Fix sending empty token if worker was delayed

 - If the worker that stores the new token has not yet been executed and the user manually toggles push notifications in settings, an empty/outdated token may be sent. To prevent this from happening, when opening the user settings page, request the latest FCM token and update the stored value if necessary.

Author: jpelgrom

app/src/main/java/nl/jpelgrm/movienotifier/service/FcmRefreshWorker.java

@@ -3,11 +3,6 @@
 import android.content.Context;
 import android.content.SharedPreferences;
 
-import java.io.IOException;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.work.Constraints;
@@ -16,6 +11,11 @@
 import androidx.work.OneTimeWorkRequest;
 import androidx.work.Worker;
 import androidx.work.WorkerParameters;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+
 import nl.jpelgrm.movienotifier.data.APIHelper;
 import nl.jpelgrm.movienotifier.data.AppDatabase;
 import nl.jpelgrm.movienotifier.models.User;

app/src/main/java/nl/jpelgrm/movienotifier/ui/settings/SettingsAccountOverviewFragment.java

@@ -7,6 +7,7 @@
 import android.os.Build;
 import android.os.Bundle;
 import android.provider.Settings;
+import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -15,17 +16,19 @@
 import android.widget.ScrollView;
 import android.widget.TextView;
 
-import com.google.android.material.snackbar.Snackbar;
-
-import java.util.ArrayList;
-import java.util.Collections;
-
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.widget.SwitchCompat;
 import androidx.coordinatorlayout.widget.CoordinatorLayout;
 import androidx.fragment.app.Fragment;
+
+import com.google.android.material.snackbar.Snackbar;
+import com.google.firebase.iid.FirebaseInstanceId;
+
+import java.util.ArrayList;
+import java.util.Collections;
+
 import butterknife.BindView;
 import butterknife.ButterKnife;
 import nl.jpelgrm.movienotifier.BuildConfig;
@@ -90,6 +93,8 @@ public void onCreate(@Nullable Bundle savedInstanceState) {
 
         settings = getContext().getSharedPreferences("settings", Context.MODE_PRIVATE);
         notificationSettings = getContext().getSharedPreferences("notifications", Context.MODE_PRIVATE);
+
+        verifyFCMToken();
     }
 
     @Nullable
@@ -180,7 +185,11 @@ private void togglePushNotifications() {
         boolean setToEnabled = notificationsPush.isChecked();
         if(setToEnabled) {
             if(!toUpdate.getFcmTokens().contains(token)) {
-                changed = toUpdate.getFcmTokens().add(token);
+                if(!token.equals("")) {
+                    changed = toUpdate.getFcmTokens().add(token);
+                } else {
+                    notificationsPush.setChecked(false);
+                }
             }
         } else {
             if(toUpdate.getFcmTokens().contains(token)) {
@@ -445,6 +454,18 @@ public void onFailure(@NonNull Call<ResponseBody> call, @NonNull Throwable t) {
         }).setNegativeButton(R.string.no, null).show();
     }
 
+    private void verifyFCMToken() {
+        FirebaseInstanceId.getInstance().getInstanceId().addOnCompleteListener(task -> {
+            if(task.isSuccessful() && task.getResult() != null) {
+                String storedToken = notificationSettings.getString("token", "");
+                String receivedToken = task.getResult().getToken();
+                if(!storedToken.equals(receivedToken)) {
+                    notificationSettings.edit().putString("token", receivedToken).apply();
+                }
+            }
+        });
+    }
+
     private void setFieldsEnabled(boolean enabled) {
         accountSwitch.setClickable(enabled);
         accountName.setClickable(enabled);