src/com/android/launcher3/allapps/AllAppsGridAdapter.java - platform/packages/apps/Launcher3 - Git at Google

 /*
  * Copyright (C) 2015 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 com.android.launcher3.allapps;

 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.PointF;
 import android.graphics.Rect;
 import android.os.Handler;
 import android.support.v7.widget.GridLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewConfiguration;
 import android.view.ViewGroup;
 import android.widget.TextView;
 import com.android.launcher3.AppInfo;
 import com.android.launcher3.BubbleTextView;
 import com.android.launcher3.R;
 import com.android.launcher3.Utilities;
 import com.android.launcher3.util.Thunk;

 import java.util.HashMap;
 import java.util.List;


 /**
  * The grid view adapter of all the apps.
  */
 class AllAppsGridAdapter extends RecyclerView.Adapter<AllAppsGridAdapter.ViewHolder> {

     public static final String TAG = "AppsGridAdapter";
     private static final boolean DEBUG = false;

     // A section break in the grid
     public static final int SECTION_BREAK_VIEW_TYPE = 0;
     // A normal icon
     public static final int ICON_VIEW_TYPE = 1;
     // A prediction icon
     public static final int PREDICTION_ICON_VIEW_TYPE = 2;
     // The message shown when there are no filtered results
     public static final int EMPTY_SEARCH_VIEW_TYPE = 3;

     /**
      * ViewHolder for each icon.
      */
     public static class ViewHolder extends RecyclerView.ViewHolder {
         public View mContent;

         public ViewHolder(View v) {
             super(v);
             mContent = v;
         }
     }

     /**
      * Helper class to size the grid items.
      */
     public class GridSpanSizer extends GridLayoutManager.SpanSizeLookup {

         public GridSpanSizer() {
             super();
             setSpanIndexCacheEnabled(true);
         }

         @Override
         public int getSpanSize(int position) {
             if (mApps.hasNoFilteredResults()) {
                 // Empty view spans full width
                 return mAppsPerRow;
             }

             switch (mApps.getAdapterItems().get(position).viewType) {
                 case AllAppsGridAdapter.ICON_VIEW_TYPE:
                 case AllAppsGridAdapter.PREDICTION_ICON_VIEW_TYPE:
                     return 1;
                 default:
                     // Section breaks span the full width
                     return mAppsPerRow;
             }
         }
     }

     /**
      * Helper class to draw the section headers
      */
     public class GridItemDecoration extends RecyclerView.ItemDecoration {

         private static final boolean DEBUG_SECTION_MARGIN = false;
         private static final boolean FADE_OUT_SECTIONS = false;

         private HashMap<String, PointF> mCachedSectionBounds = new HashMap<>();
         private Rect mTmpBounds = new Rect();

         @Override
         public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
             if (mApps.hasFilter() || mAppsPerRow == 0) {
                 return;
             }

             if (DEBUG_SECTION_MARGIN) {
                 Paint p = new Paint();
                 p.setColor(0x33ff0000);
                 c.drawRect(mBackgroundPadding.left, 0, mBackgroundPadding.left + mSectionNamesMargin,
                         parent.getMeasuredHeight(), p);
             }

             List<AlphabeticalAppsList.AdapterItem> items = mApps.getAdapterItems();
             boolean hasDrawnPredictedAppsDivider = false;
             boolean showSectionNames = mSectionNamesMargin > 0;
             int childCount = parent.getChildCount();
             int lastSectionTop = 0;
             int lastSectionHeight = 0;
             for (int i = 0; i < childCount; i++) {
                 View child = parent.getChildAt(i);
                 ViewHolder holder = (ViewHolder) parent.getChildViewHolder(child);
                 if (!isValidHolderAndChild(holder, child, items)) {
                     continue;
                 }

                 if (shouldDrawItemDivider(holder, items) && !hasDrawnPredictedAppsDivider) {
                     // Draw the divider under the predicted apps
                     int top = child.getTop() + child.getHeight() + mPredictionBarDividerOffset;
                     c.drawLine(mBackgroundPadding.left, top,
                             parent.getWidth() - mBackgroundPadding.right, top,
                             mPredictedAppsDividerPaint);
                     hasDrawnPredictedAppsDivider = true;

