Android Studio项目raw文件夹map_style文件引用未解析

Here are actionable fixes to resolve the unresolved reference issue, even after rebuilding and restarting Android Studio:

• Verify the raw resource file details
  Ensure the file in src/main/res/raw is named exactly map_style (case-sensitive, no uppercase letters, spaces, or special characters except underscores). File extensions (like .json) are ignored by the Android resource system, so the resource name will be map_style regardless of the extension.

• Check the R class import
  Make sure you’re importing your app’s package-specific R class (e.g., com.yourappname.R) instead of the default android.R. The latter doesn’t include your custom resources.

• Clean and rebuild with cache invalidation
  Try a deeper clean than just a standard rebuild:

  1. Go to Build > Clean Project
  2. Go to File > Invalidate Caches..., check "Clear file system cache and local history", then click "Invalidate and Restart"
  3. After restart, run Build > Rebuild Project

• Validate the resource file content
  If the map style JSON file has syntax errors, Android may fail to generate the resource entry. Use a JSON validator to check for issues like missing commas, mismatched brackets, or invalid property names.

• Check the raw folder location
  Confirm the raw folder is directly under src/main/res/ (not in src/test/res or another subdirectory). Android only processes resources in the main source set by default.

• Use getIdentifier as a temporary workaround
  If the R class still doesn’t pick up the resource, use getResources().getIdentifier() to fetch the resource ID dynamically:

  int mapStyleResId = getContext().getResources().getIdentifier("map_style", "raw", getContext().getPackageName());
  if (mapStyleResId != 0) {
      googleMap.setMapStyle(MapStyleOptions.loadRawResourceStyle(getContext(), mapStyleResId));
  }
  

  This bypasses the R class and directly looks up the resource by name.

• Check module dependencies
  If the raw resource is in a separate module, ensure that module is added as a dependency in your app’s build.gradle file, and that resources are set to be accessible (no resource hiding rules applied).

内容的提问来源于stack exchange，提问作者Marc Exposito Francisco