Add keyboard support to Grid-based Recents.

Test: Checked that pressing tab, shift + tab, alt + tab, alt + shift +
tab work for task navigation in Recents on local sw600dp device. Also
checked that Recents on phones work properly.
Bug: 32101881
Change-Id: I3e4cd212d2900523ece30a85cae7fb73a9594efb

packages/SystemUI/res/drawable/recents_grid_task_view_focus_frame_background.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2017 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<shape xmlns:android="http://schemas.android.com/apk/res/android">
+  <solid android:color="#61FFFFFF" />
+  <corners android:radius="8dp"/>
+</shape>

packages/SystemUI/res/values/dimens_grid.xml

@@ -21,5 +21,6 @@
   <dimen name="recents_grid_padding_task_view">20dp</dimen>
   <dimen name="recents_grid_task_view_header_height">44dp</dimen>
   <dimen name="recents_grid_task_view_header_button_padding">8dp</dimen>
+  <dimen name="recents_grid_task_view_focused_frame_thickness">8dp</dimen>
 </resources>
 

packages/SystemUI/src/com/android/systemui/recents/RecentsActivityLaunchState.java

@@ -50,7 +50,7 @@ public class RecentsActivityLaunchState {
     /**
      * Returns the task to focus given the current launch state.
      */
-    public int getInitialFocusTaskIndex(int numTasks) {
+    public int getInitialFocusTaskIndex(int numTasks, boolean useGridLayout) {
         RecentsDebugFlags debugFlags = Recents.getDebugFlags();
         RecentsActivityLaunchState launchState = Recents.getConfiguration().getLaunchState();
         if (launchedFromApp) {
@@ -66,6 +66,11 @@ public class RecentsActivityLaunchState {
                 return numTasks - 1;
             }
 
+            if (useGridLayout) {
+                // If coming from another app to the grid layout, focus the front most task
+                return numTasks - 1;
+            }
+
             // If coming from another app, focus the next task
             return Math.max(0, numTasks - 2);
         } else {

packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java

@@ -70,6 +70,7 @@ import com.android.systemui.recents.events.activity.LaunchTaskStartedEvent;
 import com.android.systemui.recents.events.activity.MultiWindowStateChangedEvent;
 import com.android.systemui.recents.events.activity.PackagesChangedEvent;
 import com.android.systemui.recents.events.activity.ShowStackActionButtonEvent;
+import com.android.systemui.recents.events.component.RecentsVisibilityChangedEvent;
 import com.android.systemui.recents.events.ui.AllTaskViewsDismissedEvent;
 import com.android.systemui.recents.events.ui.DeleteTaskDataEvent;
 import com.android.systemui.recents.events.ui.DismissAllTaskViewsEvent;
@@ -93,6 +94,7 @@ import com.android.systemui.recents.model.Task;
 import com.android.systemui.recents.model.TaskStack;
 
 import com.android.systemui.recents.views.grid.GridTaskView;
+import com.android.systemui.recents.views.grid.TaskViewFocusFrame;
 import java.io.PrintWriter;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -206,6 +208,10 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
     private int mLastWidth;
     private int mLastHeight;
 
+    // We keep track of the task view focused by user interaction and draw a frame around it in the
+    // grid layout.
+    private TaskViewFocusFrame mTaskViewFocusFrame;
+
     // A convenience update listener to request updating clipping of tasks
     private ValueAnimator.AnimatorUpdateListener mRequestUpdateClippingListener =
             new ValueAnimator.AnimatorUpdateListener() {
@@ -265,6 +271,14 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         mDisplayOrientation = Utilities.getAppConfiguration(mContext).orientation;
         mDisplayRect = ssp.getDisplayRect();
 
