java - 获取节点的父节点(Firebase)

Question

我是 android 应用程序的初学者，谁能帮助我并告诉我如何检索当前用户 ID 的生成的 id 值节点？请在我的代码下面找到。谢谢

FirebaseAuth firebaseAuth = FirebaseAuth.getInstance();
FirebaseDatabase mDatabase = FirebaseDatabase.getInstance();
DatabaseReference mDb = mDatabase.getReference();
FirebaseUser user = firebaseAuth.getCurrentUser();
final String userKey = user.getUid();

    mDb.child("students").child(currentuser).getRef().addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        String reference = dataSnapshot.getRef().toString();
        String userID = dataSnapshot.child("level").getValue(String.class);
        textViewStudentName.setText(reference);
    }
    @Override
    public void onCancelled(DatabaseError databaseError) {
    }
});

Answer 1

试试下面得到level :

DatabaseReference fireReference = FirebaseDatabase.getInstance().getReference("students");

fireReference.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

        for(DataSnapshot childSnapshot: dataSnapshot.getChildren()) {
            if(childSnapshot.hasChild(userKey)) {

                String userID = childSnapshot.child(userKey).child("level").getValue(String.class);

                break;
            }
        }
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {

    }
});