                 } else if (showSectionNames && shouldDrawItemSection(holder, i, items)) {
                     // At this point, we only draw sections for each section break;
                     int viewTopOffset = (2 * child.getPaddingTop());
                     int pos = holder.getPosition();
                     AlphabeticalAppsList.AdapterItem item = items.get(pos);
                     AlphabeticalAppsList.SectionInfo sectionInfo = item.sectionInfo;

                     // Draw all the sections for this index
                     String lastSectionName = item.sectionName;
                     for (int j = item.sectionAppIndex; j < sectionInfo.numApps; j++, pos++) {
                         AlphabeticalAppsList.AdapterItem nextItem = items.get(pos);
                         String sectionName = nextItem.sectionName;
                         if (nextItem.sectionInfo != sectionInfo) {
                             break;
                         }
                         if (j > item.sectionAppIndex && sectionName.equals(lastSectionName)) {
                             continue;
                         }


                         // Find the section name bounds
                         PointF sectionBounds = getAndCacheSectionBounds(sectionName);

                         // Calculate where to draw the section
                         int sectionBaseline = (int) (viewTopOffset + sectionBounds.y);
                         int x = mIsRtl ?
                                 parent.getWidth() - mBackgroundPadding.left - mSectionNamesMargin :
                                         mBackgroundPadding.left;
                         x += (int) ((mSectionNamesMargin - sectionBounds.x) / 2f);
                         int y = child.getTop() + sectionBaseline;

                         // Determine whether this is the last row with apps in that section, if
                         // so, then fix the section to the row allowing it to scroll past the
                         // baseline, otherwise, bound it to the baseline so it's in the viewport
                         int appIndexInSection = items.get(pos).sectionAppIndex;
                         int nextRowPos = Math.min(items.size() - 1,
                                 pos + mAppsPerRow - (appIndexInSection % mAppsPerRow));
                         AlphabeticalAppsList.AdapterItem nextRowItem = items.get(nextRowPos);
                         boolean fixedToRow = !sectionName.equals(nextRowItem.sectionName);
                         if (!fixedToRow) {
                             y = Math.max(sectionBaseline, y);
                         }

                         // In addition, if it overlaps with the last section that was drawn, then
                         // offset it so that it does not overlap
                         if (lastSectionHeight > 0 && y <= (lastSectionTop + lastSectionHeight)) {
                             y += lastSectionTop - y + lastSectionHeight;
                         }

                         // Draw the section header
                         if (FADE_OUT_SECTIONS) {
                             int alpha = 255;
                             if (fixedToRow) {
                                 alpha = Math.min(255,
                                         (int) (255 * (Math.max(0, y) / (float) sectionBaseline)));
                             }
                             mSectionTextPaint.setAlpha(alpha);
                         }
                         c.drawText(sectionName, x, y, mSectionTextPaint);

                         lastSectionTop = y;
                         lastSectionHeight = (int) (sectionBounds.y + mSectionHeaderOffset);
                         lastSectionName = sectionName;
                     }
                     i += (sectionInfo.numApps - item.sectionAppIndex);
                 }
             }
         }

         @Override
         public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
                 RecyclerView.State state) {
             // Do nothing
         }

         /**
          * Given a section name, return the bounds of the given section name.
          */
         private PointF getAndCacheSectionBounds(String sectionName) {
             PointF bounds = mCachedSectionBounds.get(sectionName);
             if (bounds == null) {
                 mSectionTextPaint.getTextBounds(sectionName, 0, sectionName.length(), mTmpBounds);
                 bounds = new PointF(mSectionTextPaint.measureText(sectionName), mTmpBounds.height());
                 mCachedSectionBounds.put(sectionName, bounds);
             }
             return bounds;
         }

