根据系统时间设置现在格式化日期时间

Calendar mDummyDate;
mDummyDate = Calendar.getInstance();
        java.text.DateFormat shortDateFormat = DateFormat.getDateFormat(context);//注意这个要导入 import android.text.format.DateFormat;  这个包而不是 java下的包，倒错会报错的
        final Calendar now = Calendar.getInstance();
        mDummyDate.setTimeZone(now.getTimeZone());
        mDummyDate.set(now.get(Calendar.YEAR), 11, 31, 13, 0, 0);
        Date dummyDate = mDummyDate.getTime();
        Log.i(TAG, "date format: " + shortDateFormat.format(dummyDate));
       // if (format != null && !format.equals("")) {
            SimpleDateFormat formatter = new SimpleDateFormat(shortDateFormat.format(date));
            String mTimestampd = formatter.format(date);
            String time = MessageUtils.formatDateStampString(context, date);
            String showtime = mTimestampd + " " + time;
            mTimestampHW = showtime;
            Log.i(TAG, " mTimestampHW = "+mTimestampHW);
            System.out.println(" date = " + date + " date+ mTimestamp = showtime==" + showtime + "  mTimestampHW  =  " + mTimestampHW);
       // } else {
           
        //    mTimestampHW = MessageUtils.formatDateStampString(context, date, true);
            Log.i(TAG, " mTimestampHW = "+mTimestampHW);
//=====================================================================
//格式化时间 
public static String formatDateStampString(Context context, long when) {
        Time then = new Time();
        then.set(when);
        Time now = new Time();
        now.setToNow();
        // Basic settings for formatDateTime() we want for all cases.
        int format_flags = DateUtils.FORMAT_NO_NOON_MIDNIGHT |
                           DateUtils.FORMAT_ABBREV_ALL |
                           DateUtils.FORMAT_CAP_AMPM;
            format_flags |= DateUtils.FORMAT_SHOW_TIME;;
        return DateUtils.formatDateTime(context, when, format_flags);
    }
//格式化日期和时间
    public static String formatTimeStampString(Context context, long when, boolean fullFormat) {
        Time then = new Time();
        then.set(when);
        Time now = new Time();
        now.setToNow();

        // Basic settings for formatDateTime() we want for all cases.
        int format_flags = DateUtils.FORMAT_NO_NOON_MIDNIGHT |
                           DateUtils.FORMAT_ABBREV_ALL |
                           DateUtils.FORMAT_CAP_AMPM;

        // If the message is from a different year, show the date and year.
        if (then.year != now.year) {
            format_flags |= DateUtils.FORMAT_SHOW_YEAR | DateUtils.FORMAT_SHOW_DATE;
        } else if (then.yearDay != now.yearDay) {
            // If it is from a different day than today, show only the date.
            format_flags |= DateUtils.FORMAT_SHOW_DATE;
        } else {
            // Otherwise, if the message is from today, show the time.
            format_flags |= DateUtils.FORMAT_SHOW_TIME;
        }

        // If the caller has asked for full details, make sure to show the date
        // and time no matter what we've determined above (but still make showing
        // the year only happen if it is a different year from today).
        if (fullFormat) {
            format_flags |= (DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_SHOW_TIME);
           
           
        }

        return DateUtils.formatDateTime(context, when, format_flags);}