Fix android detection when python4android is present

Use the builtin mActivity of python4android to get hold of our main activity, which is capable of generating a proper application context.

Author: tmolitor-stud-tu

src/platformdirs/android.py

@@ -6,7 +6,7 @@
 import re
 import sys
 from functools import lru_cache
-from typing import cast
+from typing import TYPE_CHECKING, cast
 
 from .api import PlatformDirsABC
 
@@ -119,14 +119,31 @@ def site_runtime_dir(self) -> str:
 @lru_cache(maxsize=1)
 def _android_folder() -> str | None:
     """:return: base folder for the Android OS or None if it cannot be found"""
-    try:
-        # First try to get a path to android app via pyjnius
-        from jnius import autoclass  # noqa: PLC0415
-
-        context = autoclass("android.content.Context")
-        result: str | None = context.getFilesDir().getParentFile().getAbsolutePath()
-    except Exception:  # noqa: BLE001
-        # if fails find an android folder looking a path on the sys.path
+    result: str | None = None
+    # type checker isn't happy with our "import android", just don't do this when type checking
+    # see https://stackoverflow.com/a/61394121
+    if not TYPE_CHECKING:
+        try:
+            # First try to get a path to android app using python4android (if available)...
+            from android import mActivity  # noqa: PLC0415
+
+            context = cast("android.content.Context", mActivity.getApplicationContext())  # noqa: F821
+            result = context.getFilesDir().getParentFile().getAbsolutePath()
+        except Exception:  # noqa: BLE001
+            result = None
+    if result is None:
+        try:
+            # ...and fall back to using plain pyjnius, if python4android isn't
+            # available or doesn't deliver any useful result...
+            from jnius import autoclass  # noqa: PLC0415
+
+            context = autoclass("android.content.Context")
+            result = context.getFilesDir().getParentFile().getAbsolutePath()
+        except Exception:  # noqa: BLE001
+            result = None
+    if result is None:
+        # and if that fails, too, find an android folder looking at path on the sys.path
+        # warning: only works for apps installed under /data, not adopted storage etc.
         pattern = re.compile(r"/data/(data|user/\d+)/(.+)/files")
         for path in sys.path:
             if pattern.match(path):