AlarmManager 和 ScheduledExecutorService 之间的区别
除了设置准确时间（即午夜）与设置延迟（即 24 小时）之外，使用 AlarmManager 和 ScheduledExecutorService 定期运行任务之间有什么区别？
就我而言，我需要每天晚上运行一些代码来检查新数据，并在有新数据时创建新通知。
谢谢！
Besides setting and exact time (i.e. midnight) versus setting a delay (i.e. 24 hours), what's the difference between using AlarmManager and ScheduledExecutorService to run a task periodically?
In my case, I need to run a little bit of code to check for new data every night and create a new notification if there is new data.
Thanks!
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ScheduledExecutorService在您的应用程序进程中运行。如果应用程序进程终止，则所有计划任务都不会运行。因此需要服务（以便您的流程超出生命周期的“活动”活动部分）。而
AlarmManager是一直运行的关键系统服务。如果您的应用程序安排了某些操作并被终止，则AlarmManager可能会再次启动应用程序（通过PendingIntent）。这里没有人提到的最后一个主要区别是
AlarmManager了解WakeLock和电源管理。这意味着AlarmManager可以在指定时间唤醒Android设备来运行计划任务。而ScheduledExecutorService对电源管理一无所知，并且只会在设备未处于深度睡眠状态时启动任务（即它可能会错过时间）。ScheduledExecutorServiceruns in your application process. If application process dies, none of the scheduled tasks will run. Hence the need forService(so your process lives beyond Activities active part of lifecycle).While
AlarmManageris critical system service that runs all the time. And if your application scheduled something and was killed, thenAlarmManagermay start application again (viaPendingIntent).And the last major difference that no one mentioned here is that
AlarmManagerknows aboutWakeLocks and power management. This means thatAlarmManagermay wake up Android device at specified time to run scheduled task. WhileScheduledExecutorServiceknows nothing about power management and will only start task when device is not in deep sleep (i.e. it can simply miss the time).仅当您有某个组件（例如
Service）始终运行时，ScheduledExecutorService才会起作用。因此，它应该只在组件由于其他原因而位于内存中的情况下使用，从而为用户增加价值。将组件放在内存中只是为了观察时钟的滴答声，这是一种浪费，这也是用户使用任务杀手等攻击开发人员的原因之一。AlarmManager是操作系统提供的系统服务。当时间到来时它可以启动一个组件。因此，您不需要运行该组件。这是
AlarmManager的一个清晰场景。ScheduledExecutorServicewill only work if you have some component, such as aService, running all of the time. Hence, it should only be used in cases where the component would be in memory for other reasons, adding value to the user. Having a component be in memory solely to watch the clock tick by is wasteful and one of the reasons why users attack developers with task killers and such.AlarmManageris an OS-supplied system service. It can start up a component when the time rolls around. Hence, you do not need to have the component running.This is a clear scenario for
AlarmManager.我认为
ScheduledExecutorService与您的进程相关联，如果您的进程被终止，则该服务将不起作用。相比之下，AlarmManager由操作系统管理，因此即使您的应用程序未运行它也可以工作。I think
ScheduledExecutorServiceis tied to your process and will not work in case your process gets killed. In contrastAlarmManageris managed by the OS so it works even if your application is not running.