src/com/android/launcher2/PagedViewCellLayout.java - platform/packages/apps/Launcher2 - Git at Google

 /*
  * Copyright (C) 2010 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.launcher2;

 import android.content.Context;
 import android.content.res.Resources;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewDebug;
 import android.view.ViewGroup;

 import com.android.launcher.R;

 /**
  * An abstraction of the original CellLayout which supports laying out items
  * which span multiple cells into a grid-like layout.  Also supports dimming
  * to give a preview of its contents.
  */
 public class PagedViewCellLayout extends ViewGroup implements Page {
     static final String TAG = "PagedViewCellLayout";

     private int mCellCountX;
     private int mCellCountY;
     private int mOriginalCellWidth;
     private int mOriginalCellHeight;
     private int mCellWidth;
     private int mCellHeight;
     private int mOriginalWidthGap;
     private int mOriginalHeightGap;
     private int mWidthGap;
     private int mHeightGap;
     private int mMaxGap;
     protected PagedViewCellLayoutChildren mChildren;

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

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

     public PagedViewCellLayout(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);

         setAlwaysDrawnWithCacheEnabled(false);

         // setup default cell parameters
         Resources resources = context.getResources();
         mOriginalCellWidth = mCellWidth =
             resources.getDimensionPixelSize(R.dimen.apps_customize_cell_width);
         mOriginalCellHeight = mCellHeight =
             resources.getDimensionPixelSize(R.dimen.apps_customize_cell_height);
         mCellCountX = LauncherModel.getCellCountX();
         mCellCountY = LauncherModel.getCellCountY();
         mOriginalWidthGap = mOriginalHeightGap = mWidthGap = mHeightGap = -1;
         mMaxGap = resources.getDimensionPixelSize(R.dimen.apps_customize_max_gap);

         mChildren = new PagedViewCellLayoutChildren(context);
         mChildren.setCellDimensions(mCellWidth, mCellHeight);
         mChildren.setGap(mWidthGap, mHeightGap);

         addView(mChildren);
     }

     public int getCellWidth() {
         return mCellWidth;
     }

     public int getCellHeight() {
         return mCellHeight;
     }

     @Override
     public void cancelLongPress() {
         super.cancelLongPress();

         // Cancel long press for all children
         final int count = getChildCount();
         for (int i = 0; i < count; i++) {
             final View child = getChildAt(i);
             child.cancelLongPress();
         }
     }

     public boolean addViewToCellLayout(View child, int index, int childId,
             PagedViewCellLayout.LayoutParams params) {
         final PagedViewCellLayout.LayoutParams lp = params;

         // Generate an id for each view, this assumes we have at most 256x256 cells
         // per workspace screen
         if (lp.cellX >= 0 && lp.cellX <= (mCellCountX - 1) &&
                 lp.cellY >= 0 && (lp.cellY <= mCellCountY - 1)) {
             // If the horizontal or vertical span is set to -1, it is taken to
             // mean that it spans the extent of the CellLayout
             if (lp.cellHSpan < 0) lp.cellHSpan = mCellCountX;
             if (lp.cellVSpan < 0) lp.cellVSpan = mCellCountY;

             child.setId(childId);
             mChildren.addView(child, index, lp);

             return true;
         }
         return false;
     }

     @Override
     public void removeAllViewsOnPage() {
         mChildren.removeAllViews();
         setLayerType(LAYER_TYPE_NONE, null);
     }

     @Override
     public void removeViewOnPageAt(int index) {
         mChildren.removeViewAt(index);
     }

     /**
      * Clears all the key listeners for the individual icons.
      */
     public void resetChildrenOnKeyListeners() {
         int childCount = mChildren.getChildCount();
         for (int j = 0; j < childCount; ++j) {
             mChildren.getChildAt(j).setOnKeyListener(null);
         }
     }

     @Override
     public int getPageChildCount() {
         return mChildren.getChildCount();
     }

     public PagedViewCellLayoutChildren getChildrenLayout() {
         return mChildren;
     }

