         } else {
             paddingTop = 0;
             paddingBottom = vh.mPaddingBottom;
         }
         vh.getGridView().setPadding(vh.mPaddingLeft, paddingTop, vh.mPaddingRight,
                 paddingBottom);
     }

     @Override
     protected RowPresenter.ViewHolder createRowViewHolder(ViewGroup parent) {
         initStatics(parent.getContext());
         ListRowView rowView = new ListRowView(parent.getContext());
         setupFadingEffect(rowView);
         if (mRowHeight != 0) {
             rowView.getGridView().setRowHeight(mRowHeight);
         }
         return new ViewHolder(rowView, rowView.getGridView(), this);
     }

     /**
      * Dispatch item selected event using current selected item in the {@link HorizontalGridView}.
      * The method should only be called from onRowViewSelected().
      */
     @Override
     protected void dispatchItemSelectedListener(RowPresenter.ViewHolder holder, boolean selected) {
         ViewHolder vh = (ViewHolder)holder;
         ItemBridgeAdapter.ViewHolder itemViewHolder = (ItemBridgeAdapter.ViewHolder)
                 vh.mGridView.findViewHolderForPosition(vh.mGridView.getSelectedPosition());
         if (itemViewHolder == null) {
             super.dispatchItemSelectedListener(holder, selected);
             return;
         }

         if (selected) {
             if (getOnItemViewSelectedListener() != null) {
                 getOnItemViewSelectedListener().onItemSelected(
                         itemViewHolder.getViewHolder(), itemViewHolder.mItem, vh, vh.getRow());
             }
             if (getOnItemSelectedListener() != null) {
                 getOnItemSelectedListener().onItemSelected(itemViewHolder.mItem, vh.getRow());
             }
         }
     }

     @Override
     protected void onRowViewSelected(RowPresenter.ViewHolder holder, boolean selected) {
         super.onRowViewSelected(holder, selected);
         ViewHolder vh = (ViewHolder) holder;
         setVerticalPadding(vh);
         updateFooterViewSwitcher(vh);
     }

     /*
      * Show or hide hover card when row selection or expanded state is changed.
      */
     private void updateFooterViewSwitcher(ViewHolder vh) {
         if (vh.mExpanded && vh.mSelected) {
             if (mHoverCardPresenterSelector != null) {
                 vh.mHoverCardViewSwitcher.init((ViewGroup) vh.view,
                         mHoverCardPresenterSelector);
             }
             ItemBridgeAdapter.ViewHolder ibh = (ItemBridgeAdapter.ViewHolder)
                     vh.mGridView.findViewHolderForPosition(
                             vh.mGridView.getSelectedPosition());
             selectChildView(vh, ibh == null ? null : ibh.itemView);
         } else {
             if (mHoverCardPresenterSelector != null) {
                 vh.mHoverCardViewSwitcher.unselect();
             }
         }
     }

     private void setupFadingEffect(ListRowView rowView) {
         // content is completely faded at 1/2 padding of left, fading length is 1/2 of padding.
         HorizontalGridView gridView = rowView.getGridView();
         if (mBrowseRowsFadingEdgeLength < 0) {
             TypedArray ta = gridView.getContext()
                     .obtainStyledAttributes(R.styleable.LeanbackTheme);
             mBrowseRowsFadingEdgeLength = (int) ta.getDimension(
                     R.styleable.LeanbackTheme_browseRowsFadingEdgeLength, 0);
             ta.recycle();
         }
         gridView.setFadingLeftEdgeLength(mBrowseRowsFadingEdgeLength);
     }

     @Override
     protected void onRowViewExpanded(RowPresenter.ViewHolder holder, boolean expanded) {
         super.onRowViewExpanded(holder, expanded);
         ViewHolder vh = (ViewHolder) holder;
         if (getRowHeight() != getExpandedRowHeight()) {
             int newHeight = expanded ? getExpandedRowHeight() : getRowHeight();
             vh.getGridView().setRowHeight(newHeight);
         }
         setVerticalPadding(vh);
         updateFooterViewSwitcher(vh);
     }

