AndroidJniProvider now has acquire and release calls instead of get

RenderSystems/Vulkan/include/Windowing/Android/OgreVulkanAndroidWindow.h

@@ -51,11 +51,18 @@ namespace Ogre
     public:
         /** User must override this function.
         @param env [out]
-            The JNI class that is assumed to be from AttachCurrentThread.
+            The JNI class that is assumed to be from AttachCurrentThread().
         @param activity [out]
             NativeActivity object handle, used for JNI.
         */
-        virtual void get( JNIEnv **env, jobject *activity ) = 0;
+        virtual void acquire( JNIEnv **env, jobject *activity ) = 0;
+
+        /** Notifies the implementation that we're done using the env object.
+            In case the implementation wants to call DetachCurrentThread().
+        @param env
+            The JNI class that was retrieved via acquire().
+        */
+        virtual void release( JNIEnv *env ) = 0;
     };
 
     class _OgreVulkanExport VulkanAndroidWindow final : public VulkanWindowSwapChainBased

RenderSystems/Vulkan/src/Windowing/Android/OgreVulkanAndroidWindow.cpp

@@ -395,11 +395,14 @@ namespace Ogre
                          "VulkanAndroidWindow::createSwapchain" );
         }
 
-        JNIEnv *jni = 0;
-        jobject nativeActivityClass = 0;
-        mJniProvider->get( &jni, &nativeActivityClass );
-        SwappyVk_initAndGetRefreshCycleDuration( jni, nativeActivityClass, mDevice->mPhysicalDevice,
-                                                 mDevice->mDevice, mSwapchain, &mRefreshDuration );
+        {
+            JNIEnv *jni = 0;
+            jobject nativeActivityClass = 0;
+            mJniProvider->acquire( &jni, &nativeActivityClass );
+            SwappyVk_initAndGetRefreshCycleDuration( jni, nativeActivityClass, mDevice->mPhysicalDevice,
+                                                     mDevice->mDevice, mSwapchain, &mRefreshDuration );
+            mJniProvider->release( jni );
+        }
 
         // Swappy wants to know the mNativeWindow every time the Swapchain changes.
         // If we try to set mNativeWindow without a valid mSwapchain yet, it won't work correctly.