CountDownTimer 倒计时的简单实用

CountDownTimer countDownTimer   =  new CountDownTimer(4000, 1000) {

    public void onTick(long millisUntilFinished) {
        mStartNavigation.setText("开始导航（" + millisUntilFinished / 1000 + "s)");
        
    }

    public void onFinish() {
        
    }
};