getting into else statement because of AsyncTask ? possibly?

Question

I have two classes, MainActivity and Tempo and their codes

MainActity.java

 public class MainActivity extends AppCompatActivity {
        Tempo m_context;

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        m_context = Tempo.getInstance();
    }
   }

public void button_clicked(View v){
         if( m_context.connect("a1",1)){
        setTitle("Yeah!");
          }else {
        setTitle("No");
        }
    }

and Tempo.java

public class Tempo{

    public boolean isConnected=false;
    private static Tempo insta;
    private Tempo() { }

    public synchronized static Tempo getInstance() {
            if (insta == null) {
                insta = new Tempo();
            }
            return insta;
    }

    public boolean connect(String a, int aa) {
    new DoTask().execute(a);
        return isConnected;
    }

    public class DoTask extends AsyncTask<String,Void,Boolean> {

        @Override
        protected Boolean doInBackground(String... params) {
            boolean result = true;
            try {
                //If I'm here everything is okay
            } catch (IOException e) {
                //If I'm here everything is !okay
                result = false;
            }
            return result;
        }

        @Override
        protected void onPostExecute(Boolean result)
        {

            isConnected = result;

        }
    }
}

Even though my work is done inside Tempo perfectly which means the boolean vars in Tempo class "result" and "isConnected" is meant to be true. No doubt they transformed to True after my work but the main issue is using those vars, I'm not able to go in if block of MainActivity.. which will change my title to "Yeah!". As per me it's because of AsyncTask throwing task in background hence making my vars remains the same(false) for some particular time??

Well, I need AsyncTask so that the UI won't stuck.

Make your AsyncTask a private class of your activity. Then you can set the title in onPostExecute when the task is done. You now try to set a title the moment the task is started. — greenapps, Apr 29 '17 at 18:16
`return isConnected` will immediately return while the Asynctask is still running — OneCricketeer, Apr 29 '17 at 18:33
@cricket_007 NullPointerException .. inside `onPostExecute(Boolean result){delegate.processFinish(result);}` — Rupesh Bhandari, Apr 30 '17 at 16:10

score 0 · Answer 1 · answered Apr 29 '17 at 18:28

onPostExecute runs in the UI thread. so you can update the ui in this method instead of your MainActivity.

public class Tempo{
Activity activity;

public boolean isConnected=false;
private static Tempo insta;
private Tempo() { }

public synchronized static Tempo getInstance() {
        if (insta == null) {
            insta = new Tempo();
        }
        return insta;
}

public boolean connect(String a, int aa,Activity a) {
this.activity= a;
new DoTask().execute(a);
    return isConnected;
}

public class DoTask extends AsyncTask<String,Void,Boolean> {

    @Override
    protected Boolean doInBackground(String... params) {
        boolean result = true;
        try {
            //If I'm here everything is okay
        } catch (IOException e) {
            //If I'm here everything is !okay
            result = false;
        }
        return result;
    }

    @Override
    protected void onPostExecute(Boolean result)
    {

        if( result){
          Activity.setTitle("Yeah!");
        }else {
          Activity.setTitle("No");
        }

    }
}
}

So as you can see I am passing the activity as a parameter then using that to update the UI in onPostExecute() method.

non-static method 'setTitle()' cannot be referenced from a static context?? — Rupesh Bhandari, Apr 29 '17 at 18:33
Passing the whole Activity to the Asynctask can cause memory leak, by the way — OneCricketeer, Apr 29 '17 at 18:34
Doing this is how you cause a memory leak. As Tempo is a singleton it could hold onto the reference to the Activity after it has been destroyed which means it can't be garbage collected. — Jahnold, Apr 29 '17 at 18:34

getting into else statement because of AsyncTask ? possibly?

1 Answers1