App crashes when clicking on notification

Question

I created an app that has chat in it and when users send messages it shows a notification to the receiver.

Now, I had like that when the user gets a notification and clicks on it, it will open the activity with all of its functionality.

The notification that I make looks like this:

public void notifyThis(String title, String message, String uniqueID, String var1, String var2, String var3) {

        Intent intent = new Intent(this, ChatActivity.class);

        intent.putExtra("ChatID",var1);
        intent.putExtra("ReceiverID",var2);
        intent.putExtra("SenderID",var3);

        int RandomID = (int) System.currentTimeMillis();

        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);

        NotificationCompat.Builder groupBuilder = new NotificationCompat.Builder(this,"191919")
                .setSmallIcon(R.drawable.ic_launcher_custom_background)
                .setGroup(uniqueID)
                .setGroupSummary(true);

        NotificationCompat.Builder messageBuilder = new NotificationCompat.Builder(this, "191919")
                .setSmallIcon(R.drawable.ic_launcher_custom_background)
                .setContentTitle(title)
                .setContentText(message)
                .setContentIntent(pendingIntent)
                .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                .setGroup( uniqueID )
                .setAutoCancel( true );

        NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
        notificationManager.notify(uniqueID,0, groupBuilder.build());
        notificationManager.notify(RandomID, messageBuilder.build());

    }

So far everything works ok and when I debug I see that var1, var2, var3 are not null and exist.

My problem is that when I click on the notification, the app crashes since it says:

java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference

But I can't understand why it gets SenderID to be null if the intent of the notification is sent with value in it and if I read it like this;

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate( savedInstanceState );

        setContentView( R.layout.activity_chat );

        getSupportActionBar().hide();

        auth = FirebaseAuth.getInstance();

        chatID = getIntent().getExtras().getString( "ChatID" );

        receiverID = getIntent().getExtras().getString( "ReceiverID" );
        SenderID = getIntent().getExtras().getString("SenderID");

        if (SenderID.equals( auth.getUid() )) { HERE I GET THE ERROR SAYING SenderID IS NULL
            NotMyID = receiverID;
        } else {
            NotMyID = SenderID;
        }
    }

Am I reading something wrong? From my understanding I send the SenderID in my notification intent and then I getExtras from that intent and it should work.

Thank you

Answer 1

Just do some changes to the notifyThis function:

PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT);