Improve screen on/off logic in slideshow.

When used as a screensaver or otherwise, the slideshow
should not keep the screen on if the device is not plugged
in. It should also allow the screen to lock while the
slideshow is playing (otherwise a device left in this state
may be left unsecured for long periods by accident).
Additionally, when used as a screensaver, it must dismiss
the keyguard in order to be shown on a secured device.

Bug: 5660833
Change-Id: I1bafc50127aaa7ae2b67235d30736faa606c5ac1

1 files changed, 54 insertions, 4 deletions

diff --git a/src/com/android/gallery3d/app/ActivityState.java b/src/com/android/gallery3d/app/ActivityState.java
index 519eaff58..1ef93a4bc 100644
--- a/src/com/android/gallery3d/app/ActivityState.java
+++ b/src/com/android/gallery3d/app/ActivityState.java
@@ -20,17 +20,30 @@ import com.android.gallery3d.ui.GLView;
 
 import android.app.ActionBar;
 import android.app.Activity;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
 import android.content.Intent;
 import android.content.res.Configuration;
+import android.os.BatteryManager;
 import android.os.Bundle;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
+import android.view.Window;
 import android.view.WindowManager;
 
 abstract public class ActivityState {
     public static final int FLAG_HIDE_ACTION_BAR = 1;
     public static final int FLAG_HIDE_STATUS_BAR = 2;
+    public static final int FLAG_SCREEN_ON = 3;
+
+    private static final int SCREEN_ON_FLAGS = (
+              WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
+            | WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON
+            | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
+        );
 
     protected GalleryActivity mActivity;
     protected Bundle mData;
@@ -47,6 +60,7 @@ abstract public class ActivityState {
     }
 
     private boolean mDestroyed = false;
+    private boolean mPlugged = false;
 
     protected ActivityState() {
     }
@@ -86,7 +100,34 @@ abstract public class ActivityState {
     protected void onCreate(Bundle data, Bundle storedState) {
     }
 
+    BroadcastReceiver mPowerIntentReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            final String action = intent.getAction();
+            if (Intent.ACTION_BATTERY_CHANGED.equals(action)) {
+                boolean plugged = (0 != intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, 0));
+
+                if (plugged != mPlugged) {
+                    mPlugged = plugged;
+                    final Window win = ((Activity) mActivity).getWindow();
+                    final WindowManager.LayoutParams params = win.getAttributes();
+                    setScreenOnFlags(params);
+                    win.setAttributes(params);
+                }
+            }
+        }
+    };
+
+    void setScreenOnFlags(WindowManager.LayoutParams params) {
+        if (mPlugged && 0 != (mFlags & FLAG_SCREEN_ON)) {
+            params.flags |= SCREEN_ON_FLAGS;
+        } else {
+            params.flags &= ~SCREEN_ON_FLAGS;
+        }
+    }
+
     protected void onPause() {
+        ((Activity) mActivity).unregisterReceiver(mPowerIntentReceiver);
     }
 
     // should only be called by StateManager
@@ -108,21 +149,30 @@ abstract public class ActivityState {
 
         activity.invalidateOptionsMenu();
 
+        final Window win = activity.getWindow();
+        final WindowManager.LayoutParams params = win.getAttributes();
+
         if ((mFlags & FLAG_HIDE_STATUS_BAR) != 0) {
-            WindowManager.LayoutParams params = ((Activity) mActivity).getWindow().getAttributes();
             params.systemUiVisibility = View.SYSTEM_UI_FLAG_LOW_PROFILE;
-            ((Activity) mActivity).getWindow().setAttributes(params);
         } else {
-            WindowManager.LayoutParams params = ((Activity) mActivity).getWindow().getAttributes();
             params.systemUiVisibility = View.SYSTEM_UI_FLAG_VISIBLE;
-            ((Activity) mActivity).getWindow().setAttributes(params);
         }
 
+        setScreenOnFlags(params);
+        win.setAttributes(params);
+
         ResultEntry entry = mReceivedResults;
         if (entry != null) {
             mReceivedResults = null;
             onStateResult(entry.requestCode, entry.resultCode, entry.resultData);
         }
+
+        if (0 != (mFlags & FLAG_SCREEN_ON)) {
+            // we need to know whether the device is plugged in to do this correctly
+            final IntentFilter filter = new IntentFilter();
+            filter.addAction(Intent.ACTION_BATTERY_CHANGED);
+            activity.registerReceiver(mPowerIntentReceiver, filter);
+        }
         onResume();
     }