     @Override
     protected void onBindRowViewHolder(RowPresenter.ViewHolder holder, Object item) {
         super.onBindRowViewHolder(holder, item);
         ViewHolder vh = (ViewHolder) holder;
         ListRow rowItem = (ListRow) item;
         vh.mItemBridgeAdapter.setAdapter(rowItem.getAdapter());
         vh.mGridView.setAdapter(vh.mItemBridgeAdapter);
     }

     @Override
     protected void onUnbindRowViewHolder(RowPresenter.ViewHolder holder) {
         ViewHolder vh = (ViewHolder) holder;
         vh.mGridView.setAdapter(null);
         vh.mItemBridgeAdapter.clear();
         super.onUnbindRowViewHolder(holder);
     }

     /**
      * ListRowPresenter overrides the default select effect of {@link RowPresenter}
      * and return false.
      */
     @Override
     public final boolean isUsingDefaultSelectEffect() {
         return false;
     }

     /**
      * Returns true so that default select effect is applied to each individual
      * child of {@link HorizontalGridView}.  Subclass may return false to disable
      * the default implementation.
      * @see #onSelectLevelChanged(RowPresenter.ViewHolder)
      */
     public boolean isUsingDefaultListSelectEffect() {
         return true;
     }

     /**
      * Returns true if SDK >= 18, where default shadow
      * is applied to each individual child of {@link HorizontalGridView}.
      * Subclass may return false to disable.
      */
     public boolean isUsingDefaultShadow() {
         return ShadowOverlayContainer.supportsShadow();
     }

     /**
      * Returns true if SDK >= L, where Z shadow is enabled so that Z order is enabled
      * on each child of horizontal list.   If subclass returns false in isUsingDefaultShadow()
      * and does not use Z-shadow on SDK >= L, it should override isUsingZOrder() return false.
      */
     public boolean isUsingZOrder() {
         return ShadowHelper.getInstance().usesZShadow();
     }

     /**
      * Enable or disable child shadow.
      * This is not only for enable/disable default shadow implementation but also subclass must
      * respect this flag.
      */
     public final void setShadowEnabled(boolean enabled) {
         mShadowEnabled = enabled;
     }

     /**
      * Returns true if child shadow is enabled.
      * This is not only for enable/disable default shadow implementation but also subclass must
      * respect this flag.
      */
     public final boolean getShadowEnabled() {
         return mShadowEnabled;
     }

     /**
      * Enables or disabled rounded corners on children of this row.
      * Supported on Android SDK >= L.
      */
     public final void enableChildRoundedCorners(boolean enable) {
         mRoundedCornersEnabled = enable;
     }

     /**
      * Returns true if rounded corners are enabled for children of this row.
      */
     public final boolean areChildRoundedCornersEnabled() {
         return mRoundedCornersEnabled;
     }

     final boolean needsDefaultShadow() {
         return isUsingDefaultShadow() && getShadowEnabled();
     }

     @Override
     public boolean canDrawOutOfBounds() {
         return needsDefaultShadow();
     }

     /**
      * Applies select level to header and draw a default color dim over each child
      * of {@link HorizontalGridView}.
      * <p>
      * Subclass may override this method.  A subclass
      * needs to call super.onSelectLevelChanged() for applying header select level
      * and optionally applying a default select level to each child view of
      * {@link HorizontalGridView} if {@link #isUsingDefaultListSelectEffect()}
      * is true.  Subclass may override {@link #isUsingDefaultListSelectEffect()} to return
      * false and deal with the individual item select level by itself.
      * </p>
      */
     @Override
     protected void onSelectLevelChanged(RowPresenter.ViewHolder holder) {
         super.onSelectLevelChanged(holder);
         if (needsDefaultListSelectEffect()) {
             ViewHolder vh = (ViewHolder) holder;
             int dimmedColor = vh.mColorDimmer.getPaint().getColor();
             for (int i = 0, count = vh.mGridView.getChildCount(); i < count; i++) {
                 ShadowOverlayContainer wrapper = (ShadowOverlayContainer) vh.mGridView.getChildAt(i);
                 wrapper.setOverlayColor(dimmedColor);
             }
             if (vh.mGridView.getFadingLeftEdge()) {
                 vh.mGridView.invalidate();
             }
         }
     }

