Android中Handler实现倒计时的两种方式

//在向服务端发送获取验证码成功的回调函数中，开始发消息：mHandler.obtainMessage();mHandler.sendEmptyMessage(MSG_CODE);//消息的处理： private static final int MSG_CODE = 0; private int limitTime = 121; private Handler mHandler = new Handler(new Handler.Callback() {    @Override    public boolean handleMessage(Message msg) {      if(msg.what==MSG_CODE){        limitTime--;        if(limitTime>0){          mHandler.sendEmptyMessageDelayed(MSG_CODE,1000);          mBtnVerify.setText("倒计时："+limitTime+"s");        }else{          mBtnVerify.setText("获取验证码");        }        return true;      }      return false;    }  });