         /**
          * Returns whether we consider this a valid view holder for us to draw a divider or section for.
          */
         private boolean isValidHolderAndChild(ViewHolder holder, View child,
                 List<AlphabeticalAppsList.AdapterItem> items) {
             // Ensure item is not already removed
             GridLayoutManager.LayoutParams lp = (GridLayoutManager.LayoutParams)
                     child.getLayoutParams();
             if (lp.isItemRemoved()) {
                 return false;
             }
             // Ensure we have a valid holder
             if (holder == null) {
                 return false;
             }
             // Ensure we have a holder position
             int pos = holder.getPosition();
             if (pos < 0 || pos >= items.size()) {
                 return false;
             }
             return true;
         }

         /**
          * Returns whether to draw the divider for a given child.
          */
         private boolean shouldDrawItemDivider(ViewHolder holder,
                 List<AlphabeticalAppsList.AdapterItem> items) {
             int pos = holder.getPosition();
             return items.get(pos).viewType == AllAppsGridAdapter.PREDICTION_ICON_VIEW_TYPE;
         }

         /**
          * Returns whether to draw the section for the given child.
          */
         private boolean shouldDrawItemSection(ViewHolder holder, int childIndex,
                 List<AlphabeticalAppsList.AdapterItem> items) {
             int pos = holder.getPosition();
             AlphabeticalAppsList.AdapterItem item = items.get(pos);

             // Ensure it's an icon
             if (item.viewType != AllAppsGridAdapter.ICON_VIEW_TYPE) {
                 return false;
             }
             // Draw the section header for the first item in each section
             return (childIndex == 0) ||
                     (items.get(pos - 1).viewType == AllAppsGridAdapter.SECTION_BREAK_VIEW_TYPE);
         }
     }

     private LayoutInflater mLayoutInflater;
     @Thunk AlphabeticalAppsList mApps;
     private GridLayoutManager mGridLayoutMgr;
     private GridSpanSizer mGridSizer;
     private GridItemDecoration mItemDecoration;
     private View.OnTouchListener mTouchListener;
     private View.OnClickListener mIconClickListener;
     private View.OnLongClickListener mIconLongClickListener;
     @Thunk final Rect mBackgroundPadding = new Rect();
     @Thunk int mPredictionBarDividerOffset;
     @Thunk int mAppsPerRow;
     @Thunk boolean mIsRtl;
     private String mEmptySearchText;

     // Section drawing
     @Thunk int mSectionNamesMargin;
     @Thunk int mSectionHeaderOffset;
     @Thunk Paint mSectionTextPaint;
     @Thunk Paint mPredictedAppsDividerPaint;

     public AllAppsGridAdapter(Context context, AlphabeticalAppsList apps,
             View.OnTouchListener touchListener, View.OnClickListener iconClickListener,
             View.OnLongClickListener iconLongClickListener) {
         Resources res = context.getResources();
         mApps = apps;
         mGridSizer = new GridSpanSizer();
         mGridLayoutMgr = new GridLayoutManager(context, 1, GridLayoutManager.VERTICAL, false);
         mGridLayoutMgr.setSpanSizeLookup(mGridSizer);
         mItemDecoration = new GridItemDecoration();
         mLayoutInflater = LayoutInflater.from(context);
         mTouchListener = touchListener;
         mIconClickListener = iconClickListener;
         mIconLongClickListener = iconLongClickListener;
         mSectionNamesMargin = res.getDimensionPixelSize(R.dimen.all_apps_grid_view_start_margin);
         mSectionHeaderOffset = res.getDimensionPixelSize(R.dimen.all_apps_grid_section_y_offset);

         mSectionTextPaint = new Paint();
         mSectionTextPaint.setTextSize(res.getDimensionPixelSize(
                 R.dimen.all_apps_grid_section_text_size));
         mSectionTextPaint.setColor(res.getColor(R.color.all_apps_grid_section_text_color));
         mSectionTextPaint.setAntiAlias(true);

         mPredictedAppsDividerPaint = new Paint();
         mPredictedAppsDividerPaint.setStrokeWidth(Utilities.pxFromDp(1f, res.getDisplayMetrics()));
         mPredictedAppsDividerPaint.setColor(0x1E000000);
         mPredictedAppsDividerPaint.setAntiAlias(true);
         mPredictionBarDividerOffset =
                 (-res.getDimensionPixelSize(R.dimen.all_apps_prediction_icon_bottom_padding) +
                         res.getDimensionPixelSize(R.dimen.all_apps_icon_top_bottom_padding)) / 2;
     }

