“setExact"和“setAlarmClock"之间的区别 [英] Difference between 'setExact' and 'setAlarmClock'

问题描述

在我应该在指定时间触发警报的应用程序中，警报的目的是通过 Notification 通知用户，我对获得不准确的结果感到绝望.闹钟响了，但不是在指定的时间.当闹钟设置和应该响起的时间之间的时间很长时，这是系统性的.为此，我使用了 setExact(RTC_WAKEUP,time,intent).经过多次尝试，终于看到并尝试了setAlarmClock函数，一切顺利！！

In my application which was supposed to trigger an alarm at a specified time, alarm whose purpose was to inform the user via a Notification, I despaired at obtaining a non precise result. The alarm was ringing, but not at the specified time. This was systematic when the time between the setting of the alarm and the time it was supposed to go off was long. For this, I was using setExact(RTC_WAKEUP,time,intent). After many attemps to make it work, I finally saw and tried the setAlarmClock function, and everything went fine!!

根据 javadoc，setAlarmClock 与 setExact 相同，只是它隐含了 RTC_WAKEUP.据我所知，至少还存在另一个差异.有人知道吗?

According to the javadoc, setAlarmClock is identical to setExact except that it implies RTC_WAKEUP. As far as I see, at least one other difference exists. Does anyone know it?

推荐答案

setExact() 和 setAlarmClock() 都对 setImpl().如果您对 setExact() 调用使用 RTC_WAKEUP，唯一的区别是 AlarmClockInfo 类型的最终参数.

setExact() and setAlarmClock() both make very similar calls to setImpl(). If you use RTC_WAKEUP for your setExact() call, the only difference is the final arg of type AlarmClockInfo.

在服务端，调用在set().在该方法的末尾，我们可以看到额外参数的不同之处:

On the service side, the call is received in set(). At the end of that method, we can see the difference the extra argument makes:

@Override
public void set(int type, long triggerAtTime, long windowLength, long interval, int flags,
        PendingIntent operation, WorkSource workSource,
        AlarmManager.AlarmClockInfo alarmClock) {
    final int callingUid = Binder.getCallingUid();
    if (workSource != null) {
        getContext().enforcePermission(
                android.Manifest.permission.UPDATE_DEVICE_STATS,
                Binder.getCallingPid(), callingUid, "AlarmManager.set");
    }

    // No incoming callers can request either WAKE_FROM_IDLE or
    // ALLOW_WHILE_IDLE_UNRESTRICTED -- we will apply those later as appropriate.
    flags &= ~(AlarmManager.FLAG_WAKE_FROM_IDLE
            | AlarmManager.FLAG_ALLOW_WHILE_IDLE_UNRESTRICTED);

    // Only the system can use FLAG_IDLE_UNTIL -- this is used to tell the alarm
    // manager when to come out of idle mode, which is only for DeviceIdleController.
    if (callingUid != Process.SYSTEM_UID) {
        flags &= ~AlarmManager.FLAG_IDLE_UNTIL;
    }

    // If the caller is a core system component, and not calling to do work on behalf
    // of someone else, then always set ALLOW_WHILE_IDLE_UNRESTRICTED.  This means we
    // will allow these alarms to go off as normal even while idle, with no timing
    // restrictions.
    if (callingUid < Process.FIRST_APPLICATION_UID && workSource == null) {
        flags |= AlarmManager.FLAG_ALLOW_WHILE_IDLE_UNRESTRICTED;
    }

    // If this is an exact time alarm, then it can't be batched with other alarms.
    if (windowLength == AlarmManager.WINDOW_EXACT) {
        flags |= AlarmManager.FLAG_STANDALONE;
    }

    // If this alarm is for an alarm clock, then it must be standalone and we will
    // use it to wake early from idle if needed.
    if (alarmClock != null) {
        flags |= AlarmManager.FLAG_WAKE_FROM_IDLE | AlarmManager.FLAG_STANDALONE;
    }

    setImpl(type, triggerAtTime, windowLength, interval, operation,
            flags, workSource, alarmClock, callingUid);
}

如果有一个非空的 alarmClock 参数，请求会在 FLAG_STANDALONE 之上获得 FLAG_WAKE_FROM_IDLE 标志，你会得到在这两种情况下.以及对 的评论FLAG_WAKE_FROM_IDLE 说:

If there's a non-null alarmClock argument, the request gets the FLAG_WAKE_FROM_IDLE flag, on top of FLAG_STANDALONE, which you'll get in both cases. And the comment for FLAG_WAKE_FROM_IDLE says:

闹钟标志:即使设备空闲，此闹钟也会唤醒设备.例如，这是闹钟的闹钟.

Flag for alarms: this alarm would like to wake the device even if it is idle. This is, for example, an alarm for an alarm clock.

如果你愿意，你可以深入了解的用法FLAG_WAKE_FROM_IDLE -- 但据我所知，这就是区别.您的正常"确切警报不会将设备从空闲状态唤醒，但使用 setAlarmClock() 设置的警报会.

If you want, you can dig into the usage of FLAG_WAKE_FROM_IDLE -- but that's the difference, as far as I can tell. Your "normal" exact alarms do not wake the device from idle, but the alarm set with setAlarmClock() does.

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