     @Override
     public void freeze(RowPresenter.ViewHolder holder, boolean freeze) {
         ViewHolder vh = (ViewHolder) holder;
         vh.mGridView.setScrollEnabled(!freeze);
     }

     @Override
     public void setEntranceTransitionState(RowPresenter.ViewHolder holder,
             boolean afterEntrance) {
         super.setEntranceTransitionState(holder, afterEntrance);
         ((ViewHolder) holder).mGridView.setChildrenVisibility(
                 afterEntrance? View.VISIBLE : View.INVISIBLE);
     }
 }
	/*
	* Copyright (C) 2014 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.support.v17.leanback.widget;

	import android.content.Context;
	import android.content.res.TypedArray;
	import android.support.v17.leanback.R;
	import android.support.v17.leanback.graphics.ColorOverlayDimmer;
	import android.util.Log;
	import android.view.View;
	import android.view.ViewGroup;
	import android.view.ViewGroup.LayoutParams;

	import java.util.HashMap;

	/**
	* ListRowPresenter renders {@link ListRow} using a
	* {@link HorizontalGridView} hosted in a {@link ListRowView}.
	*
	* <h3>Hover card</h3>
	* Optionally, {@link #setHoverCardPresenterSelector(PresenterSelector)} can be used to
	* display a view for the currently focused list item below the rendered
	* list. This view is known as a hover card.
	*
	* <h3>Selection animation</h3>
	* ListRowPresenter disables {@link RowPresenter}'s default dimming effect and draw
	* a dim overlay on top of each individual child items. Subclass may override and disable
	* {@link #isUsingDefaultListSelectEffect()} and write its own dim effect in
	* {@link #onSelectLevelChanged(RowPresenter.ViewHolder)}.
	*
	* <h3>Shadow</h3>
	* ListRowPresenter applies a default shadow to child of each view. Call
	* {@link #setShadowEnabled(boolean)} to disable shadow. Subclass may override and return
	* false in {@link #isUsingDefaultShadow()} and replace with its own shadow implementation.
	*/
	public class ListRowPresenter extends RowPresenter {

	private static final String TAG = "ListRowPresenter";
	private static final boolean DEBUG = false;

	private static final int DEFAULT_RECYCLED_POOL_SIZE = 24;

	public static class ViewHolder extends RowPresenter.ViewHolder {
	final ListRowPresenter mListRowPresenter;
	final HorizontalGridView mGridView;
	ItemBridgeAdapter mItemBridgeAdapter;
	final HorizontalHoverCardSwitcher mHoverCardViewSwitcher = new HorizontalHoverCardSwitcher();
	final int mPaddingTop;
	final int mPaddingBottom;
	final int mPaddingLeft;
	final int mPaddingRight;

	public ViewHolder(View rootView, HorizontalGridView gridView, ListRowPresenter p) {
	super(rootView);
	mGridView = gridView;
	mListRowPresenter = p;
	mPaddingTop = mGridView.getPaddingTop();
	mPaddingBottom = mGridView.getPaddingBottom();
	mPaddingLeft = mGridView.getPaddingLeft();
	mPaddingRight = mGridView.getPaddingRight();
	}

	public final ListRowPresenter getListRowPresenter() {
	return mListRowPresenter;
	}

	public final HorizontalGridView getGridView() {
	return mGridView;
	}

	public final ItemBridgeAdapter getBridgeAdapter() {
	return mItemBridgeAdapter;
	}
	}

	class ListRowPresenterItemBridgeAdapter extends ItemBridgeAdapter {
	ListRowPresenter.ViewHolder mRowViewHolder;

	ListRowPresenterItemBridgeAdapter(ListRowPresenter.ViewHolder rowViewHolder) {
	mRowViewHolder = rowViewHolder;
	}