     @Override
     public View getChildOnPageAt(int i) {
         return mChildren.getChildAt(i);
     }

     @Override
     public int indexOfChildOnPage(View v) {
         return mChildren.indexOfChild(v);
     }

     public int getCellCountX() {
         return mCellCountX;
     }

     public int getCellCountY() {
         return mCellCountY;
     }

     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
         int widthSpecSize = MeasureSpec.getSize(widthMeasureSpec);

         int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);
         int heightSpecSize =  MeasureSpec.getSize(heightMeasureSpec);

         if (widthSpecMode == MeasureSpec.UNSPECIFIED || heightSpecMode == MeasureSpec.UNSPECIFIED) {
             throw new RuntimeException("CellLayout cannot have UNSPECIFIED dimensions");
         }

         int numWidthGaps = mCellCountX - 1;
         int numHeightGaps = mCellCountY - 1;

         if (mOriginalWidthGap < 0 || mOriginalHeightGap < 0) {
             int hSpace = widthSpecSize - getPaddingLeft() - getPaddingRight();
             int vSpace = heightSpecSize - getPaddingTop() - getPaddingBottom();
             int hFreeSpace = hSpace - (mCellCountX * mOriginalCellWidth);
             int vFreeSpace = vSpace - (mCellCountY * mOriginalCellHeight);
             mWidthGap = Math.min(mMaxGap, numWidthGaps > 0 ? (hFreeSpace / numWidthGaps) : 0);
             mHeightGap = Math.min(mMaxGap,numHeightGaps > 0 ? (vFreeSpace / numHeightGaps) : 0);

             mChildren.setGap(mWidthGap, mHeightGap);
         } else {
             mWidthGap = mOriginalWidthGap;
             mHeightGap = mOriginalHeightGap;
         }

         // Initial values correspond to widthSpecMode == MeasureSpec.EXACTLY
         int newWidth = widthSpecSize;
         int newHeight = heightSpecSize;
         if (widthSpecMode == MeasureSpec.AT_MOST) {
             newWidth = getPaddingLeft() + getPaddingRight() + (mCellCountX * mCellWidth) +
                 ((mCellCountX - 1) * mWidthGap);
             newHeight = getPaddingTop() + getPaddingBottom() + (mCellCountY * mCellHeight) +
                 ((mCellCountY - 1) * mHeightGap);
             setMeasuredDimension(newWidth, newHeight);
         }

         final int count = getChildCount();
         for (int i = 0; i < count; i++) {
             View child = getChildAt(i);
             int childWidthMeasureSpec =
                 MeasureSpec.makeMeasureSpec(newWidth - getPaddingLeft() -
                         getPaddingRight(), MeasureSpec.EXACTLY);
             int childheightMeasureSpec =
                 MeasureSpec.makeMeasureSpec(newHeight - getPaddingTop() -
                         getPaddingBottom(), MeasureSpec.EXACTLY);
             child.measure(childWidthMeasureSpec, childheightMeasureSpec);
         }

         setMeasuredDimension(newWidth, newHeight);
     }

     int getContentWidth() {
         return getWidthBeforeFirstLayout() + getPaddingLeft() + getPaddingRight();
     }

     int getContentHeight() {
         if (mCellCountY > 0) {
             return mCellCountY * mCellHeight + (mCellCountY - 1) * Math.max(0, mHeightGap);
         }
         return 0;
     }

     int getWidthBeforeFirstLayout() {
         if (mCellCountX > 0) {
             return mCellCountX * mCellWidth + (mCellCountX - 1) * Math.max(0, mWidthGap);
         }
         return 0;
     }

     @Override
     protected void onLayout(boolean changed, int l, int t, int r, int b) {
         int count = getChildCount();
         for (int i = 0; i < count; i++) {
             View child = getChildAt(i);
             child.layout(getPaddingLeft(), getPaddingTop(),
                 r - l - getPaddingRight(), b - t - getPaddingBottom());
         }
     }

