Remember that app entered doze mode and inform user when returning

briar-android/src/main/java/org/briarproject/briar/android/BriarService.java

@@ -3,12 +3,16 @@ package org.briarproject.briar.android;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
 import android.app.Service;
+import android.content.BroadcastReceiver;
 import android.content.ComponentName;
+import android.content.Context;
 import android.content.Intent;
+import android.content.IntentFilter;
 import android.content.ServiceConnection;
 import android.os.Binder;
-import android.os.Build;
 import android.os.IBinder;
+import android.os.PowerManager;
+import android.support.annotation.Nullable;
 import android.support.v4.app.NotificationCompat;
 import android.support.v4.content.ContextCompat;
 
@@ -28,12 +32,15 @@ import javax.inject.Inject;
 import static android.app.PendingIntent.FLAG_UPDATE_CURRENT;
 import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TOP;
 import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
 import static android.support.v4.app.NotificationCompat.CATEGORY_SERVICE;
 import static android.support.v4.app.NotificationCompat.PRIORITY_MIN;
 import static android.support.v4.app.NotificationCompat.VISIBILITY_SECRET;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.ALREADY_RUNNING;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.SUCCESS;
+import static org.briarproject.briar.android.util.UiUtils.needsDozeWhitelisting;
 
 public class BriarService extends Service {
 
@@ -45,6 +52,9 @@ public class BriarService extends Service {
 
 	private final AtomicBoolean created = new AtomicBoolean(false);
 	private final Binder binder = new BriarBinder();
+	@Nullable
+	private BriarBroadcastReceiver receiver = null;
+	private boolean hasDozed = false;
 
 	@Inject
 	protected DatabaseConfig databaseConfig;
@@ -84,7 +94,7 @@ public class BriarService extends Service {
 		Intent i = new Intent(this, NavDrawerActivity.class);
 		i.setFlags(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_CLEAR_TOP);
 		b.setContentIntent(PendingIntent.getActivity(this, 0, i, 0));
-		if (Build.VERSION.SDK_INT >= 21) {
+		if (SDK_INT >= 21) {
 			b.setCategory(CATEGORY_SERVICE);
 			b.setVisibility(VISIBILITY_SECRET);
 		}
@@ -109,6 +119,7 @@ public class BriarService extends Service {
 				}
 			}
 		}.start();
+		registerBroadcastReceiver();
 	}
 
 	private void showStartupFailureNotification(StartResult result) {
@@ -153,6 +164,7 @@ public class BriarService extends Service {
 	public void onDestroy() {
 		super.onDestroy();
 		LOG.info("Destroyed");
+		if (receiver != null) unregisterReceiver(receiver);
 		stopForeground(true);
 		// Stop the services in a background thread
 		new Thread() {
@@ -170,6 +182,21 @@ public class BriarService extends Service {
 		// FIXME: Work out what to do about it
 	}
 
+	private void registerBroadcastReceiver() {
+		if (SDK_INT < 23) return;
+		IntentFilter filter = new IntentFilter(ACTION_DEVICE_IDLE_MODE_CHANGED);
+		if (receiver == null) receiver = new BriarBroadcastReceiver();
+		registerReceiver(receiver, filter);
+	}
+
+	public boolean hasDozed() {
+		return hasDozed;
+	}
+
+	public void resetDozeFlag() {
+		hasDozed = false;
+	}
+
 	/**
 	 * Waits for all services to start before returning.
 	 */
@@ -225,4 +252,15 @@ public class BriarService extends Service {
 			return binder;
 		}
 	}
+
+	public class BriarBroadcastReceiver extends BroadcastReceiver {
+		@Override
+		public void onReceive(Context context, Intent intent) {
+			if (SDK_INT < 23 || !needsDozeWhitelisting(getApplicationContext()))
+				return;
+			PowerManager pm = (PowerManager) getSystemService(POWER_SERVICE);
+			if (pm.isDeviceIdleMode()) hasDozed = true;
+		}
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/activity/BriarActivity.java

@@ -4,15 +4,18 @@ import android.annotation.SuppressLint;
 import android.content.Intent;
 import android.os.Build;
 import android.support.v7.app.ActionBar;
+import android.support.v7.app.AlertDialog;
 import android.support.v7.widget.Toolbar;
 import android.transition.Slide;
 import android.transition.Transition;
 import android.view.Gravity;
 import android.view.Window;
+import android.widget.CheckBox;
 
