Add logging to debug problems with the Android app

* Add logging for activity lifecycle handlers
* Log the return code of the Qt event loop

This is a bit excessive and should probably be revereted later. For the
time being it is helpful, though.

Author: Martchus

tray/android/src/io/github/martchus/syncthingtray/Activity.java

@@ -10,6 +10,7 @@
 import android.view.HapticFeedbackConstants;
 import android.view.View;
 import android.widget.Toast;
+import android.util.Log;
 
 import androidx.core.content.FileProvider;
 
@@ -21,6 +22,7 @@
 import io.github.martchus.syncthingtray.Util;
 
 public class Activity extends QtActivity {
+    private static final String TAG = "SyncthingActivity";
 
     public boolean performHapticFeedback() {
         View rootView = getWindow().getDecorView().getRootView();
@@ -109,11 +111,13 @@ public void stopSyncthingService() {
     void handleSendText(Intent intent) {
         String sharedText = intent.getStringExtra(Intent.EXTRA_TEXT);
         if (sharedText != null) {
+            Log.i(TAG, "Sending shared text to Qt Quick app");
             sendAndroidIntentToQtQuickApp("sharedtext:" + sharedText, false);
         }
     }
 
     public void onCreate (Bundle savedInstanceState) {
+        Log.i(TAG, "Creating");
         super.onCreate(savedInstanceState);
         Intent intent = getIntent();
         String action = intent.getAction();
@@ -123,6 +127,31 @@ public void onCreate (Bundle savedInstanceState) {
         }
     }
 
+    public void onStart() {
+        Log.i(TAG, "Starting");
+        super.onStart();
+    }
+
+    public void onResume() {
+        Log.i(TAG, "Resuming");
+        super.onResume();
+    }
+
+    public void onPause() {
+        Log.i(TAG, "Pausing");
+        super.onPause();
+    }
+
+    public void onStop() {
+        Log.i(TAG, "Stopping");
+        super.onStop();
+    }
+
+    public void onDestroy() {
+        Log.i(TAG, "Destroying");
+        super.onDestroy();
+    }
+
     protected void onNewIntent(Intent intent) {
         boolean fromNotification = intent.getBooleanExtra("notification", false);
         if (fromNotification) {

tray/application/main.cpp

@@ -312,7 +312,11 @@ static int runApplication(int argc, const char *const *argv)
         quickApp.applySettings();
         QObject::connect(&app, &QCoreApplication::aboutToQuit, &quickApp, &App::shutdown);
         SyncthingLauncher::setMainInstance(quickApp.launcher());
-        return app.exec();
+        const auto res = app.exec();
+#if defined(Q_OS_ANDROID)
+        qDebug() << "Qt event loop exited with return code " << res;
+#endif
+        return res;
     }
 #endif