如何在Android中从Cloud Firestore Firebase获取或获取数据

Question

I am using this code:

DocumentReference docRef = db.collection("Users").document("user_01");
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
    @Override
    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
        if (task.isSuccessful()) {
            DocumentSnapshot document = task.getResult();
            if (document != null && document.exists()) {

            } else {
                Log.d(TAG, "No such document");
            }
        } else {
            Log.d(TAG, "get failed with ", task.getException());
        }
    }
});

But I don't know how to get. I know with the help of put() I able to insert data on Cloud Firestore, but I don't know how to fetch data which is placed in user_01 .

Answer 1

Assuming you have a property caled name under each user object, to solve this, please use the following code:

DocumentReference docRef = db.collection("Users").document("user_01");
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
    @Override
    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
        if (task.isSuccessful()) {
            DocumentSnapshot document = task.getResult();
            if (document != null && document.exists()) {
                Log.d("TAG", document.getString("name")); //Print the name
            } else {
                Log.d(TAG, "No such document");
            }
        } else {
            Log.d(TAG, "get failed with ", task.getException());
        }
    }
});