am 4c58c48: Fixes #1844053. Home was accepting all drops, even when ther

Merge commit '4c58c485d8c02f8ca7e8b4d93140440f6a3a5131'

* commit '4c58c485d8c02f8ca7e8b4d93140440f6a3a5131':
  Fixes #1844053. Home was accepting all drops, even when there was no room left for a drop. This change fixes this while retaining the 'snap to vacant cell' ability added in Cupcake.

src/com/android/launcher/CellLayout.java

@@ -939,7 +939,7 @@ out:            for (int i = x; i < x + spanX - 1 && x < xCount; i++) {
         int maxVacantSpanYSpanX;
         final Rect current = new Rect();
 
-        private void clearVacantCells() {
+        void clearVacantCells() {
             final ArrayList<VacantCell> list = vacantCells;
             final int count = list.size();
 
@@ -980,6 +980,10 @@ out:            for (int i = x; i < x + spanX - 1 && x < xCount; i++) {
          * @return True if a vacant cell of the specified dimension was found, false otherwise.
          */
         boolean findCellForSpan(int[] cellXY, int spanX, int spanY) {
+            return findCellForSpan(cellXY, spanX, spanY, true);
+        }
+
+        boolean findCellForSpan(int[] cellXY, int spanX, int spanY, boolean clear) {
             final ArrayList<VacantCell> list = vacantCells;
             final int count = list.size();
 
@@ -1013,7 +1017,7 @@ out:            for (int i = x; i < x + spanX - 1 && x < xCount; i++) {
                 }
             }
 
-            clearVacantCells();
+            if (clear) clearVacantCells();
 
             return found;
         }

src/com/android/launcher/Workspace.java

@@ -272,6 +272,7 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
      * @param currentScreen
      */
     void setCurrentScreen(int currentScreen) {
+        clearVacantCache();
         mCurrentScreen = Math.max(0, Math.min(currentScreen, getChildCount() - 1));
         scrollTo(mCurrentScreen * getWidth(), 0);
         invalidate();
@@ -345,6 +346,8 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
             throw new IllegalStateException("The screen must be >= 0 and < " + getChildCount());
         }
 
+        clearVacantCache();
+
         final CellLayout group = (CellLayout) getChildAt(screen);
         CellLayout.LayoutParams lp = (CellLayout.LayoutParams) child.getLayoutParams();
         if (lp == null) {
@@ -379,6 +382,13 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
         return null;
     }
 
+    private void clearVacantCache() {
+        if (mVacantCache != null) {
+            mVacantCache.clearVacantCells();
+            mVacantCache = null;
+        }
+    }
+    
     /**
      * Returns the coordinate of a vacant cell for the current screen.
      */
@@ -840,6 +850,7 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
     void snapToScreen(int whichScreen) {
         if (!mScroller.isFinished()) return;
 
+        clearVacantCache();
         enableChildrenCache();
 
         whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));
@@ -934,7 +945,7 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
 
     public void onDragEnter(DragSource source, int x, int y, int xOffset, int yOffset,
             Object dragInfo) {
-        mVacantCache = null;
+        clearVacantCache();
     }
 
     public void onDragOver(DragSource source, int x, int y, int xOffset, int yOffset,
@@ -943,7 +954,7 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
 
     public void onDragExit(DragSource source, int x, int y, int xOffset, int yOffset,
             Object dragInfo) {
-        mVacantCache = null;
+        clearVacantCache();
     }
 
     private void onDropExternal(int x, int y, Object dragInfo, CellLayout cellLayout) {
@@ -1001,8 +1012,17 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
      */
     public boolean acceptDrop(DragSource source, int x, int y,
             int xOffset, int yOffset, Object dragInfo) {
-        // Workspaces accept everything
-        return true;
+        final CellLayout layout = getCurrentDropLayout();
+        final CellLayout.CellInfo cellInfo = mDragInfo;
+        final int spanX = cellInfo == null ? 1 : cellInfo.spanX;
+        final int spanY = cellInfo == null ? 1 : cellInfo.spanY;
+
+        if (mVacantCache == null) {
+            final View ignoreView = cellInfo == null ? null : cellInfo.cell;
+            mVacantCache = layout.findAllVacantCells(null, ignoreView);
+        }
+
+        return mVacantCache.findCellForSpan(mTempEstimate, spanX, spanY, false);
     }
     
     /**
@@ -1080,14 +1100,14 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
     }
 
     public void scrollLeft() {
-        mVacantCache = null;
+        clearVacantCache();
         if (mNextScreen == INVALID_SCREEN && mCurrentScreen > 0 && mScroller.isFinished()) {
             snapToScreen(mCurrentScreen - 1);
         }
     }
 
     public void scrollRight() {
-        mVacantCache = null;
+        clearVacantCache();
         if (mNextScreen == INVALID_SCREEN && mCurrentScreen < getChildCount() -1 &&
                 mScroller.isFinished()) {
             snapToScreen(mCurrentScreen + 1);
@@ -1269,10 +1289,6 @@ public class Workspace extends ViewGroup implements DropTarget, DragSource, Drag
         }
     }
 
-    // TODO: remove widgets when appwidgetmanager tells us they're gone
-//    void removeAppWidgetsForProvider() {
-//    }
-
     void moveToDefaultScreen() {
         snapToScreen(mDefaultScreen);
         getChildAt(mDefaultScreen).requestFocus();