     /**
      * Sets the number of apps per row.
      */
     public void setNumAppsPerRow(int appsPerRow) {
         mAppsPerRow = appsPerRow;
         mGridLayoutMgr.setSpanCount(appsPerRow);
     }

     /**
      * Sets whether we are in RTL mode.
      */
     public void setRtl(boolean rtl) {
         mIsRtl = rtl;
     }

     /**
      * Sets the text to show when there are no apps.
      */
     public void setEmptySearchText(String query) {
         mEmptySearchText = query;
     }

     /**
      * Notifies the adapter of the background padding so that it can draw things correctly in the
      * item decorator.
      */
     public void updateBackgroundPadding(Rect padding) {
         mBackgroundPadding.set(padding);
     }

     /**
      * Returns the grid layout manager.
      */
     public GridLayoutManager getLayoutManager() {
         return mGridLayoutMgr;
     }

     /**
      * Returns the item decoration for the recycler view.
      */
     public RecyclerView.ItemDecoration getItemDecoration() {
         // We don't draw any headers when we are uncomfortably dense
         return mItemDecoration;
     }

     @Override
     public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
         switch (viewType) {
             case EMPTY_SEARCH_VIEW_TYPE:
                 return new ViewHolder(mLayoutInflater.inflate(R.layout.all_apps_empty_search, parent,
                         false));
             case SECTION_BREAK_VIEW_TYPE:
                 return new ViewHolder(new View(parent.getContext()));
             case ICON_VIEW_TYPE: {
                 BubbleTextView icon = (BubbleTextView) mLayoutInflater.inflate(
                         R.layout.all_apps_icon, parent, false);
                 icon.setOnTouchListener(mTouchListener);
                 icon.setOnClickListener(mIconClickListener);
                 icon.setOnLongClickListener(mIconLongClickListener);
                 icon.setLongPressTimeout(ViewConfiguration.get(parent.getContext())
                         .getLongPressTimeout());
                 icon.setFocusable(true);
                 return new ViewHolder(icon);
             }
             case PREDICTION_ICON_VIEW_TYPE: {
                 BubbleTextView icon = (BubbleTextView) mLayoutInflater.inflate(
                         R.layout.all_apps_prediction_bar_icon, parent, false);
                 icon.setOnTouchListener(mTouchListener);
                 icon.setOnClickListener(mIconClickListener);
                 icon.setOnLongClickListener(mIconLongClickListener);
                 icon.setLongPressTimeout(ViewConfiguration.get(parent.getContext())
                         .getLongPressTimeout());
                 icon.setFocusable(true);
                 return new ViewHolder(icon);
             }
             default:
                 throw new RuntimeException("Unexpected view type");
         }
     }

     @Override
     public void onBindViewHolder(ViewHolder holder, int position) {
         switch (holder.getItemViewType()) {
             case ICON_VIEW_TYPE: {
                 AppInfo info = mApps.getAdapterItems().get(position).appInfo;
                 BubbleTextView icon = (BubbleTextView) holder.mContent;
                 icon.applyFromApplicationInfo(info);
                 break;
             }
             case PREDICTION_ICON_VIEW_TYPE: {
                 AppInfo info = mApps.getAdapterItems().get(position).appInfo;
                 BubbleTextView icon = (BubbleTextView) holder.mContent;
                 icon.applyFromApplicationInfo(info);
                 break;
             }
             case EMPTY_SEARCH_VIEW_TYPE:
                 TextView emptyViewText = (TextView) holder.mContent.findViewById(R.id.empty_text);
                 emptyViewText.setText(mEmptySearchText);
                 break;
         }
     }

     @Override
     public int getItemCount() {
         if (mApps.hasNoFilteredResults()) {
             // For the empty view
             return 1;
         }
         return mApps.getAdapterItems().size();
     }

     @Override
     public int getItemViewType(int position) {
         if (mApps.hasNoFilteredResults()) {
             return EMPTY_SEARCH_VIEW_TYPE;
         }