+        // Create a frame to draw around the focused task view
+        if (Recents.getConfiguration().isGridEnabled) {
+            mTaskViewFocusFrame = new TaskViewFocusFrame(mContext, this,
+                mLayoutAlgorithm.mTaskGridLayoutAlgorithm);
+            addView(mTaskViewFocusFrame);
+            getViewTreeObserver().addOnGlobalFocusChangeListener(mTaskViewFocusFrame);
+        }
+
         int taskBarDismissDozeDelaySeconds = getResources().getInteger(
                 R.integer.recents_task_bar_dismiss_delay_seconds);
         mUIDozeTrigger = new DozeTrigger(taskBarDismissDozeDelaySeconds, new Runnable() {
@@ -878,7 +892,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
      *
      * @return whether or not the stack will scroll as a part of this focus change
      */
-    private boolean setFocusedTask(int taskIndex, boolean scrollToTask,
+    public boolean setFocusedTask(int taskIndex, boolean scrollToTask,
             final boolean requestViewFocus) {
         return setFocusedTask(taskIndex, scrollToTask, requestViewFocus, 0);
     }
@@ -888,7 +902,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
      *
      * @return whether or not the stack will scroll as a part of this focus change
      */
-    private boolean setFocusedTask(int focusTaskIndex, boolean scrollToTask,
+    public boolean setFocusedTask(int focusTaskIndex, boolean scrollToTask,
             boolean requestViewFocus, int timerIndicatorDuration) {
         // Find the next task to focus
         int newFocusedTaskIndex = mStack.getTaskCount() > 0 ?
@@ -940,6 +954,10 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
                     newFocusedTaskView.setFocusedState(true, requestViewFocus);
                 }
             }
+            // Any time a task view gets the focus, we move the focus frame around it.
+            if (mTaskViewFocusFrame != null) {
+                mTaskViewFocusFrame.moveGridTaskViewFocus(getChildViewForTask(newFocusedTask));
+            }
         }
         return willScroll;
     }
@@ -1005,20 +1023,28 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
             float stackScroll = mStackScroller.getStackScroll();
             ArrayList<Task> tasks = mStack.getStackTasks();
             int taskCount = tasks.size();
-            if (forward) {
+            if (useGridLayout()) {
-                // Walk backwards and focus the next task smaller than the current stack scroll
+                // For the grid layout, we directly set focus to the most recently used task
-                for (newIndex = taskCount - 1; newIndex >= 0; newIndex--) {
+                // no matter we're moving forwards or backwards.
-                    float taskP = mLayoutAlgorithm.getStackScrollForTask(tasks.get(newIndex));
+                newIndex = taskCount - 1;
-                    if (Float.compare(taskP, stackScroll) <= 0) {
-                        break;
-                    }
-                }
             } else {
-                // Walk forwards and focus the next task larger than the current stack scroll
+                // For the grid layout we pick a proper task to focus, according to the current
-                for (newIndex = 0; newIndex < taskCount; newIndex++) {
+                // stack scroll.
-                    float taskP = mLayoutAlgorithm.getStackScrollForTask(tasks.get(newIndex));
+                if (forward) {
-                    if (Float.compare(taskP, stackScroll) >= 0) {
+                    // Walk backwards and focus the next task smaller than the current stack scroll
-                        break;
+                    for (newIndex = taskCount - 1; newIndex >= 0; newIndex--) {
+                        float taskP = mLayoutAlgorithm.getStackScrollForTask(tasks.get(newIndex));
+                        if (Float.compare(taskP, stackScroll) <= 0) {
+                            break;
+                        }
+                    }
+                } else {
+                    // Walk forwards and focus the next task larger than the current stack scroll
+                    for (newIndex = 0; newIndex < taskCount; newIndex++) {
+                        float taskP = mLayoutAlgorithm.getStackScrollForTask(tasks.get(newIndex));
+                        if (Float.compare(taskP, stackScroll) >= 0) {
+                            break;
+                        }
                     }
                 }
             }
@@ -1037,20 +1063,23 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
     /**
      * Resets the focused task.
      */
-    void resetFocusedTask(Task task) {
+    public void resetFocusedTask(Task task) {
         if (task != null) {
             TaskView tv = getChildViewForTask(task);
             if (tv != null) {
                 tv.setFocusedState(false, false /* requestViewFocus */);
             }
         }
+        if (mTaskViewFocusFrame != null) {
+            mTaskViewFocusFrame.moveGridTaskViewFocus(null);
+        }
         mFocusedTask = null;
     }
 
