Android利用CountDownTimer类实现倒计时功能

public class MainActivity extends Activity {
	private MyCount mc;
	private TextView tv;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv = (TextView)findViewById(R.id.show);
        mc = new MyCount(70000, 1000);
        mc.start();
    }
    class MyCount extends CountDownTimer{

		public MyCount(long millisInFuture, long countDownInterval) {
			super(millisInFuture, countDownInterval);
			System.out.println("你好");
		}
		@Override
		public void onTick(long millisUntilFinished) {
			Date date = new Date(millisUntilFinished);
			SimpleDateFormat sdf = new SimpleDateFormat("hh:mm:ss");
			String str = sdf.format(date);
			System.out.println(str);
			tv.setText("请等待70秒("+millisUntilFinished / 1000 +")...");
		}
		@Override
		public void onFinish() {
			tv.setText("finish");
		}
    }
    @Override
    protected void onDestroy() {
    	super.onDestroy();
    	mc.cancel();
    }
}