android: update activity lib, optimize app exit

app/src/main/java/mw/gri/android/BackgroundService.java

@@ -31,11 +31,13 @@ public class BackgroundService extends Service {
             mNotificationBuilder.setContentText(getSyncStatusText());
             NotificationManager manager = getSystemService(NotificationManager.class);
             manager.notify(SYNC_STATUS_NOTIFICATION_ID, mNotificationBuilder.build());
-            // Send broadcast to MainActivity if app exit is needed after node stop.
+
+            // Send broadcast to MainActivity if exit from the app is needed after node stop.
             if (exitAppAfterNodeStop()) {
-                sendBroadcast(new Intent(MainActivity.FINISH_ACTIVITY_ACTION));
+                sendBroadcast(new Intent(MainActivity.STOP_APP_ACTION));
                 mStopped = true;
             }
+
             // Repeat notification update if service is not stopped.
             if (!mStopped) {
                 mHandler.postDelayed(this, 500);
@@ -45,10 +47,15 @@ public class BackgroundService extends Service {
 
     @Override
     public void onCreate() {
+        if (mStopped) {
+            return;
+        }
+
         // Prevent CPU to sleep at background.
         PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
         mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
         mWakeLock.acquire();
+
         // Create channel to show notifications.
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             NotificationChannel notificationChannel = new NotificationChannel(
@@ -58,6 +65,7 @@ public class BackgroundService extends Service {
             NotificationManager manager = getSystemService(NotificationManager.class);
             manager.createNotificationChannel(notificationChannel);
         }
+
         // Show notification with sync status.
         Intent i = getPackageManager().getLaunchIntentForPackage(this.getPackageName());
         PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, i, PendingIntent.FLAG_IMMUTABLE);
@@ -67,8 +75,10 @@ public class BackgroundService extends Service {
                 .setSmallIcon(R.drawable.ic_stat_name)
                 .setContentIntent(pendingIntent);
         Notification notification = mNotificationBuilder.build();
+
         // Start service at foreground state to prevent killing by system.
         startForeground(SYNC_STATUS_NOTIFICATION_ID, notification);
+
         // Update sync status at notification.
         mHandler.post(mUpdateSyncStatus);
     }
@@ -98,16 +108,20 @@ public class BackgroundService extends Service {
 
     public void onStop() {
         mStopped = true;
+
         // Stop updating the notification.
         mHandler.removeCallbacks(mUpdateSyncStatus);
+
         // Remove service from foreground state.
         stopForeground(Service.STOP_FOREGROUND_REMOVE);
+
         // Remove notification.
         NotificationManager notificationManager = getSystemService(NotificationManager.class);
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             notificationManager.deleteNotificationChannel(TAG);
         }
         notificationManager.cancel(SYNC_STATUS_NOTIFICATION_ID);
+
         // Release wake lock to allow CPU to sleep at background.
         if (mWakeLock.isHeld()) {
             mWakeLock.release();
@@ -149,6 +163,6 @@ public class BackgroundService extends Service {
     private native String getSyncStatusText();
     // Get sync title text for notification from native code.
     private native String getSyncTitle();
-    // Check if exit app is needed after node stop from native code.
+    // Check if app from the app is needed after node stop from native code.
     private native boolean exitAppAfterNodeStop();
 }

app/src/main/java/mw/gri/android/MainActivity.java

@@ -5,7 +5,6 @@ import android.os.Bundle;
 import android.os.Process;
 import android.system.ErrnoException;
 import android.system.Os;
-import android.util.Log;
 import android.view.KeyEvent;
 import android.view.View;
 import androidx.core.graphics.Insets;
@@ -14,14 +13,11 @@ import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
 import com.google.androidgamesdk.GameActivity;
 
-import java.util.concurrent.atomic.AtomicBoolean;
-
 import static android.content.ClipDescription.MIMETYPE_TEXT_HTML;
 import static android.content.ClipDescription.MIMETYPE_TEXT_PLAIN;
 
 public class MainActivity extends GameActivity {
-
-    public static String FINISH_ACTIVITY_ACTION = "MainActivity.finish";
+    public static String STOP_APP_ACTION = "STOP_APP";
 
     static {
         System.loadLibrary("grim");
@@ -30,9 +26,9 @@ public class MainActivity extends GameActivity {
     private final BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context ctx, Intent i) {
-            if (i.getAction().equals(FINISH_ACTIVITY_ACTION)) {
-                unregisterReceiver(this);
+            if (i.getAction().equals(STOP_APP_ACTION)) {
                 onExit();
+                Process.killProcess(Process.myPid());
             }
         }
     };
@@ -48,7 +44,7 @@ public class MainActivity extends GameActivity {
         super.onCreate(null);
 
         // Register receiver to finish activity from the BackgroundService.
-        registerReceiver(mBroadcastReceiver, new IntentFilter(FINISH_ACTIVITY_ACTION));
+        registerReceiver(mBroadcastReceiver, new IntentFilter(STOP_APP_ACTION));
 
         // Start notification service.
         BackgroundService.start(this);
@@ -99,43 +95,33 @@ public class MainActivity extends GameActivity {
     // Implemented into native code to handle key code BACK event.
     public native void onBack();
 
-    private boolean mManualExit;
-    private final AtomicBoolean mActivityDestroyed = new AtomicBoolean(false);
+    // Actions on app exit.
+    private void onExit() {
+        unregisterReceiver(mBroadcastReceiver);
+        BackgroundService.stop(this);
+    }
 
     @Override
     protected void onDestroy() {
-        if (!mManualExit) {
-            unregisterReceiver(mBroadcastReceiver);
-            onTermination();
-        }
+        onExit();
 
-        // Temp fix: kill process after 3 seconds to prevent app hanging at next launch.
+        // Kill process after 3 seconds if app was terminated from recent apps to prevent app hanging.
         new Thread(() -> {
             try {
+                onTermination();
                 Thread.sleep(3000);
-                if (!mActivityDestroyed.get()) {
-                    Process.killProcess(Process.myPid());
-                }
+                Process.killProcess(Process.myPid());
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
         }).start();
+
+        // Destroy an app and kill process.
         super.onDestroy();
-        mActivityDestroyed.set(true);
+        Process.killProcess(Process.myPid());
     }
 
-    // Called from native code.
-    public void onExit() {
-        // Return if exit was already requested.
-        if (mManualExit) {
-            return;
-        }
-        mManualExit = true;
-        BackgroundService.stop(this);
-        finish();
-    }
-
-    // Notify native code to stop activity (e.g. node) on app destroy.
+    // Notify native code to stop activity (e.g. node) if app was terminated from recent apps.
     public native void onTermination();
 
     // Called from native code to set text into clipboard.