How to design a Custom Generic Thread class (send and recieve data) in Android

Question

I want to make a Custom Generic Thread Class for heavy network operations.

I know how to use AsyncTask , been using it, but now it sometimes crashes, since AsyncTask is not recommended for operations which take more than 5 seconds.. And for implementing OOP principles (re-usability) I decided to make a separate common Thread class which all my Transaction Screens can use to send and receive data from the network ! I don't want to make a separate thread for each screen.. I searched the internet and the stackoverflow for all possible solutions...

This is what I've tried so far...

import mainMenu.AccountBean;
import parser.ParserMain;
import parser.ValuesBean;

public class NetworkThread implements Runnable {
private String proccessCode;
private AccountBean ab;
private ValuesBean vb;
private String[] sd;

public NetworkThread(String proccessCode, AccountBean ab, String[]sd){
    this.proccessCode = proccessCode;
    this.ab = ab;
    this.sd = sd;

}


@Override
public void run() {
    ParserMain pm = new ParserMain();
    try {
        // this method does socket based transactions..
        vb = pm.commenceTransaction(proccessCode, ab, sd); // I want this object 'vb' sent back to my activity..
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();



     }

  }

}

My SomeActivity's Button Listener

submit.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            NetworkThread nt = new NetworkThread("1234",ab, someOtherValuesHere);
            Handler h = new Handler();
            h.post(nt); //  <= how to get value from here
        }
    });

My Questions are how to get value from this Handler ?? I've seen many examples on Message but in my scenario where do I implement Message in Activity or the Thread class ? If there is another approach preferred I'm open to suggestions, Thanks.

Answer 1

You aren't running this in a separate Thread , despite the fact that you've named it NetworkThread , it isn't a Thread This is running on the main (UI) thread, which isn't what you want.

Change NetworkThread so that it extends Thread , not Runnable . Then do this:

    @Override
    public void onClick(View v) {
        NetworkThread nt = new NetworkThread("1234",ab, someOtherValuesHere);
        nt.start();
    }

To get data from NetworkThread back to the calling Activity, you could do something like this:

Declare a callback interface in NetworkThread :

public Interface NetworkThreadCallback {
    void reportData(ValuesBean vb);
}

and declare a member variable in NetworkThread :

private NetworkThreadCallback callback;

Then, in NetworkThread constructor, add a parameter NetworkThreadCallback callback and store that in the member variable callback . After you've successfully called commenceTransaction , do this:

callback.reportData(vb);

Each calling Activity needs to implement NetworkThreadCallback and have a method

public void reportData(ValuesBean vb) {
    // Do something with the ValuesBean here...
}

You just need to understand that this technique is not as robust as using a Service . If your process goes to the background (User presses HOME button, takes a phone call, etc.) Android can kill your process at any time. In this case your NetworkThread will just go away.