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I'm trying to get a String value from my Firestore Database and assigning it to a TextView to test my connection to the database, but I'm not having any luck at all.

I have all dependencies in my .gradle file and both my app and firestore are linked. My Firestore usage even says I have read the database 27 times so far, but I can't seem to get the String value and use it in my TextView.

Here's what I've right now after trying numerous other ways

    FirebaseFirestore db = FirebaseFirestore.getInstance();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu);

        tvMenu = findViewById(R.id.tvMainMenu);
        btOpenOs = findViewById(R.id.btNewOs);

        DocumentReference docRef =
                db.collection("usuarios")
                        .document("idtest");

        docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                if (task.isSuccessful()) {
                    DocumentSnapshot document = task.getResult();
                    if (document.exists()) {
                        String dbValue = document.getString("password");
                        Log.d("TAG", "DocumentSnapshot data: " + document.getData());
                    } else {
                        Log.d("TAG", "No such document");
                    }
                } else {
                    Log.d("TAG", "get failed with ", task.getException());
                }
            }
        });

        tvMenu.setText(value);

    }

This just sets my TextView to nothing, as if the string value was null. The value I'm expecting is "teste".

Leonardo Maito
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  • If you understand Kotlin, this [resource](https://medium.com/firebase-tips-tricks/how-to-read-data-from-cloud-firestore-using-get-bf03b6ee4953) might help. – Alex Mamo Aug 16 '22 at 07:33
  • 1
    It seems to address the same issues that Frank linked in his comment, the fact that it is an asynchronous operation and I didn't take that into consideration. But thank you, it might come in handy – Leonardo Maito Aug 16 '22 at 19:23

1 Answers1

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Any code that needs to have access to the data from the database, has to be inside the completion listener that gets called when that data is available.

So:

docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
    @Override
    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
        if (task.isSuccessful()) {
            DocumentSnapshot document = task.getResult();
            if (document.exists()) {
                String dbValue = document.getString("password");
                tvMenu.setText(dbValue); // 
            } else {
                Log.d("TAG", "No such document");
            }
        } else {
            Log.d("TAG", "get failed with ", task.getException());
        }
    }
});

For more on this, see:

Frank van Puffelen
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  • It seems that it doesn't work due to the fact that Firestore calls are asynchronous and I did not take that into account when trying to read the data and set it to my TextView. I will have to look deeper into this issue that some users are facing in the links you provided. Thank you. – Leonardo Maito Aug 15 '22 at 19:54