Allow dragging to dock single tasks.

Bug: 27696141
Change-Id: I538cd4753d47a3606a87ac096d4ea86f6263a2ed
diff --git a/packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java b/packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java
index f33ef65..aab45b5d 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java
@@ -749,7 +749,7 @@
     public final void onBusEvent(AllTaskViewsDismissedEvent event) {
         SystemServicesProxy ssp = Recents.getSystemServices();
         if (ssp.hasDockedTask()) {
-            mRecentsView.showEmptyView(R.string.recents_empty_message_dismissed_all);
+            mRecentsView.showEmptyView(event.msgResId);
         } else {
             // Just go straight home (no animation necessary because there are no more task views)
             dismissRecentsToHome(false /* animateTaskViews */);
diff --git a/packages/SystemUI/src/com/android/systemui/recents/events/ui/AllTaskViewsDismissedEvent.java b/packages/SystemUI/src/com/android/systemui/recents/events/ui/AllTaskViewsDismissedEvent.java
index cf74519..0352161 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/events/ui/AllTaskViewsDismissedEvent.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/events/ui/AllTaskViewsDismissedEvent.java
@@ -22,5 +22,10 @@
  * This is sent whenever all the task views in a stack have been dismissed.
  */
 public class AllTaskViewsDismissedEvent extends EventBus.Event {
-    // Simple event
+
+    public final int msgResId;
+
+    public AllTaskViewsDismissedEvent(int msgResId) {
+        this.msgResId = msgResId;
+    }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/recents/history/RecentsHistoryAdapter.java b/packages/SystemUI/src/com/android/systemui/recents/history/RecentsHistoryAdapter.java
index 5eeda72..16385c9 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/history/RecentsHistoryAdapter.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/history/RecentsHistoryAdapter.java
@@ -245,7 +245,7 @@
             if (row.getViewType() == TASK_ROW_VIEW_TYPE) {
                 TaskRow taskRow = (TaskRow) row;
                 Task task = taskRow.task;
-                mStack.removeTask(task, AnimationProps.IMMEDIATE);
+                mStack.removeTask(task, AnimationProps.IMMEDIATE, false /* fromDockGesture */);
                 EventBus.getDefault().send(new DeleteTaskDataEvent(task));
                 i = removeTaskRow(i);
             }
@@ -326,7 +326,7 @@
     public void onTaskRemoved(Task task, int position) {
         // Since this is removed from the history, we need to update the stack as well to ensure
         // that the model is correct. Since the stack is hidden, we can update it immediately.
-        mStack.removeTask(task, AnimationProps.IMMEDIATE);
+        mStack.removeTask(task, AnimationProps.IMMEDIATE, false /* fromDockGesture */);
         removeTaskRow(position);
         if (mRows.isEmpty()) {
             dismissHistory();
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 4d1c552..193bfff 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/model/TaskStack.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/model/TaskStack.java
@@ -219,7 +219,7 @@
          * Notifies when a task has been removed from the stack.
          */
         void onStackTaskRemoved(TaskStack stack, Task removedTask, boolean wasFrontMostTask,
-            Task newFrontMostTask, AnimationProps animation);
+            Task newFrontMostTask, AnimationProps animation, boolean fromDockGesture);
 
         /**
          * Notifies when a task has been removed from the history.
@@ -513,14 +513,15 @@
      * Removes a task from the stack, with an additional {@param animation} hint to the callbacks on
      * how they should update themselves.
      */
-    public void removeTask(Task t, AnimationProps animation) {
+    public void removeTask(Task t, AnimationProps animation, boolean fromDockGesture) {
         if (mStackTaskList.contains(t)) {
             boolean wasFrontMostTask = (getStackFrontMostTask(false /* includeFreeform */) == t);
             removeTaskImpl(mStackTaskList, t);
             Task newFrontMostTask = getStackFrontMostTask(false  /* includeFreeform */);
             if (mCb != null) {
                 // Notify that a task has been removed
-                mCb.onStackTaskRemoved(this, t, wasFrontMostTask, newFrontMostTask, animation);
+                mCb.onStackTaskRemoved(this, t, wasFrontMostTask, newFrontMostTask, animation,
+                        fromDockGesture);
             }
         } else if (mHistoryTaskList.contains(t)) {
             removeTaskImpl(mHistoryTaskList, t);
@@ -558,9 +559,9 @@
                 if (notifyStackChanges) {
                     // If we are notifying, then remove the task now, otherwise the raw task list
                     // will be reset at the end of this method
-                    removeTask(task, AnimationProps.IMMEDIATE);
+                    removeTask(task, AnimationProps.IMMEDIATE, false /* fromDockGesture */);
                     mCb.onStackTaskRemoved(this, task, i == (taskCount - 1), null,
-                            AnimationProps.IMMEDIATE);
+                            AnimationProps.IMMEDIATE, false /* fromDockGesture */);
                 }
             }
             task.setGroup(null);
diff --git a/packages/SystemUI/src/com/android/systemui/recents/tv/views/TaskStackHorizontalGridView.java b/packages/SystemUI/src/com/android/systemui/recents/tv/views/TaskStackHorizontalGridView.java
index 4458639..cf8c9bb 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/tv/views/TaskStackHorizontalGridView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/tv/views/TaskStackHorizontalGridView.java
@@ -135,7 +135,7 @@
 
