gistfile1.txt

trait InMainThread {
  private val handler = new Handler

  def mainThread(block: => Unit) {
    handler.post(new Runnable {
      def run { block }
    })
  }
}


class MyGUIView extends Activity with InMainThread {

  private var view: TextView = _

  override def onCreate(savedInstanceState: Bundle) {
    super.onCreate(savedInstanceState)
    view = new TextView(this)
    setContentView(view)
  }

  def methodCalledByBackgroundThread() {
    // Can't invoke view.setText directly because not on the GUI thread, instead...
    mainThread { view.setText("Background thread did this.") }
  }

}