Reset the task stack instead of the view when Recents is hidden. (Bug. 18436876, Bug. 18394126, Bug. 18432310)

This will remove the need for having all the null checks in TaskStackView.
We also remove the check when launching tasks (the fail case is worse
when the activity fails to load).  And the CL also fix the header focus
animation, and an issue with tasks not getting laid out when the stack is
set again.

Change-Id: I9b4cd50d76f72ba3d16dd1b8e2d9bbf9f1f24d2b

7 files changed, 50 insertions, 85 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/recents/AlternateRecentsComponent.java b/packages/SystemUI/src/com/android/systemui/recents/AlternateRecentsComponent.java
index bb9a105..a42b124 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/AlternateRecentsComponent.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/AlternateRecentsComponent.java
@@ -169,7 +169,8 @@ public class AlternateRecentsComponent implements ActivityOptions.OnAnimationSta
     /** Hides the recents */
     public void onHideRecents(boolean triggeredFromAltTab, boolean triggeredFromHomeKey) {
         if (mBootCompleted) {
-            if (isRecentsTopMost(getTopMostTask(), null)) {
+            ActivityManager.RunningTaskInfo topTask = getTopMostTask();
+            if (topTask != null && isRecentsTopMost(topTask, null)) {
                 // Notify recents to hide itself
                 Intent intent = new Intent(ACTION_HIDE_RECENTS_ACTIVITY);
                 intent.setPackage(mContext.getPackageName());
@@ -216,6 +217,8 @@ public class AlternateRecentsComponent implements ActivityOptions.OnAnimationSta
         if (stack.getTaskCount() == 0) return;
 
         ActivityManager.RunningTaskInfo runningTask = getTopMostTask();
+        // Return early if there is no running task (can't determine affiliated tasks in this case)
+        if (runningTask == null) return;
         // Return early if the running task is in the home stack (optimization)
         if (mSystemServicesProxy.isInHomeStack(runningTask.id)) return;
 
@@ -369,8 +372,8 @@ public class AlternateRecentsComponent implements ActivityOptions.OnAnimationSta
         // If Recents is the front most activity, then we should just communicate with it directly
         // to launch the first task or dismiss itself
         ActivityManager.RunningTaskInfo topTask = getTopMostTask();
-        AtomicBoolean isTopTaskHome = new AtomicBoolean();
-        if (isRecentsTopMost(topTask, isTopTaskHome)) {
+        AtomicBoolean isTopTaskHome = new AtomicBoolean(true);
+        if (topTask != null && isRecentsTopMost(topTask, isTopTaskHome)) {
             // Notify recents to toggle itself
             Intent intent = new Intent(ACTION_TOGGLE_RECENTS_ACTIVITY);
             intent.setPackage(mContext.getPackageName());
@@ -389,8 +392,8 @@ public class AlternateRecentsComponent implements ActivityOptions.OnAnimationSta
     void startRecentsActivity() {
         // Check if the top task is in the home stack, and start the recents activity
         ActivityManager.RunningTaskInfo topTask = getTopMostTask();
-        AtomicBoolean isTopTaskHome = new AtomicBoolean();
-        if (!isRecentsTopMost(topTask, isTopTaskHome)) {
+        AtomicBoolean isTopTaskHome = new AtomicBoolean(true);
+        if (topTask == null || !isRecentsTopMost(topTask, isTopTaskHome)) {
             startRecentsActivity(topTask, isTopTaskHome.get());
         }
     }
@@ -504,7 +507,7 @@ public class AlternateRecentsComponent implements ActivityOptions.OnAnimationSta
         TaskStackViewLayoutAlgorithm.VisibilityReport stackVr =
                 mDummyStackView.computeStackVisibilityReport();
         boolean hasRecentTasks = stack.getTaskCount() > 0;
-        boolean useThumbnailTransition = !isTopTaskHome && hasRecentTasks;
+        boolean useThumbnailTransition = (topTask != null) && !isTopTaskHome && hasRecentTasks;
 
         if (useThumbnailTransition) {
             // Ensure that we load the running task's icon
diff --git a/packages/SystemUI/src/com/android/systemui/recents/model/TaskStack.java b/packages/SystemUI/src/com/android/systemui/recents/model/TaskStack.java
index a37b9e6..255d642 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/model/TaskStack.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/model/TaskStack.java
@@ -61,6 +61,14 @@ class FilteredTaskList {
         }
     }
 