         AlphabeticalAppsList.AdapterItem item = mApps.getAdapterItems().get(position);
         return item.viewType;
     }
 }
	/*
	* Copyright (C) 2015 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 com.android.launcher3.allapps;

	import android.content.Context;
	import android.content.res.Resources;
	import android.graphics.Canvas;
	import android.graphics.Paint;
	import android.graphics.PointF;
	import android.graphics.Rect;
	import android.os.Handler;
	import android.support.v7.widget.GridLayoutManager;
	import android.support.v7.widget.RecyclerView;
	import android.view.LayoutInflater;
	import android.view.View;
	import android.view.ViewConfiguration;
	import android.view.ViewGroup;
	import android.widget.TextView;
	import com.android.launcher3.AppInfo;
	import com.android.launcher3.BubbleTextView;
	import com.android.launcher3.R;
	import com.android.launcher3.Utilities;
	import com.android.launcher3.util.Thunk;

	import java.util.HashMap;
	import java.util.List;


	/**
	* The grid view adapter of all the apps.
	*/
	class AllAppsGridAdapter extends RecyclerView.Adapter<AllAppsGridAdapter.ViewHolder> {

	public static final String TAG = "AppsGridAdapter";
	private static final boolean DEBUG = false;

	// A section break in the grid
	public static final int SECTION_BREAK_VIEW_TYPE = 0;
	// A normal icon
	public static final int ICON_VIEW_TYPE = 1;
	// A prediction icon
	public static final int PREDICTION_ICON_VIEW_TYPE = 2;
	// The message shown when there are no filtered results
	public static final int EMPTY_SEARCH_VIEW_TYPE = 3;

	/**
	* ViewHolder for each icon.
	*/
	public static class ViewHolder extends RecyclerView.ViewHolder {
	public View mContent;

	public ViewHolder(View v) {
	super(v);
	mContent = v;
	}
	}

	/**
	* Helper class to size the grid items.
	*/
	public class GridSpanSizer extends GridLayoutManager.SpanSizeLookup {

	public GridSpanSizer() {
	super();
	setSpanIndexCacheEnabled(true);
	}

	@Override
	public int getSpanSize(int position) {
	if (mApps.hasNoFilteredResults()) {
	// Empty view spans full width
	return mAppsPerRow;
	}

	switch (mApps.getAdapterItems().get(position).viewType) {
	case AllAppsGridAdapter.ICON_VIEW_TYPE:
	case AllAppsGridAdapter.PREDICTION_ICON_VIEW_TYPE:
	return 1;
	default:
	// Section breaks span the full width
	return mAppsPerRow;
	}
	}
	}

	/**
	* Helper class to draw the section headers
	*/
	public class GridItemDecoration extends RecyclerView.ItemDecoration {

	private static final boolean DEBUG_SECTION_MARGIN = false;
	private static final boolean FADE_OUT_SECTIONS = false;

	private HashMap<String, PointF> mCachedSectionBounds = new HashMap<>();
	private Rect mTmpBounds = new Rect();

	@Override
	public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
	if (mApps.hasFilter() \|\| mAppsPerRow == 0) {
	return;
	}

	if (DEBUG_SECTION_MARGIN) {
	Paint p = new Paint();
	p.setColor(0x33ff0000);
	c.drawRect(mBackgroundPadding.left, 0, mBackgroundPadding.left + mSectionNamesMargin,
	parent.getMeasuredHeight(), p);
	}

	List<AlphabeticalAppsList.AdapterItem> items = mApps.getAdapterItems();
	boolean hasDrawnPredictedAppsDivider = false;
	boolean showSectionNames = mSectionNamesMargin > 0;
	int childCount = parent.getChildCount();
	int lastSectionTop = 0;
	int lastSectionHeight = 0;
	for (int i = 0; i < childCount; i++) {
	View child = parent.getChildAt(i);
	ViewHolder holder = (ViewHolder) parent.getChildViewHolder(child);
	if (!isValidHolderAndChild(holder, child, items)) {
	continue;
	}

	if (shouldDrawItemDivider(holder, items) && !hasDrawnPredictedAppsDivider) {
	// Draw the divider under the predicted apps
	int top = child.getTop() + child.getHeight() + mPredictionBarDividerOffset;
	c.drawLine(mBackgroundPadding.left, top,
	parent.getWidth() - mBackgroundPadding.right, top,
	mPredictedAppsDividerPaint);
	hasDrawnPredictedAppsDivider = true;

