CountDownTimer ---实现计数器

1)定义一个类继承CountDownTimer

private class TimeCount extends CountDownTimer {    public TimeCount(long millisInFuture, long countDownInterval) {        super(millisInFuture, countDownInterval);//参数依次为总时长,和计时的时间间隔    }    @Override    public void onFinish() {//计时完毕时触发        getBtn.setText("重新验证");        getBtn.setClickable(true);    }    @Override    public void onTick(long millisUntilFinished) {//计时过程显示        getBtn.setClickable(false);        getBtn.setText(millisUntilFinished / 1000 + "秒");    }}

2)实例化该类，并调用start方法

private TimeCount time;time.start();//开始计时