Fix EditText RenderNode invalidation bugs

EditText uses a TextDisplayList data structure to hold RenderNode
objects for optimized incremental drawing. This data structure uses an
isDirty flag to indicate when it has been invalidated and needs to be
re-rendered. This flag was not being computed correctly, leading to
excessive re-rendering.

This patch clears isDirty after rendering text into the RenderNode, so
that it can be reused until it is invalidated, and also explicitly sets
it when it is recycled.

Bug: 19371378
Change-Id: I70239cc30e43bb8631dfffc2ea2705e8d4c452f4

1 files changed, 4 insertions, 0 deletions

diff --git a/core/java/android/widget/Editor.java b/core/java/android/widget/Editor.java
index d5166f3..4752594 100644
--- a/core/java/android/widget/Editor.java
+++ b/core/java/android/widget/Editor.java
@@ -1352,6 +1352,9 @@ public class Editor {
                             searchStartIndex);
                     // Note how dynamic layout's internal block indices get updated from Editor
                     blockIndices[i] = blockIndex;
+                    if (mTextDisplayLists[blockIndex] != null) {
+                        mTextDisplayLists[blockIndex].isDirty = true;
+                    }
                     searchStartIndex = blockIndex + 1;
                 }
 
@@ -1388,6 +1391,7 @@ public class Editor {
                             // brings this range of text back to the top left corner of the viewport
                             hardwareCanvas.translate(-left, -top);
                             layout.drawText(hardwareCanvas, blockBeginLine, blockEndLine);
+                            mTextDisplayLists[blockIndex].isDirty = false;
                             // No need to untranslate, previous context is popped after
                             // drawDisplayList
                         } finally {