簡單實現textview文本每隔兩秒就改變一次

//這個方法能夠實現文本每隔兩秒就改變一次,
    public void textTask(){
         final android.os.Handler handler=new android.os.Handler(){
            @Override
            public void handleMessage(Message msg) {
                if ((msg.arg1)%2==0){
                    tv.setText("22222");
                }else {
                    tv.setText("11111");
                }
                super.handleMessage(msg);
            }
        };

        new Thread(new Runnable() {
            @Override
            public void run() {
                int count=1;
                while (flag){//這是個死循環,須要在activity消失時,把flag設爲false,結束循環
                    Message msg=new Message();
                    msg.arg1=count;
                    handler.sendMessage(msg);
                    count++;
                    try {
                        Thread.sleep(2000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }).start();
    }

    @Override
    protected void onStop() {
        flag=false;
        super.onStop();
    }