UE4 如何用C++创建Timeline 计时器

1.1  前期准备工作

先创建一个UE4的C++项目，然后创建曲线，设置曲线，这里设置的点是（0,0）（300,300），创建C++Actor类

这里是引用

2.2代码部分

```.h文件
//定义一个浮点曲线
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "TimeCurve")
		UCurveFloat* MyTimeCurve;
	//创建一个时间轴注意头文件#include"RuntimeEngineClassesComponentsTimelineComponent.h"
	FTimeline MyTime;
	//定义时间轴曲线更新事件
	FOnTimelineFloatStatic OnMyCallTimeDelegate;
	//定义时间轴曲线播放结束事件
	FOnTimelineEventStatic OnMyFinishTimeDelegate;
	//每帧执行回调函数
	UFUNCTION()
		void CallTime();

	//时间轴播放结束回调函数
	UFUNCTION()
		void FinishTime();
	//分钟
	UPROPERTY(VisibleDefaultsOnly, Category = "RenderText")
		UTextRenderComponent* Seconds;
	//秒
	UPROPERTY(VisibleDefaultsOnly, Category = "RenderText")
		UTextRenderComponent* Minutes;
	//设置:
	UPROPERTY(VisibleDefaultsOnly, Category = "RenderText")
		UTextRenderComponent* Dian;
	float FloatCurveVal;


```cpp文件
AMyTime::AMyTime()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;
	//设置分 文本渲染器
	Seconds = CreateDefaultSubobject(TEXT("SecondsText"));
	Seconds->SetWorldSize(20.f);
	Seconds->SetTextRenderColor(FColor::Black);
	Seconds->SetHorizontalAlignment(EHTA_Center);
	Seconds->SetupAttachment(RootComponent);
	//设置秒 文本渲染器
	Minutes = CreateDefaultSubobject(TEXT("MinutesText"));
	Minutes->SetWorldSize(20.f);
	Minutes->SetTextRenderColor(FColor::Black);
	Minutes->SetHorizontalAlignment(EHTA_Center);
	Minutes->SetupAttachment(Seconds);
	Minutes->SetRelativeLocation(FVector(0,-40,0));
	static ConstructorHelpers::FObjectFinderCurve(TEXT("CurveFloat'/Game/MyTimeCurveFloat.MyTimeCurveFloat'"));
	MyTimeCurve = Curve.Object;

	//设置:
	Dian = CreateDefaultSubobject(TEXT("dianText"));
	Dian->SetWorldSize(20.f);
	Dian->SetTextRenderColor(FColor::Black);
	Dian->SetHorizontalAlignment(EHTA_Center);
	Dian->SetupAttachment(Seconds);
	Dian->SetRelativeLocation(FVector(0, -20, 0));
	Dian->SetText(TEXT(":"));
}
void AMyTime::BeginPlay()
{
	Super::BeginPlay();
	//初始化
	OnMyCallTimeDelegate.BindUFunction(this, TEXT("CallTime"));
	MyTime.AddInterpFloat(MyTimeCurve,OnMyCallTimeDelegate);

	OnMyFinishTimeDelegate.BindUFunction(this,TEXT("FinishTime"));
	MyTime.SetTimelineFinishedFunc(OnMyFinishTimeDelegate);


	MyTime.ReverseFromEnd();
}

// Called every frame
void AMyTime::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);
	MyTime.TickTimeline(DeltaTime);
}

void AMyTime::CallTime()
{
	FloatCurveVal = MyTimeCurve->GetFloatValue(MyTime.GetPlaybackPosition());
	//将整型变量转成字符
	FString strSecondTime = FString::FromInt(UKismetMathLibrary::FFloor(FloatCurveVal/60));
	Seconds->SetText(strSecondTime);
	//设置秒
	int32 intMinutes = FloatCurveVal - (UKismetMathLibrary::FFloor(FloatCurveVal/60) * 60);
	//将整型变量转成字符
	FString strMinuteTime = FString::FromInt(UKismetMathLibrary::FFloor(intMinutes));
	Minutes->SetText(strMinuteTime);
	GEngine->AddOnScreenDebugMessage(-1, 2.0f, FColor::Red, TEXT("TimeStart"));
}

void AMyTime::FinishTime()
{
	GEngine->AddOnScreenDebugMessage(-1, 2.0f, FColor::Red, TEXT("TimeFinish"));
}

结果运行: