Question

在java类中，我使用了一些随机的用户名和全名进行测试，但现在我想获取Firebase的Mates节点中当前用户的子用户名和用户名列表。

public class User
{

    public String fullname;
    public String username;




      public User()
        {
            FirebaseAuth mAuth=FirebaseAuth.getInstance();
            String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
            DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
            DatabaseReference uidRef = rootRef.child("Mates").child(uid);
            ValueEventListener valueEventListener = new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    List<User> USERS = new ArrayList<>();
                    for(DataSnapshot ds : dataSnapshot.getChildren()) {
                        User user = ds.getValue(User.class);
                        USERS.add(user);
                        Log.d(TAG, user.getUsername() + " / " + user.getFullname());
                    }

                    //Do what you need to do with your userList
                }

                @Override
                public void onCancelled(@NonNull DatabaseError databaseError) {
                    Log.d(TAG, databaseError.getMessage()); //Don't ignore errors!
                }
            };
            uidRef.addListenerForSingleValueEvent(valueEventListener);
        }

        public User(String fullname, String username) {
            this.fullname = fullname;
            this.username = username;
        }


        public String getFullname() {
            return fullname;
        }

        public String getUsername() {
            return username;
        }

        public static List<User> USERS ;

    }

我想将此用户替换为当前用户的子级的Firebase用户，在这里放置我的数据库映像。

Answer 1

明确表示您要将Java类的全名和用户名替换为firebase。对？

Answer 2

您的班级用户属性可能是private，否则您会从Firebase获取数据时出错。访问此链接以使用列表https://firebase.google.com/docs/database/android/lists-of-data?authuser=0

Answer 3

According to your comment, to get all user objects that exist within Mates/uid, please use the following lines of code:

String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference uidRef = rootRef.child("Mates").child(uid);
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        List<User> userList = new ArrayList<>();
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            User user = ds.getValue(User.class);
            userList.add(user);
            Log.d(TAG, user.getUsername() + " / " + user.getFullname());
        }

        //Do what you need to do with your userList
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {
        Log.d(TAG, databaseError.getMessage()); //Don't ignore errors!
    }
};
uidRef.addListenerForSingleValueEvent(valueEventListener);

The output in the logcat will be all usernames and fullnames of all users that exist within the uid.

如何从Firebase获取用户名和全名的字符串列表？

3 个答案: