C++ class Accessed None trying to read property In blueprint

Development Programming & Scripting
1

I have made a very simple class in c++

#pragma once

#include "CoreMinimal.h"
#include "UObject/NoExportTypes.h"
#include "MyObject.generated.h"

UCLASS(BlueprintType)
class MYPROJECT2_API UMyObject : public UObject
{
	GENERATED_BODY()

public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	int32 number = 0;
};

and in blueprint, I made an actor

317614-actor.png

in this actor,I created a variable

317615-variable.png

then i try to print the value of this class

317617-printvalue.png
317617-printvalue.png755×306 34.3 KB

but in my world,in the message log,it shows the error of “Accessed None trying to read property”

317618-messagelog.png
317618-messagelog.png1275×130 9.9 KB

I want to find a solution but i cannot find one.So how to make this possible?

Thanks for your help in advance !

2

You created a variable but you didn’t instantiated it or assigned any object to it. Therefore, its value is still null.

3

Yes,I notice that,but how to initialize an object for my own class.I cannot choose the default value for the class in blueprint. And in c++, i think there are Default constructors for my class,so i think it is the problem of the blueprint.

4

C++ refresh:

class MyClass {...};

MyClass* obj;   // it's just a pointer to a MyClass object. It doesn't call any ctor. It doesn't instantiate any object.

To instantiate an UObject (and others):