Java – dataSnapshot.getChildren() gets the user ID but does not get the value

When you run this code:

private void getData(DataSnapshot dataSnapshot) {
    for(DataSnapshot ds : dataSnapshot.getChildren()){
        Log.d(TAG, "UserID inside getData: "+userID);
        Log.d(TAG, "User Name inside getData: "+ds.child(userID).child("name").getValue());
        Log.d(TAG, "DS inside getData: "+ds.child(userID));

hospitalCity = String.valueOf(ds.child(userID).child("city").getValue());
        Log.d(TAG, "User city inside getData: "+ds.child(userID).child("city").getValue());

break;
    }
}

The log shows:

UserID inside getData: Lsncj8CIsfTQXc7E425AtLuDI5v2
User Name inside getData: null
DS inside getData: DataSnapshot { key = Lsncj8CIsfTQXc7E425AtLuDI5v2, value = null }

D/DonorList: User city inside getData: null

Here is the database:

As you can see, it gets the key, but the value is null, although the database shows that there is a value in it.

In order to obtain the data under the Hospital node, you need to modify the following reference:

hospitalDatabase = FirebaseDatabase.getInstance().getReference();

with

hospitalDatabase = FirebaseDatabase.getInstance().getReference().child("Hospital");

To get the data in the getData() method, use the following code:

private void getData(DataSnapshot dataSnapshot) {
    for(DataSnapshot ds : dataSnapshot.getChildren()) {
        String key = ds.getKey();
        String city = ds.child("city").getValue(String.class);
        String name = ds.child("name").getValue(String.class);
    }
}

ds.getKey() returns userId

ds.child("city").getValue(String.class) will return the city.

ds.child("name").getValue(String.class) returns the name.