Android WorkManager 中的异步工作者 [英] Asynchronous Worker in Android WorkManager

问题描述

Google 最近发布了新的 WorkManager 架构组件.通过在 Worker 类中实现 doWork() 可以很容易地安排同步工作，但是如果我想要怎么办在后台做一些异步工作?例如，我想使用 Retrofit 进行网络服务调用.我知道我可以发出同步网络请求，但它会阻塞线程并且感觉不对.是否有任何解决方案或目前不支持?

Google recently announced new WorkManager architecture component. It makes it easy to schedule synchronous work by implementing doWork() in Worker class, but what if I want to do some asynchronous work in the background? For example, I want to make a network service call using Retrofit. I know I can make a synchronous network request, but it would block the thread and just feels wrong. Is there any solution for this or it is just not supported at the moment?

推荐答案

Per WorkManager文档:

默认情况下，WorkManager 在后台线程上运行其操作.如果您已经在后台线程上运行并且需要同步(阻塞)调用 WorkManager，请使用 synchronous() 来访问此类方法.

By default, WorkManager runs its operations on a background thread. If you are already running on a background thread and have need for synchronous (blocking) calls to WorkManager, use synchronous() to access such methods.

因此，如果您不使用synchronous()，您可以安全地从doWork() 执行同步网络调用.从设计的角度来看，这也是一种更好的方法，因为回调很混乱.

Therefore, if you don't use synchronous(), you can safely perform sync network calls from doWork(). This is also a better approach from design perspective because callbacks are messy.

也就是说，如果您真的想从 doWork() 触发异步作业，您需要暂停执行线程并在异步作业完成后使用 wait/notify 机制(或其他一些线程管理机制，例如 Semaphore).在大多数情况下，我不建议这样做.

That said, if you really want to fire async jobs from doWork(), you'll need to pause the execution thread and resume it upon async job completion using wait/notify mechanism (or some other thread management mechanism e.g. Semaphore). Not something I would recommend in most cases.

顺便提一下，WorkManager 还处于非常早期的 alpha 阶段.

As a side note, WorkManager is in very early alpha.

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