Question

In my application I have two threads (I’m using AsyncTask class). in doInBackground() method of each thread i’m calling my own getNewsItems(Url url) method, this method will connect to server and get response. after that in onPostExecute() method of each thread, i’ll call displayData() method to show results on screen.

The problem is when i run, the application crashes. I think its because these two thread have access to common methods in same time because when i separate common methods then the app runs successfully. I have no idea is it because of don’t use of serialization?

Thanks

Answer 1

you can put a synchronized modifier to your method that is accessed by multiple threads.

e.g.

public synchronized void getNewsItems(Url url){
    //some logic here
}

so that, When one thread is executing a synchronized method for an object, all other threads that invoke synchronized methods for the same object block (suspend execution) until the first thread is done with the object.

you can also read about it here: http://docs.oracle.com/javase/tutorial/essential/concurrency/syncmeth.html

UPDATE:

you can have the getNewsItems(Url url) in a separate class like this:

public class NewsItems{
  getNewsItems(Url url){
    //some logic here
  }
}

and then instantiate it within your threads like this:

public void run(){
  NewsItems ni = new NewsItems();
  ni.getNewsItems(url);
}

this way, same method will be called but in different class instances…