     /**
      * Returns the focused task.
      */
-    Task getFocusedTask() {
+    public Task getFocusedTask() {
         return mFocusedTask;
     }
 
@@ -1253,6 +1282,9 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         for (int i = 0; i < taskViewCount; i++) {
             measureTaskView(mTmpTaskViews.get(i));
         }
+        if (mTaskViewFocusFrame != null) {
+            mTaskViewFocusFrame.measure();
+        }
 
         setMeasuredDimension(width, height);
         mLastWidth = width;
@@ -1287,6 +1319,9 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         for (int i = 0; i < taskViewCount; i++) {
             layoutTaskView(changed, mTmpTaskViews.get(i));
         }
+        if (mTaskViewFocusFrame != null) {
+            mTaskViewFocusFrame.layout();
+        }
 
         if (changed) {
             if (mStackScroller.isScrollOutOfBounds()) {
@@ -1339,10 +1374,19 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         // until after the enter-animation
         RecentsConfiguration config = Recents.getConfiguration();
         RecentsActivityLaunchState launchState = config.getLaunchState();
-        int focusedTaskIndex = launchState.getInitialFocusTaskIndex(mStack.getTaskCount());
+
-        if (focusedTaskIndex != -1) {
+        // We set the initial focused task view iff the following conditions are satisfied:
-            setFocusedTask(focusedTaskIndex, false /* scrollToTask */,
+        // 1. Recents is showing task views in stack layout.
-                    false /* requestViewFocus */);
+        // 2. Recents is launched with ALT + TAB.
+        boolean setFocusOnFirstLayout = !useGridLayout() ||
+            Recents.getConfiguration().getLaunchState().launchedWithAltTab;
+        if (setFocusOnFirstLayout) {
+            int focusedTaskIndex = launchState.getInitialFocusTaskIndex(mStack.getTaskCount(),
+                useGridLayout());
+            if (focusedTaskIndex != -1) {
+                setFocusedTask(focusedTaskIndex, false /* scrollToTask */,
+                        false /* requestViewFocus */);
+            }
         }
         updateStackActionButtonVisibility();
     }
@@ -1443,6 +1487,11 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         // Remove the task from the ignored set
         removeIgnoreTask(removedTask);
 
+        // Resize the grid layout task view focus frame
+        if (mTaskViewFocusFrame != null) {
+            mTaskViewFocusFrame.resize();
+        }
+
         // If requested, relayout with the given animation
         if (animation != null) {
             updateLayoutAlgorithm(true /* boundScroll */);
@@ -1740,10 +1789,18 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         int taskViewExitToHomeDuration = TaskStackAnimationHelper.EXIT_TO_HOME_TRANSLATION_DURATION;
         animateFreeformWorkspaceBackgroundAlpha(0, new AnimationProps(taskViewExitToHomeDuration,
                 Interpolators.FAST_OUT_SLOW_IN));
+
+        // Dismiss the grid task view focus frame
+        if (mTaskViewFocusFrame != null) {
+            mTaskViewFocusFrame.moveGridTaskViewFocus(null);
+        }
     }
 
     public final void onBusEvent(DismissFocusedTaskViewEvent event) {
         if (mFocusedTask != null) {
+            if (mTaskViewFocusFrame != null) {
+                mTaskViewFocusFrame.moveGridTaskViewFocus(null);
+            }
             TaskView tv = getChildViewForTask(mFocusedTask);
             if (tv != null) {
                 tv.dismissTask();
@@ -2073,6 +2130,12 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         mResetToInitialStateWhenResized = true;
     }
 