     @Override
     public boolean onTouchEvent(MotionEvent event) {
         boolean result = super.onTouchEvent(event);
         int count = getPageChildCount();
         if (count > 0) {
             // We only intercept the touch if we are tapping in empty space after the final row
             View child = getChildOnPageAt(count - 1);
             int bottom = child.getBottom();
             int numRows = (int) Math.ceil((float) getPageChildCount() / getCellCountX());
             if (numRows < getCellCountY()) {
                 // Add a little bit of buffer if there is room for another row
                 bottom += mCellHeight / 2;
             }
             result = result || (event.getY() < bottom);
         }
         return result;
     }

     public void enableCenteredContent(boolean enabled) {
         mChildren.enableCenteredContent(enabled);
     }

     @Override
     protected void setChildrenDrawingCacheEnabled(boolean enabled) {
         mChildren.setChildrenDrawingCacheEnabled(enabled);
     }

     public void setCellCount(int xCount, int yCount) {
         mCellCountX = xCount;
         mCellCountY = yCount;
         requestLayout();
     }

     public void setGap(int widthGap, int heightGap) {
         mOriginalWidthGap = mWidthGap = widthGap;
         mOriginalHeightGap = mHeightGap = heightGap;
         mChildren.setGap(widthGap, heightGap);
     }

     public int[] getCellCountForDimensions(int width, int height) {
         // Always assume we're working with the smallest span to make sure we
         // reserve enough space in both orientations
         int smallerSize = Math.min(mCellWidth, mCellHeight);

         // Always round up to next largest cell
         int spanX = (width + smallerSize) / smallerSize;
         int spanY = (height + smallerSize) / smallerSize;

         return new int[] { spanX, spanY };
     }

     /**
      * Start dragging the specified child
      *
      * @param child The child that is being dragged
      */
     void onDragChild(View child) {
         PagedViewCellLayout.LayoutParams lp = (PagedViewCellLayout.LayoutParams) child.getLayoutParams();
         lp.isDragging = true;
     }

     /**
      * Estimates the number of cells that the specified width would take up.
      */
     public int estimateCellHSpan(int width) {
         // We don't show the next/previous pages any more, so we use the full width, minus the
         // padding
         int availWidth = width - (getPaddingLeft() + getPaddingRight());

         // We know that we have to fit N cells with N-1 width gaps, so we just juggle to solve for N
         int n = Math.max(1, (availWidth + mWidthGap) / (mCellWidth + mWidthGap));

         // We don't do anything fancy to determine if we squeeze another row in.
         return n;
     }

     /**
      * Estimates the number of cells that the specified height would take up.
      */
     public int estimateCellVSpan(int height) {
         // The space for a page is the height - top padding (current page) - bottom padding (current
         // page)
         int availHeight = height - (getPaddingTop() + getPaddingBottom());

         // We know that we have to fit N cells with N-1 height gaps, so we juggle to solve for N
         int n = Math.max(1, (availHeight + mHeightGap) / (mCellHeight + mHeightGap));

         // We don't do anything fancy to determine if we squeeze another row in.
         return n;
     }

     /** Returns an estimated center position of the cell at the specified index */
     public int[] estimateCellPosition(int x, int y) {
         return new int[] {
                 getPaddingLeft() + (x * mCellWidth) + (x * mWidthGap) + (mCellWidth / 2),
                 getPaddingTop() + (y * mCellHeight) + (y * mHeightGap) + (mCellHeight / 2)
         };
     }

     public void calculateCellCount(int width, int height, int maxCellCountX, int maxCellCountY) {
         mCellCountX = Math.min(maxCellCountX, estimateCellHSpan(width));
         mCellCountY = Math.min(maxCellCountY, estimateCellVSpan(height));
         requestLayout();
     }

