Android Oreo（API 26） - 在外部存储中创建目录

Question

I've been developing an app on nougat that creates a directory in the external storage.

I used to do it like this:

final File dir = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/Chords/Processed Audio");
dir.mkdirs();

This code does not seem to work on API 26 (Android Oreo). The directory is not created.

How can I achieve the same thing, preferably that works on all android version from API 21 to API 26?

Answer 1

I have no problems running your existing code on a Nexus 5X running Android 8.0. Using adb shell ls /storage/emulated/0 , I see Chores/ , and inside there I see Processed Audio/ . This is for an app with WRITE_EXTERNAL_STORAGE permission, including runtime permissions.

That being said, ideally, do not use string concatenation to create File objects. Instead, use:

final File dir = new File(new File(Environment.getExternalStorageDirectory(), "Chords"), "Processed Audio");

Answer 2

@Daniele，请参阅https://stackoverflow.com/a/44455957/966789和https://stackoverflow.com/a/33031091/966789(Android为Android 6.0添加了新的权限模型（Marshmallow）。如果你的targetSdkVersion> = 23如果您在Marshmallow（或更高版本）设备上运行，则可能需要启用运行时权限。您还应该阅读有关运行时权限更改的更多信息。如果您使用的是targetSdkVersion> = 24，则还必须将FileProvider配置为show in以下示例使用com.codepath.fileprovider并且应该与指定的权限XML标记匹配）