	} else if (showSectionNames && shouldDrawItemSection(holder, i, items)) {
	// At this point, we only draw sections for each section break;
	int viewTopOffset = (2 * child.getPaddingTop());
	int pos = holder.getPosition();
	AlphabeticalAppsList.AdapterItem item = items.get(pos);
	AlphabeticalAppsList.SectionInfo sectionInfo = item.sectionInfo;

	// Draw all the sections for this index
	String lastSectionName = item.sectionName;
	for (int j = item.sectionAppIndex; j < sectionInfo.numApps; j++, pos++) {
	AlphabeticalAppsList.AdapterItem nextItem = items.get(pos);
	String sectionName = nextItem.sectionName;
	if (nextItem.sectionInfo != sectionInfo) {
	break;
	}
	if (j > item.sectionAppIndex && sectionName.equals(lastSectionName)) {
	continue;
	}


	// Find the section name bounds
	PointF sectionBounds = getAndCacheSectionBounds(sectionName);

	// Calculate where to draw the section
	int sectionBaseline = (int) (viewTopOffset + sectionBounds.y);
	int x = mIsRtl ?
	parent.getWidth() - mBackgroundPadding.left - mSectionNamesMargin :
	mBackgroundPadding.left;
	x += (int) ((mSectionNamesMargin - sectionBounds.x) / 2f);
	int y = child.getTop() + sectionBaseline;

	// Determine whether this is the last row with apps in that section, if
	// so, then fix the section to the row allowing it to scroll past the
	// baseline, otherwise, bound it to the baseline so it's in the viewport
	int appIndexInSection = items.get(pos).sectionAppIndex;
	int nextRowPos = Math.min(items.size() - 1,
	pos + mAppsPerRow - (appIndexInSection % mAppsPerRow));
	AlphabeticalAppsList.AdapterItem nextRowItem = items.get(nextRowPos);
	boolean fixedToRow = !sectionName.equals(nextRowItem.sectionName);
	if (!fixedToRow) {
	y = Math.max(sectionBaseline, y);
	}

	// In addition, if it overlaps with the last section that was drawn, then
	// offset it so that it does not overlap
	if (lastSectionHeight > 0 && y <= (lastSectionTop + lastSectionHeight)) {
	y += lastSectionTop - y + lastSectionHeight;
	}

	// Draw the section header
	if (FADE_OUT_SECTIONS) {
	int alpha = 255;
	if (fixedToRow) {
	alpha = Math.min(255,
	(int) (255 * (Math.max(0, y) / (float) sectionBaseline)));
	}
	mSectionTextPaint.setAlpha(alpha);
	}
	c.drawText(sectionName, x, y, mSectionTextPaint);

	lastSectionTop = y;
	lastSectionHeight = (int) (sectionBounds.y + mSectionHeaderOffset);
	lastSectionName = sectionName;
	}
	i += (sectionInfo.numApps - item.sectionAppIndex);
	}
	}
	}

	@Override
	public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
	RecyclerView.State state) {
	// Do nothing
	}

	/**
	* Given a section name, return the bounds of the given section name.
	*/
	private PointF getAndCacheSectionBounds(String sectionName) {
	PointF bounds = mCachedSectionBounds.get(sectionName);
	if (bounds == null) {
	mSectionTextPaint.getTextBounds(sectionName, 0, sectionName.length(), mTmpBounds);
	bounds = new PointF(mSectionTextPaint.measureText(sectionName), mTmpBounds.height());
	mCachedSectionBounds.put(sectionName, bounds);
	}
	return bounds;
	}

