Update the package name in the app build.gradle

Also only change the name of the activity in AndroidManifest.xml, not all of the descriptive text saying to change the name of the activity.

build-scripts/create-android-project.py

@@ -98,6 +98,16 @@ def gradle_add_prefab_and_aar(path, aar):
     with open(path, "w") as f:
         f.write(data)
 
+def gradle_add_package_name(path, package_name):
+    with open(path) as f:
+        data = f.read()
+
+    data, count = re.subn("org.libsdl.app", package_name, data)
+    assert count >= 1
+
+    with open(path, "w") as f:
+        f.write(data)
+
 
 def main():
     description = "Create a simple Android gradle project from input sources."
@@ -190,6 +200,9 @@ def main():
 
         print(f"WARNING: copy { aar } to { aar_libs_folder }", file=sys.stderr)
 
+    # Add the package name to build.gradle
+    gradle_add_package_name(build_path / "app/build.gradle", args.package_name)
+
     # Create entry activity, subclassing SDLActivity
     activity = args.package_name[args.package_name.rfind(".") + 1:].capitalize() + "Activity"
     activity_path = build_path / "app/src/main/java" / args.package_name.replace(".", "/") / f"{activity}.java"
@@ -206,7 +219,7 @@ def main():
         """))
 
     # Add the just-generated activity to the Android manifest
-    replace_in_file(build_path / "app/src/main/AndroidManifest.xml", "SDLActivity", activity)
+    replace_in_file(build_path / "app/src/main/AndroidManifest.xml", 'name="SDLActivity"', f'name="{activity}"')
 
     # Update project and build
     print("To build and install to a device for testing, run the following:")