在虚幻引擎C ++中设置计时器

Question

I am having trouble creating a timer in Unreal Engine 4. The problem is in GetWorldTimerManager. When I call set timer on this I get an E0070 incomplete type error. Normally this means that I have failed to include something

void ACubeFarmBlock::HandleClicked()
{
    if (!bIsPlanted)
    {
        bIsPlanted = true;

        // Change material
        BlockMesh->SetMaterial(0, OrangeMaterial);

        // Determine when to harvest
        GetWorldTimerManager().SetTimer(HarvestTimerHandle, &ACubeFarmBlock::Harvest, HarvestTime,false);
    }
}

HarvestTimerHandle is defined in the header. Below is the list of includes. MyActor.h contains a method that defines GetWorldTimerManager so I think I have included everything. It is worth it to note that when I looked the timer function up online I found several sites where this set timer method included a this argument inserted between the HarvestTimerHandle argument and the &ACubeFormBlock::Harvest argument. Including this does not make my error go away.

#include "CubeFarmBlock.h"
#include "CubeFarmBlockGrid.h"
#include "UObject/ConstructorHelpers.h"
#include "Components/StaticMeshComponent.h"
#include "Engine/StaticMesh.h"
#include "Materials/MaterialInstance.h"
#include "MyActor.h"

The errors:

..\\CubeFarmBlock.cpp(76): note: see reference to function template instantiation 'TFunction::TFunction(FunctorType &&)' being compiled 1> with 1> [ 1> FunctorType=void (__cdecl ACubeFarmBlock::* )(float) 1> ]

Severity Code Description Project File Line Suppression State Error (active)
E0070 incomplete type is not allowed CubeFarm ..\\CubeFarmBlock.cpp 78 Severity
Code Description Project File Line Suppression State Error (active) E0070
incomplete type is not allowed CubeFarm ..\\CubeFarmBlock.cpp 78

Answer 1

In your header file create a handler FTimerHandle InputTimeHandle;

Then in your cpp file

GetWorld()->GetTimerManager().SetTimer(InputTimeHandle,this, &AMyPlayerController::GetInputTimer, 1, true,0.5f);

You are only missing parameters

Answer 2

Ok, so for a warning, I've never used UE4, however...

This error says that you are trying to bind a member function to a TFunction:

'TFunction::TFunction(FunctorType &&)' being compiled 1> with 1> 
    [ 1> FunctorType=void (__cdecl ACubeFarmBlock::* )(float) 1> ]

Member functions need an Object to point to.. I think you are missing the 'this' parameter. Without looking it up, I think you either need to:

• Bind this to the TFunction you are trying to pass the Timer OR

• Use another SetTimer overload that lets you pass this as a parameter .

Eg

GetWorldTimerManager().SetTimer(HarvestTimerHandle, this, &ACubeFarmBlock::Harvest, HarvestTime,false);

---

I can't find any simple references online, but if you search for Member Function pointers and perhaps the hidden this parameter you can get an idea as to what is going wrong.