src/com/android/launcher3/AppsContainerRecyclerView.java - LeafOS-Project/android_packages_apps_Launcher3 - Gitiles

 /*
  * 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;

 import android.animation.ObjectAnimator;
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.support.v7.widget.RecyclerView;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewConfiguration;

 import java.util.List;

 /**
  * A RecyclerView with custom fastscroll support.  This is the main container for the all apps
  * icons.
  */
 public class AppsContainerRecyclerView extends RecyclerView
         implements RecyclerView.OnItemTouchListener {

     private static final float FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR = 1.5f;

     private AlphabeticalAppsList mApps;
     private int mNumAppsPerRow;

     private Drawable mScrollbar;
     private Drawable mFastScrollerBg;
     private Rect mVerticalScrollbarBounds = new Rect();
     private boolean mDraggingFastScroller;
     private String mFastScrollSectionName;
     private Paint mFastScrollTextPaint;
     private Rect mFastScrollTextBounds = new Rect();
     private float mFastScrollAlpha;
     private int mDownX;
     private int mDownY;
     private int mLastX;
     private int mLastY;
     private int mScrollbarWidth;
     private int mScrollbarMinHeight;
     private int mScrollbarInset;

     public AppsContainerRecyclerView(Context context) {
         this(context, null);
     }

     public AppsContainerRecyclerView(Context context, AttributeSet attrs) {
         this(context, attrs, 0);
     }

     public AppsContainerRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
         this(context, attrs, defStyleAttr, 0);
     }

     public AppsContainerRecyclerView(Context context, AttributeSet attrs, int defStyleAttr,
             int defStyleRes) {
         super(context, attrs, defStyleAttr);

         Resources res = context.getResources();
         int fastScrollerSize = res.getDimensionPixelSize(R.dimen.apps_view_fast_scroll_popup_size);
         mScrollbar = res.getDrawable(R.drawable.apps_list_scrollbar_thumb);
         mFastScrollerBg = res.getDrawable(R.drawable.apps_list_fastscroll_bg);
         mFastScrollerBg.setBounds(0, 0, fastScrollerSize, fastScrollerSize);
         mFastScrollTextPaint = new Paint();
         mFastScrollTextPaint.setColor(Color.WHITE);
         mFastScrollTextPaint.setAntiAlias(true);
         mFastScrollTextPaint.setTextSize(res.getDimensionPixelSize(
                 R.dimen.apps_view_fast_scroll_text_size));
         mScrollbarWidth = res.getDimensionPixelSize(R.dimen.apps_view_fast_scroll_bar_width);
         mScrollbarMinHeight =
                 res.getDimensionPixelSize(R.dimen.apps_view_fast_scroll_bar_min_height);
         mScrollbarInset =
                 res.getDimensionPixelSize(R.dimen.apps_view_fast_scroll_scrubber_touch_inset);
         setFastScrollerAlpha(getFastScrollerAlpha());
     }

     /**
      * Sets the list of apps in this view, used to determine the fastscroll position.
      */
     public void setApps(AlphabeticalAppsList apps) {
         mApps = apps;
     }

     /**
      * Sets the number of apps per row in this recycler view.
      */
     public void setNumAppsPerRow(int rowSize) {
         mNumAppsPerRow = rowSize;
     }

     /**
      * Sets the fast scroller alpha.
      */
     public void setFastScrollerAlpha(float alpha) {
         mFastScrollAlpha = alpha;
         invalidateFastScroller();
     }

     /**
      * Gets the fast scroller alpha.
      */
     public float getFastScrollerAlpha() {
         return mFastScrollAlpha;
     }

     /**
      * Returns the scroll bar width.
      */
     public int getScrollbarWidth() {
         return mScrollbarWidth;
     }

     @Override
     protected void onFinishInflate() {
         addOnItemTouchListener(this);
     }

     @Override
     protected void dispatchDraw(Canvas canvas) {
         super.dispatchDraw(canvas);
         drawVerticalScrubber(canvas);
         drawFastScrollerPopup(canvas);
     }

