Blog post snippet

threading_2.java

public class TestActivity extends Activity {

    // ...
    // all standard stuff

    @Override
    public void onCreate(Bundle savedInstanceState) {

        // ...
        // all standard stuff

        // we're creating a new handler here
        // and we're in the UI Thread (default)
        // so this Handler is associated with the UI thread
        Handler mHandler = new Handler();

        // I want to start doing something really long
        // which means I should run the fella in another thread.
        // I do that by sending a message - in the form of another runnable object

        // But first, I'm going to create a Runnable object or a message for this
        Runnable mRunnableOnSeparateThread = new Runnable() {
            @Override
            public void run () {

                // do some long operation
                longOperation();

                // After mRunnableOnSeparateThread is done with it's job,
                // I need to tell the user that i'm done
                // which means I need to send a message back to the UI thread

                // who do we know that's associated with the UI thread?
                mHandler.post(new Runnable(){
                    @Override
                    public void run(){
                        // do some UI related thing
                        // like update a progress bar or TextView
                        // ....
                    }
                });


            }
        };

        // Cool but I've not executed the mRunnableOnSeparateThread yet
        // I've only defined the message to be sent
        // When I execute it though, I want it to be in a different thread
        // that was the whole point.

        new Thread(mRunnableOnSeparateThread).start();
    }

 }