	/**
	* Returns whether we consider this a valid view holder for us to draw a divider or section for.
	*/
	private boolean isValidHolderAndChild(ViewHolder holder, View child,
	List<AlphabeticalAppsList.AdapterItem> items) {
	// Ensure item is not already removed
	GridLayoutManager.LayoutParams lp = (GridLayoutManager.LayoutParams)
	child.getLayoutParams();
	if (lp.isItemRemoved()) {
	return false;
	}
	// Ensure we have a valid holder
	if (holder == null) {
	return false;
	}
	// Ensure we have a holder position
	int pos = holder.getPosition();
	if (pos < 0 \|\| pos >= items.size()) {
	return false;
	}
	return true;
	}

	/**
	* Returns whether to draw the divider for a given child.
	*/
	private boolean shouldDrawItemDivider(ViewHolder holder,
	List<AlphabeticalAppsList.AdapterItem> items) {
	int pos = holder.getPosition();
	return items.get(pos).viewType == AllAppsGridAdapter.PREDICTION_ICON_VIEW_TYPE;
	}

	/**
	* Returns whether to draw the section for the given child.
	*/
	private boolean shouldDrawItemSection(ViewHolder holder, int childIndex,
	List<AlphabeticalAppsList.AdapterItem> items) {
	int pos = holder.getPosition();
	AlphabeticalAppsList.AdapterItem item = items.get(pos);

	// Ensure it's an icon
	if (item.viewType != AllAppsGridAdapter.ICON_VIEW_TYPE) {
	return false;
	}
	// Draw the section header for the first item in each section
	return (childIndex == 0) \|\|
	(items.get(pos - 1).viewType == AllAppsGridAdapter.SECTION_BREAK_VIEW_TYPE);
	}
	}

	private LayoutInflater mLayoutInflater;
	@Thunk AlphabeticalAppsList mApps;
	private GridLayoutManager mGridLayoutMgr;
	private GridSpanSizer mGridSizer;
	private GridItemDecoration mItemDecoration;
	private View.OnTouchListener mTouchListener;
	private View.OnClickListener mIconClickListener;
	private View.OnLongClickListener mIconLongClickListener;
	@Thunk final Rect mBackgroundPadding = new Rect();
	@Thunk int mPredictionBarDividerOffset;
	@Thunk int mAppsPerRow;
	@Thunk boolean mIsRtl;
	private String mEmptySearchText;

	// Section drawing
	@Thunk int mSectionNamesMargin;
	@Thunk int mSectionHeaderOffset;
	@Thunk Paint mSectionTextPaint;
	@Thunk Paint mPredictedAppsDividerPaint;

	public AllAppsGridAdapter(Context context, AlphabeticalAppsList apps,
	View.OnTouchListener touchListener, View.OnClickListener iconClickListener,
	View.OnLongClickListener iconLongClickListener) {
	Resources res = context.getResources();
	mApps = apps;
	mGridSizer = new GridSpanSizer();
	mGridLayoutMgr = new GridLayoutManager(context, 1, GridLayoutManager.VERTICAL, false);
	mGridLayoutMgr.setSpanSizeLookup(mGridSizer);
	mItemDecoration = new GridItemDecoration();
	mLayoutInflater = LayoutInflater.from(context);
	mTouchListener = touchListener;
	mIconClickListener = iconClickListener;
	mIconLongClickListener = iconLongClickListener;
	mSectionNamesMargin = res.getDimensionPixelSize(R.dimen.all_apps_grid_view_start_margin);
	mSectionHeaderOffset = res.getDimensionPixelSize(R.dimen.all_apps_grid_section_y_offset);

	mSectionTextPaint = new Paint();
	mSectionTextPaint.setTextSize(res.getDimensionPixelSize(
	R.dimen.all_apps_grid_section_text_size));
	mSectionTextPaint.setColor(res.getColor(R.color.all_apps_grid_section_text_color));
	mSectionTextPaint.setAntiAlias(true);

	mPredictedAppsDividerPaint = new Paint();
	mPredictedAppsDividerPaint.setStrokeWidth(Utilities.pxFromDp(1f, res.getDisplayMetrics()));
	mPredictedAppsDividerPaint.setColor(0x1E000000);
	mPredictedAppsDividerPaint.setAntiAlias(true);
	mPredictionBarDividerOffset =
	(-res.getDimensionPixelSize(R.dimen.all_apps_prediction_icon_bottom_padding) +
	res.getDimensionPixelSize(R.dimen.all_apps_icon_top_bottom_padding)) / 2;
	}

