验证码倒计时

//参数一为总时间60s，参数二为间隔时间1s
private CountDownTimer timer = new CountDownTimer(60000, 1000) {    
@Override   
 public void onTick(long millisUntilFinished) {        
tv.setText((millisUntilFinished / 1000) + "秒后可重发");   
 }   
 @Override   
 public void onFinish() {        
tv.setEnabled(true);       
 tv.setText("获取验证码");   
 }};

timer.start()启动
timer.cancel()取消