如何设置闹钟在固定时间正确触发? [英] How to set an alarm to fire properly at fixed time?

问题描述

我有这个代码

Calendar c = new GregorianCalendar();
        c.add(Calendar.DAY_OF_YEAR, 1);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 22);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);

        // We want the alarm to go off 30 seconds from now.
        long firstTime = SystemClock.elapsedRealtime();
        firstTime += 30*1000;
        long a=c.getTimeInMillis();

        // Schedule the alarm!
        AlarmManager am = (AlarmManager)ctx.getSystemService(Context.ALARM_SERVICE);
        am.setRepeating(AlarmManager.ELAPSED_REALTIME_WAKEUP,
                c.getTimeInMillis(), 1*60*60*1000, sender);

不在23:22h

我做错了什么?我注意到 firstTime 和 c.getTimeInMillis() 在大小和长度上有很大不同.当我使用firstTime时，所以当设置为30秒时，警报执行得很好.

What I am doing wrong? I noticed firstTime and c.getTimeInMillis() differs a lot in size and length. When I use firstTime, so when set to 30 seconds, the alarm is executed well.

推荐答案

您使用的是 AlarmManager.ELAPSED_REALTIME_WAKEUP 标志，但您使用的是日历对象.这两件事不能放在一起.

You are using the AlarmManager.ELAPSED_REALTIME_WAKEUP flag, but you are using a Calendar object. These two things don't go together.

您需要使用 AlarmManager.RTC 或 AlarmManager.RTC_WAKEUP 如果您使用日历或日期对象(自 1970 年以来的毫秒数)指定闹钟时间.

You need to use AlarmManager.RTC or AlarmManager.RTC_WAKEUP if you are specifying the alarm time using a Calendar or Date object (milliseconds since 1970).

当您通过 SystemClock.elapsedRealtime() 指定闹钟时间时，您使用 AlarmManager.ELAPSED_REALTIME 或 AlarmManager.ELAPSED_REALTIME_WAKEUP(自手机开机).

You use AlarmManager.ELAPSED_REALTIME or AlarmManager.ELAPSED_REALTIME_WAKEUP when you are specifying the alarm time via SystemClock.elapsedRealtime() (milliseconds since the phone booted).

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