     /**
      * We intercept the touch handling only to support fast scrolling when initiated from the
      * scroll bar.  Otherwise, we fall back to the default RecyclerView touch handling.
      */
     @Override
     public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent ev) {
         return handleTouchEvent(ev);
     }

     @Override
     public void onTouchEvent(RecyclerView rv, MotionEvent ev) {
         handleTouchEvent(ev);
     }

     /**
      * Handles the touch event and determines whether to show the fast scroller (or updates it if
      * it is already showing).
      */
     private boolean handleTouchEvent(MotionEvent ev) {
         ViewConfiguration config = ViewConfiguration.get(getContext());

         int action = ev.getAction();
         int x = (int) ev.getX();
         int y = (int) ev.getY();
         switch (action) {
             case MotionEvent.ACTION_DOWN:
                 // Keep track of the down positions
                 mDownX = mLastX = x;
                 mDownY = mLastY = y;
                 stopScroll();
                 break;
             case MotionEvent.ACTION_MOVE:
                 // Check if we are scrolling
                 if (!mDraggingFastScroller && isPointNearScrollbar(mDownX, mDownY) &&
                         Math.abs(y - mDownY) > config.getScaledTouchSlop()) {
                     getParent().requestDisallowInterceptTouchEvent(true);
                     mDraggingFastScroller = true;
                     animateFastScrollerVisibility(true);
                 }
                 if (mDraggingFastScroller) {
                     mLastX = x;
                     mLastY = y;

                     // Scroll to the right position, and update the section name
                     int top = getPaddingTop() + (mFastScrollerBg.getBounds().height() / 2);
                     int bottom = getHeight() - getPaddingBottom() -
                             (mFastScrollerBg.getBounds().height() / 2);
                     float boundedY = (float) Math.max(top, Math.min(bottom, y));
                     mFastScrollSectionName = scrollToPositionAtProgress((boundedY - top) /
                             (bottom - top));
                     invalidateFastScroller();
                 }
                 break;
             case MotionEvent.ACTION_UP:
             case MotionEvent.ACTION_CANCEL:
                 mDraggingFastScroller = false;
                 animateFastScrollerVisibility(false);
                 break;
         }
         return mDraggingFastScroller;

     }

     /**
      * Animates the visibility of the fast scroller popup.
      */
     private void animateFastScrollerVisibility(boolean visible) {
         ObjectAnimator anim = ObjectAnimator.ofFloat(this, "fastScrollerAlpha", visible ? 1f : 0f);
         anim.setDuration(visible ? 200 : 150);
         anim.start();
     }

     /**
      * Returns whether a given point is near the scrollbar.
      */
     private boolean isPointNearScrollbar(int x, int y) {
         // Check if we are scrolling
         updateVerticalScrollbarBounds();
         mVerticalScrollbarBounds.inset(mScrollbarInset, mScrollbarInset);
         return mVerticalScrollbarBounds.contains(x, y);
     }

     /**
      * Draws the fast scroller popup.
      */
     private void drawFastScrollerPopup(Canvas canvas) {
         int x;
         int y;
         boolean isRtl = (getResources().getConfiguration().getLayoutDirection() ==
                 LAYOUT_DIRECTION_RTL);

         if (mFastScrollAlpha > 0f) {
             // Calculate the position for the fast scroller popup
             Rect bgBounds = mFastScrollerBg.getBounds();
             if (isRtl) {
                 x = getPaddingLeft() + getScrollBarSize();
             } else {
                 x = getWidth() - getPaddingRight() - getScrollBarSize() - bgBounds.width();
             }
             y = mLastY - (int) (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * bgBounds.height());
             y = Math.max(getPaddingTop(), Math.min(y, getHeight() - getPaddingBottom() -
                     bgBounds.height()));

             // Draw the fast scroller popup
             int restoreCount = canvas.save(Canvas.MATRIX_SAVE_FLAG);
             canvas.translate(x, y);
             mFastScrollerBg.setAlpha((int) (mFastScrollAlpha * 255));
             mFastScrollerBg.draw(canvas);
             mFastScrollTextPaint.setAlpha((int) (mFastScrollAlpha * 255));
             mFastScrollTextPaint.getTextBounds(mFastScrollSectionName, 0,
                     mFastScrollSectionName.length(), mFastScrollTextBounds);
             canvas.drawText(mFastScrollSectionName,
                     (bgBounds.width() - mFastScrollTextBounds.width()) / 2,
                     bgBounds.height() - (bgBounds.height() - mFastScrollTextBounds.height()) / 2,
                     mFastScrollTextPaint);
             canvas.restoreToCount(restoreCount);
         }
     }