+    /** Resets this FilteredTaskList. */
+    void reset() {
+        mTasks.clear();
+        mFilteredTasks.clear();
+        mTaskIndices.clear();
+        mFilter = null;
+    }
+
     /** Removes the task filter and returns the previous touch state */
     void removeFilter() {
         mFilter = null;
@@ -190,6 +198,14 @@ public class TaskStack {
         mCb = cb;
     }
 
+    /** Resets this TaskStack. */
+    public void reset() {
+        mCb = null;
+        mTaskList.reset();
+        mGroups.clear();
+        mAffinitiesGroups.clear();
+    }
+
     /** Adds a new task */
     public void addTask(Task t) {
         mTaskList.add(t);
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java b/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java
index 77a050a..46a5d8d 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java
@@ -65,7 +65,6 @@ public class RecentsView extends FrameLayout implements TaskStackView.TaskStackV
     ArrayList<TaskStack> mStacks;
     View mSearchBar;
     RecentsViewCallbacks mCb;
-    boolean mAlreadyLaunchingTask;
 
     public RecentsView(Context context) {
         super(context);
@@ -121,7 +120,10 @@ public class RecentsView extends FrameLayout implements TaskStackView.TaskStackV
 
         // Update the stack views that we are keeping
         for (int i = 0; i < numTaskStacksToKeep; i++) {
-            stackViews.get(i).setStack(stacks.get(i));
+            TaskStackView tsv = stackViews.get(i);
+            // If onRecentsHidden is not triggered, we need to the stack view again here
+            tsv.reset();
+            tsv.setStack(stacks.get(i));
         }
 
         // Add remaining/recreate stack views
@@ -144,8 +146,6 @@ public class RecentsView extends FrameLayout implements TaskStackView.TaskStackV
             }
         }
 
-        // Reset the launched state
-        mAlreadyLaunchingTask = false;
         // Trigger a new layout
         requestLayout();
     }
@@ -402,11 +402,6 @@ public class RecentsView extends FrameLayout implements TaskStackView.TaskStackV
         if (mCb != null) {
             mCb.onTaskViewClicked();
         }
-        // Skip if we are already launching tasks
-        if (mAlreadyLaunchingTask) {
-            return;
-        }
-        mAlreadyLaunchingTask = true;
 
         // Upfront the processing of the thumbnail
         TaskViewTransform transform = new TaskViewTransform();
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
index 5732879..2623db3 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
@@ -132,21 +132,13 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
     /** Sets the task stack */
     void setStack(TaskStack stack) {
-        // Unset the old stack
-        if (mStack != null) {
-            mStack.setCallbacks(null);
-
-            // Return all existing views to the pool
-            reset();
-            // Layout again with the new stack
-            requestLayout();
-        }
-
         // Set the new stack
         mStack = stack;
         if (mStack != null) {
             mStack.setCallbacks(this);
         }
+        // Layout again with the new stack
+        requestLayout();
     }
 
     /** Sets the debug overlay */
@@ -178,6 +170,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         }
 
         // Reset the stack state
+        mStack.reset();
         mStackViewsDirty = true;
         mStackViewsClipDirty = true;
         mAwaitingFirstLayout = true;
@@ -239,11 +232,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
                                        float stackScroll,
                                        int[] visibleRangeOut,
                                        boolean boundTranslationsToRect) {
-        // XXX: We should be intelligent about where to look for the visible stack range using the
-        //      current stack scroll.
-        // XXX: We should log extra cases like the ones below where we don't expect to hit very often
-        // XXX: Print out approximately how many indices we have to go through to find the first visible transform
-
         int taskTransformCount = taskTransforms.size();
         int taskCount = tasks.size();
         int frontMostVisibleIndex = -1;
@@ -295,20 +283,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         return frontMostVisibleIndex != -1 && backMostVisibleIndex != -1;
     }
 