     /**
      * Estimates the width that the number of hSpan cells will take up.
      */
     public int estimateCellWidth(int hSpan) {
         // TODO: we need to take widthGap into effect
         return hSpan * mCellWidth;
     }

     /**
      * Estimates the height that the number of vSpan cells will take up.
      */
     public int estimateCellHeight(int vSpan) {
         // TODO: we need to take heightGap into effect
         return vSpan * mCellHeight;
     }

     @Override
     public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
         return new PagedViewCellLayout.LayoutParams(getContext(), attrs);
     }

     @Override
     protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
         return p instanceof PagedViewCellLayout.LayoutParams;
     }

     @Override
     protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
         return new PagedViewCellLayout.LayoutParams(p);
     }

     public static class LayoutParams extends ViewGroup.MarginLayoutParams {
         /**
          * Horizontal location of the item in the grid.
          */
         @ViewDebug.ExportedProperty
         public int cellX;

         /**
          * Vertical location of the item in the grid.
          */
         @ViewDebug.ExportedProperty
         public int cellY;

         /**
          * Number of cells spanned horizontally by the item.
          */
         @ViewDebug.ExportedProperty
         public int cellHSpan;

         /**
          * Number of cells spanned vertically by the item.
          */
         @ViewDebug.ExportedProperty
         public int cellVSpan;

         /**
          * Is this item currently being dragged
          */
         public boolean isDragging;

         // a data object that you can bind to this layout params
         private Object mTag;

         // X coordinate of the view in the layout.
         @ViewDebug.ExportedProperty
         int x;
         // Y coordinate of the view in the layout.
         @ViewDebug.ExportedProperty
         int y;

         public LayoutParams() {
             super(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
             cellHSpan = 1;
             cellVSpan = 1;
         }

         public LayoutParams(Context c, AttributeSet attrs) {
             super(c, attrs);
             cellHSpan = 1;
             cellVSpan = 1;
         }

         public LayoutParams(ViewGroup.LayoutParams source) {
             super(source);
             cellHSpan = 1;
             cellVSpan = 1;
         }

         public LayoutParams(LayoutParams source) {
             super(source);
             this.cellX = source.cellX;
             this.cellY = source.cellY;
             this.cellHSpan = source.cellHSpan;
             this.cellVSpan = source.cellVSpan;
         }

         public LayoutParams(int cellX, int cellY, int cellHSpan, int cellVSpan) {
             super(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
             this.cellX = cellX;
             this.cellY = cellY;
             this.cellHSpan = cellHSpan;
             this.cellVSpan = cellVSpan;
         }

         public void setup(int cellWidth, int cellHeight, int widthGap, int heightGap,
                 int hStartPadding, int vStartPadding) {

             final int myCellHSpan = cellHSpan;
             final int myCellVSpan = cellVSpan;
             final int myCellX = cellX;
             final int myCellY = cellY;

             width = myCellHSpan * cellWidth + ((myCellHSpan - 1) * widthGap) -
                     leftMargin - rightMargin;
             height = myCellVSpan * cellHeight + ((myCellVSpan - 1) * heightGap) -
                     topMargin - bottomMargin;

             if (LauncherApplication.isScreenLarge()) {
                 x = hStartPadding + myCellX * (cellWidth + widthGap) + leftMargin;
                 y = vStartPadding + myCellY * (cellHeight + heightGap) + topMargin;
             } else {
                 x = myCellX * (cellWidth + widthGap) + leftMargin;
                 y = myCellY * (cellHeight + heightGap) + topMargin;
             }
         }

         public Object getTag() {
             return mTag;
         }

         public void setTag(Object tag) {
             mTag = tag;
         }

         public String toString() {
             return "(" + this.cellX + ", " + this.cellY + ", " +
                 this.cellHSpan + ", " + this.cellVSpan + ")";
         }
     }
 }

 interface Page {
     public int getPageChildCount();
     public View getChildOnPageAt(int i);
     public void removeAllViewsOnPage();
     public void removeViewOnPageAt(int i);
     public int indexOfChildOnPage(View v);
 }
	/*
	* Copyright (C) 2010 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.launcher2;

	import android.content.Context;
	import android.content.res.Resources;
	import android.util.AttributeSet;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.ViewDebug;
	import android.view.ViewGroup;

	import com.android.launcher.R;

