如何从Firebase检索UID并将其添加到Firebase DB的子级

Question

first off I am very new to firebase database. I am looking into how do i retrieve the current UID (that is currenty logged into) from firebase and insert it into child of firebase along with a value all through the oncreate.

I'm trying to push mycurrent UID and it's value to Firebase. I am having trouble pushing it to firebase. Here is my firebase structure:

(eg, UID Fo2SfEfryWEjmxr4yIQwM5LQQx2 and the value '720' in fire base)

After trying out, i am still unable to get the following code to retrieve UID. I'm having trouble with (new ValueEventListener() as well as this line.

Map<String, Queue> data = postSnapshot.getValue(new GenericTypeIndicator<Map<String, Queue>>() {});

Here is my onCreate for reference

    mRef = new Firebase("https://sunwayfinancequeue.firebaseio.com/");
    mRef.child("UserQueue");
    mRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot snapshot) {
            for (DataSnapshot postSnapshot : snapshot.getChildren()) {
                Queue queue = postSnapshot.getValue(Queue.class);
                System.out.println(Queue.getTotalqueue() + " - " + Queue.getServingqueue());
                Map<String, Queue> data = postSnapshot.getValue(new GenericTypeIndicator<Map<String, Queue>>() {});
                Map.Entry<String, Queue> entry = data.entrySet().iterator().next();
                String uid = entry.getKey();
                Log.d("Firebase UID ", uid);

            }
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {
            System.out.println("The read failed: " + firebaseError.getMessage());

        }
    });

Here is my constructor:

public class Queue {

private static double servingqueue;
private static double totalqueue;
private static String uid;

public Queue(Double servingqueue, Double totalqueue) {
    Queue.servingqueue = servingqueue;
    Queue.totalqueue = totalqueue;

}

public static double getServingqueue() {
    return servingqueue;
}

public static void setServingqueue(double servingqueue) {
    Queue.servingqueue = servingqueue;
}

public static double getTotalqueue() {
    return totalqueue;
}

public static void setTotalqueue(double totalqueue) {
    Queue.totalqueue = totalqueue;
}

public static String getUid() {
    return uid;
}

public static void setUid(String uid) {
    Queue.uid = uid;
    }
}

Answer 1

You are using the legacy Firebase Database SDK, 2.5.x . If you are just getting started with using the database, it would be better to use the new 9.xx SDK , especially if you are using Firebase Authentication from the new SDK. You will likely encounter problems if you use the old and new SDKs in the same build. See the Upgrade Guide .

Answer 2

You want to use Firebase authentication. Check out this link to set up Firebase authentication for your Android App:

https://firebase.google.com/docs/auth/android/start/

This link will help you manage the users and show you how to get the current user's UID:

https://firebase.google.com/docs/auth/android/manage-users

Once you have Firebase Authentication set up you would use this piece of code to get the UID of the current user.

FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if (user != null) {
    String UID = user.getUid();
} else {
    // No user is signed in
}