一．创建

二．ＵＩ里声明变量

创建类

public:
	UPROPERTY(EditAnywhere,BlueprintReadWrite,Category  = "MyWidget")
	float CurrentHealth = 100.0f;
	UPROPERTY(EditAnywhere,BlueprintReadWrite,Category = "MyWidget")
	float MaxHealth = 100.0f; //可以给默认值

绑定监听函数

函数里使用父类变量进行计算　百分比

三．在Character里声明

重写受伤虚函数　

#include "MyHealthWidget.h"

	UWidgetComponent* MyWidgetHealth;

	virtual float TakeDamage(float DamageAmount,FDamageEvent const &DamageEvent,class AController*EventInstigator,AActor* DamagerCausser)override; //重写系统内部的TakeDamage 

四．编写逻辑

创建对象

MyWidgetHealth = CreateDefaultSubobject<UWidgetComponent>(TEXT("MyWidgetComponent"));
MyWidgetHealth->SetupAttachment(RootComponent);
static ConstructorHelpers::FClassFinder<UUserWidget>WidgetClass(TEXT("/Script/UMGEditor.WidgetBlueprint'/Game/UMG_Health.UMG_Health_C'"));    //静态加载
MyWidgetHealth->SetWidgetClass(WidgetClass.Class);
MyWidgetHealth->SetRelativeLocation(FVector(0,0,100)); 
MyWidgetHealth->SetWidgetSpace(EWidgetSpace::Screen);  //  输出到屏幕
MyWidgetHealth->SetDrawSize(FVector2D(400,20));

受伤－５血量

float AMyCharacter::TakeDamage(float DamageAmount, FDamageEvent const& DamageEvent, AController* EventInstigator, AActor* DamagerCausser)
{
	UMyHealthWidget* MyWidget = Cast<UMyHealthWidget>(MyWidgetHealth->GetUserWidgetObject());
	if (MyWidget)
	{
		if (MyWidget->CurrentHealth > 0)
		{
			MyWidget->CurrentHealth -= 5.f;
		}
		else
		{
			return 0.f;
		}
	}
	return 0.0f;
}

五．造成角色伤害物体

#include "Kismet/GameplayStatics.h"  //Aplaydamage 函数库里的头文件
#include "MyCharacter.h"  //后面用于转化

UFUNCTION()
void BeginOverlapFunction(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);
UFUNCTION()
void EndOverlapFunction( UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex); //四个参数
// FComponentEndOverlapSignature, UPrimitiveComponent, OnComponentEndOverlap, UPrimitiveComponent*, OverlappedComponent, AActor*, OtherActor, UPrimitiveComponent*, OtherComp, int32, OtherBodyIndex
UFUNCTION()
void HitOverlaoFunction(UPrimitiveComponent* HitComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit);
//UPrimitiveComponent*, HitComponent, AActor*, OtherActor, UPrimitiveComponent*, OtherComp, FVector, NormalImpulse, const FHitResult&, Hit

逻辑碰撞，判断是否是角色。再造成ＡｐｐｌｙＤａｍａｇｅ伤害。

void AMyActor::BeginOverlapFunction(UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
	AMyCharacter* MyCharacter = Cast<AMyCharacter>(OtherActor); //转换
	if (MyCharacter)
	{
		UGameplayStatics::ApplyDamage(MyCharacter,5.0f,nullptr,this,UDamageType::StaticClass());  //应用伤害
	}
	GEngine->AddOnScreenDebugMessage(-1,5.0f,FColor::Red,TEXT("BeginOverLapEvent is Success"));
	MyParticle->Activate(); //激活
}

void AMyActor::EndOverlapFunction( UPrimitiveComponent* OverlappedComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex)
{
	MyParticle->Deactivate(); //失效
	GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Red, TEXT("EndOverlapEvent is Success"));
}

void AMyActor::HitOverlaoFunction(UPrimitiveComponent* HitComponent, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit)
{
	GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Red, TEXT("HitOverlapEvent is Success"));
}