listview倒计时

来源：互联网发布：数据迁移编辑：程序博客网时间：2024/06/06 14:23

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();   }}
2.在布局文件里引用这个自定义view

<com.widget.CustomDigitalClock                    android:id="@+id/tv_timer_o"                    android:layout_width="wrap_content"                    android:layout_height="wrap_content"                    android:text="00:01"                    android:textSize="@dimen/common_font_sw320dp_of_10.5"                    android:textColor="@color/myred"                    android:layout_below="@+id/iv_status_o"                    android:gravity="center_horizontal"                    android:layout_centerHorizontal="true"                    android:layout_marginTop="@dimen/common_sw320dp_of_14"/>

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<Long> 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<Long>  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<Long> 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。

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