	/**
	* An abstraction of the original CellLayout which supports laying out items
	* which span multiple cells into a grid-like layout. Also supports dimming
	* to give a preview of its contents.
	*/
	public class PagedViewCellLayout extends ViewGroup implements Page {
	static final String TAG = "PagedViewCellLayout";

	private int mCellCountX;
	private int mCellCountY;
	private int mOriginalCellWidth;
	private int mOriginalCellHeight;
	private int mCellWidth;
	private int mCellHeight;
	private int mOriginalWidthGap;
	private int mOriginalHeightGap;
	private int mWidthGap;
	private int mHeightGap;
	private int mMaxGap;
	protected PagedViewCellLayoutChildren mChildren;

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

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

	public PagedViewCellLayout(Context context, AttributeSet attrs, int defStyle) {
	super(context, attrs, defStyle);

	setAlwaysDrawnWithCacheEnabled(false);

	// setup default cell parameters
	Resources resources = context.getResources();
	mOriginalCellWidth = mCellWidth =
	resources.getDimensionPixelSize(R.dimen.apps_customize_cell_width);
	mOriginalCellHeight = mCellHeight =
	resources.getDimensionPixelSize(R.dimen.apps_customize_cell_height);
	mCellCountX = LauncherModel.getCellCountX();
	mCellCountY = LauncherModel.getCellCountY();
	mOriginalWidthGap = mOriginalHeightGap = mWidthGap = mHeightGap = -1;
	mMaxGap = resources.getDimensionPixelSize(R.dimen.apps_customize_max_gap);

	mChildren = new PagedViewCellLayoutChildren(context);
	mChildren.setCellDimensions(mCellWidth, mCellHeight);
	mChildren.setGap(mWidthGap, mHeightGap);

	addView(mChildren);
	}

	public int getCellWidth() {
	return mCellWidth;
	}

	public int getCellHeight() {
	return mCellHeight;
	}

	@Override
	public void cancelLongPress() {
	super.cancelLongPress();

	// Cancel long press for all children
	final int count = getChildCount();
	for (int i = 0; i < count; i++) {
	final View child = getChildAt(i);
	child.cancelLongPress();
	}
	}

	public boolean addViewToCellLayout(View child, int index, int childId,
	PagedViewCellLayout.LayoutParams params) {
	final PagedViewCellLayout.LayoutParams lp = params;

	// Generate an id for each view, this assumes we have at most 256x256 cells
	// per workspace screen
	if (lp.cellX >= 0 && lp.cellX <= (mCellCountX - 1) &&
	lp.cellY >= 0 && (lp.cellY <= mCellCountY - 1)) {
	// If the horizontal or vertical span is set to -1, it is taken to
	// mean that it spans the extent of the CellLayout
	if (lp.cellHSpan < 0) lp.cellHSpan = mCellCountX;
	if (lp.cellVSpan < 0) lp.cellVSpan = mCellCountY;

	child.setId(childId);
	mChildren.addView(child, index, lp);

	return true;
	}
	return false;
	}

	@Override
	public void removeAllViewsOnPage() {
	mChildren.removeAllViews();
	setLayerType(LAYER_TYPE_NONE, null);
	}

	@Override
	public void removeViewOnPageAt(int index) {
	mChildren.removeViewAt(index);
	}

	/**
	* Clears all the key listeners for the individual icons.
	*/
	public void resetChildrenOnKeyListeners() {
	int childCount = mChildren.getChildCount();
	for (int j = 0; j < childCount; ++j) {
	mChildren.getChildAt(j).setOnKeyListener(null);
	}
	}

