【UE4/C++】綁定輸入響應

.h

#include "GameFramework/Pawn.h"
#include "MyPawn.generated.h"

UCLASS()
class PROJ3_API AMyPawn : public APawn
{
	GENERATED_BODY()

public:
	// Sets default values for this pawn's properties
	AMyPawn();

	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	
	// Called every frame
	virtual void Tick( float DeltaSeconds ) override;

	// Called to bind functionality to input
	virtual void SetupPlayerInputComponent(class UInputComponent* InputComponent) override;

	void Move_XAxis(float AxisValue);
	void Move_YAxis(float AxisValue);
	void StartGrowing();
	void StopGrowing();
        FVector CurrentVelocity;
        bool bGrowing;
};

.cpp

#include "Proj3.h"
#include "MyPawn.h"


// Sets default values
AMyPawn::AMyPawn()
{
 	// Set this pawn to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;
	AutoPossessPlayer = EAutoReceiveInput::Player0;
}

// Called when the game starts or when spawned
void AMyPawn::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AMyPawn::Tick( float DeltaTime )
{
	Super::Tick( DeltaTime );
}

// Called to bind functionality to input
void AMyPawn::SetupPlayerInputComponent(class UInputComponent* InputComponent)
{
	Super::SetupPlayerInputComponent(InputComponent);
	InputComponent->BindAction("Fire", IE_Pressed, this, &AMyPawn::StartGrowing);
	InputComponent->BindAction("Fire", IE_Released, this, &AMyPawn::StopGrowing);

	InputComponent->BindAxis("MoveX", this, &AMyPawn::Move_XAxis);
	InputComponent->BindAxis("MoveY", this, &AMyPawn::Move_YAxis);

}
void AMyPawn::Move_XAxis(float AxisValue)
{
	CurrentVelocity.X = FMath::Clamp(AxisValue, -1.0f, 1.0f)*100.0f;
}
void AMyPawn::Move_YAxis(float AxisValue)
{
	CurrentVelocity.Y = FMath::Clamp(AxisValue, -1.0f, 1.0f)*100.0f;
}
void AMyPawn::StartGrowing()
{
	bGrowing = true;
}
void AMyPawn::StopGrowing()
{
	bGrowing = false;
}

關鍵點：

1.AutoPossessPlayer = EAutoReceiveInput::Player0;

2.SetupPlayerInputComponent.

對於BindAction和BindAxis的第一個參數，指的是在項目中設置的鍵盤映射（例子中的項目設定了一個鍵'Fire'）