Android: add robustness. check that the native code is run for the first time.

android-project/app/src/main/java/org/libsdl/app/SDLActivity.java

@@ -398,6 +398,24 @@ public class SDLActivity extends Activity implements View.OnSystemUiVisibilityCh
            return;
         }
 
+
+        /* Control activity re-creation */
+        /* Robustness: check that the native code is run for the first time.
+         * (Maybe Activity was reset, but not the native code.) */
+        {
+            int run_count = SDLActivity.nativeCheckSDLThreadCounter(); /* get and increment a native counter */
+            if (run_count != 0) {
+                boolean allow_recreate = SDLActivity.nativeAllowRecreateActivity();
+                if (allow_recreate) {
+                    Log.v(TAG, "activity re-created // run_count: " + run_count);
+                } else {
+                    Log.v(TAG, "activity finished // run_count: " + run_count);
+                    System.exit(0);
+                    return;
+                }
+            }
+        }
+
         // Set up JNI
         SDL.setupJNI();
 
@@ -971,6 +989,7 @@ public class SDLActivity extends Activity implements View.OnSystemUiVisibilityCh
     public static native void onNativeLocaleChanged();
     public static native void onNativeDarkModeChanged(boolean enabled);
     public static native boolean nativeAllowRecreateActivity();
+    public static native int nativeCheckSDLThreadCounter();
 
     /**
      * This method is called by SDL using JNI.

src/core/android/SDL_android.c

@@ -170,6 +170,9 @@ JNIEXPORT void JNICALL SDL_JAVA_INTERFACE(nativePermissionResult)(
 JNIEXPORT jboolean JNICALL SDL_JAVA_INTERFACE(nativeAllowRecreateActivity)(
     JNIEnv *env, jclass jcls);
 
+JNIEXPORT int JNICALL SDL_JAVA_INTERFACE(nativeCheckSDLThreadCounter)(
+    JNIEnv *env, jclass jcls);
+
 static JNINativeMethod SDLActivity_tab[] = {
     { "nativeGetVersion", "()Ljava/lang/String;", SDL_JAVA_INTERFACE(nativeGetVersion) },
     { "nativeSetupJNI", "()I", SDL_JAVA_INTERFACE(nativeSetupJNI) },
@@ -203,6 +206,7 @@ static JNINativeMethod SDLActivity_tab[] = {
     { "nativeAddTouch", "(ILjava/lang/String;)V", SDL_JAVA_INTERFACE(nativeAddTouch) },
     { "nativePermissionResult", "(IZ)V", SDL_JAVA_INTERFACE(nativePermissionResult) },
     { "nativeAllowRecreateActivity", "()Z", SDL_JAVA_INTERFACE(nativeAllowRecreateActivity) },
+    { "nativeCheckSDLThreadCounter", "()I", SDL_JAVA_INTERFACE(nativeCheckSDLThreadCounter) }
 };
 
 /* Java class SDLInputConnection */
@@ -738,7 +742,15 @@ JNIEXPORT void JNICALL SDL_JAVA_CONTROLLER_INTERFACE(nativeSetupJNI)(JNIEnv *env
 /* SDL main function prototype */
 typedef int (*SDL_main_func)(int argc, char *argv[]);
 
-static int run_count = 1;
+static int run_count = 0;
+
+JNIEXPORT int JNICALL SDL_JAVA_INTERFACE(nativeCheckSDLThreadCounter)(
+    JNIEnv *env, jclass jcls)
+{
+    int tmp = run_count;
+    run_count += 1;
+    return tmp;
+}
 
 static void SDLCALL SDL_AllowRecreateActivityChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
 {