timer_task.java

private void shceduleSomething() {
    final Handler handler = new Handler();
    Timer timer = new Timer();
    TimerTask doAsynchronousTask = new TimerTask() {
        @Override
        public void run() {
            handler.post(new Runnable() {
                public void run() {
                    doSomething();
                }
            });
        }
    };
    timer.schedule(doAsynchronousTask, 3000);
}