	@Override
	public void onBind(final ItemBridgeAdapter.ViewHolder viewHolder) {
	// Only when having an OnItemClickListner, we will attach the OnClickListener.
	if (getOnItemClickedListener() != null \|\| getOnItemViewClickedListener() != null) {
	viewHolder.mHolder.view.setOnClickListener(new View.OnClickListener() {
	@Override
	public void onClick(View v) {
	ItemBridgeAdapter.ViewHolder ibh = (ItemBridgeAdapter.ViewHolder)
	mRowViewHolder.mGridView.getChildViewHolder(viewHolder.itemView);
	if (getOnItemClickedListener() != null) {
	getOnItemClickedListener().onItemClicked(ibh.mItem,
	(ListRow) mRowViewHolder.mRow);
	}
	if (getOnItemViewClickedListener() != null) {
	getOnItemViewClickedListener().onItemClicked(viewHolder.mHolder,
	ibh.mItem, mRowViewHolder, (ListRow) mRowViewHolder.mRow);
	}
	}
	});
	}
	}

	@Override
	public void onUnbind(ItemBridgeAdapter.ViewHolder viewHolder) {
	if (getOnItemClickedListener() != null \|\| getOnItemViewClickedListener() != null) {
	viewHolder.mHolder.view.setOnClickListener(null);
	}
	}

	@Override
	public void onAttachedToWindow(ItemBridgeAdapter.ViewHolder viewHolder) {
	if (viewHolder.itemView instanceof ShadowOverlayContainer) {
	int dimmedColor = mRowViewHolder.mColorDimmer.getPaint().getColor();
	((ShadowOverlayContainer) viewHolder.itemView).setOverlayColor(dimmedColor);
	}
	mRowViewHolder.syncActivatedStatus(viewHolder.itemView);
	}

	@Override
	public void onAddPresenter(Presenter presenter, int type) {
	mRowViewHolder.getGridView().getRecycledViewPool().setMaxRecycledViews(
	type, getRecycledPoolSize(presenter));
	}
	}

	private int mRowHeight;
	private int mExpandedRowHeight;
	private PresenterSelector mHoverCardPresenterSelector;
	private int mZoomFactor;
	private boolean mShadowEnabled = true;
	private int mBrowseRowsFadingEdgeLength = -1;
	private boolean mRoundedCornersEnabled = true;
	private HashMap<Presenter, Integer> mRecycledPoolSize = new HashMap<Presenter, Integer>();

	private static int sSelectedRowTopPadding;
	private static int sExpandedSelectedRowTopPadding;
	private static int sExpandedRowNoHovercardBottomPadding;

	/**
	* Constructs a ListRowPresenter with defaults.
	* Uses {@link FocusHighlight#ZOOM_FACTOR_MEDIUM} for focus zooming.
	*/
	public ListRowPresenter() {
	this(FocusHighlight.ZOOM_FACTOR_MEDIUM);
	}

	/**
	* Constructs a ListRowPresenter with the given parameters.
	*
	* @param zoomFactor Controls the zoom factor used when an item view is focused. One of
	* {@link FocusHighlight#ZOOM_FACTOR_NONE},
	* {@link FocusHighlight#ZOOM_FACTOR_SMALL},
	* {@link FocusHighlight#ZOOM_FACTOR_XSMALL},
	* {@link FocusHighlight#ZOOM_FACTOR_MEDIUM},
	* {@link FocusHighlight#ZOOM_FACTOR_LARGE}
	*/
	public ListRowPresenter(int zoomFactor) {
	if (!FocusHighlightHelper.isValidZoomIndex(zoomFactor)) {
	throw new IllegalArgumentException("Unhandled zoom factor");
	}
	mZoomFactor = zoomFactor;
	}

	/**
	* Sets the row height for rows created by this Presenter. Rows
	* created before calling this method will not be updated.
	*
	* @param rowHeight Row height in pixels, or WRAP_CONTENT, or 0
	* to use the default height.
	*/
	public void setRowHeight(int rowHeight) {
	mRowHeight = rowHeight;
	}

