Fixed animation ordering bug in LayoutTransition.

This bug caused an artifact in Recent Apps where you might see things
pop to their end location before popping back and then animating correctly
into place.

Change-Id: Ia7313ec76cc42162528c3c167b8bc562284b14bc

1 files changed, 23 insertions, 19 deletions

diff --git a/core/java/android/animation/LayoutTransition.java b/core/java/android/animation/LayoutTransition.java
index d25de97..2c1f578 100644
--- a/core/java/android/animation/LayoutTransition.java
+++ b/core/java/android/animation/LayoutTransition.java
@@ -25,6 +25,7 @@ import android.view.animation.DecelerateInterpolator;
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 
 /**
@@ -178,14 +179,17 @@ public class LayoutTransition {
      * the transition. The reason for this is that a further layout event should cause
      * existing animations to stop where they are prior to starting new animations. So
      * we cache all of the current animations in this map for possible cancellation on
-     * another layout event.
+     * another layout event. LinkedHashMaps are used to preserve the order in which animations
+     * are inserted, so that we process events (such as setting up start values) in the same order.
      */
-    private final HashMap<View, Animator> pendingAnimations = new HashMap<View, Animator>();
-    private final HashMap<View, Animator> currentChangingAnimations = new HashMap<View, Animator>();
-    private final HashMap<View, Animator> currentAppearingAnimations =
-            new HashMap<View, Animator>();
-    private final HashMap<View, Animator> currentDisappearingAnimations =
+    private final HashMap<View, Animator> pendingAnimations =
             new HashMap<View, Animator>();
+    private final LinkedHashMap<View, Animator> currentChangingAnimations =
+            new LinkedHashMap<View, Animator>();
+    private final LinkedHashMap<View, Animator> currentAppearingAnimations =
+            new LinkedHashMap<View, Animator>();
+    private final LinkedHashMap<View, Animator> currentDisappearingAnimations =
+            new LinkedHashMap<View, Animator>();
 
     /**
      * This hashmap is used to track the listeners that have been added to the children of
@@ -547,7 +551,7 @@ public class LayoutTransition {
     }
 
     /**
-     * This function sets up runs animations on all of the views that change during layout.
+     * This function sets up animations on all of the views that change during layout.
      * For every child in the parent, we create a change animation of the appropriate
      * type (appearing or disappearing) and ask it to populate its start values from its
      * target view. We add layout listeners to all child views and listen for changes. For
@@ -821,24 +825,24 @@ public class LayoutTransition {
      */
     public void cancel() {
         if (currentChangingAnimations.size() > 0) {
-            HashMap<View, Animator> currentAnimCopy =
-                    (HashMap<View, Animator>) currentChangingAnimations.clone();
+            LinkedHashMap<View, Animator> currentAnimCopy =
+                    (LinkedHashMap<View, Animator>) currentChangingAnimations.clone();
             for (Animator anim : currentAnimCopy.values()) {
                 anim.cancel();
             }
             currentChangingAnimations.clear();
         }
         if (currentAppearingAnimations.size() > 0) {
-            HashMap<View, Animator> currentAnimCopy =
-                    (HashMap<View, Animator>) currentAppearingAnimations.clone();
+            LinkedHashMap<View, Animator> currentAnimCopy =
+                    (LinkedHashMap<View, Animator>) currentAppearingAnimations.clone();
             for (Animator anim : currentAnimCopy.values()) {
                 anim.end();
             }
             currentAppearingAnimations.clear();
         }
         if (currentDisappearingAnimations.size() > 0) {
-            HashMap<View, Animator> currentAnimCopy =
-                    (HashMap<View, Animator>) currentDisappearingAnimations.clone();
+            LinkedHashMap<View, Animator> currentAnimCopy =
+                    (LinkedHashMap<View, Animator>) currentDisappearingAnimations.clone();
             for (Animator anim : currentAnimCopy.values()) {
                 anim.end();
             }
@@ -859,8 +863,8 @@ public class LayoutTransition {
             case CHANGE_APPEARING:
             case CHANGE_DISAPPEARING:
                 if (currentChangingAnimations.size() > 0) {
-                    HashMap<View, Animator> currentAnimCopy =
-                            (HashMap<View, Animator>) currentChangingAnimations.clone();
+                    LinkedHashMap<View, Animator> currentAnimCopy =
+                            (LinkedHashMap<View, Animator>) currentChangingAnimations.clone();
                     for (Animator anim : currentAnimCopy.values()) {
                         anim.cancel();
                     }
@@ -869,8 +873,8 @@ public class LayoutTransition {
                 break;
             case APPEARING:
                 if (currentAppearingAnimations.size() > 0) {
-                    HashMap<View, Animator> currentAnimCopy =
-                            (HashMap<View, Animator>) currentAppearingAnimations.clone();
+                    LinkedHashMap<View, Animator> currentAnimCopy =
+                            (LinkedHashMap<View, Animator>) currentAppearingAnimations.clone();
                     for (Animator anim : currentAnimCopy.values()) {
                         anim.end();
                     }
@@ -879,8 +883,8 @@ public class LayoutTransition {
                 break;
             case DISAPPEARING:
                 if (currentDisappearingAnimations.size() > 0) {
-                    HashMap<View, Animator> currentAnimCopy =
-                            (HashMap<View, Animator>) currentDisappearingAnimations.clone();
+                    LinkedHashMap<View, Animator> currentAnimCopy =
+                            (LinkedHashMap<View, Animator>) currentDisappearingAnimations.clone();
                     for (Animator anim : currentAnimCopy.values()) {
                         anim.end();
                     }