已Root的LG Stylo 3 Plus（Android7）SD卡写入权限问题求助

Hey there, I get how frustrating it is when you just want to use your SD card normally and hit these roadblocks. Let's break down your questions and walk through possible solutions:

Do you need to modify each app's manifest? #

If you're trying to get your own developed app to write to the SD card, then yes, you'll need to adjust its manifest. But if you're dealing with third-party apps not being able to write, modifying their manifests isn't feasible (you'd need to recompile them, which isn't practical for most users).

What to add to the manifest (for your own app): #

• For Android versions below 10 (API 29):
  • Add these permissions inside the <manifest> tag:

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    

  • Note: You'll also need to request these permissions dynamically at runtime, not just declare them in the manifest.
• For Android 10 and above:
  • The WRITE_EXTERNAL_STORAGE permission no longer grants access to the SD card's root. Instead, use the Storage Access Framework (SAF) to let users select the SD card directory they want your app to access. Alternatively, if you're targeting API 29+, you can add this attribute to your <application> tag for temporary backward compatibility:

    <application android:requestLegacyExternalStorage="true">
    

    Keep in mind this is not a long-term solution—Google recommends migrating to SAF for persistent, compliant access.

Other Solutions to Try #

• Check the SD card physical lock: Some SD cards have a tiny switch on the side that locks them in read-only mode. Flip that switch and try writing again.
• Test with the system file manager: Open your LG's built-in file manager and try saving a file to the SD card. If that fails, the issue might be with the SD card itself (corrupted, damaged, or incorrectly formatted). Back up your data first, then try reformatting the card or using a different one.
• Enable SD card write access in system settings: Some LG devices have a dedicated setting to allow app write access to the SD card. Navigate to Settings > Storage > SD Card and look for options like "Allow write access" or "Set as internal storage" (note: setting as internal storage will encrypt the card and tie it exclusively to your device).
• Use a SAF-compatible file manager: Even for third-party apps, many modern file managers support the Storage Access Framework. Use one of these tools to browse and write to the SD card—it bypasses traditional permission restrictions.
• Check for system updates: LG occasionally releases patches to fix storage-related bugs. Go to Settings > System > Software Update to see if there's an update available for your Stylo 3 Plus.

Since SDfix resolved the display issue but didn't fix the write problem, it's likely either a permission quirk specific to LG's software, a physical issue with the SD card, or a need to adopt newer storage frameworks instead of relying on old permission models.

内容的提问来源于stack exchange，提问作者20GT