	/**
	* Returns the row height for list rows created by this Presenter.
	*/
	public int getRowHeight() {
	return mRowHeight;
	}

	/**
	* Sets the expanded row height for rows created by this Presenter.
	* If not set, expanded rows have the same height as unexpanded
	* rows.
	*
	* @param rowHeight The row height in to use when the row is expanded,
	* in pixels, or WRAP_CONTENT, or 0 to use the default.
	*/
	public void setExpandedRowHeight(int rowHeight) {
	mExpandedRowHeight = rowHeight;
	}

	/**
	* Returns the expanded row height for rows created by this Presenter.
	*/
	public int getExpandedRowHeight() {
	return mExpandedRowHeight != 0 ? mExpandedRowHeight : mRowHeight;
	}

	/**
	* Returns the zoom factor used for focus highlighting.
	*/
	public final int getZoomFactor() {
	return mZoomFactor;
	}

	private ItemBridgeAdapter.Wrapper mCardWrapper = new ItemBridgeAdapter.Wrapper() {
	@Override
	public View createWrapper(View root) {
	ShadowOverlayContainer wrapper = new ShadowOverlayContainer(root.getContext());
	wrapper.setLayoutParams(
	new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
	wrapper.initialize(needsDefaultShadow(),
	needsDefaultListSelectEffect(),
	areChildRoundedCornersEnabled());
	return wrapper;
	}
	@Override
	public void wrap(View wrapper, View wrapped) {
	((ShadowOverlayContainer) wrapper).wrap(wrapped);
	}
	};

	@Override
	protected void initializeRowViewHolder(RowPresenter.ViewHolder holder) {
	super.initializeRowViewHolder(holder);
	final ViewHolder rowViewHolder = (ViewHolder) holder;
	rowViewHolder.mItemBridgeAdapter = new ListRowPresenterItemBridgeAdapter(rowViewHolder);
	if (needsDefaultListSelectEffect() \|\| needsDefaultShadow()
	\|\| areChildRoundedCornersEnabled()) {
	rowViewHolder.mItemBridgeAdapter.setWrapper(mCardWrapper);
	}
	if (needsDefaultListSelectEffect()) {
	ShadowOverlayContainer.prepareParentForShadow(rowViewHolder.mGridView);
	}
	FocusHighlightHelper.setupBrowseItemFocusHighlight(rowViewHolder.mItemBridgeAdapter,
	mZoomFactor, false);
	rowViewHolder.mGridView.setFocusDrawingOrderEnabled(!isUsingZOrder());
	rowViewHolder.mGridView.setOnChildSelectedListener(
	new OnChildSelectedListener() {
	@Override
	public void onChildSelected(ViewGroup parent, View view, int position, long id) {
	selectChildView(rowViewHolder, view);
	}
	});
	}

	final boolean needsDefaultListSelectEffect() {
	return isUsingDefaultListSelectEffect() && getSelectEffectEnabled();
	}

	/**
	* Sets the recycled pool size for the given presenter.
	*/
	public void setRecycledPoolSize(Presenter presenter, int size) {
	mRecycledPoolSize.put(presenter, size);
	}

	/**
	* Returns the recycled pool size for the given presenter.
	*/
	public int getRecycledPoolSize(Presenter presenter) {
	return mRecycledPoolSize.containsKey(presenter) ? mRecycledPoolSize.get(presenter) :
	DEFAULT_RECYCLED_POOL_SIZE;
	}

	/**
	* Set {@link PresenterSelector} used for showing a select object in a hover card.
	*/
	public final void setHoverCardPresenterSelector(PresenterSelector selector) {
	mHoverCardPresenterSelector = selector;
	}

	/**
	* Get {@link PresenterSelector} used for showing a select object in a hover card.
	*/
	public final PresenterSelector getHoverCardPresenterSelector() {
	return mHoverCardPresenterSelector;
	}

