code: public void onReceivedStartJob(JobParameters params) {
          mShowStartView.setBackgroundColor(startJobColor);
          Message m = Message.obtain(mHandler, MSG_UNCOLOUR_START);
          mHandler.sendMessageDelayed(m, 1000L); // uncolour in 1 second.
          mParamsTextView.setText("Executing: " + params.getJobId() + " " + params.getExtras());
      }
docs: Receives callback from the service when a job has landed on the app. Colours the UI and post
  a message to uncolour it after a second.