     /**
      * Draws the vertical scrollbar.
      */
     private void drawVerticalScrubber(Canvas canvas) {
         updateVerticalScrollbarBounds();

         // Draw the scroll bar
         int restoreCount = canvas.save(Canvas.MATRIX_SAVE_FLAG);
         canvas.translate(mVerticalScrollbarBounds.left, mVerticalScrollbarBounds.top);
         mScrollbar.setBounds(0, 0, mScrollbarWidth, mVerticalScrollbarBounds.height());
         mScrollbar.draw(canvas);
         canvas.restoreToCount(restoreCount);
     }

     /**
      * Invalidates the fast scroller popup.
      */
     private void invalidateFastScroller() {
         invalidate(getWidth() - getPaddingRight() - getScrollBarSize() -
                 mFastScrollerBg.getIntrinsicWidth(), 0, getWidth(), getHeight());
     }

     /**
      * Maps the progress (from 0..1) to the position that should be visible
      */
     private String scrollToPositionAtProgress(float progress) {
         List<AlphabeticalAppsList.SectionInfo> sections = mApps.getSections();
         // Get the total number of rows
         int rowCount = getNumRows();

         // Find the index of the first app in that row and scroll to that position
         int rowAtProgress = (int) (progress * rowCount);
         int appIndex = 0;
         rowCount = 0;
         for (AlphabeticalAppsList.SectionInfo info : sections) {
             int numRowsInSection = (int) Math.ceil((float) info.numAppsInSection / mNumAppsPerRow);
             if (rowCount + numRowsInSection > rowAtProgress) {
                 appIndex += (rowAtProgress - rowCount) * mNumAppsPerRow;
                 break;
             }
             rowCount += numRowsInSection;
             appIndex += info.numAppsInSection;
         }
         appIndex = Math.max(0, Math.min(mApps.getAppsWithoutSectionBreaks().size() - 1, appIndex));
         AppInfo appInfo = mApps.getAppsWithoutSectionBreaks().get(appIndex);
         int sectionedAppIndex = mApps.getApps().indexOf(appInfo);
         scrollToPosition(sectionedAppIndex);

         // Returns the section name of the row
         return mApps.getSectionNameForApp(appInfo);
     }

     /**
      * Returns the bounds for the scrollbar.
      */
     private void updateVerticalScrollbarBounds() {
         int x;
         int y;
         boolean isRtl = (getResources().getConfiguration().getLayoutDirection() ==
                 LAYOUT_DIRECTION_RTL);

         // Skip early if there are no items
         if (mApps.getApps().isEmpty()) {
             mVerticalScrollbarBounds.setEmpty();
             return;
         }

         // Find the index and height of the first visible row (all rows have the same height)
         int rowIndex = -1;
         int rowTopOffset = -1;
         int rowHeight = -1;
         int rowCount = getNumRows();
         int childCount = getChildCount();
         for (int i = 0; i < childCount; i++) {
             View child = getChildAt(i);
             int position = getChildPosition(child);
             if (position != NO_POSITION) {
                 AppInfo info = mApps.getApps().get(position);
                 if (info != AlphabeticalAppsList.SECTION_BREAK_INFO) {
                     int appIndex = mApps.getAppsWithoutSectionBreaks().indexOf(info);
                     rowIndex = findRowForAppIndex(appIndex);
                     rowTopOffset = getLayoutManager().getDecoratedTop(child);
                     rowHeight = child.getHeight();
                     break;
                 }
             }
         }

         if (rowIndex != -1) {
             int height = getHeight() - getPaddingTop() - getPaddingBottom();
             int totalScrollHeight = rowCount * rowHeight;
             if (totalScrollHeight > height) {
                 int scrollbarHeight = Math.max(mScrollbarMinHeight,
                         (int) (height / ((float) totalScrollHeight / height)));