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.controller.BriarController;
 import org.briarproject.briar.android.controller.DbController;
+import org.briarproject.briar.android.controller.handler.UiResultHandler;
 import org.briarproject.briar.android.login.PasswordActivity;
 import org.briarproject.briar.android.panic.ExitActivity;
 
@@ -25,7 +28,9 @@ import static android.content.Intent.FLAG_ACTIVITY_CLEAR_TASK;
 import static android.content.Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS;
 import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 import static android.content.Intent.FLAG_ACTIVITY_NO_ANIMATION;
+import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_DOZE_WHITELISTING;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_PASSWORD;
+import static org.briarproject.briar.android.util.UiUtils.getDozeWhitelistingIntent;
 
 @SuppressLint("Registered")
 public abstract class BriarActivity extends BaseActivity {
@@ -59,6 +64,13 @@ public abstract class BriarActivity extends BaseActivity {
 		if (!briarController.hasEncryptionKey() && !isFinishing()) {
 			Intent i = new Intent(this, PasswordActivity.class);
 			startActivityForResult(i, REQUEST_PASSWORD);
+		} else {
+			briarController.hasDozed(new UiResultHandler<Boolean>(this) {
+				@Override
+				public void onResultUi(Boolean result) {
+					if (result) showDozeDialog();
+				}
+			});
 		}
 	}
 
@@ -97,6 +109,29 @@ public abstract class BriarActivity extends BaseActivity {
 		return toolbar;
 	}
 
+	private void showDozeDialog() {
+		AlertDialog.Builder b =
+				new AlertDialog.Builder(this, R.style.BriarDialogTheme);
+		b.setMessage(getString(R.string.warning_dozed,
+				getString(R.string.app_name)));
+		b.setView(R.layout.checkbox);
+		b.setPositiveButton(R.string.fix,
+				(dialog, which) -> {
+					Intent i = getDozeWhitelistingIntent(BriarActivity.this);
+					startActivityForResult(i, REQUEST_DOZE_WHITELISTING);
+					dialog.dismiss();
+				});
+		b.setNegativeButton(R.string.cancel,
+				(dialog, which) -> dialog.dismiss());
+		b.setOnDismissListener(dialog -> {
+			CheckBox checkBox = (CheckBox) ((AlertDialog) dialog)
+					.findViewById(R.id.checkbox);
+			if (checkBox.isChecked())
+				briarController.doNotNotifyWhenDozed();
+		});
+		b.show();
+	}
+
 	protected void signOut(boolean removeFromRecentApps) {
 		if (briarController.hasEncryptionKey()) {
 			// Don't use UiResultHandler because we want the result even if

briar-android/src/main/java/org/briarproject/briar/android/controller/BriarController.java

@@ -8,5 +8,13 @@ public interface BriarController extends ActivityLifecycleController {
 
 	boolean hasEncryptionKey();
 
+	/**
+	 * Returns true via the handler when the app has dozed
+	 * without being white-listed.
+	 */
+	void hasDozed(ResultHandler<Boolean> handler);
+
+	void doNotNotifyWhenDozed();
+
 	void signOut(ResultHandler<Void> eventHandler);
 }

briar-android/src/main/java/org/briarproject/briar/android/controller/BriarControllerImpl.java

@@ -6,30 +6,48 @@ import android.os.IBinder;
 import android.support.annotation.CallSuper;
 
 import org.briarproject.bramble.api.db.DatabaseConfig;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.settings.Settings;
+import org.briarproject.bramble.api.settings.SettingsManager;
 import org.briarproject.briar.android.BriarService;
 import org.briarproject.briar.android.BriarService.BriarServiceConnection;
 import org.briarproject.briar.android.controller.handler.ResultHandler;
 
+import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
+import static org.briarproject.briar.android.util.UiUtils.needsDozeWhitelisting;
+
 public class BriarControllerImpl implements BriarController {
 
 	private static final Logger LOG =
 			Logger.getLogger(BriarControllerImpl.class.getName());
 
+	private static final String HAS_DOZED_ASK_AGAIN = "hasDozedAskAgain";
+
 	private final BriarServiceConnection serviceConnection;
 	private final DatabaseConfig databaseConfig;
+	@DatabaseExecutor
+	private final Executor databaseExecutor;
+	private final SettingsManager settingsManager;
 	private final Activity activity;
 
 	private boolean bound = false;
 
