Remove back button when on home screen

Add OverviewInteractionState to handle setting OverviewInteractionFlags.

Hide back button when in NORMAL state and launcher's window is focused.
Show it when in other states or when launcher's window loses focus.

Change-Id: I35919561b9972789e995f1cc434c23e2afe9e77c

2 files changed, 72 insertions, 3 deletions

diff --git a/quickstep/src/com/android/launcher3/uioverrides/UiFactory.java b/quickstep/src/com/android/launcher3/uioverrides/UiFactory.java
index b4f40c215..92b38fe01 100644
--- a/quickstep/src/com/android/launcher3/uioverrides/UiFactory.java
+++ b/quickstep/src/com/android/launcher3/uioverrides/UiFactory.java
@@ -16,12 +16,11 @@
 
 package com.android.launcher3.uioverrides;
 
-import android.content.pm.PackageManager;
+import static com.android.launcher3.LauncherState.NORMAL;
+
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.PointF;
-import android.os.Bundle;
-import android.view.View;
 import android.view.View.AccessibilityDelegate;
 
 import com.android.launcher3.Launcher;
@@ -29,6 +28,7 @@ import com.android.launcher3.LauncherStateManager.StateHandler;
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.graphics.BitmapRenderer;
 import com.android.launcher3.util.TouchController;
+import com.android.quickstep.OverviewInteractionState;
 import com.android.quickstep.RecentsView;
 import com.android.systemui.shared.recents.view.RecentsTransition;
 
@@ -68,6 +68,11 @@ public class UiFactory {
         OptionsPopupView.show(launcher, touchPoint.x, touchPoint.y);
     }
 
+    public static void onLauncherStateOrFocusChanged(Launcher launcher) {
+        OverviewInteractionState.setBackButtonVisible(launcher, !launcher.isInState(NORMAL)
+                || !launcher.hasWindowFocus());
+    }
+
     public static Bitmap createFromRenderer(int width, int height, boolean forceSoftwareRenderer,
             BitmapRenderer renderer) {
         if (USE_HARDWARE_BITMAP && !forceSoftwareRenderer) {
diff --git a/quickstep/src/com/android/quickstep/OverviewInteractionState.java b/quickstep/src/com/android/quickstep/OverviewInteractionState.java
new file mode 100644
index 000000000..9be12bdb9
--- /dev/null
+++ b/quickstep/src/com/android/quickstep/OverviewInteractionState.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2018 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.quickstep;
+
+import static com.android.systemui.shared.system.NavigationBarCompat.FLAG_HIDE_BACK_BUTTON;
+
+import android.content.Context;
+import android.os.RemoteException;
+import android.util.Log;
+
+import com.android.systemui.shared.recents.ISystemUiProxy;
+
+/**
+ * Sets overview interaction flags, such as:
+ *
+ *   - FLAG_DISABLE_QUICK_SCRUB
+ *   - FLAG_DISABLE_SWIPE_UP
+ *   - FLAG_HIDE_BACK_BUTTON
+ *   - FLAG_SHOW_OVERVIEW_BUTTON
+ *
+ * @see com.android.systemui.shared.system.NavigationBarCompat.InteractionType and associated flags.
+ */
+public class OverviewInteractionState {
+
+    private static final String TAG = "OverviewFlags";
+
+    private static int sFlags;
+
+    public static void setBackButtonVisible(Context context, boolean visible) {
+        updateOverviewInteractionFlag(context, FLAG_HIDE_BACK_BUTTON, !visible);
+    }
+
+    private static void updateOverviewInteractionFlag(Context context, int flag, boolean enabled) {
+        if (enabled) {
+            sFlags |= flag;
+        } else {
+            sFlags &= ~flag;
+        }
+
+        ISystemUiProxy systemUiProxy = RecentsModel.getInstance(context).getSystemUiProxy();
+        if (systemUiProxy == null) {
+            Log.w(TAG, "Unable to update overview interaction flags; not bound to service");
+            return;
+        }
+        try {
+            systemUiProxy.setInteractionState(sFlags);
+        } catch (RemoteException e) {
+            Log.w(TAG, "Unable to update overview interaction flags", e);
+        }
+    }
+}