                 // Calculate the position and size of the scroll bar
                 if (isRtl) {
                     x = getPaddingLeft();
                 } else {
                     x = getWidth() - getPaddingRight() - mScrollbarWidth;
                 }

                 // To calculate the offset, we compute the percentage of the total scrollable height
                 // that the user has already scrolled and then map that to the scroll bar bounds
                 int availableY = totalScrollHeight - height;
                 int availableScrollY = height - scrollbarHeight;
                 y = (rowIndex * rowHeight) - rowTopOffset;
                 y = getPaddingTop() +
                         (int) (((float) (getPaddingTop() + y) / availableY) * availableScrollY);

                 mVerticalScrollbarBounds.set(x, y, x + mScrollbarWidth, y + scrollbarHeight);
                 return;
             }
         }
         mVerticalScrollbarBounds.setEmpty();
     }

     /**
      * Returns the row index for a given position in the list.
      */
     private int findRowForAppIndex(int position) {
         List<AlphabeticalAppsList.SectionInfo> sections = mApps.getSections();
         int appIndex = 0;
         int rowCount = 0;
         for (AlphabeticalAppsList.SectionInfo info : sections) {
             int numRowsInSection = (int) Math.ceil((float) info.numAppsInSection / mNumAppsPerRow);
             if (appIndex + info.numAppsInSection > position) {
                 return rowCount + ((position - appIndex) / mNumAppsPerRow);
             }
             appIndex += info.numAppsInSection;
             rowCount += numRowsInSection;
         }
         return appIndex;
     }

     /**
      * Returns the total number of rows in the list.
      */
     private int getNumRows() {
         List<AlphabeticalAppsList.SectionInfo> sections = mApps.getSections();
         int rowCount = 0;
         for (AlphabeticalAppsList.SectionInfo info : sections) {
             int numRowsInSection = (int) Math.ceil((float) info.numAppsInSection / mNumAppsPerRow);
             rowCount += numRowsInSection;
         }
         return rowCount;
     }
 }
	/*
	* 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;

	import android.animation.ObjectAnimator;
	import android.content.Context;
	import android.content.res.Resources;
	import android.graphics.Canvas;
	import android.graphics.Color;
	import android.graphics.Paint;
	import android.graphics.Rect;
	import android.graphics.drawable.Drawable;
	import android.support.v7.widget.RecyclerView;
	import android.util.AttributeSet;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.ViewConfiguration;

	import java.util.List;

	/**
	* A RecyclerView with custom fastscroll support. This is the main container for the all apps
	* icons.
	*/
	public class AppsContainerRecyclerView extends RecyclerView
	implements RecyclerView.OnItemTouchListener {

	private static final float FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR = 1.5f;

	private AlphabeticalAppsList mApps;
	private int mNumAppsPerRow;

	private Drawable mScrollbar;
	private Drawable mFastScrollerBg;
	private Rect mVerticalScrollbarBounds = new Rect();
	private boolean mDraggingFastScroller;
	private String mFastScrollSectionName;
	private Paint mFastScrollTextPaint;
	private Rect mFastScrollTextBounds = new Rect();
	private float mFastScrollAlpha;
	private int mDownX;
	private int mDownY;
	private int mLastX;
	private int mLastY;
	private int mScrollbarWidth;
	private int mScrollbarMinHeight;
	private int mScrollbarInset;

	public AppsContainerRecyclerView(Context context) {
	this(context, null);
	}

	public AppsContainerRecyclerView(Context context, AttributeSet attrs) {
	this(context, attrs, 0);
	}

	public AppsContainerRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
	this(context, attrs, defStyleAttr, 0);
	}

	public AppsContainerRecyclerView(Context context, AttributeSet attrs, int defStyleAttr,
	int defStyleRes) {
	super(context, attrs, defStyleAttr);