 	@Inject
 	BriarControllerImpl(BriarServiceConnection serviceConnection,
-			DatabaseConfig databaseConfig, Activity activity) {
+			DatabaseConfig databaseConfig,
+			@DatabaseExecutor Executor databaseExecutor,
+			SettingsManager settingsManager, Activity activity) {
 		this.serviceConnection = serviceConnection;
 		this.databaseConfig = databaseConfig;
+		this.databaseExecutor = databaseExecutor;
+		this.settingsManager = settingsManager;
 		this.activity = activity;
 	}
 
@@ -65,6 +83,50 @@ public class BriarControllerImpl implements BriarController {
 		return databaseConfig.getEncryptionKey() != null;
 	}
 
+	@Override
+	public void hasDozed(ResultHandler<Boolean> handler) {
+		// check this first, to hit the DbThread only when really necessary
+		if (!needsDozeWhitelisting(activity)) {
+			handler.onResult(false);
+			return;
+		}
+		databaseExecutor.execute(() -> {
+			try {
+				Settings settings =
+						settingsManager.getSettings(SETTINGS_NAMESPACE);
+				boolean ask = settings.getBoolean(HAS_DOZED_ASK_AGAIN, true);
+				if (!ask) {
+					handler.onResult(false);
+					return;
+				}
+				IBinder binder = serviceConnection.waitForBinder();
+				BriarService service =
+						((BriarService.BriarBinder) binder).getService();
+				handler.onResult(service.hasDozed());
+				service.resetDozeFlag();
+			} catch (InterruptedException e) {
+				LOG.warning("Interrupted while waiting for service");
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING))
+					LOG.log(WARNING, e.toString(), e);
+			}
+		});
+	}
+
+	@Override
+	public void doNotNotifyWhenDozed() {
+		databaseExecutor.execute(() -> {
+			try {
+				Settings settings = new Settings();
+				settings.putBoolean(HAS_DOZED_ASK_AGAIN, false);
+				settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING))
+					LOG.log(WARNING, e.toString(), e);
+			}
+		});
+	}
+
 	@Override
 	public void signOut(ResultHandler<Void> eventHandler) {
 		new Thread() {

briar-android/src/main/java/org/briarproject/briar/android/navdrawer/NavDrawerControllerImpl.java

@@ -158,42 +158,37 @@ public class NavDrawerControllerImpl extends DbControllerImpl
 	}
 
 	@Override
-	public void askDozeWhitelisting(final Context ctx,
-			final ResultHandler<Boolean> handler) {
+	public void askDozeWhitelisting(Context ctx,
+			ResultHandler<Boolean> handler) {
+		// check this first, to hit the DbThread only when really necessary
 		if (!needsDozeWhitelisting(ctx)) {
 			handler.onResult(false);
 			return;
 		}
-		runOnDbThread(new Runnable() {
-			@Override
-			public void run() {
-				try {
-					Settings settings =
-							settingsManager.getSettings(SETTINGS_NAMESPACE);
-					boolean ask = settings.getBoolean(DOZE_ASK_AGAIN, true);
-					handler.onResult(ask);
-				} catch (DbException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-					handler.onResult(true);
-				}
+		runOnDbThread(() -> {
+			try {
+				Settings settings =
+						settingsManager.getSettings(SETTINGS_NAMESPACE);
+				boolean ask = settings.getBoolean(DOZE_ASK_AGAIN, true);
+				handler.onResult(ask);
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING))
+					LOG.log(WARNING, e.toString(), e);
+				handler.onResult(true);
 			}
 		});
 	}
 
 	@Override
 	public void doNotAskAgainForDozeWhiteListing() {
-		runOnDbThread(new Runnable() {
-			@Override
-			public void run() {
-				try {
-					Settings settings = new Settings();
-					settings.putBoolean(DOZE_ASK_AGAIN, false);
-					settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
-				} catch (DbException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-				}
+		runOnDbThread(() -> {
+			try {
+				Settings settings = new Settings();
+				settings.putBoolean(DOZE_ASK_AGAIN, false);
+				settingsManager.mergeSettings(settings, SETTINGS_NAMESPACE);
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING))
+					LOG.log(WARNING, e.toString(), e);
 			}
 		});
 	}