From 687e5500421b4d99f864bebfed6c573dc4f38191 Mon Sep 17 00:00:00 2001
From: George Mount <mount@google.com>
Date: Wed, 2 Nov 2016 14:33:18 -0700
Subject: [PATCH] Don't update fragments if the manager's state doesn't change.

Bug 32610133

A change in behavior was introduced in which the dispatch* methods
moved the state of the manager's fragments even when the manager's
state doesn't change.

Test: I88f5a3313ad05429167c417b840f888f86fd1c11

Change-Id: Ie260b1c57fae505b2636ff7572a493a92449dff4
---
 core/java/android/app/BackStackRecord.java |  4 +--
 core/java/android/app/FragmentManager.java | 35 +++++++++++++++-------
 2 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/core/java/android/app/BackStackRecord.java b/core/java/android/app/BackStackRecord.java
index cf794c5b410ee..42a2f19503b64 100644
--- a/core/java/android/app/BackStackRecord.java
+++ b/core/java/android/app/BackStackRecord.java
@@ -762,7 +762,7 @@ final class BackStackRecord extends FragmentTransaction implements
         }
         if (!mAllowOptimization) {
             // Added fragments are added at the end to comply with prior behavior.
-            mManager.moveToState(mManager.mCurState);
+            mManager.moveToState(mManager.mCurState, true);
         }
     }
 
@@ -808,7 +808,7 @@ final class BackStackRecord extends FragmentTransaction implements
             }
         }
         if (!mAllowOptimization) {
-            mManager.moveToState(mManager.mCurState);
+            mManager.moveToState(mManager.mCurState, true);
         }
     }
 
diff --git a/core/java/android/app/FragmentManager.java b/core/java/android/app/FragmentManager.java
index 5a2c5e771807c..07ef136e7ac51 100644
--- a/core/java/android/app/FragmentManager.java
+++ b/core/java/android/app/FragmentManager.java
@@ -1445,11 +1445,24 @@ final class FragmentManagerImpl extends FragmentManager implements LayoutInflate
         }
     }
 
-    void moveToState(int newState) {
+    /**
+     * Changes the state of the fragment manager to {@code newState}. If the fragment manager
+     * changes state or {@code always} is {@code true}, any fragments within it have their
+     * states updated as well.
+     *
+     * @param newState The new state for the fragment manager
+     * @param always If {@code true}, all fragments update their state, even
+     *               if {@code newState} matches the current fragment manager's state.
+     */
+    void moveToState(int newState, boolean always) {
         if (mHost == null && newState != Fragment.INITIALIZING) {
             throw new IllegalStateException("No activity");
         }
 
+        if (!always && mCurState == newState) {
+            return;
+        }
+
         mCurState = newState;
 
         if (mActive != null) {
@@ -2024,7 +2037,7 @@ final class FragmentManagerImpl extends FragmentManager implements LayoutInflate
             // need to run something now
             FragmentTransition.startTransitions(this, records, isRecordPop, startIndex,
                     postponeIndex, true);
-            moveToState(mCurState);
+            moveToState(mCurState, true);
         }
 
         for (int recordNum = startIndex; recordNum < endIndex; recordNum++) {
@@ -2117,7 +2130,7 @@ final class FragmentManagerImpl extends FragmentManager implements LayoutInflate
             FragmentTransition.startTransitions(this, records, isRecordPop, 0, 1, true);
         }
         if (moveToState) {
-            moveToState(mCurState);
+            moveToState(mCurState, true);
         } else if (mActive != null) {
             final int numActive = mActive.size();
             for (int i = 0; i < numActive; i++) {
@@ -2691,40 +2704,40 @@ final class FragmentManagerImpl extends FragmentManager implements LayoutInflate
     
     public void dispatchCreate() {
         mStateSaved = false;
-        moveToState(Fragment.CREATED);
+        moveToState(Fragment.CREATED, false);
     }
     
     public void dispatchActivityCreated() {
         mStateSaved = false;
-        moveToState(Fragment.ACTIVITY_CREATED);
+        moveToState(Fragment.ACTIVITY_CREATED, false);
     }
     
     public void dispatchStart() {
         mStateSaved = false;
-        moveToState(Fragment.STARTED);
+        moveToState(Fragment.STARTED, false);
     }
     
     public void dispatchResume() {
         mStateSaved = false;
-        moveToState(Fragment.RESUMED);
+        moveToState(Fragment.RESUMED, false);
     }
     
     public void dispatchPause() {
-        moveToState(Fragment.STARTED);
+        moveToState(Fragment.STARTED, false);
     }
     
     public void dispatchStop() {
-        moveToState(Fragment.STOPPED);
+        moveToState(Fragment.STOPPED, false);
     }
     
     public void dispatchDestroyView() {
-        moveToState(Fragment.CREATED);
+        moveToState(Fragment.CREATED, false);
     }
 
     public void dispatchDestroy() {
         mDestroyed = true;
         execPendingActions();
-        moveToState(Fragment.INITIALIZING);
+        moveToState(Fragment.INITIALIZING, false);
         mHost = null;
         mContainer = null;
         mParent = null;