Observer do not update data

Question

I implements an observer for a model's datas; I have 2 activity, that share that datas. In my first activity I set the model like:

public void refreshValue (String id, Data data){
ConnectionModel.getInstance().updateConnection(data);

In the model the updateConnection is like:

public class ConnectionModel extends Observable{
//...
  synchronized Connection getConnection() {
    return connection;
  }
  void updateConnection(Data data){
      synchronized (this) {
          connection.setData(data);
      }
      setChanged();
      notifyObservers();
  }
}

In the second activity I set the observer like:

public class secondView extends AppCompatActivity implements Observer {
public void observe(Observable o) {
    o.addObserver(this);
}
//...
public void refreshView(){
    Connection connection = ConnectionModel.getInstance().getConnection();       
    heartRate.setText(connection.toString());
}


@Override
public void update(Observable o, Object arg) {
    refreshView();
    Log.d("update", "data is change");
}

I also tried to use LiveData with a ViewModel, but same result.

Where am I doing wrong?

Thanks a lot.

Answer 1

You need to add the secondView Activity as the Observer of the ConnectionModel by calling:

ConnectionModel.getInstance().addObserver(this);

inside the secondView activity.