+    public final void onBusEvent(RecentsVisibilityChangedEvent event) {
+        if (!event.visible && mTaskViewFocusFrame != null) {
+            mTaskViewFocusFrame.moveGridTaskViewFocus(null);
+        }
+    }
+
     public void reloadOnConfigurationChange() {
         mStableLayoutAlgorithm.reloadOnConfigurationChange(getContext());
         mLayoutAlgorithm.reloadOnConfigurationChange(getContext());

packages/SystemUI/src/com/android/systemui/recents/views/TaskStackViewTouchHandler.java

@@ -342,8 +342,9 @@ class TaskStackViewTouchHandler implements SwipeHelper.Callback {
                         mSv.invalidate();
                     }
 
-                    // Reset the focused task after the user has scrolled
+                    // Reset the focused task after the user has scrolled, but we have no scrolling
-                    if (!mSv.mTouchExplorationEnabled) {
+                    // in grid layout and therefore we don't want to reset the focus there.
+                    if (!mSv.mTouchExplorationEnabled && !mSv.useGridLayout()) {
                         mSv.resetFocusedTask(mSv.getFocusedTask());
                     }
                 } else if (mActiveTaskView == null) {

packages/SystemUI/src/com/android/systemui/recents/views/grid/TaskGridLayoutAlgorithm.java

@@ -51,6 +51,9 @@ public class TaskGridLayoutAlgorithm  {
     private float mAppAspectRatio;
     private Rect mSystemInsets = new Rect();
 
+    /** The thickness of the focused task view frame. */
+    private int mFocusedFrameThickness;
+
     /**
      * When the amount of tasks is determined, the size and position of every task view can be
      * decided. Each instance of TaskGridRectInfo store the task view information for a certain
@@ -137,6 +140,9 @@ public class TaskGridLayoutAlgorithm  {
     public void reloadOnConfigurationChange(Context context) {
         Resources res = context.getResources();
         mPaddingTaskView = res.getDimensionPixelSize(R.dimen.recents_grid_padding_task_view);
+        mFocusedFrameThickness = res.getDimensionPixelSize(
+            R.dimen.recents_grid_task_view_focused_frame_thickness);
+
         mTaskGridRect = new Rect();
         mTitleBarHeight = res.getDimensionPixelSize(R.dimen.recents_grid_task_view_header_height);
 
@@ -223,7 +229,18 @@ public class TaskGridLayoutAlgorithm  {
         return buttonRect;
     }
 
+    public void updateTaskGridRect(int taskCount) {
+        if (taskCount > 0) {
+            TaskGridRectInfo gridInfo = mTaskGridRectInfoList[taskCount - 1];
+            mTaskGridRect.set(gridInfo.size);
+        }
+    }
+
     public Rect getTaskGridRect() {
         return mTaskGridRect;
     }
+
+    public int getFocusFrameThickness() {
+        return mFocusedFrameThickness;
+    }
 }

packages/SystemUI/src/com/android/systemui/recents/views/grid/TaskViewFocusFrame.java

