# Use of undeclared identifier 'FJavaWrapper'

**URL:** <https://forums.unrealengine.com/t/use-of-undeclared-identifier-fjavawrapper/474623>\
**Category:** Platform & Builds\
**Tags:** c-build, unreal-engine, packaging-projects, question\
**Created:** [November 17, 2020, 2:42pm UTC](https://forums.unrealengine.com/t/use-of-undeclared-identifier-fjavawrapper/474623 "2020-11-17T14:42:45Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![progy85](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@progy85](https://forums.unrealengine.com/u/progy85)\
**Post date:** [November 17, 2020, 2:42pm UTC](https://forums.unrealengine.com/t/use-of-undeclared-identifier-fjavawrapper/474623/1 "2020-11-17T14:42:45Z")

</div>

hi,

after package for android I got:  
MyUserWidget.cpp(11,38): error: use of undeclared identifier ‘FJavaWrapper’

This I got problem only in if use custom widget, if used actor works…

Build in VS works ok, in UE4 in output log I got error.

My code:

```
// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "Blueprint/UserWidget.h"
#include "MyUserWidget.generated.h"

/**
 * 
 */
UCLASS()
class MYPROJECT11_API UMyUserWidget : public UUserWidget
{
	GENERATED_BODY()

		UFUNCTION(BlueprintCallable)
		void ToggleOrientation();
	
};

#include "MyUserWidget.h"

void UMyUserWidget::ToggleOrientation()
{
#if PLATFORM_ANDROID || PLATFORM_IOS 
    JNIEnv* JE = FAndroidApplication::GetJavaEnv();
    jmethodID SetOrientationID = FJavaWrapper::FindMethod(JE, FJavaWrapper::GameActivityClassID, "setRequestedOrientation", "(I)V", false);
    FJavaWrapper::CallVoidMethod(JE, FJavaWrapper::GameActivityThis, SetOrientationID, 0);
#else 

#endif 
  }
```

---

<div class="post-metadata">

**Author:** ![LogierJan](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/logierjan/32/88718_2.png) [@LogierJan](https://forums.unrealengine.com/u/LogierJan)\
**Post date:** [November 17, 2020, 2:54pm UTC](https://forums.unrealengine.com/t/use-of-undeclared-identifier-fjavawrapper/474623/2 "2020-11-17T14:54:34Z")

</div>

Aren’t you missing an include for FJavaWrapper?

```
#include "Android/AndroidJNI.h"
```

---

<div class="post-metadata">

**Author:** ![progy85](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@progy85](https://forums.unrealengine.com/u/progy85)\
**Post date:** [November 19, 2020, 6:29am UTC](https://forums.unrealengine.com/t/use-of-undeclared-identifier-fjavawrapper/474623/3 "2020-11-19T06:29:51Z")

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yes, i forgot thanks!