请阅读 Emacs 说明书中的 Android appendix。
其中提到：
@cindex file system limitations, Android 11 On Android 11 and later, the Android system restricts applications from accessing files in the @file{/sdcard} directory using file-related system calls such as @code{open} and @code{readdir}.
This restriction is known as ``Scoped Storage’', and supposedly makes the system more secure. Unfortunately, it also means that Emacs cannot access files in those directories, despite holding the necessary permissions. Thankfully, the Open Handset Alliance’s version of Android allows this restriction to be disabled on a per-program basis; the corresponding option in the system settings panel is:
@indentedblock System → Apps → Special App Access → All files access → Emacs @end indentedblock