Use VaultLockReceiver in a Context-registered manner

Turns out we can't listen from ACTION_SCREEN_OFF from a
manifest-registered broadcast receiver

app/src/main/AndroidManifest.xml

@@ -97,7 +97,6 @@
         <receiver android:name=".receivers.VaultLockReceiver" android:exported="false">
             <intent-filter>
                 <action android:name="${applicationId}.LOCK_VAULT" />
-                <action android:name="android.intent.action.SCREEN_OFF" />
             </intent-filter>
         </receiver>
 

app/src/main/java/com/beemdevelopment/aegis/AegisApplicationBase.java

@@ -4,6 +4,7 @@ import android.app.Application;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
 import android.content.Intent;
+import android.content.IntentFilter;
 import android.content.pm.ShortcutInfo;
 import android.content.pm.ShortcutManager;
 import android.graphics.drawable.Icon;
@@ -11,11 +12,13 @@ import android.os.Build;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.RequiresApi;
+import androidx.core.content.ContextCompat;
 import androidx.lifecycle.Lifecycle;
 import androidx.lifecycle.LifecycleEventObserver;
 import androidx.lifecycle.LifecycleOwner;
 import androidx.lifecycle.ProcessLifecycleOwner;
 
+import com.beemdevelopment.aegis.receivers.VaultLockReceiver;
 import com.beemdevelopment.aegis.ui.MainActivity;
 import com.beemdevelopment.aegis.util.IOUtils;
 import com.beemdevelopment.aegis.vault.VaultManager;
@@ -48,6 +51,10 @@ public abstract class AegisApplicationBase extends Application {
         Iconics.init(this);
         Iconics.registerFont(new MaterialDesignIconic());
 
+        VaultLockReceiver lockReceiver = new VaultLockReceiver();
+        IntentFilter intentFilter = new IntentFilter(Intent.ACTION_SCREEN_OFF);
+        ContextCompat.registerReceiver(this, lockReceiver, intentFilter, ContextCompat.RECEIVER_NOT_EXPORTED);
+
         // lock the app if the user moves the application to the background
         ProcessLifecycleOwner.get().getLifecycle().addObserver(new AppLifecycleObserver());
 

app/src/main/java/com/beemdevelopment/aegis/receivers/VaultLockReceiver.java

@@ -22,8 +22,9 @@ public class VaultLockReceiver extends BroadcastReceiver {
 
     @Override
     public void onReceive(Context context, Intent intent) {
-        if (!intent.getAction().equals(ACTION_LOCK_VAULT)
-                && !intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
+        if (intent.getAction() == null
+                || (!intent.getAction().equals(ACTION_LOCK_VAULT)
+                && !intent.getAction().equals(Intent.ACTION_SCREEN_OFF))) {
             return;
         }
 

app/src/main/java/com/beemdevelopment/aegis/services/NotificationService.java

@@ -29,14 +29,14 @@ public class NotificationService extends Service {
 
     @SuppressLint("LaunchActivityFromNotification")
     public void serviceMethod() {
-        Intent intent = new Intent(this, VaultLockReceiver.class);
-        intent.setAction(VaultLockReceiver.ACTION_LOCK_VAULT);
-        intent.setPackage(BuildConfig.APPLICATION_ID);
-
         int flags = PendingIntent.FLAG_ONE_SHOT;
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
             flags |= PendingIntent.FLAG_IMMUTABLE;
         }
+
+        Intent intent = new Intent(this, VaultLockReceiver.class);
+        intent.setAction(VaultLockReceiver.ACTION_LOCK_VAULT);
+        intent.setPackage(BuildConfig.APPLICATION_ID);
         PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 1, intent, flags);
 
         NotificationCompat.Builder builder = new NotificationCompat.Builder(this, CHANNEL_ID)