	Resources res = context.getResources();
	int fastScrollerSize = res.getDimensionPixelSize(R.dimen.apps_view_fast_scroll_popup_size);
	mScrollbar = res.getDrawable(R.drawable.apps_list_scrollbar_thumb);
	mFastScrollerBg = res.getDrawable(R.drawable.apps_list_fastscroll_bg);
	mFastScrollerBg.setBounds(0, 0, fastScrollerSize, fastScrollerSize);
	mFastScrollTextPaint = new Paint();
	mFastScrollTextPaint.setColor(Color.WHITE);
	mFastScrollTextPaint.setAntiAlias(true);
	mFastScrollTextPaint.setTextSize(res.getDimensionPixelSize(
	R.dimen.apps_view_fast_scroll_text_size));
	mScrollbarWidth = res.getDimensionPixelSize(R.dimen.apps_view_fast_scroll_bar_width);
	mScrollbarMinHeight =
	res.getDimensionPixelSize(R.dimen.apps_view_fast_scroll_bar_min_height);
	mScrollbarInset =
	res.getDimensionPixelSize(R.dimen.apps_view_fast_scroll_scrubber_touch_inset);
	setFastScrollerAlpha(getFastScrollerAlpha());
	}

	/**
	* Sets the list of apps in this view, used to determine the fastscroll position.
	*/
	public void setApps(AlphabeticalAppsList apps) {
	mApps = apps;
	}

	/**
	* Sets the number of apps per row in this recycler view.
	*/
	public void setNumAppsPerRow(int rowSize) {
	mNumAppsPerRow = rowSize;
	}

	/**
	* Sets the fast scroller alpha.
	*/
	public void setFastScrollerAlpha(float alpha) {
	mFastScrollAlpha = alpha;
	invalidateFastScroller();
	}

	/**
	* Gets the fast scroller alpha.
	*/
	public float getFastScrollerAlpha() {
	return mFastScrollAlpha;
	}

	/**
	* Returns the scroll bar width.
	*/
	public int getScrollbarWidth() {
	return mScrollbarWidth;
	}

	@Override
	protected void onFinishInflate() {
	addOnItemTouchListener(this);
	}

	@Override
	protected void dispatchDraw(Canvas canvas) {
	super.dispatchDraw(canvas);
	drawVerticalScrubber(canvas);
	drawFastScrollerPopup(canvas);
	}

	/**
	* We intercept the touch handling only to support fast scrolling when initiated from the
	* scroll bar. Otherwise, we fall back to the default RecyclerView touch handling.
	*/
	@Override
	public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent ev) {
	return handleTouchEvent(ev);
	}

	@Override
	public void onTouchEvent(RecyclerView rv, MotionEvent ev) {
	handleTouchEvent(ev);
	}

	/**
	* Handles the touch event and determines whether to show the fast scroller (or updates it if
	* it is already showing).
	*/
	private boolean handleTouchEvent(MotionEvent ev) {
	ViewConfiguration config = ViewConfiguration.get(getContext());

	int action = ev.getAction();
	int x = (int) ev.getX();
	int y = (int) ev.getY();
	switch (action) {
	case MotionEvent.ACTION_DOWN:
	// Keep track of the down positions
	mDownX = mLastX = x;
	mDownY = mLastY = y;
	stopScroll();
	break;
	case MotionEvent.ACTION_MOVE:
	// Check if we are scrolling
	if (!mDraggingFastScroller && isPointNearScrollbar(mDownX, mDownY) &&
	Math.abs(y - mDownY) > config.getScaledTouchSlop()) {
	getParent().requestDisallowInterceptTouchEvent(true);
	mDraggingFastScroller = true;
	animateFastScrollerVisibility(true);
	}
	if (mDraggingFastScroller) {
	mLastX = x;
	mLastY = y;

	// Scroll to the right position, and update the section name
	int top = getPaddingTop() + (mFastScrollerBg.getBounds().height() / 2);
	int bottom = getHeight() - getPaddingBottom() -
	(mFastScrollerBg.getBounds().height() / 2);
	float boundedY = (float) Math.max(top, Math.min(bottom, y));
	mFastScrollSectionName = scrollToPositionAtProgress((boundedY - top) /
	(bottom - top));
	invalidateFastScroller();
	}
	break;
	case MotionEvent.ACTION_UP:
	case MotionEvent.ACTION_CANCEL:
	mDraggingFastScroller = false;
	animateFastScrollerVisibility(false);
	break;
	}
	return mDraggingFastScroller;

