倒计时短信验证

public class MainActivity extends Activity { 

private TimeCount timeCount; 

private Button btn; 

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

//这里设置时间
timeCount = new TimeCount(30000, 1000); 
btn = (Button) findViewById(R.id.btn); 

btn.setOnClickListener(new OnClickListener() { 

@Override 
public void onClick(View v) { 
timeCount.start(); 
} 

}); 
} 

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

public void onFinish() { //计时完毕时触发
btn.setText("获取验证码"); 
btn.setBackgroundResource(R.drawable.obtain_btn_bg);//正常背景 
btn.setClickable(true); 
} 

public void onTick(long millisUntilFinished) { //计时过程显示
btn.setClickable(false); 
btn.setBackgroundResource(R.drawable.obtain_reading);//倒计时时灰色背景 

btn.setText(millisUntilFinished / 1000 + "s后重新获取"); 
} 
} 
}