从firebase数据库填充textView

Question

I am trying to populate a TextView from a firebase database. Here is the sample json file.

{
 "Player" : {
  "Club" : "Valley Rovers",
  "Name" : "John Murphy"
 }
}

Here is my android code:

public class MainActivity extends AppCompatActivity {

private   TextView mPlayer;
private DatabaseReference mDatabase;




@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mPlayer = (TextView) findViewById(R.id.player);;

    mDatabase = FirebaseDatabase.getInstance().getReference("Player").child("Name");

    final String player = mDatabase.push().getKey();

    mDatabase.child("Name").addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            // Check for null
            if (player == null) {
                Log.e(TAG, "User data is null!");
                return;
            }




            mPlayer.setText(player);




        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

}

I want to add the name John Murphy to the firebase database and doing so the TextView mPlayer will populate with John Murphy.

Answer 1

You are getting the child "Name" twice on your code (leading to Player/Name/Name). Remove it from the mDatabase initialization:

mDatabase = FirebaseDatabase.getInstance().getReference("Player");

And you're never really getting the value from the DataSnapshot received. To do so, use this:

mDatabase.child("Name").addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String playerName = dataSnapshot.getValue(String.class);
            mPlayer.setText(playerName);
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

In case someone wants to use POJO approach to this problem in future, follow the example below:

Remove the child("Name") from mDatabase.child("Name").addValueEventListener(new ValueEventListener() unless you want to fetch the "Name" child only. Also remember to effect the correction made on mDatabase initialization.

mDatabase.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        // String playerName = dataSnapshot.getValue(String.class);
        PlayerModel playerModel =  dataSnapshot.getValue(PlayerModel.class);
         ((TextView)findViewById(R.id.textviewName)).setText(playerModel.getName());
        ((TextView)findViewById(R.id.textviewClub)).setText(playerModel.getClub());
        // mPlayer.setText(playerName);
    }