	@Override
	public int getPageChildCount() {
	return mChildren.getChildCount();
	}

	public PagedViewCellLayoutChildren getChildrenLayout() {
	return mChildren;
	}

	@Override
	public View getChildOnPageAt(int i) {
	return mChildren.getChildAt(i);
	}

	@Override
	public int indexOfChildOnPage(View v) {
	return mChildren.indexOfChild(v);
	}

	public int getCellCountX() {
	return mCellCountX;
	}

	public int getCellCountY() {
	return mCellCountY;
	}

	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
	int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);
	int widthSpecSize = MeasureSpec.getSize(widthMeasureSpec);

	int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);
	int heightSpecSize = MeasureSpec.getSize(heightMeasureSpec);

	if (widthSpecMode == MeasureSpec.UNSPECIFIED \|\| heightSpecMode == MeasureSpec.UNSPECIFIED) {
	throw new RuntimeException("CellLayout cannot have UNSPECIFIED dimensions");
	}

	int numWidthGaps = mCellCountX - 1;
	int numHeightGaps = mCellCountY - 1;

	if (mOriginalWidthGap < 0 \|\| mOriginalHeightGap < 0) {
	int hSpace = widthSpecSize - getPaddingLeft() - getPaddingRight();
	int vSpace = heightSpecSize - getPaddingTop() - getPaddingBottom();
	int hFreeSpace = hSpace - (mCellCountX * mOriginalCellWidth);
	int vFreeSpace = vSpace - (mCellCountY * mOriginalCellHeight);
	mWidthGap = Math.min(mMaxGap, numWidthGaps > 0 ? (hFreeSpace / numWidthGaps) : 0);
	mHeightGap = Math.min(mMaxGap,numHeightGaps > 0 ? (vFreeSpace / numHeightGaps) : 0);

	mChildren.setGap(mWidthGap, mHeightGap);
	} else {
	mWidthGap = mOriginalWidthGap;
	mHeightGap = mOriginalHeightGap;
	}

	// Initial values correspond to widthSpecMode == MeasureSpec.EXACTLY
	int newWidth = widthSpecSize;
	int newHeight = heightSpecSize;
	if (widthSpecMode == MeasureSpec.AT_MOST) {
	newWidth = getPaddingLeft() + getPaddingRight() + (mCellCountX * mCellWidth) +
	((mCellCountX - 1) * mWidthGap);
	newHeight = getPaddingTop() + getPaddingBottom() + (mCellCountY * mCellHeight) +
	((mCellCountY - 1) * mHeightGap);
	setMeasuredDimension(newWidth, newHeight);
	}

	final int count = getChildCount();
	for (int i = 0; i < count; i++) {
	View child = getChildAt(i);
	int childWidthMeasureSpec =
	MeasureSpec.makeMeasureSpec(newWidth - getPaddingLeft() -
	getPaddingRight(), MeasureSpec.EXACTLY);
	int childheightMeasureSpec =
	MeasureSpec.makeMeasureSpec(newHeight - getPaddingTop() -
	getPaddingBottom(), MeasureSpec.EXACTLY);
	child.measure(childWidthMeasureSpec, childheightMeasureSpec);
	}

	setMeasuredDimension(newWidth, newHeight);
	}

	int getContentWidth() {
	return getWidthBeforeFirstLayout() + getPaddingLeft() + getPaddingRight();
	}

	int getContentHeight() {
	if (mCellCountY > 0) {
	return mCellCountY * mCellHeight + (mCellCountY - 1) * Math.max(0, mHeightGap);
	}
	return 0;
	}

