Скачать или смотреть Understanding the File.listFiles() Issue in Android: Why Only Subdirectories are Returned

Discover why Android's `File.listFiles()` only returns subdirectories and find effective solutions to access all files in a directory.
---
This video is based on the question https://stackoverflow.com/q/66816442/ asked by the user 'Michael Zaharov' ( https://stackoverflow.com/u/15182054/ ) and on the answer https://stackoverflow.com/a/66820585/ provided by the user 'Michael Zaharov' ( https://stackoverflow.com/u/15182054/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Android File.listFiles() returns only subdirectories

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the File.listFiles() Issue in Android

When working on Android applications, developers often encounter challenges when trying to access files in the external storage. A common issue arises when using the File.listFiles() method, which unexpectedly returns only subdirectories, leaving out the actual files. In this guide, we'll dive into this problem and illustrate how to properly retrieve files from a directory.

The Problem: What’s Going Wrong?

Imagine you have a directory in your Android device's external storage that contains both files and subdirectories. You want to list all the contents—files and folders alike. You might write the following code:

[[See Video to Reveal this Text or Code Snippet]]

However, many developers have reported that this code only returns the subdirectories and not the files present in the specified directory. If you find yourself in this situation, don't worry! Let's break down the solution.

Why Does This Happen?

The main issue stems from Android's evolving permission model, particularly with changes introduced in Android 11:

Scoped Storage: Starting with Android 10 (API level 29), scoped storage was introduced, which restricts how apps can access external storage. Apps can only access their own files and, in some cases, media files.

Media Access Only: In Android 11, apps have limited access to only media files under certain circumstances. If the files you are trying to access are not categorized as media files, listFiles() might ignore them entirely.

Solution: Adjusting Your Target SDK Version

One effective workaround, as identified in a recent discussion, is to change your target SDK version back to Android 10 (API level 29):

Open your build.gradle file.

Locate the targetSdkVersion setting:

[[See Video to Reveal this Text or Code Snippet]]

Sync your project: This will apply the changes.

By downgrading the target SDK version to 29, you effectively revert your app’s handling of external storage permissions to a more permissive model, allowing access to both files and subdirectories.

Conclusion

In conclusion, if you are facing the issue of File.listFiles() returning only subdirectories in your Android application, consider the implications of the targeted API level and how scoped storage affects file access. By adjusting the target SDK version to 29, you can restore access to both files and folders in the specified directory.

If you're still having issues after changing the target SDK version, make sure to check your file permissions and ensure that your app is granted permission to read external storage.

By understanding these guidelines, you can avoid pitfalls and ensure a smoother file handling experience on Android.