	/*
	* Perform operations when a child of horizontal grid view is selected.
	*/
	private void selectChildView(ViewHolder rowViewHolder, View view) {
	if (view != null) {
	if (rowViewHolder.mExpanded && rowViewHolder.mSelected) {
	ItemBridgeAdapter.ViewHolder ibh = (ItemBridgeAdapter.ViewHolder)
	rowViewHolder.mGridView.getChildViewHolder(view);

	if (mHoverCardPresenterSelector != null) {
	rowViewHolder.mHoverCardViewSwitcher.select(rowViewHolder.mGridView, view,
	ibh.mItem);
	}
	if (getOnItemViewSelectedListener() != null) {
	getOnItemViewSelectedListener().onItemSelected(ibh.mHolder, ibh.mItem,
	rowViewHolder, rowViewHolder.mRow);
	}
	if (getOnItemSelectedListener() != null) {
	getOnItemSelectedListener().onItemSelected(ibh.mItem, rowViewHolder.mRow);
	}
	}
	} else {
	if (mHoverCardPresenterSelector != null) {
	rowViewHolder.mHoverCardViewSwitcher.unselect();
	}
	if (getOnItemViewSelectedListener() != null) {
	getOnItemViewSelectedListener().onItemSelected(null, null,
	rowViewHolder, rowViewHolder.mRow);
	}
	if (getOnItemSelectedListener() != null) {
	getOnItemSelectedListener().onItemSelected(null, rowViewHolder.mRow);
	}
	}
	}

	private static void initStatics(Context context) {
	if (sSelectedRowTopPadding == 0) {
	sSelectedRowTopPadding = context.getResources().getDimensionPixelSize(
	R.dimen.lb_browse_selected_row_top_padding);
	sExpandedSelectedRowTopPadding = context.getResources().getDimensionPixelSize(
	R.dimen.lb_browse_expanded_selected_row_top_padding);
	sExpandedRowNoHovercardBottomPadding = context.getResources().getDimensionPixelSize(
	R.dimen.lb_browse_expanded_row_no_hovercard_bottom_padding);
	}
	}

	private int getSpaceUnderBaseline(ListRowPresenter.ViewHolder vh) {
	RowHeaderPresenter.ViewHolder headerViewHolder = vh.getHeaderViewHolder();
	if (headerViewHolder != null) {
	if (getHeaderPresenter() != null) {
	return getHeaderPresenter().getSpaceUnderBaseline(headerViewHolder);
	}
	return headerViewHolder.view.getPaddingBottom();
	}
	return 0;
	}

	private void setVerticalPadding(ListRowPresenter.ViewHolder vh) {
	int paddingTop, paddingBottom;
	// Note: sufficient bottom padding needed for card shadows.
	if (vh.isExpanded()) {
	int headerSpaceUnderBaseline = getSpaceUnderBaseline(vh);
	if (DEBUG) Log.v(TAG, "headerSpaceUnderBaseline " + headerSpaceUnderBaseline);
	paddingTop = (vh.isSelected() ? sExpandedSelectedRowTopPadding : vh.mPaddingTop) -
	headerSpaceUnderBaseline;
	paddingBottom = mHoverCardPresenterSelector == null ?
	sExpandedRowNoHovercardBottomPadding : vh.mPaddingBottom;
	} else if (vh.isSelected()) {
	paddingTop = sSelectedRowTopPadding - vh.mPaddingBottom;
	paddingBottom = sSelectedRowTopPadding;
	} else {
	paddingTop = 0;
	paddingBottom = vh.mPaddingBottom;
	}
	vh.getGridView().setPadding(vh.mPaddingLeft, paddingTop, vh.mPaddingRight,
	paddingBottom);
	}

	@Override
	protected RowPresenter.ViewHolder createRowViewHolder(ViewGroup parent) {
	initStatics(parent.getContext());
	ListRowView rowView = new ListRowView(parent.getContext());
	setupFadingEffect(rowView);
	if (mRowHeight != 0) {
	rowView.getGridView().setRowHeight(mRowHeight);
	}
	return new ViewHolder(rowView, rowView.getGridView(), this);
	}

