安卓 用Handler封装一个计时器，比如穿入20，那么TextView就显示1秒，2秒……10秒

private class MHandler extends Handler{

private int time;
private TextView textView;
private int currenTime;

public MHandler(int time,TextView textView){

this.time = time;
this.textView = textView;
}
@Override
public void handleMessage(Message msg) {
if(currenTime<=time){
textView.setText(currenTime+"秒");
currenTime++;
sendEmptyMessageDelayed(0,1000);
}
}
}

使用new MHandler(20,textView).sendEmptyMessage(0);可以实现需要的需求。