Accessing UI thread handler from a service

Question

I am trying some thing new on Android for which I need to access the handler of the UI thread.

I know the following:

1. The UI thread has its own handler

Answer 1

Solution:

1. Create a Handler with Looper from Main Thread : requestHandler
2. Create a Handler with Looper from Main Thread: responseHandler and override handleMessage method
3. post a Runnable task on requestHandler
4. Inside Runnable task, call sendMessage on responseHandler
5. This sendMessage result invocation of handleMessage in responseHandler.
6. Get attributes from the Message and process it, update UI

Sample code:

    /* Handler from UI Thread to send request */

    Handler requestHandler = new Handler(Looper.getMainLooper());

     /* Handler from UI Thread to process messages */

    final Handler responseHandler = new Handler(Looper.getMainLooper()) {
        @Override
        public void handleMessage(Message msg) {

            /* Processing handleMessage */

            Toast.makeText(MainActivity.this,
                    "Runnable completed with result:"+(String)msg.obj,
                    Toast.LENGTH_LONG)
                    .show();
        }
    };

    for ( int i=0; i<10; i++) {
        Runnable myRunnable = new Runnable() {
            @Override
            public void run() {
                try {
                   /* Send an Event to UI Thread through message. 
                      Add business logic and prepare message by 
                      replacing example code */

                    String text = "" + (++rId);
                    Message msg = new Message();

                    msg.obj = text.toString();
                    responseHandler.sendMessage(msg);
                    System.out.println(text.toString());

                } catch (Exception err) {
                    err.printStackTrace();
                }
            }
        };
        requestHandler.post(myRunnable);
    }