commit dae57a14141a90d71332086c3d6e8bd3ebf84fe5
author Alexandra Gherghina <alexgherghina@google.com> Wed Mar 12 19:15:26 2014 +0000
committer Alexandra Gherghina <alexgherghina@google.com> Thu Mar 13 08:55:56 2014 +0000
tree 490bfad2b26919cb0ad87e1d9bb91aa8e962a122
parent ad895779f8b8d63832a4195e4e895641985f97ad

Check for empty activity stack. This avoids a null pointer exception
when switching from an user with no open apps.

Change-Id: I02629818f2bc82ee3a2825cf484ef1e32e3e6067

services/core/java/com/android/server/am/ActivityStackSupervisor.java

diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index 9636de7..b2cf846 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -2469,7 +2469,10 @@
             for (int stackNdx = stacks.size() - 1; stackNdx >= 0; --stackNdx) {
                 final ActivityStack stack = stacks.get(stackNdx);
                 stack.switchUserLocked(userId);
-                mWindowManager.moveTaskToTop(stack.topTask().taskId);
+                TaskRecord task = stack.topTask();
+                if (task != null) {
+                    mWindowManager.moveTaskToTop(task.taskId);
+                }
             }
         }
 
@@ -2480,7 +2483,10 @@
         final boolean homeInFront = stack.isHomeStack();
         if (stack.isOnHomeDisplay()) {
             moveHomeStack(homeInFront);
-            mWindowManager.moveTaskToTop(stack.topTask().taskId);
+            TaskRecord task = stack.topTask();
+            if (task != null) {
+                mWindowManager.moveTaskToTop(task.taskId);
+            }
         } else {
             // Stack was moved to another display while user was swapped out.
             resumeHomeActivity(null);