	int getWidthBeforeFirstLayout() {
	if (mCellCountX > 0) {
	return mCellCountX * mCellWidth + (mCellCountX - 1) * Math.max(0, mWidthGap);
	}
	return 0;
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
	int count = getChildCount();
	for (int i = 0; i < count; i++) {
	View child = getChildAt(i);
	child.layout(getPaddingLeft(), getPaddingTop(),
	r - l - getPaddingRight(), b - t - getPaddingBottom());
	}
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
	boolean result = super.onTouchEvent(event);
	int count = getPageChildCount();
	if (count > 0) {
	// We only intercept the touch if we are tapping in empty space after the final row
	View child = getChildOnPageAt(count - 1);
	int bottom = child.getBottom();
	int numRows = (int) Math.ceil((float) getPageChildCount() / getCellCountX());
	if (numRows < getCellCountY()) {
	// Add a little bit of buffer if there is room for another row
	bottom += mCellHeight / 2;
	}
	result = result \|\| (event.getY() < bottom);
	}
	return result;
	}

	public void enableCenteredContent(boolean enabled) {
	mChildren.enableCenteredContent(enabled);
	}

	@Override
	protected void setChildrenDrawingCacheEnabled(boolean enabled) {
	mChildren.setChildrenDrawingCacheEnabled(enabled);
	}

	public void setCellCount(int xCount, int yCount) {
	mCellCountX = xCount;
	mCellCountY = yCount;
	requestLayout();
	}

	public void setGap(int widthGap, int heightGap) {
	mOriginalWidthGap = mWidthGap = widthGap;
	mOriginalHeightGap = mHeightGap = heightGap;
	mChildren.setGap(widthGap, heightGap);
	}

	public int[] getCellCountForDimensions(int width, int height) {
	// Always assume we're working with the smallest span to make sure we
	// reserve enough space in both orientations
	int smallerSize = Math.min(mCellWidth, mCellHeight);

	// Always round up to next largest cell
	int spanX = (width + smallerSize) / smallerSize;
	int spanY = (height + smallerSize) / smallerSize;

	return new int[] { spanX, spanY };
	}

	/**
	* Start dragging the specified child
	*
	* @param child The child that is being dragged
	*/
	void onDragChild(View child) {
	PagedViewCellLayout.LayoutParams lp = (PagedViewCellLayout.LayoutParams) child.getLayoutParams();
	lp.isDragging = true;
	}

	/**
	* Estimates the number of cells that the specified width would take up.
	*/
	public int estimateCellHSpan(int width) {
	// We don't show the next/previous pages any more, so we use the full width, minus the
	// padding
	int availWidth = width - (getPaddingLeft() + getPaddingRight());

	// We know that we have to fit N cells with N-1 width gaps, so we just juggle to solve for N
	int n = Math.max(1, (availWidth + mWidthGap) / (mCellWidth + mWidthGap));

	// We don't do anything fancy to determine if we squeeze another row in.
	return n;
	}

	/**
	* Estimates the number of cells that the specified height would take up.
	*/
	public int estimateCellVSpan(int height) {
	// The space for a page is the height - top padding (current page) - bottom padding (current
	// page)
	int availHeight = height - (getPaddingTop() + getPaddingBottom());

	// We know that we have to fit N cells with N-1 height gaps, so we juggle to solve for N
	int n = Math.max(1, (availHeight + mHeightGap) / (mCellHeight + mHeightGap));

	// We don't do anything fancy to determine if we squeeze another row in.
	return n;
	}

	/** Returns an estimated center position of the cell at the specified index */
	public int[] estimateCellPosition(int x, int y) {
	return new int[] {
	getPaddingLeft() + (x * mCellWidth) + (x * mWidthGap) + (mCellWidth / 2),
	getPaddingTop() + (y * mCellHeight) + (y * mHeightGap) + (mCellHeight / 2)
	};
	}

	public void calculateCellCount(int width, int height, int maxCellCountX, int maxCellCountY) {
	mCellCountX = Math.min(maxCellCountX, estimateCellHSpan(width));
	mCellCountY = Math.min(maxCellCountY, estimateCellVSpan(height));
	requestLayout();
	}

	/**
	* Estimates the width that the number of hSpan cells will take up.
	*/
	public int estimateCellWidth(int hSpan) {
	// TODO: we need to take widthGap into effect
	return hSpan * mCellWidth;
	}