	/**
	* Sets the number of apps per row.
	*/
	public void setNumAppsPerRow(int appsPerRow) {
	mAppsPerRow = appsPerRow;
	mGridLayoutMgr.setSpanCount(appsPerRow);
	}

	/**
	* Sets whether we are in RTL mode.
	*/
	public void setRtl(boolean rtl) {
	mIsRtl = rtl;
	}

	/**
	* Sets the text to show when there are no apps.
	*/
	public void setEmptySearchText(String query) {
	mEmptySearchText = query;
	}

	/**
	* Notifies the adapter of the background padding so that it can draw things correctly in the
	* item decorator.
	*/
	public void updateBackgroundPadding(Rect padding) {
	mBackgroundPadding.set(padding);
	}

	/**
	* Returns the grid layout manager.
	*/
	public GridLayoutManager getLayoutManager() {
	return mGridLayoutMgr;
	}

	/**
	* Returns the item decoration for the recycler view.
	*/
	public RecyclerView.ItemDecoration getItemDecoration() {
	// We don't draw any headers when we are uncomfortably dense
	return mItemDecoration;
	}

	@Override
	public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
	switch (viewType) {
	case EMPTY_SEARCH_VIEW_TYPE:
	return new ViewHolder(mLayoutInflater.inflate(R.layout.all_apps_empty_search, parent,
	false));
	case SECTION_BREAK_VIEW_TYPE:
	return new ViewHolder(new View(parent.getContext()));
	case ICON_VIEW_TYPE: {
	BubbleTextView icon = (BubbleTextView) mLayoutInflater.inflate(
	R.layout.all_apps_icon, parent, false);
	icon.setOnTouchListener(mTouchListener);
	icon.setOnClickListener(mIconClickListener);
	icon.setOnLongClickListener(mIconLongClickListener);
	icon.setLongPressTimeout(ViewConfiguration.get(parent.getContext())
	.getLongPressTimeout());
	icon.setFocusable(true);
	return new ViewHolder(icon);
	}
	case PREDICTION_ICON_VIEW_TYPE: {
	BubbleTextView icon = (BubbleTextView) mLayoutInflater.inflate(
	R.layout.all_apps_prediction_bar_icon, parent, false);
	icon.setOnTouchListener(mTouchListener);
	icon.setOnClickListener(mIconClickListener);
	icon.setOnLongClickListener(mIconLongClickListener);
	icon.setLongPressTimeout(ViewConfiguration.get(parent.getContext())
	.getLongPressTimeout());
	icon.setFocusable(true);
	return new ViewHolder(icon);
	}
	default:
	throw new RuntimeException("Unexpected view type");
	}
	}

	@Override
	public void onBindViewHolder(ViewHolder holder, int position) {
	switch (holder.getItemViewType()) {
	case ICON_VIEW_TYPE: {
	AppInfo info = mApps.getAdapterItems().get(position).appInfo;
	BubbleTextView icon = (BubbleTextView) holder.mContent;
	icon.applyFromApplicationInfo(info);
	break;
	}
	case PREDICTION_ICON_VIEW_TYPE: {
	AppInfo info = mApps.getAdapterItems().get(position).appInfo;
	BubbleTextView icon = (BubbleTextView) holder.mContent;
	icon.applyFromApplicationInfo(info);
	break;
	}
	case EMPTY_SEARCH_VIEW_TYPE:
	TextView emptyViewText = (TextView) holder.mContent.findViewById(R.id.empty_text);
	emptyViewText.setText(mEmptySearchText);
	break;
	}
	}

	@Override
	public int getItemCount() {
	if (mApps.hasNoFilteredResults()) {
	// For the empty view
	return 1;
	}
	return mApps.getAdapterItems().size();
	}

	@Override
	public int getItemViewType(int position) {
	if (mApps.hasNoFilteredResults()) {
	return EMPTY_SEARCH_VIEW_TYPE;
	}

	AlphabeticalAppsList.AdapterItem item = mApps.getAdapterItems().get(position);
	return item.viewType;
	}
	}