Android进阶之ListView实现多条数据同时倒计时功能

1 概述

最近在做一个网购APP,有个小功能就是限时抢购商品在限定时间内有优惠活动，我们需要给每个件商品做一个倒计时显示告诉用户还剩下多少时间。项目中我们有用到ListView和GridView来加载我们的商品数据，对每条数据（对应一件商品）进行倒计时。倒计时实现方式很多，常用的有以下方式：

1，采用Handle与线程的sleep(long)

2，采用Handler的postDelayed(Runnable, long)方法

3，采用Handler与timer及TimerTask结合的方法

在实现过程中也有一小点问题，就是开始实现了计时，但是每当上下拉刷新时，时间就会错乱。后来经过调整，终于实现了所要的效果。下面讲下用到的实现方式，还有另外一种方式类似，只是把hander及时间 处理放到adapter中了，用的Handler+Timer+TimerTask实现的：

2 Handler+Timer+TimerTask

2.1 ShopActivity

public class ShopActivity extends Activity {

private ListView  lv;
private ShopAdapter pmAdapter;
private Timer timer = new Timer();
private TimerTask timerTask;
private List<MyData> dataList;

@SuppressLint("HandlerLeak")
private Handler mHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
if (msg.what == 1) {
for (int i = 0; i < mMyMatchList.size(); i++) {
//这是服务器当前时间，以此时间为基数进行倒时计，1000为毫秒
dataList.get(i).setServerDate(Long.valueOf(dataList.get(i).getServerDate())+ 1000 + "");
serverTime = Long.valueOf(mMyMatchList.get(i).getServerDate());
pmAdapter.notifyDataSetChanged();
}
}
}
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_shop);
//接下来要从服务端取到数据，加入dataList中
dataList=new ArrayList<MyData>();
lv= (ListView) this.findViewById(R.id.shop_lv);
pmAdapter = new ShopAdapter(ShopActivity.this, this);
lv.setAdapter(pmAdapter);

timerTask = new TimerTask() {
@Override
public void run() {
Message message = Message.obtain();
message.what = 1;
mHandler.sendMessage(message);
}
};
timer.schedule(timerTask, 1000, 1000);
}

@Override
protected void onResume() {
super.onResume();
}

@Override
protected void onDestroy() {
if (null != timer) {
timer.cancel();
}
super.onDestroy();
}
}

2.2 ShopAdapter

最后在适配器类ShopAdapter中，根据服务器返回的商品优惠截止时间和服务器时间，把数据加上去就可以了：

TextView timeTv=findViewById();
timeTv.setText(getTimeFromInt(结束时间-服务器时间));//getTimeFromInt这个方法是计算时间差并转换成所需要格式的：

public String getTimeFromInt(long time) {
if (time <= 0) {
return "已结束";
}

long day = time / (1 * 60 * 60 * 24);
long hour = time / (1 * 60 * 60) % 24;
long minute = time / (1 * 60) % 60;
long second = time / (1) % 60;
return "还剩：" + day + "天" + hour + "小时" + minute + "分" + second + "秒";
}

或者：
/**
* 设置时间值
* @param millisUntilFinished
* @param tvTime
*/
public void setTime(long millisUntilFinished,TextView tvTime) {
final int SECONDS = 60;//秒数
final int MINUTES = 60 * 60;//小时
long first = 0, twice = 0, third = 0;
long mtmp = 0, mtmp2 = 0;

//获取当前时间总秒数
first = millisUntilFinished / 1000;
//小于一分钟 只显示秒
if (first < SECONDS) {
tvTime.setText("00:00:" + (first < 10 ? "0" + first : first));
} else if (first < MINUTES) {
twice = first % 60;
mtmp = first / 60;
if (twice == 0) {
tvTime.setText("00:" + (mtmp < 10 ? "0" + mtmp : mtmp) + ":00");
} else {
tvTime.setText("00:" + (mtmp < 10 ? "0" + mtmp : mtmp) + ":" + (twice < 10 ? "0" + twice : twice));
}
} else {
twice = first % 3600;
mtmp = first / 3600;
if (twice == 0) {
tvTime.setText("0" + first / 3600 + ":00:00");
} else {
if (twice < SECONDS) {
tvTime.setText((mtmp < 10 ? "0" + mtmp : mtmp) + ":00:" + (twice < 10 ? "0" + twice : twice));
} else {
third = twice % 60;
mtmp2 = twice / 60;
if (third == 0) {
tvTime.setText((mtmp < 10 ? "0" + mtmp : mtmp) + ":" + (mtmp2 < 10 ? "0" + mtmp2 : mtmp2) + ":00");
} else {
tvTime.setText((mtmp < 10 ? "0" + mtmp : mtmp) + ":" + (mtmp2 < 10 ? "0" + mtmp2 : mtmp2) + ":" + third);
}
}
}
}
}