	}

	/**
	* Animates the visibility of the fast scroller popup.
	*/
	private void animateFastScrollerVisibility(boolean visible) {
	ObjectAnimator anim = ObjectAnimator.ofFloat(this, "fastScrollerAlpha", visible ? 1f : 0f);
	anim.setDuration(visible ? 200 : 150);
	anim.start();
	}

	/**
	* Returns whether a given point is near the scrollbar.
	*/
	private boolean isPointNearScrollbar(int x, int y) {
	// Check if we are scrolling
	updateVerticalScrollbarBounds();
	mVerticalScrollbarBounds.inset(mScrollbarInset, mScrollbarInset);
	return mVerticalScrollbarBounds.contains(x, y);
	}

	/**
	* Draws the fast scroller popup.
	*/
	private void drawFastScrollerPopup(Canvas canvas) {
	int x;
	int y;
	boolean isRtl = (getResources().getConfiguration().getLayoutDirection() ==
	LAYOUT_DIRECTION_RTL);

	if (mFastScrollAlpha > 0f) {
	// Calculate the position for the fast scroller popup
	Rect bgBounds = mFastScrollerBg.getBounds();
	if (isRtl) {
	x = getPaddingLeft() + getScrollBarSize();
	} else {
	x = getWidth() - getPaddingRight() - getScrollBarSize() - bgBounds.width();
	}
	y = mLastY - (int) (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * bgBounds.height());
	y = Math.max(getPaddingTop(), Math.min(y, getHeight() - getPaddingBottom() -
	bgBounds.height()));

	// Draw the fast scroller popup
	int restoreCount = canvas.save(Canvas.MATRIX_SAVE_FLAG);
	canvas.translate(x, y);
	mFastScrollerBg.setAlpha((int) (mFastScrollAlpha * 255));
	mFastScrollerBg.draw(canvas);
	mFastScrollTextPaint.setAlpha((int) (mFastScrollAlpha * 255));
	mFastScrollTextPaint.getTextBounds(mFastScrollSectionName, 0,
	mFastScrollSectionName.length(), mFastScrollTextBounds);
	canvas.drawText(mFastScrollSectionName,
	(bgBounds.width() - mFastScrollTextBounds.width()) / 2,
	bgBounds.height() - (bgBounds.height() - mFastScrollTextBounds.height()) / 2,
	mFastScrollTextPaint);
	canvas.restoreToCount(restoreCount);
	}
	}

	/**
	* Draws the vertical scrollbar.
	*/
	private void drawVerticalScrubber(Canvas canvas) {
	updateVerticalScrollbarBounds();

	// Draw the scroll bar
	int restoreCount = canvas.save(Canvas.MATRIX_SAVE_FLAG);
	canvas.translate(mVerticalScrollbarBounds.left, mVerticalScrollbarBounds.top);
	mScrollbar.setBounds(0, 0, mScrollbarWidth, mVerticalScrollbarBounds.height());
	mScrollbar.draw(canvas);
	canvas.restoreToCount(restoreCount);
	}

	/**
	* Invalidates the fast scroller popup.
	*/
	private void invalidateFastScroller() {
	invalidate(getWidth() - getPaddingRight() - getScrollBarSize() -
	mFastScrollerBg.getIntrinsicWidth(), 0, getWidth(), getHeight());
	}

	/**
	* Maps the progress (from 0..1) to the position that should be visible
	*/
	private String scrollToPositionAtProgress(float progress) {
	List<AlphabeticalAppsList.SectionInfo> sections = mApps.getSections();
	// Get the total number of rows
	int rowCount = getNumRows();

