listview倒计时
记录一个我花了较长时间解决的一个需求，在listview的每个item里加上倒计时，精确到秒，具体看图
这只是有一个item的时候有倒计时，当这里有好几个倒计时，并且每个时间都不一样，很容易想到会出现的问题：
1.倒计时显示不准确
2.由于listview的getView方法里会复用convertView导致每次滑动listview时，数据混乱，尤其是，第二页的item会复用第一页的item的倒计时啊！！
我之前的解决方法是参考了网上找的demo，然而引起了第二个问题，一度我把这个需求给搁置了，后期才解决
下面附demo，是在网上找的demo的基础上，自己做了修改，成功解决了问题：
1.首先我们需要一个自定义的倒计时控件，完整demo如下：CustomDigitalClock.class
public class CustomDigitalClock extends DigitalClock {
Calendar mCalendar;
private final static String m12 = "h:mm aa";
private final static String m24 = "k:mm";
private FormatChangeObserver mFormatChangeObserver;
private Runnable mTicker;
private Handler mHandler;
private long endTime;
private ClockListener mClockListener;
private boolean mTickerStopped = false;
@SuppressWarnings("unused")
private String mFormat;
public CustomDigitalClock(Context context) {
super(context);
initClock(context);
}
public CustomDigitalClock(Context context, AttributeSet attrs) {
super(context, attrs);
initClock(context);
}
private void initClock(Context context) {
if (mCalendar == null) {
mCalendar = Calendar.getInstance();
}
mFormatChangeObserver = new FormatChangeObserver();
if (getContext()!=null){
getContext().getContentResolver().registerContentObserver(Settings.System.CONTENT_URI, true, mFormatChangeObserver);
setFormat();
}
}
@Override
protected void onAttachedToWindow() {
mTickerStopped = false;
super.onAttachedToWindow();
mHandler = new Handler();
/**
* requests a tick on the next hard-second boundary
*/
mTicker = new Runnable() {
public void run() {
if (mTickerStopped)
return;
long currentTime = System.currentTimeMillis();
if (currentTime / 1000 == endTime / 1000 - 5 * 60) {
mClockListener.remainFiveMinutes();
}
long distanceTime = endTime - currentTime;
distanceTime /= 1000;
if (distanceTime == 0) {
//setText("00:00:00");
setText("00:00");//设置时间
onDetachedFromWindow();
mClockListener.timeEnd();
} else if (distanceTime < 0) {
setText("00:00");
} else {
setText(dealTime(distanceTime));
}
invalidate();
long now = SystemClock.uptimeMillis();
long next = now + (1000 - now % 1000);
mHandler.postAtTime(mTicker, next);
}
};
mTicker.run();
}
/**
* @param time
* @return
*/
public static String dealTime(long time) {
StringBuffer returnString = new StringBuffer();
long day = time / (24 * 60 * 60);
long hours = (time % (24 * 60 * 60)) / (60 * 60);
long minutes = ((time % (24 * 60 * 60)) % (60 * 60)) / 60;
long second = ((time % (24 * 60 * 60)) % (60 * 60)) % 60;
//String dayStr = String.valueOf(day);
//String hoursStr = timeStrFormat(String.valueOf(hours));
String minutesStr = timeStrFormat(String.valueOf(minutes));
String secondStr = timeStrFormat(String.valueOf(second));
returnString.append(minutesStr).append(":").append(secondStr);
return returnString.toString();//此处不需要天数倒计时和小时的倒计时，可根据需要添加
}
/**
* format time
*
* @param timeStr
* @return
*/
private static String timeStrFormat(String timeStr) {
switch (timeStr.length()) {
case 1:
timeStr = "0" + timeStr;
break;
}
return timeStr;
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
mTickerStopped = true;
}
/**
* Clock end time from now on.
*
* @param endTime
*/
public void setEndTime(long endTime) {
this.endTime = endTime;
}
/**
* Pulls 12/24 mode from system settings
*/
private boolean get24HourMode() {
return android.text.format.DateFormat.is24HourFormat(getContext());
}
private void setFormat() {
if (get24HourMode()) {
mFormat = m24;
} else {
mFormat = m12;
}
}
private class FormatChangeObserver extends ContentObserver {
public FormatChangeObserver() {
super(new Handler());
}
@Override
public void onChange(boolean selfChange) {
setFormat();
}
}
public void setClockListener(ClockListener clockListener) {
this.mClockListener = clockListener;
}
public interface ClockListener{
void timeEnd();
void remainFiveMinutes();
}
}3.在adapter的getView方法里给这个控件，设置值
//产生一个当前的毫秒，这个毫秒其实就是自1970年1月1日0时起的毫秒数
long curTime = System.currentTimeMillis();
//获取系统当前时间，精确到秒
String systemhms = DateFormatUtils.getSystemhms();
//得到剩余时间和系统当前时间的剩余时间，精确到秒
List list = DateFormatUtils.calculateTime(systemhms, listEntity.getExpireTime());
Long hour=new Long(list.get(0));
Long min=new Long(list.get(1));
Long s=new Long(list.get(2));
Long totalLong=hour*3600*1000+min*60*1000+s*1000;//有4秒的误差，在这里暂且加上4000
holder.tv_timer_o.setEndTime(curTime +totalLong);
holder.tv_timer_o.setClockListener(new CustomDigitalClock.ClockListener() { // register the clock's listener
@Override
public void timeEnd() {
// The clock time is ended.
}
@Override
public void remainFiveMinutes() {
// The clock time is remain five minutes.
}
}); 其中 listEntity.getExpireTime()是由json解析得到的字段，本身是一个“2016-03-17 10:57:12”的格式，代表到
“2016-03-17 10:57:12”时结束倒计时,下面附上日期util的calculateTime()方法，该方法是用来计算时差的：
public static List calculateTime(String firstTime,String secondTime){
SimpleDateFormat dfs = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
long between = 0;
try {
/*java.util.Date begin = dfs.parse("2009-07-10 10:22:21.214");
java.util.Date end = dfs.parse("2009-07-20 11:24:49.145");*/
Date begin=dfs.parse(firstTime);
Date end= dfs.parse(secondTime);
between = (end.getTime() - begin.getTime());// 得到两者的毫秒数
} catch (Exception ex) {
ex.printStackTrace();
}
long day = between / (24 * 60 * 60 * 1000);
long hour = (between / (60 * 60 * 1000) - day * 24);
long min = ((between / (60 * 1000)) - day * 24 * 60 - hour * 60);
long s = (between / 1000 - day * 24 * 60 * 60 - hour * 60 * 60 - min * 60);
long ms = (between - day * 24 * 60 * 60 * 1000 - hour * 60 * 60 * 1000
- min * 60 * 1000 - s * 1000);//毫秒
/*System.out.println(day + "天" + hour + "小时" + min + "分" + s + "秒"
+ "毫秒");*/
List list=new ArrayList<>();
list.add(hour);
list.add(min);
list.add(s);
return list;
//return hour + ":" + min + ":" + s ;
} 以上，解决了listview的倒计时的准确性以及滑动时数据混乱。