android中的Handler方法简单两种用法

  final android.os.Handler handler = new android.os.Handler();
        handler.post(new Runnable() {
            @Override
            public void run() {
                a=a+1;
                tv1.setText(""+a);
                //refresh at once
               // handler.post(this);
                //refresh after 1 second
                //handler.postDelayed(this, 1000);

                //run after systemtime 5 seconds
                handler.postAtTime(this, android.os.SystemClock.uptimeMillis() + 5000);
            }
        });

 handler = new android.os.Handler()
        {

            @Override
            public void handleMessage(Message msg) {
                super.handleMessage(msg);
                switch (msg.what) {
                    case 1:
                        a=2+a;
                        tv1.setText(""+a);
                        break;
                    default:
                        break;
                }
            }
        };



        Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                Message message=new Message();
                message.what=1;
                handler.sendMessage(message);
            }
        },0,3000);

用timer类安排一个任务0表示没有延迟立刻执行，每3秒一次通过handler发送一个信息。