-    /**
-     * Gets the stack transforms of a list of tasks, and returns the visible range of tasks. This
-     * call is less optimal than calling updateStackTransforms directly.
-     */
-    private ArrayList<TaskViewTransform> getStackTransforms(ArrayList<Task> tasks,
-                                                            float stackScroll,
-                                                            int[] visibleRangeOut,
-                                                            boolean boundTranslationsToRect) {
-        ArrayList<TaskViewTransform> taskTransforms = new ArrayList<TaskViewTransform>();
-        updateStackTransforms(taskTransforms, tasks, stackScroll, visibleRangeOut,
-                boundTranslationsToRect);
-        return taskTransforms;
-    }
-
     /** Synchronizes the views with the model */
     boolean synchronizeStackViewsWithModel() {
         if (mStackViewsDirty) {
@@ -440,8 +414,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
     /** Updates the min and max virtual scroll bounds */
     void updateMinMaxScroll(boolean boundScrollToNewMinMax, boolean launchedWithAltTab,
             boolean launchedFromHome) {
-        if (mStack == null) return;
-
         // Compute the min and max scroll values
         mLayoutAlgorithm.computeMinMaxScroll(mStack.getTasks(), launchedWithAltTab, launchedFromHome);
 
@@ -498,7 +470,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
     }
 
     /**
-     * Ensures that there is a task focused, if nothign is focused, then we will use the task
+     * Ensures that there is a task focused, if nothing is focused, then we will use the task
      * at the center of the visible stack.
      */
     public boolean ensureFocusedTask() {
@@ -545,8 +517,11 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
     /** Dismisses the focused task. */
     public void dismissFocusedTask() {
-        // Return early if there is no focused task index
-        if (mFocusedTaskIndex < 0) return;
+        // Return early if the focused task index is invalid
+        if (mFocusedTaskIndex < 0 || mFocusedTaskIndex >= mStack.getTaskCount()) {
+            mFocusedTaskIndex = -1;
+            return;
+        }
 
         Task t = mStack.getTasks().get(mFocusedTaskIndex);
         TaskView tv = getChildViewForTask(t);
@@ -567,8 +542,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
     @Override
     public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
         super.onInitializeAccessibilityEvent(event);
-        if (mStack == null) return;
-
         int childCount = getChildCount();
         if (childCount > 0) {
             TaskView backMostTask = (TaskView) getChildAt(0);
@@ -599,8 +572,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
     @Override
     public void computeScroll() {
-        if (mStack == null) return;
-
         mStackScroller.computeScroll();
         // Synchronize the views
         synchronizeStackViewsWithModel();
@@ -643,11 +614,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
      */
     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
-        if (mStack == null) {
-            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
-            return;
-        }
-
         int width = MeasureSpec.getSize(widthMeasureSpec);
         int height = MeasureSpec.getSize(heightMeasureSpec);
 
@@ -660,10 +626,9 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         // If this is the first layout, then scroll to the front of the stack and synchronize the
         // stack views immediately to load all the views
         if (mAwaitingFirstLayout) {
-            if (mStackScroller.setStackScrollToInitialState()) {
-                requestSynchronizeStackViewsWithModel();
-                synchronizeStackViewsWithModel();
-            }
+            mStackScroller.setStackScrollToInitialState();
+            requestSynchronizeStackViewsWithModel();
+            synchronizeStackViewsWithModel();
         }
 
         // Measure each of the TaskViews
@@ -694,11 +659,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
      */
     @Override
     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
-        if (mStack == null) {
-            super.onLayout(changed, left, top, right, bottom);
-            return;
-        }
-
         // Layout each of the children
         int childCount = getChildCount();
         for (int i = 0; i < childCount; i++) {
@@ -856,7 +816,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
     /** Final callback after Recents is finally hidden. */
     void onRecentsHidden() {
-        setStack(null);
+        reset();
     }
 
