Android内置倒计时类CountDownTimer

package com.example.countdowntimertest;

import android.app.Activity;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {
TextView tv ;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

tv = (TextView) findViewById(R.id.countDownTimerTxt);

new CountDownTimer(30000,1000) {//两个参数，前一个指倒计时的总时间，后一个指多长时间倒数一下。

@Override
public void onTick(long millisUntilFinished) {
// TODO Auto-generated method stub
tv.setText("seconds remainling:"+ millisUntilFinished/1000);
}

@Override
public void onFinish() {
// TODO Auto-generated method stub
tv.setText("done");
}
}.start();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}

}