[UI] android.app.NativeActivity > WindowedAppActivity + code style

src/xenia/ui/windowed_app_context_android.h

@@ -10,8 +10,10 @@
 #ifndef XENIA_UI_WINDOWED_APP_CONTEXT_ANDROID_H_
 #define XENIA_UI_WINDOWED_APP_CONTEXT_ANDROID_H_
 
+#include <android/asset_manager.h>
+#include <android/configuration.h>
 #include <android/looper.h>
-#include <android/native_activity.h>
+#include <jni.h>
 #include <array>
 #include <memory>
 
@@ -25,13 +27,6 @@ class WindowedApp;
 
 class AndroidWindowedAppContext final : public WindowedAppContext {
  public:
-  // For calling from android.app.func_name exports.
-  static void StartAppOnActivityCreate(
-      ANativeActivity* activity, void* saved_state, size_t saved_state_size,
-      std::unique_ptr<WindowedApp> (*app_creator)(
-          WindowedAppContext& app_context));
-
-  ANativeActivity* activity() const { return activity_; }
   WindowedApp* app() const { return app_.get(); }
 
   void NotifyUILoopOfPendingFunctions() override;
@@ -45,6 +40,12 @@ class AndroidWindowedAppContext final : public WindowedAppContext {
   AndroidWindow* GetActivityWindow() const { return activity_window_; }
   void SetActivityWindow(AndroidWindow* window) { activity_window_ = window; }
 
+  // For calling from WindowedAppActivity native methods.
+  static AndroidWindowedAppContext* JniActivityInitializeWindowedAppOnCreate(
+      JNIEnv* jni_env, jobject activity, jstring windowed_app_identifier,
+      jobject asset_manager);
+  void JniActivityOnDestroy();
+
  private:
   enum class UIThreadLooperCallbackCommand : uint8_t {
     kDestroy,
@@ -55,13 +56,14 @@ class AndroidWindowedAppContext final : public WindowedAppContext {
 
   // Don't delete this object directly externally if successfully initialized as
   // the looper may still execute the callback for pending commands after an
-  // external ANativeActivity_removeFd, and the callback receives a pointer to
-  // the context - deletion must be deferred and done in the callback itself.
+  // external ALooper_removeFd, and the callback receives a pointer to the
+  // context - deletion must be deferred and done in the callback itself.
   // Defined in the translation unit where WindowedApp is complete because of
   // std::unique_ptr.
   ~AndroidWindowedAppContext();
 
-  bool Initialize(ANativeActivity* activity);
+  bool Initialize(JNIEnv* ui_thread_jni_env, jobject activity,
+                  jobject asset_manager);
   void Shutdown();
 
   // Call this function instead of deleting the object directly, so if needed,
@@ -75,10 +77,29 @@ class AndroidWindowedAppContext final : public WindowedAppContext {
   bool InitializeApp(std::unique_ptr<WindowedApp> (*app_creator)(
       WindowedAppContext& app_context));
 
-  static void OnActivityDestroy(ANativeActivity* activity);
+  // Useful notes about JNI usage on Android within Xenia:
+  // - All static libraries defining JNI native functions must be linked to
+  //   shared libraries via LOCAL_WHOLE_STATIC_LIBRARIES.
+  // - If method or field IDs are cached, a global reference to the class needs
+  //   to be held - it prevents the class from being unloaded by the class
+  //   loaders (in a way that would make the IDs invalid when it's reloaded).
+  // - GetStringUTFChars (UTF-8) returns null-terminated strings, GetStringChars
+  //   (UTF-16) does not.
+  JNIEnv* ui_thread_jni_env_ = nullptr;
+
+  // The object reference must be held by the app according to
+  // AAssetManager_fromJava documentation.
+  jobject asset_manager_jobject_ = nullptr;
+  AAssetManager* asset_manager_ = nullptr;
+
+  AConfiguration* configuration_ = nullptr;
 
   bool android_base_initialized_ = false;
 
+  jobject activity_ = nullptr;
+  jclass activity_class_ = nullptr;
+  jmethodID activity_method_finish_ = nullptr;
+
   // May be read by non-UI threads in NotifyUILoopOfPendingFunctions.
   ALooper* ui_thread_looper_ = nullptr;
   // [1] (the write file descriptor) may be referenced as read-only by non-UI
@@ -86,11 +107,6 @@ class AndroidWindowedAppContext final : public WindowedAppContext {
   std::array<int, 2> ui_thread_looper_callback_pipe_{-1, -1};
   bool ui_thread_looper_callback_registered_ = false;
 
-  // TODO(Triang3l): Switch from ANativeActivity to the context itself being the
-  // object for communication with the Java code when NativeActivity isn't used
-  // anymore as its functionality is heavily limited.
-  ANativeActivity* activity_ = nullptr;
-
   AndroidWindow* activity_window_ = nullptr;
 
   std::unique_ptr<WindowedApp> app_;