Android闹钟程序周期循环提醒源码(AlarmManager)

Android系统提供了AlarmManager类来管理闹钟定时提醒任务。通过AlarmManager实现定时提醒及定时循环提醒。那么，AlarmManager类可以应用到以下场景：
1、定时循环启动组件（Component，如Activity、BroadcastReceiver），这样能替代在后台启动Service进行定时提醒任务
2、实现闹钟的按小时、天、周等形式的定时循环提醒功能。

定时启动组件很简单，下面贴出闹钟按天、周形式的定时循环提醒功能的核心代码。此功能核心的是计算出下一次闹钟提醒时间，代码如下：

/*
 * 闹钟三种设置模式（dateMode）：
 * 1、DATE_MODE_FIX：指定日期，如20120301   , 参数dateValue格式：2012-03-01
 * 2、DATE_MODE_WEEK：按星期提醒，如星期一、星期三 ,  参数dateValue格式：1,3
 * 3、DATE_MODE_MONTH：按月提醒，如3月2、3号，4月2、3号,  参数dateValue格式：3,4|2,3
 *  
 * startTime:为当天开始时间，如上午9点, 参数格式为09:00
 */
public static long getNextAlarmTime(int dateMode, String dateValue,
        String startTime) {
    final SimpleDateFormat fmt = new SimpleDateFormat();
    final Calendar c = Calendar.getInstance();
    final long now = System.currentTimeMillis();

    // 设置开始时间
    try {
        if(Task.DATE_MODE_FIX == dateMode) {
            fmt.applyPattern("yyyy-MM-dd");
            Date d = fmt.parse(dateValue);
            c.setTimeInMillis(d.getTime());
        }

        fmt.applyPattern("HH:mm");
        Date d = fmt.parse(startTime);
        c.set(Calendar.HOUR_OF_DAY, d.getHours());
        c.set(Calendar.MINUTE, d.getMinutes());
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
    } catch (Exception e) {
        e.printStackTrace();
    }

    long nextTime = 0;
    if (Task.DATE_MODE_FIX == dateMode) { // 按指定日期
        nextTime = c.getTimeInMillis();
        // 指定日期已过
        if (now >= nextTime) nextTime = 0;
    } else if (Task.DATE_MODE_WEEK == dateMode) { // 按周
        final long[] checkedWeeks = parseDateWeeks(dateValue);
        if (null != checkedWeeks) {
            for (long week : checkedWeeks) {
                c.set(Calendar.DAY_OF_WEEK, (int) (week + 1));

                long triggerAtTime = c.getTimeInMillis();
                if (triggerAtTime <= now) { // 下周
                    triggerAtTime += AlarmManager.INTERVAL_DAY * 7;
                }
                // 保存最近闹钟时间
                if (0 == nextTime) {
                    nextTime = triggerAtTime;
                } else {
                    nextTime = Math.min(triggerAtTime, nextTime);
                }
            }
        }
    } else if (Task.DATE_MODE_MONTH == dateMode) { // 按月
        final long[][] items = parseDateMonthsAndDays(dateValue);
        final long[] checkedMonths = items[0];
        final long[] checkedDays = items[1];

        if (null != checkedDays && null != checkedMonths) {
            boolean isAdd = false;
            for (long month : checkedMonths) {
                c.set(Calendar.MONTH, (int) (month - 1));
                for (long day : checkedDays) {
                    c.set(Calendar.DAY_OF_MONTH, (int) day);

                    long triggerAtTime = c.getTimeInMillis();
                    if (triggerAtTime <= now) { // 下一年
                        c.add(Calendar.YEAR, 1);
                        triggerAtTime = c.getTimeInMillis();
                        isAdd = true;
                    } else {
                        isAdd = false;
                    }
                    if (isAdd) {
                        c.add(Calendar.YEAR, -1);
                    }
                    // 保存最近闹钟时间
                    if (0 == nextTime) {
                        nextTime = triggerAtTime;
                    } else {
                        nextTime = Math.min(triggerAtTime, nextTime);
                    }
                }
            }
        }
    }
    return nextTime;
}

public static long[] parseDateWeeks(String value) {
    long[] weeks = null;
    try {
        final String[] items = value.split(",");
        weeks = new long[items.length];
        int i = 0;
        for (String s : items) {
            weeks[i++] = Long.valueOf(s);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return weeks;
}

public static long[][] parseDateMonthsAndDays(String value) {
    long[][] values = new long[2][];
    try {
        final String[] items = value.split("\\|");
        final String[] monthStrs = items[0].split(",");
        final String[] dayStrs = items[1].split(",");
        values[0] = new long[monthStrs.length];
        values[1] = new long[dayStrs.length];

        int i = 0;
        for (String s : monthStrs) {
            values[0][i++] = Long.valueOf(s);
        }
        i = 0;
        for (String s : dayStrs) {
            values[1][i++] = Long.valueOf(s);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return values;

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