	/**
	* Estimates the height that the number of vSpan cells will take up.
	*/
	public int estimateCellHeight(int vSpan) {
	// TODO: we need to take heightGap into effect
	return vSpan * mCellHeight;
	}

	@Override
	public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
	return new PagedViewCellLayout.LayoutParams(getContext(), attrs);
	}

	@Override
	protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
	return p instanceof PagedViewCellLayout.LayoutParams;
	}

	@Override
	protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
	return new PagedViewCellLayout.LayoutParams(p);
	}

	public static class LayoutParams extends ViewGroup.MarginLayoutParams {
	/**
	* Horizontal location of the item in the grid.
	*/
	@ViewDebug.ExportedProperty
	public int cellX;

	/**
	* Vertical location of the item in the grid.
	*/
	@ViewDebug.ExportedProperty
	public int cellY;

	/**
	* Number of cells spanned horizontally by the item.
	*/
	@ViewDebug.ExportedProperty
	public int cellHSpan;

	/**
	* Number of cells spanned vertically by the item.
	*/
	@ViewDebug.ExportedProperty
	public int cellVSpan;

	/**
	* Is this item currently being dragged
	*/
	public boolean isDragging;

	// a data object that you can bind to this layout params
	private Object mTag;

	// X coordinate of the view in the layout.
	@ViewDebug.ExportedProperty
	int x;
	// Y coordinate of the view in the layout.
	@ViewDebug.ExportedProperty
	int y;

	public LayoutParams() {
	super(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
	cellHSpan = 1;
	cellVSpan = 1;
	}

	public LayoutParams(Context c, AttributeSet attrs) {
	super(c, attrs);
	cellHSpan = 1;
	cellVSpan = 1;
	}

	public LayoutParams(ViewGroup.LayoutParams source) {
	super(source);
	cellHSpan = 1;
	cellVSpan = 1;
	}

	public LayoutParams(LayoutParams source) {
	super(source);
	this.cellX = source.cellX;
	this.cellY = source.cellY;
	this.cellHSpan = source.cellHSpan;
	this.cellVSpan = source.cellVSpan;
	}

	public LayoutParams(int cellX, int cellY, int cellHSpan, int cellVSpan) {
	super(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
	this.cellX = cellX;
	this.cellY = cellY;
	this.cellHSpan = cellHSpan;
	this.cellVSpan = cellVSpan;
	}

	public void setup(int cellWidth, int cellHeight, int widthGap, int heightGap,
	int hStartPadding, int vStartPadding) {

	final int myCellHSpan = cellHSpan;
	final int myCellVSpan = cellVSpan;
	final int myCellX = cellX;
	final int myCellY = cellY;

	width = myCellHSpan * cellWidth + ((myCellHSpan - 1) * widthGap) -
	leftMargin - rightMargin;
	height = myCellVSpan * cellHeight + ((myCellVSpan - 1) * heightGap) -
	topMargin - bottomMargin;

	if (LauncherApplication.isScreenLarge()) {
	x = hStartPadding + myCellX * (cellWidth + widthGap) + leftMargin;
	y = vStartPadding + myCellY * (cellHeight + heightGap) + topMargin;
	} else {
	x = myCellX * (cellWidth + widthGap) + leftMargin;
	y = myCellY * (cellHeight + heightGap) + topMargin;
	}
	}

	public Object getTag() {
	return mTag;
	}

	public void setTag(Object tag) {
	mTag = tag;
	}

	public String toString() {
	return "(" + this.cellX + ", " + this.cellY + ", " +
	this.cellHSpan + ", " + this.cellVSpan + ")";
	}
	}
	}

	interface Page {
	public int getPageChildCount();
	public View getChildOnPageAt(int i);
	public void removeAllViewsOnPage();
	public void removeViewOnPageAt(int i);
	public int indexOfChildOnPage(View v);
	}