1 files changed, 47 insertions, 20 deletions

diff --git a/src/com/android/launcher3/BaseRecyclerView.java b/src/com/android/launcher3/BaseRecyclerView.java
index 9d713e338..f8ef1e156 100644
--- a/src/com/android/launcher3/BaseRecyclerView.java
+++ b/src/com/android/launcher3/BaseRecyclerView.java
@@ -52,8 +52,8 @@ public abstract class BaseRecyclerView extends RecyclerView
         public int rowIndex;
         // The offset of the first visible row
         public int rowTopOffset;
-        // The height of a given row (they are currently all the same height)
-        public int rowHeight;
+        // The adapter position of the first visible item
+        public int itemPos;
     }
 
     protected BaseRecyclerViewFastScrollBar mScrollbar;
@@ -187,15 +187,21 @@ public abstract class BaseRecyclerView extends RecyclerView
     }
 
     /**
+     * Returns the visible height of the recycler view:
+     *   VisibleHeight = View height - top padding - bottom padding
+     */
+    protected int getVisibleHeight() {
+        int visibleHeight = getHeight() - mBackgroundPadding.top - mBackgroundPadding.bottom;
+        return visibleHeight;
+    }
+
+    /**
      * Returns the available scroll height:
      *   AvailableScrollHeight = Total height of the all items - last page height
-     *
-     * This assumes that all rows are the same height.
      */
-    protected int getAvailableScrollHeight(int rowCount, int rowHeight) {
-        int visibleHeight = getHeight() - mBackgroundPadding.top - mBackgroundPadding.bottom;
-        int scrollHeight = getPaddingTop() + rowCount * rowHeight + getPaddingBottom();
-        int availableScrollHeight = scrollHeight - visibleHeight;
+    protected int getAvailableScrollHeight(int rowCount) {
+        int totalHeight = getPaddingTop() + getTop(rowCount) + getPaddingBottom();
+        int availableScrollHeight = totalHeight - getVisibleHeight();
         return availableScrollHeight;
     }
 
@@ -204,8 +210,7 @@ public abstract class BaseRecyclerView extends RecyclerView
      *   AvailableScrollBarHeight = Total height of the visible view - thumb height
      */
     protected int getAvailableScrollBarHeight() {
-        int visibleHeight = getHeight() - mBackgroundPadding.top - mBackgroundPadding.bottom;
-        int availableScrollBarHeight = visibleHeight - mScrollbar.getThumbHeight();
+        int availableScrollBarHeight = getVisibleHeight() - mScrollbar.getThumbHeight();
         return availableScrollBarHeight;
     }
 
@@ -223,6 +228,13 @@ public abstract class BaseRecyclerView extends RecyclerView
         return defaultInactiveThumbColor;
     }
 
+    /**
+     * Returns the scrollbar for this recycler view.
+     */
+    public BaseRecyclerViewFastScrollBar getScrollBar() {
+        return mScrollbar;
+    }
+
     @Override
     protected void dispatchDraw(Canvas canvas) {
         super.dispatchDraw(canvas);
@@ -243,7 +255,7 @@ public abstract class BaseRecyclerView extends RecyclerView
             int rowCount) {
         // Only show the scrollbar if there is height to be scrolled
         int availableScrollBarHeight = getAvailableScrollBarHeight();
-        int availableScrollHeight = getAvailableScrollHeight(rowCount, scrollPosState.rowHeight);
+        int availableScrollHeight = getAvailableScrollHeight(rowCount);
         if (availableScrollHeight <= 0) {
             mScrollbar.setThumbOffset(-1, -1);
             return;
@@ -252,8 +264,7 @@ public abstract class BaseRecyclerView extends RecyclerView
         // Calculate the current scroll position, the scrollY of the recycler view accounts for the
         // view padding, while the scrollBarY is drawn right up to the background padding (ignoring
         // padding)
-        int scrollY = getPaddingTop() +
-                (scrollPosState.rowIndex * scrollPosState.rowHeight) - scrollPosState.rowTopOffset;
+        int scrollY = getScrollTop(scrollPosState);
         int scrollBarY = mBackgroundPadding.top +
                 (int) (((float) scrollY / availableScrollHeight) * availableScrollBarHeight);
 
@@ -268,7 +279,7 @@ public abstract class BaseRecyclerView extends RecyclerView
     }
 
     /**
-     * Returns whether fast scrolling is supported in the current state.
+     * @return whether fast scrolling is supported in the current state.
      */
     protected boolean supportsFastScrolling() {
         return true;
@@ -277,22 +288,38 @@ public abstract class BaseRecyclerView extends RecyclerView
     /**
      * Maps the touch (from 0..1) to the adapter position that should be visible.
      * <p>Override in each subclass of this base class.
+     *
+     * @return the scroll top of this recycler view.
      */
-    public abstract String scrollToPositionAtProgress(float touchFraction);
+    protected int getScrollTop(ScrollPositionState scrollPosState) {
+        return getPaddingTop() + getTop(scrollPosState.rowIndex) -
+                scrollPosState.rowTopOffset;
+    }
 
     /**
-     * Updates the bounds for the scrollbar.
+     * Returns information about the item that the recycler view is currently scrolled to.
+     */
+    protected abstract void getCurScrollState(ScrollPositionState stateOut, int viewTypeMask);
+
+    /**
+     * Returns the top (or y position) of the row at the specified index.
+     */
+    protected abstract int getTop(int rowIndex);
+
+    /**
+     * Maps the touch (from 0..1) to the adapter position that should be visible.
      * <p>Override in each subclass of this base class.
      */
-    public abstract void onUpdateScrollbar(int dy);
+    protected abstract String scrollToPositionAtProgress(float touchFraction);
 
     /**
+     * Updates the bounds for the scrollbar.
      * <p>Override in each subclass of this base class.
      */
-    public void onFastScrollCompleted() {}
+    protected abstract void onUpdateScrollbar(int dy);
 
     /**
-     * Returns information about the item that the recycler view is currently scrolled to.
+     * <p>Override in each subclass of this base class.
      */
-    protected abstract void getCurScrollState(ScrollPositionState stateOut);
+    protected void onFastScrollCompleted() {}
 }
\ No newline at end of file