正如问题中正确指出的，API 26 Context#getCacheDir() 来释放应用程序缓存中的空间.

As correctly stated in the question, the API 26 Intent.ACTION_DEVICE_STORAGE_LOW is deprecated and Context#getCacheDir() is advised to be used instead to free up space from you application's cache.

此操作存在多个问题(下文列举)，但首先:请注意，保持高速缓存合理小"(例如1 MB)是一种很好的做法，我引用:

There are multiple problems with this (enumerated below), but first: note that it is good practice to keep cache 'reasonably small' (e.g. 1 MB), I quote:

getCacheDir()

返回一个文件，该文件代表应用程序的临时缓存文件的内部目录.请确保在不再需要每个文件后将其删除，并对在任何给定时间使用的内存量实施合理的大小限制，例如1MB.

Returns a File representing an internal directory for your app's temporary cache files. Be sure to delete each file once it is no longer needed and implement a reasonable size limit for the amount of memory you use at any given time, such as 1MB.

警告:如果系统存储空间不足，则可能会在没有警告的情况下删除您的缓存文件.

Caution: If the system runs low on storage, it may delete your cache files without warning.

(源)

因此，这里存在三个问题:

So, there are three problems here:

1. 我们应该清除缓存，但是它可能已经相当小(例如1 MB)，因此清除缓存可能不会释放足够的空间，使空闲存储再次变为OK(类似于已弃用的因此，清除缓存似乎无济于事，所以我将不介绍如何执行此操作的详细信息.

   So, clearing the cache doesn't seem to help, so I won't go into the details of how to do that.

   但是，按照此答案，我们可以假设系统在空闲存储空间为10％时进入了我们要检测的低存储状态.根据链接的答案，这个数字是Android的默认值，但是并没有阻止设备制造商(或ROM开发人员)更改它.

   However, as per this answer, we could assume that at 10% free storage the system enters the low storage state that we want to detect. This number is Android's default, but there's little preventing a device manufacturer (or ROM developer) from changing it, according to the linked answer.

   在这一点上，对我来说，这10％是一个神奇的数字，我想知道是否可以通过编程确定该阈值.如果您知道怎么做，请编辑我的答案，自己发布答案或对我的答案发表评论.

   要使用 getCacheDir()进行此操作，可以使用以下代码:

   To do this using getCacheDir(), you could use the following:

   Java，来自 Context (例如 Activity ):

   Java, from a Context (e.g. Activity):

   File cacheDir = getCacheDir();
   if (cacheDir.getUsableSpace() * 100 / cacheDir.getTotalSpace() <= 10) { // Alternatively, use cacheDir.getFreeSpace()
     // Handle storage low state
   } else {
     // Handle storage ok state
   }
   

   科特琳，来自 Context (例如 Activity ):

   Kotlin, from a Context (e.g. Activity):

   if (cacheDir.usableSpace * 100 / cacheDir.totalSpace <= 10) { // Alternatively, use cacheDir.freeSpace
     // Handle storage low state
   } else {
     // Handle storage ok state
   }
   

   现在，是使用可用空间还是可用空间，这对我来说还不是很清楚.差异在此处进行了描述.

   Now, whether to use the usable space or free space, that's not entirely clear to me. The difference is described here.

   深入研究Android源代码后，我发现无法访问我的代码的系统服务，该服务会检查存储空间是否不足: StorageManager#getStorageLowBytes ，我都无法访问.如果这可以通过某些非骇客的方式实现，那将是获得低存储字节阈值的一种方式.在那里，您可以看到源使用 getUsableSpace()，因此这也是我为代码段选择该代码而不是 getFreeSpace()的原因.

   Diving into the Android source I found a system service, that I cannot access in my code, that checks for low storage: DeviceStorageMonitorService. It gets its lowBytes variable from StorageManager#getStorageLowBytes, which I cannot access either. If that would be possible in some non-hacky way, that would be a way to get the low storage bytes threshold. There you see the source uses getUsableSpace(), so that's why I chose that instead of getFreeSpace() too for my code snippets.