     public boolean isTransformedTouchPointInView(float x, float y, View child) {
@@ -1030,8 +990,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
     @Override
     public void prepareViewToLeavePool(TaskView tv, Task task, boolean isNewView) {
-        if (mStack == null) return;
-
         // It is possible for a view to be returned to the view pool before it is laid out,
         // which means that we will need to relayout the view when it is first used next.
         boolean requiresRelayout = tv.getWidth() <= 0 && !isNewView;
@@ -1170,8 +1128,6 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
     @Override
     public void onPackagesChanged(RecentsPackageMonitor monitor, String packageName, int userId) {
-        if (mStack == null) return;
-
         // Compute which components need to be removed
         HashSet<ComponentName> removedComponents = monitor.computeComponentsRemoved(
                 mStack.getTaskKeys(), packageName, userId);
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackViewLayoutAlgorithm.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackViewLayoutAlgorithm.java
index 5767e18..26fbbf4 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackViewLayoutAlgorithm.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackViewLayoutAlgorithm.java
@@ -274,6 +274,7 @@ public class TaskStackViewLayoutAlgorithm {
 
     /** Returns the scroll to such task top = 1f; */
     float getStackScrollForTask(Task t) {
+        if (!mTaskProgressMap.containsKey(t.key)) return 0f;
         return mTaskProgressMap.get(t.key);
     }
 
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskView.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskView.java
index d42fa15..de5974f 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskView.java
@@ -350,7 +350,7 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
             public void run() {
                 enableFocusAnimations();
             }
-        }, (startDelay / 2));
+        }, startDelay);
     }
 
     public void fadeInActionButton(int delay, int duration) {
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewHeader.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewHeader.java
index 1e5d9fc..464d007 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewHeader.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewHeader.java
@@ -69,6 +69,7 @@ public class TaskViewHeader extends FrameLayout {
     RippleDrawable mBackground;
     GradientDrawable mBackgroundColorDrawable;
     AnimatorSet mFocusAnimator;
+    String mDismissContentDescription;
 
     // Static highlight that we draw at the top of each view
     static Paint sHighlightPaint;
@@ -105,6 +106,8 @@ public class TaskViewHeader extends FrameLayout {
         Resources res = context.getResources();
         mLightDismissDrawable = res.getDrawable(R.drawable.recents_dismiss_light);
         mDarkDismissDrawable = res.getDrawable(R.drawable.recents_dismiss_dark);
+        mDismissContentDescription =
+                res.getString(R.string.accessibility_recents_item_will_be_dismissed);
 
         // Configure the highlight paint
         if (sHighlightPaint == null) {
@@ -127,14 +130,6 @@ public class TaskViewHeader extends FrameLayout {
 
     @Override
     protected void onFinishInflate() {
-        // Set the outline provider
-        setOutlineProvider(new ViewOutlineProvider() {
-            @Override
-            public void getOutline(View view, Outline outline) {
-                outline.setRect(0, 0, getMeasuredWidth(), getMeasuredHeight());
-            }
-        });
-
         // Initialize the icon and description views
         mApplicationIcon = (ImageView) findViewById(R.id.application_icon);
         mActivityDescription = (TextView) findViewById(R.id.activity_description);
@@ -217,9 +212,8 @@ public class TaskViewHeader extends FrameLayout {
                 mConfig.taskBarViewLightTextColor : mConfig.taskBarViewDarkTextColor);
         mDismissButton.setImageDrawable(t.useLightOnPrimaryColor ?
                 mLightDismissDrawable : mDarkDismissDrawable);
-        mDismissButton.setContentDescription(
-                getContext().getString(R.string.accessibility_recents_item_will_be_dismissed,
-                        t.activityLabel));
+        mDismissButton.setContentDescription(String.format(mDismissContentDescription,
+                t.activityLabel));
     }
 
     /** Unbinds the bar view from the task */
@@ -307,7 +301,7 @@ public class TaskViewHeader extends FrameLayout {
             int currentColor = mBackgroundColor;
             int lightPrimaryColor = getSecondaryColor(mCurrentPrimaryColor, mCurrentPrimaryColorIsDark);
             ValueAnimator backgroundColor = ValueAnimator.ofObject(new ArgbEvaluator(),
-                    lightPrimaryColor, currentColor);
+                    currentColor, lightPrimaryColor);
             backgroundColor.addListener(new AnimatorListenerAdapter() {
                 @Override
                 public void onAnimationStart(Animator animation) {