@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.recents.views.grid;
+
+import android.content.Context;
+import android.graphics.Rect;
+import android.util.AttributeSet;
+import android.view.View;
+
+import android.view.ViewTreeObserver.OnGlobalFocusChangeListener;
+import com.android.systemui.R;
+import com.android.systemui.recents.model.TaskStack;
+import com.android.systemui.recents.views.TaskStackView;
+
+public class TaskViewFocusFrame extends View implements OnGlobalFocusChangeListener {
+
+    private TaskStackView mSv;
+    private TaskGridLayoutAlgorithm mTaskGridLayoutAlgorithm;
+    public TaskViewFocusFrame(Context context) {
+        this(context, null);
+    }
+
+    public TaskViewFocusFrame(Context context, AttributeSet attrs) {
+        this(context, attrs, 0);
+    }
+
+    public TaskViewFocusFrame(Context context, AttributeSet attrs, int defStyleAttr) {
+        this(context, attrs, defStyleAttr, 0);
+    }
+
+    public TaskViewFocusFrame(Context context, AttributeSet attrs, int defStyleAttr,
+        int defStyleRes) {
+        super(context, attrs, defStyleAttr, defStyleRes);
+        setBackground(mContext.getDrawable(
+            R.drawable.recents_grid_task_view_focus_frame_background));
+        setFocusable(false);
+        hide();
+    }
+
+    public TaskViewFocusFrame(Context context, TaskStackView stackView,
+        TaskGridLayoutAlgorithm taskGridLayoutAlgorithm) {
+        this(context);
+        mSv = stackView;
+        mTaskGridLayoutAlgorithm = taskGridLayoutAlgorithm;
+    }
+
+    /**
+     * Measure the width and height of the focus frame according to the current grid task view size.
+     */
+    public void measure() {
+        int thickness = mTaskGridLayoutAlgorithm.getFocusFrameThickness();
+        Rect rect = mTaskGridLayoutAlgorithm.getTaskGridRect();
+        measure(
+            MeasureSpec.makeMeasureSpec(rect.width() + thickness * 2, MeasureSpec.EXACTLY),
+            MeasureSpec.makeMeasureSpec(rect.height() + thickness * 2, MeasureSpec.EXACTLY));
+    }
+
+    /**
+     * Layout the focus frame with its size.
+     */
+    public void layout() {
+        layout(0, 0, getMeasuredWidth(), getMeasuredHeight());
+    }
+
+    /**
+     * Update the current size of grid task view and the focus frame.
+     */
+    public void resize() {
+        if (mSv.useGridLayout()) {
+            mTaskGridLayoutAlgorithm.updateTaskGridRect(mSv.getStack().getTaskCount());
+            measure();
+            requestLayout();
+        }
+    }
+
+    /**
+     * Move the task view focus frame to surround the newly focused view. If it's {@code null} or
+     * it's not an instance of GridTaskView, we hide the focus frame.
+     * @param newFocus The newly focused view.
+     */
+    public void moveGridTaskViewFocus(View newFocus) {
+        if (mSv.useGridLayout()) {
+            // The frame only shows up in the grid layout. It shouldn't show up in the stack
+            // layout including when we're in the split screen.
+            if (newFocus instanceof GridTaskView) {
+                // If the focus goes to a GridTaskView, we show the frame and layout it.
+                int[] location = new int[2];
+                newFocus.getLocationInWindow(location);
+                int thickness = mTaskGridLayoutAlgorithm.getFocusFrameThickness();
+                setTranslationX(location[0] - thickness);
+                setTranslationY(location[1] - thickness);
+                show();
+            } else {
+                // If focus goes to other views, we hide the frame.
+                hide();
+            }
+        }
+    }
+
+    @Override
+    public void onGlobalFocusChanged(View oldFocus, View newFocus) {
+        if (!mSv.useGridLayout()) {
+            return;
+        }
+        if (newFocus == null) {
+            // We're going to touch mode, unset the focus.
+            moveGridTaskViewFocus(null);
+            return;
+        }
+        if (oldFocus == null) {
+            // We're returning from touch mode, set the focus to the previously focused task.
+            final TaskStack stack = mSv.getStack();
+            final int taskCount = stack.getTaskCount();
+            final int k = stack.indexOfStackTask(mSv.getFocusedTask());
+            final int taskIndexToFocus = k == -1 ? (taskCount - 1) : (k % taskCount);
+            mSv.setFocusedTask(taskIndexToFocus, false, true);
+        }
+    }
+
+    private void show() {
+        setAlpha(1f);
+    }
+
+    private void hide() {
+        setAlpha(0f);
+    }
+}