	// Find the index of the first app in that row and scroll to that position
	int rowAtProgress = (int) (progress * rowCount);
	int appIndex = 0;
	rowCount = 0;
	for (AlphabeticalAppsList.SectionInfo info : sections) {
	int numRowsInSection = (int) Math.ceil((float) info.numAppsInSection / mNumAppsPerRow);
	if (rowCount + numRowsInSection > rowAtProgress) {
	appIndex += (rowAtProgress - rowCount) * mNumAppsPerRow;
	break;
	}
	rowCount += numRowsInSection;
	appIndex += info.numAppsInSection;
	}
	appIndex = Math.max(0, Math.min(mApps.getAppsWithoutSectionBreaks().size() - 1, appIndex));
	AppInfo appInfo = mApps.getAppsWithoutSectionBreaks().get(appIndex);
	int sectionedAppIndex = mApps.getApps().indexOf(appInfo);
	scrollToPosition(sectionedAppIndex);

	// Returns the section name of the row
	return mApps.getSectionNameForApp(appInfo);
	}

	/**
	* Returns the bounds for the scrollbar.
	*/
	private void updateVerticalScrollbarBounds() {
	int x;
	int y;
	boolean isRtl = (getResources().getConfiguration().getLayoutDirection() ==
	LAYOUT_DIRECTION_RTL);

	// Skip early if there are no items
	if (mApps.getApps().isEmpty()) {
	mVerticalScrollbarBounds.setEmpty();
	return;
	}

	// Find the index and height of the first visible row (all rows have the same height)
	int rowIndex = -1;
	int rowTopOffset = -1;
	int rowHeight = -1;
	int rowCount = getNumRows();
	int childCount = getChildCount();
	for (int i = 0; i < childCount; i++) {
	View child = getChildAt(i);
	int position = getChildPosition(child);
	if (position != NO_POSITION) {
	AppInfo info = mApps.getApps().get(position);
	if (info != AlphabeticalAppsList.SECTION_BREAK_INFO) {
	int appIndex = mApps.getAppsWithoutSectionBreaks().indexOf(info);
	rowIndex = findRowForAppIndex(appIndex);
	rowTopOffset = getLayoutManager().getDecoratedTop(child);
	rowHeight = child.getHeight();
	break;
	}
	}
	}

	if (rowIndex != -1) {
	int height = getHeight() - getPaddingTop() - getPaddingBottom();
	int totalScrollHeight = rowCount * rowHeight;
	if (totalScrollHeight > height) {
	int scrollbarHeight = Math.max(mScrollbarMinHeight,
	(int) (height / ((float) totalScrollHeight / height)));

	// Calculate the position and size of the scroll bar
	if (isRtl) {
	x = getPaddingLeft();
	} else {
	x = getWidth() - getPaddingRight() - mScrollbarWidth;
	}

	// To calculate the offset, we compute the percentage of the total scrollable height
	// that the user has already scrolled and then map that to the scroll bar bounds
	int availableY = totalScrollHeight - height;
	int availableScrollY = height - scrollbarHeight;
	y = (rowIndex * rowHeight) - rowTopOffset;
	y = getPaddingTop() +
	(int) (((float) (getPaddingTop() + y) / availableY) * availableScrollY);

	mVerticalScrollbarBounds.set(x, y, x + mScrollbarWidth, y + scrollbarHeight);
	return;
	}
	}
	mVerticalScrollbarBounds.setEmpty();
	}

	/**
	* Returns the row index for a given position in the list.
	*/
	private int findRowForAppIndex(int position) {
	List<AlphabeticalAppsList.SectionInfo> sections = mApps.getSections();
	int appIndex = 0;
	int rowCount = 0;
	for (AlphabeticalAppsList.SectionInfo info : sections) {
	int numRowsInSection = (int) Math.ceil((float) info.numAppsInSection / mNumAppsPerRow);
	if (appIndex + info.numAppsInSection > position) {
	return rowCount + ((position - appIndex) / mNumAppsPerRow);
	}
	appIndex += info.numAppsInSection;
	rowCount += numRowsInSection;
	}
	return appIndex;
	}

	/**
	* Returns the total number of rows in the list.
	*/
	private int getNumRows() {
	List<AlphabeticalAppsList.SectionInfo> sections = mApps.getSections();
	int rowCount = 0;
	for (AlphabeticalAppsList.SectionInfo info : sections) {
	int numRowsInSection = (int) Math.ceil((float) info.numAppsInSection / mNumAppsPerRow);
	rowCount += numRowsInSection;
	}
	return rowCount;
	}
	}