firebase - 如何从android studio中的firestore检索数据

Question

我想制作一个教育应用程序，但我不知道如何在 android Studio 中检索数据我试图在他们登录时获取并显示我的用户信息。（即：姓名、电子邮件）

这是我的代码

        fAuth = FirebaseAuth.getInstance();
        db = FirebaseFirestore.getInstance();
        storageReference = FirebaseStorage.getInstance().getReference();

     
        userId = fAuth.getCurrentUser().getUid();

        //Name Animation
        linearname.setAnimation(rightanim);

        //Email Animation
        linearemail.setAnimation(rightanim);

        //ProfileText Animation
        profile.setAnimation(rightanim);

    }


    @Override
    protected void onStart() {
        IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
        registerReceiver(networkChangeListener, filter);
        super.onStart();
    }

    @Override
    protected void onStop() {
        unregisterReceiver(networkChangeListener);
        super.onStop();
    }

    public void back(View view) {
        startActivity(new Intent(SettingsActivity.this,Home.class));
    }

    public void logout(View view) {
        fAuth.getInstance().signOut();
        startActivity(new Intent(SettingsActivity.this,MainActivity.class));
        Toast.makeText(this, "Successful Logout", Toast.LENGTH_SHORT).show();
    }
}

Answer 1

以下是有关如何从 firebase firestore 获取数据的官方文档：

我编辑了本节以更好地满足您的需求：

db.collection("YOUR COLLECTION NAME" (ie: "Users"))
    .get()
    .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            if (task.isSuccessful()) {
                for (QueryDocumentSnapshot document : task.getResult()) {
                    Log.d(TAG, document.getString("YOUR FIELD" (ie: "username" / "email")));
                }
            } else {
                Log.d(TAG, "Error getting documents: ", task.getException());
            }
        }
    });