	/**
	* Dispatch item selected event using current selected item in the {@link HorizontalGridView}.
	* The method should only be called from onRowViewSelected().
	*/
	@Override
	protected void dispatchItemSelectedListener(RowPresenter.ViewHolder holder, boolean selected) {
	ViewHolder vh = (ViewHolder)holder;
	ItemBridgeAdapter.ViewHolder itemViewHolder = (ItemBridgeAdapter.ViewHolder)
	vh.mGridView.findViewHolderForPosition(vh.mGridView.getSelectedPosition());
	if (itemViewHolder == null) {
	super.dispatchItemSelectedListener(holder, selected);
	return;
	}

	if (selected) {
	if (getOnItemViewSelectedListener() != null) {
	getOnItemViewSelectedListener().onItemSelected(
	itemViewHolder.getViewHolder(), itemViewHolder.mItem, vh, vh.getRow());
	}
	if (getOnItemSelectedListener() != null) {
	getOnItemSelectedListener().onItemSelected(itemViewHolder.mItem, vh.getRow());
	}
	}
	}

	@Override
	protected void onRowViewSelected(RowPresenter.ViewHolder holder, boolean selected) {
	super.onRowViewSelected(holder, selected);
	ViewHolder vh = (ViewHolder) holder;
	setVerticalPadding(vh);
	updateFooterViewSwitcher(vh);
	}

	/*
	* Show or hide hover card when row selection or expanded state is changed.
	*/
	private void updateFooterViewSwitcher(ViewHolder vh) {
	if (vh.mExpanded && vh.mSelected) {
	if (mHoverCardPresenterSelector != null) {
	vh.mHoverCardViewSwitcher.init((ViewGroup) vh.view,
	mHoverCardPresenterSelector);
	}
	ItemBridgeAdapter.ViewHolder ibh = (ItemBridgeAdapter.ViewHolder)
	vh.mGridView.findViewHolderForPosition(
	vh.mGridView.getSelectedPosition());
	selectChildView(vh, ibh == null ? null : ibh.itemView);
	} else {
	if (mHoverCardPresenterSelector != null) {
	vh.mHoverCardViewSwitcher.unselect();
	}
	}
	}

	private void setupFadingEffect(ListRowView rowView) {
	// content is completely faded at 1/2 padding of left, fading length is 1/2 of padding.
	HorizontalGridView gridView = rowView.getGridView();
	if (mBrowseRowsFadingEdgeLength < 0) {
	TypedArray ta = gridView.getContext()
	.obtainStyledAttributes(R.styleable.LeanbackTheme);
	mBrowseRowsFadingEdgeLength = (int) ta.getDimension(
	R.styleable.LeanbackTheme_browseRowsFadingEdgeLength, 0);
	ta.recycle();
	}
	gridView.setFadingLeftEdgeLength(mBrowseRowsFadingEdgeLength);
	}

	@Override
	protected void onRowViewExpanded(RowPresenter.ViewHolder holder, boolean expanded) {
	super.onRowViewExpanded(holder, expanded);
	ViewHolder vh = (ViewHolder) holder;
	if (getRowHeight() != getExpandedRowHeight()) {
	int newHeight = expanded ? getExpandedRowHeight() : getRowHeight();
	vh.getGridView().setRowHeight(newHeight);
	}
	setVerticalPadding(vh);
	updateFooterViewSwitcher(vh);
	}

	@Override
	protected void onBindRowViewHolder(RowPresenter.ViewHolder holder, Object item) {
	super.onBindRowViewHolder(holder, item);
	ViewHolder vh = (ViewHolder) holder;
	ListRow rowItem = (ListRow) item;
	vh.mItemBridgeAdapter.setAdapter(rowItem.getAdapter());
	vh.mGridView.setAdapter(vh.mItemBridgeAdapter);
	}

	@Override
	protected void onUnbindRowViewHolder(RowPresenter.ViewHolder holder) {
	ViewHolder vh = (ViewHolder) holder;
	vh.mGridView.setAdapter(null);
	vh.mItemBridgeAdapter.clear();
	super.onUnbindRowViewHolder(holder);
	}