     @Override
     public void onStackTaskRemoved(TaskStack stack, Task removedTask, boolean wasFrontMostTask,
-            Task newFrontMostTask, AnimationProps animation) {
+            Task newFrontMostTask, AnimationProps animation, boolean fromDockGesture) {
         getAdapter().notifyItemRemoved(stack.getStackTasks().indexOf(removedTask));
         if (mFocusedTask == removedTask) {
             resetFocusedTask(removedTask);
@@ -144,7 +144,9 @@
         if (mStack.getStackTaskCount() == 0) {
             boolean shouldFinishActivity = (mStack.getStackTaskCount() == 0);
             if (shouldFinishActivity) {
-                EventBus.getDefault().send(new AllTaskViewsDismissedEvent());
+                EventBus.getDefault().send(new AllTaskViewsDismissedEvent(fromDockGesture
+                        ? R.string.recents_empty_message
+                        : R.string.recents_empty_message_dismissed_all));
             }
         }
     }
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 9235673..db97e8f 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/RecentsView.java
@@ -632,7 +632,8 @@
                                     AnimationProps stackAnim = new AnimationProps(
                                             TaskStackView.DEFAULT_SYNC_STACK_DURATION,
                                             Interpolators.FAST_OUT_SLOW_IN);
-                                    mTaskStackView.getStack().removeTask(event.task, stackAnim);
+                                    mTaskStackView.getStack().removeTask(event.task, stackAnim,
+                                            true /* fromDockGesture */);
                                 }
                             }));
 
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/RecentsViewTouchHandler.java b/packages/SystemUI/src/com/android/systemui/recents/views/RecentsViewTouchHandler.java
index 84590f2..33d5bb7 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/RecentsViewTouchHandler.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/RecentsViewTouchHandler.java
@@ -150,8 +150,7 @@
         mTaskView.setTranslationY(y);
 
         mVisibleDockStates.clear();
-        if (ActivityManager.supportsMultiWindow() &&
-                !ssp.hasDockedTask() && mRv.getTaskStack().getTaskCount() > 1) {
+        if (ActivityManager.supportsMultiWindow() && !ssp.hasDockedTask()) {
             if (!event.task.isDockable) {
                 Toast.makeText(mRv.getContext(), R.string.recents_drag_non_dockable_task_message,
                         Toast.LENGTH_SHORT).show();
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 93b5b6c..0b20d21 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
@@ -1395,7 +1395,7 @@
      */
     @Override
     public void onStackTaskRemoved(TaskStack stack, Task removedTask, boolean wasFrontMostTask,
-            Task newFrontMostTask, AnimationProps animation) {
+            Task newFrontMostTask, AnimationProps animation, boolean fromDockGesture) {
         if (mFocusedTask == removedTask) {
             resetFocusedTask(removedTask);
         }
@@ -1426,7 +1426,9 @@
 
         // If there are no remaining tasks, then just close recents
         if (mStack.getTaskCount() == 0) {
-            EventBus.getDefault().send(new AllTaskViewsDismissedEvent());
+            EventBus.getDefault().send(new AllTaskViewsDismissedEvent(fromDockGesture
+                    ? R.string.recents_empty_message
+                    : R.string.recents_empty_message_dismissed_all));
         }
     }
 
@@ -1599,7 +1601,7 @@
                     tv.dismissTask();
                 } else {
                     // Otherwise, remove the task from the stack immediately
-                    mStack.removeTask(t, AnimationProps.IMMEDIATE);
+                    mStack.removeTask(t, AnimationProps.IMMEDIATE, false /* fromDockGesture */);
                 }
             }
         }
@@ -1937,7 +1939,7 @@
 
         // Remove the task from the stack
         mStack.removeTask(task, new AnimationProps(DEFAULT_SYNC_STACK_DURATION,
-                Interpolators.FAST_OUT_SLOW_IN));
+                Interpolators.FAST_OUT_SLOW_IN), false /* fromDockGesture */);
     }
 
     /**