同样，为了防止用户恶意的频繁发送激活码，应用中需要对用户发送激活码的时间间隔进行限制，这时就需要用到倒计时器了，大概流程是这样的：页面初始化的时候，按钮为可点击状态，用户在点击“发送激活码”后按钮变为不可点击状态，同时按钮上的文字变为倒计时状态，倒计时结束后，按钮变为可点击状态，文字变为“发送激活码”。具体逻辑看下面的代码：
复制代码 代码如下:
package cn.sunzn.countdown;

import android.app.Activity;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener {

    private TimeCount timeCount;

    private Button btn_reget_captcha;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init() {
        initView();
        initData();
    }

    private void initData() {
        timeCount = new TimeCount(60000, 1000);
    }

    private void initView() {
        btn_reget_captcha = (Button) findViewById(R.id.btn_reget_captcha);
        btn_reget_captcha.setOnClickListener(this);
    }

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

    public void onClick(View v) {
        int id = v.getId();
        switch (id) {
        case R.id.btn_reget_captcha:
            if (btn_reget_captcha.isClickable()) {
                // TODO run your logic that you want to do
                timeCount.start();
            }
            break;

        default:
            break;
        }
    }

    class TimeCount extends CountDownTimer {
        public TimeCount(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }

        public void onFinish() {
            btn_reget_captcha.setText("发送激活码");
            btn_reget_captcha.setClickable(true);
        }

        public void onTick(long millisUntilFinished) {
            btn_reget_captcha.setClickable(false);
            btn_reget_captcha.setText("在" + millisUntilFinished / 1000 + "秒后点击重发激活码");
        }
    }

}

最后，附上工程代码：CountDown