	/**
	* ListRowPresenter overrides the default select effect of {@link RowPresenter}
	* and return false.
	*/
	@Override
	public final boolean isUsingDefaultSelectEffect() {
	return false;
	}

	/**
	* Returns true so that default select effect is applied to each individual
	* child of {@link HorizontalGridView}. Subclass may return false to disable
	* the default implementation.
	* @see #onSelectLevelChanged(RowPresenter.ViewHolder)
	*/
	public boolean isUsingDefaultListSelectEffect() {
	return true;
	}

	/**
	* Returns true if SDK >= 18, where default shadow
	* is applied to each individual child of {@link HorizontalGridView}.
	* Subclass may return false to disable.
	*/
	public boolean isUsingDefaultShadow() {
	return ShadowOverlayContainer.supportsShadow();
	}

	/**
	* Returns true if SDK >= L, where Z shadow is enabled so that Z order is enabled
	* on each child of horizontal list. If subclass returns false in isUsingDefaultShadow()
	* and does not use Z-shadow on SDK >= L, it should override isUsingZOrder() return false.
	*/
	public boolean isUsingZOrder() {
	return ShadowHelper.getInstance().usesZShadow();
	}

	/**
	* Enable or disable child shadow.
	* This is not only for enable/disable default shadow implementation but also subclass must
	* respect this flag.
	*/
	public final void setShadowEnabled(boolean enabled) {
	mShadowEnabled = enabled;
	}

	/**
	* Returns true if child shadow is enabled.
	* This is not only for enable/disable default shadow implementation but also subclass must
	* respect this flag.
	*/
	public final boolean getShadowEnabled() {
	return mShadowEnabled;
	}

	/**
	* Enables or disabled rounded corners on children of this row.
	* Supported on Android SDK >= L.
	*/
	public final void enableChildRoundedCorners(boolean enable) {
	mRoundedCornersEnabled = enable;
	}

	/**
	* Returns true if rounded corners are enabled for children of this row.
	*/
	public final boolean areChildRoundedCornersEnabled() {
	return mRoundedCornersEnabled;
	}

	final boolean needsDefaultShadow() {
	return isUsingDefaultShadow() && getShadowEnabled();
	}

	@Override
	public boolean canDrawOutOfBounds() {
	return needsDefaultShadow();
	}

	/**
	* Applies select level to header and draw a default color dim over each child
	* of {@link HorizontalGridView}.
	* <p>
	* Subclass may override this method. A subclass
	* needs to call super.onSelectLevelChanged() for applying header select level
	* and optionally applying a default select level to each child view of
	* {@link HorizontalGridView} if {@link #isUsingDefaultListSelectEffect()}
	* is true. Subclass may override {@link #isUsingDefaultListSelectEffect()} to return
	* false and deal with the individual item select level by itself.
	* </p>
	*/
	@Override
	protected void onSelectLevelChanged(RowPresenter.ViewHolder holder) {
	super.onSelectLevelChanged(holder);
	if (needsDefaultListSelectEffect()) {
	ViewHolder vh = (ViewHolder) holder;
	int dimmedColor = vh.mColorDimmer.getPaint().getColor();
	for (int i = 0, count = vh.mGridView.getChildCount(); i < count; i++) {
	ShadowOverlayContainer wrapper = (ShadowOverlayContainer) vh.mGridView.getChildAt(i);
	wrapper.setOverlayColor(dimmedColor);
	}
	if (vh.mGridView.getFadingLeftEdge()) {
	vh.mGridView.invalidate();
	}
	}
	}

	@Override
	public void freeze(RowPresenter.ViewHolder holder, boolean freeze) {
	ViewHolder vh = (ViewHolder) holder;
	vh.mGridView.setScrollEnabled(!freeze);
	}

	@Override
	public void setEntranceTransitionState(RowPresenter.ViewHolder holder,
	boolean afterEntrance) {
	super.setEntranceTransitionState(holder, afterEntrance);
	((ViewHolder) holder).mGridView.setChildrenVisibility(
	afterEntrance? View.VISIBLE : View.INVISIBLE);
	}
	}