Fix for bug 7344916 text view flickers when you hit enter

The flickering was caused by trying to scroll to the cursor position
while the view was in an inconsistent state (text updated to change the
number of lines, but layout not done yet). This patch defers the actual
setting of the cursor until layout is done, when layout is pending.

Change-Id: I8ed3a402beb8058ac7a7f3935afeb946a23308ab

Author: raphlinus

core/java/android/widget/TextView.java

@@ -367,6 +367,7 @@ static class Drawables {
     private boolean mSingleLine;
     private int mDesiredHeightAtMeasure = -1;
     private boolean mIncludePad = true;
+    private int mDeferScroll = -1;
 
     // tmp primitives, so we don't alloc them on each draw
     private Rect mTempRect;
@@ -6317,6 +6318,11 @@ private void checkForRelayout() {
     @Override
     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
         super.onLayout(changed, left, top, right, bottom);
+        if (mDeferScroll >= 0) {
+            int curs = mDeferScroll;
+            mDeferScroll = -1;
+            bringPointIntoView(curs);
+        }
         if (changed && mEditor != null) mEditor.invalidateTextDisplayList();
     }
 
@@ -6399,6 +6405,10 @@ private boolean bringTextIntoView() {
      * This has to be called after layout. Returns true if anything changed.
      */
     public boolean bringPointIntoView(int offset) {
+        if (isLayoutRequested()) {
+            mDeferScroll = offset;
+            return false;
+        }
         boolean changed = false;
 
         Layout layout = isShowingHint() ? mHintLayout: mLayout;
@@ -7108,13 +7118,13 @@ void updateAfterEdit() {
             registerForPreDraw();
         }
 
+        checkForResize();
+
         if (curs >= 0) {
             mHighlightPathBogus = true;
             if (mEditor != null) mEditor.makeBlink();
             bringPointIntoView(curs);
         }
-
-        checkForResize();
     }
 
     /**
@@ -7161,6 +7171,7 @@ void spanChange(Spanned buf, Object what, int oldStart, int newStart, int oldEnd
 
             if (oldStart >= 0 || newStart >= 0) {
                 invalidateCursor(Selection.getSelectionStart(buf), oldStart, newStart);
+                checkForResize();
                 registerForPreDraw();
                 if (mEditor != null) mEditor.makeBlink();
             }