Fixed enter/exit transitions working against shared elements.

Bug 17499971

The enter and exit transitions were targeting the shared element.
This means you'd get double transitions on the shared element.

Also, the enter transition was not properly initialized to have
an invalid target so it was targeting all views.

Change-Id: I4f3510c70bea90f09be01776bc0ad1ffb42d99d5

diff --git a/core/java/android/app/BackStackRecord.java b/core/java/android/app/BackStackRecord.java
index b09f169..832e1e3 100644 (file)
--- a/core/java/android/app/BackStackRecord.java
+++ b/core/java/android/app/BackStackRecord.java
@@ -1049,12 +1049,15 @@ final class BackStackRecord extends FragmentTransaction implements
     }
 
     private static ArrayList<View> captureExitingViews(Transition exitTransition,
-            Fragment outFragment) {
+            Fragment outFragment, ArrayMap<String, View> namedViews) {
         ArrayList<View> viewList = null;
         if (exitTransition != null) {
             viewList = new ArrayList<View>();
             View root = outFragment.getView();
             root.captureTransitioningViews(viewList);
+            if (namedViews != null) {
+                viewList.removeAll(namedViews.values());
+            }
             addTargets(exitTransition, viewList);
         }
         return viewList;
@@ -1117,9 +1120,9 @@ final class BackStackRecord extends FragmentTransaction implements
                         excludeHiddenFragments(hiddenFragmentViews, inFragment.mContainerId,
                                 overallTransition);
 
+                        ArrayMap<String, View> namedViews = null;
                         if (sharedElementTransition != null) {
-                            ArrayMap<String, View> namedViews = mapSharedElementsIn(
-                                    state, isBack, inFragment);
+                            namedViews = mapSharedElementsIn(state, isBack, inFragment);
 
                             setEpicenterIn(namedViews, state);
 
@@ -1131,6 +1134,9 @@ final class BackStackRecord extends FragmentTransaction implements
                             View view = inFragment.getView();
                             if (view != null) {
                                 view.captureTransitioningViews(enteringViews);
+                                if (namedViews != null) {
+                                    enteringViews.removeAll(namedViews.values());
+                                }
                                 addTargets(enterTransition, enteringViews);
                             }
                             setSharedElementEpicenter(enterTransition, state);
@@ -1190,16 +1196,42 @@ final class BackStackRecord extends FragmentTransaction implements
                     inFragment.getAllowEnterTransitionOverlap();
         }
 
+        // Wrap the transitions. Explicit targets like in enter and exit will cause the
+        // views to be targeted regardless of excluded views. If that happens, then the
+        // excluded fragments views (hidden fragments) will still be in the transition.
+
         Transition transition;
         if (overlap) {
+            // Regular transition -- do it all together
             transition = TransitionUtils.mergeTransitions(enterTransition, exitTransition,
                     sharedElementTransition);
+            if (!(transition instanceof TransitionSet)) {
+                transition = new TransitionSet().addTransition(transition);
+            }
         } else {
-            TransitionSet staggered = new TransitionSet()
-                    .addTransition(exitTransition)
-                    .addTransition(enterTransition)
-                    .setOrdering(TransitionSet.ORDERING_SEQUENTIAL);
-            transition = TransitionUtils.mergeTransitions(staggered, sharedElementTransition);
+            // First do exit, then enter, but allow shared element transition to happen
+            // during both.
+            Transition staggered = null;
+            if (exitTransition != null && enterTransition != null) {
+                staggered = new TransitionSet()
+                        .addTransition(exitTransition)
+                        .addTransition(enterTransition)
+                        .setOrdering(TransitionSet.ORDERING_SEQUENTIAL);
+            } else if (exitTransition != null) {
+                staggered = exitTransition;
+            } else if (enterTransition != null) {
+                staggered = enterTransition;
+            }
+            if (sharedElementTransition != null) {
+                TransitionSet together = new TransitionSet();
+                if (staggered != null) {
+                    together.addTransition(staggered);
+                }
+                together.addTransition(sharedElementTransition);
+                transition = together;
+            } else {
+                transition = staggered;
+            }
         }
         return transition;
     }
@@ -1232,11 +1264,9 @@ final class BackStackRecord extends FragmentTransaction implements
                     exitTransition == null) {
                 return; // no transitions!
             }
-            ArrayList<View> exitingViews = captureExitingViews(exitTransition, outFragment);
-            if (exitingViews == null || exitingViews.isEmpty()) {
-                exitTransition = null;
+            if (enterTransition != null) {
+                enterTransition.addTarget(state.nonExistentView);
             }
-
             ArrayMap<String, View> namedViews = null;
             if (sharedElementTransition != null) {
                 namedViews = remapSharedElements(state, outFragment, isBack);
@@ -1250,11 +1280,22 @@ final class BackStackRecord extends FragmentTransaction implements
                 callback.onSharedElementStart(names, views, null);
             }
 
+            ArrayList<View> exitingViews = captureExitingViews(exitTransition, outFragment,
+                    namedViews);
+            if (exitingViews == null || exitingViews.isEmpty()) {
+                exitTransition = null;
+            }
+
             // Set the epicenter of the exit transition
-            if (mSharedElementTargetNames != null && exitTransition != null && namedViews != null) {
+            if (mSharedElementTargetNames != null && namedViews != null) {
                 View epicenterView = namedViews.get(mSharedElementTargetNames.get(0));
                 if (epicenterView != null) {
-                    setEpicenter(exitTransition, epicenterView);
+                    if (exitTransition != null) {
+                        setEpicenter(exitTransition, epicenterView);
+                    }
+                    if (sharedElementTransition != null) {
+                        setEpicenter(sharedElementTransition, epicenterView);
+                    }
                 }
             }