Android Studio I can't show incoming data

Question

In the code section below, I wanted to test the data in the log, but I get a null value, so I cannot access data from outside. I would be very glad if you could help.

I want to get value from outside. I can't do it. I'm new, please help with this.

Thanks.

public class MyApplication extends Application {

    AppLangSessionManager appLangSessionManager;
    public String isvip;
    public Boolean isads;

    @Override
    public void onCreate() {
        super.onCreate();
        FirebaseMessaging.getInstance().subscribeToTopic("all");
        appLangSessionManager = new AppLangSessionManager(getApplicationContext());
    }

    public void isVip() {
        FirebaseFirestore firebaseFirestore = FirebaseFirestore.getInstance();
        FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
        String email = user.getEmail();

        CollectionReference collectionReference = firebaseFirestore.collection("Users");
        collectionReference.whereEqualTo("user_mail",email).addSnapshotListener(new EventListener<QuerySnapshot>() {
            @Override
            public void onEvent(@Nullable QuerySnapshot value, @Nullable FirebaseFirestoreException e) {

                if (e != null)
                {
                    Toast.makeText(MyApplication.this,e.getLocalizedMessage().toString(),Toast.LENGTH_LONG).show();
                }

                if (value != null)
                {
                    for (DocumentSnapshot snapshot : value.getDocuments())
                    {
                        Map<String,Object> data = snapshot.getData();
                        Boolean deger = (Boolean) data.get("user_vip");
                        isvip = "OK";
                    }
                }
            }
        });

        System.out.println("Değer "+isvip);
    }
}

You cannot simply use the value of `isvip` outside the callback. Firebase API is asynchronous. So please check the duplicate to see how can you solve this using a custom callback. — Alex Mamo, Sep 18 '20 at 14:46
What exactly do you think should I do? I need to pull isvip value from another activity. — Mehmet Türkan, Sep 18 '20 at 14:49
I used OnCompleteListener but still cannot access it from outside. — Mehmet Türkan, Sep 18 '20 at 15:19
Have you tried the solution from the [duplicate](https://stackoverflow.com/questions/48499310/how-to-return-a-documentsnapshot-as-a-result-of-a-method) answer? If you have not, give it a try. — Alex Mamo, Sep 18 '20 at 15:25

score 0 · Answer 1 · answered Sep 18 '20 at 14:41

0

Try using an onCompletionListener instead of onEvent. Then set your System.out.println() inside your onCompletionListener brackets. Basically it takes a second to find the data in firebase and by the time it does you've already passed the println line.

answered Sep 18 '20 at 14:41

Trevor Soare

120
8

I don't want to use the OnCompletionListener in parentheses because I want to get the isvip value from another activity. – Mehmet Türkan Sep 18 '20 at 14:44
Regardless, the System.out.println will be skipped on the outside of your listener – Trevor Soare Sep 18 '20 at 15:20
I want to use the data I pulled in activityde. – Mehmet Türkan Sep 18 '20 at 15:22

Android Studio I can't show incoming data

1 Answers1