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UE 事件分发机制(二) day10
自定义事件分发机制
自建事件分发机制与结构
- Unreal推荐的游戏逻辑开发流程
- 基于 Unreal推荐的游戏逻辑开发流程，一般我们的整体规划也就是这样
- 大致结构类图
创建接口类与管理类以及所需函数
- 新建一个Unreal接口类作为接口
- 然后创建一个蓝图函数库的基类
EventInterface接口类
EventInterface.h
- 复习一下
BlueprintNativeEvent这个参数：会在C++中提供一个默认的实现，然后蓝图中去覆盖它改写它，在蓝图中实现这个函数时，如果调用一个父类的版本，它会先调用C++里面加了_Implementation这个函数，然后再去做蓝图其他的操作
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "UObject/Interface.h"
#include "EventInterface.generated.h"
// This class does not need to be modified.
UINTERFACE(MinimalAPI)
class UEventInterface : public UInterface
{
GENERATED_BODY()
};
/**
*
*/
class DISTRIBUTE_API IEventInterface
{
GENERATED_BODY()
// Add interface functions to this class. This is the class that will be inherited to implement this interface.
public:
UFUNCTION(BlueprintNativeEvent,Category="Event Dispather Tool")
void OnReceiveEvent(UObject* Data);
};
EventInterface.cpp
// Fill out your copyright notice in the Description page of Project Settings.
#include "EventInterface.h"
// Add default functionality here for any IEventInterface functions that are not pure virtual.
EventManager蓝图函数库的基类管理类
EventManager.h
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "EventManager.generated.h"
/**
*
*/
UCLASS()
class DISTRIBUTE_API UEventManager : public UBlueprintFunctionLibrary
{
GENERATED_BODY()
private:
//监听者
static TMap<FString, TArray<UObject*>> AllListeners;
public:
UFUNCTION(BlueprintCallable, Category = "Event Dispather Tool")
static void AddEventListener(FString EventName, UObject* Listener);
UFUNCTION(BlueprintCallable, Category = "Event Dispather Tool")
static void RemoveEventListener(FString EventName, UObject* Listener);
UFUNCTION(BlueprintCallable, Category = "Event Dispather Tool")
static FString DispatchEvent(FString EventName, UObject* Data);
UFUNCTION(BlueprintCallable, BlueprintPure, Category = "Event Dispather Tool")
static UObject* NameAsset(UClass* ClassType);
};
EventManager.cpp
// Fill out your copyright notice in the Description page of Project Settings.
#include "EventManager.h"
void UEventManager::AddEventListener(FString EventName, UObject* Listener)
{
}
void UEventManager::RemoveEventListener(FString EventName, UObject* Listener)
{
}
FString UEventManager::DispatchEvent(FString EventName, UObject* Data)
{
return FString();
}
UObject* UEventManager::NameAsset(UClass* ClassType)
{
return nullptr;
}
编写AddEventListener函数
-
加入接口的头文件，判断添加进来的事件名字是否为空，监听指针是否为空，检测对象是否有效，是否实现了指定的接口类
-
Listener->IsValidLowLevel()：检查对象是否有效 -
Listener->GetClass()->ImplementsInterface(UEventInterface::StaticClass())：检测接口是否实现指定接口，这里传入的UEventInterface就是接口类中的参与蓝图的类名
//初始化监听器 TMap<FString, TArray<UObject*>> UEventManager::AllListeners; void UEventManager::AddEventListener(FString EventName, UObject* Listener) { if (EventName == "" || Listener == nullptr || !Listener->IsValidLowLevel() || !Listener->GetClass()->ImplementsInterface(UEventInterface::StaticClass())) { return; } } -
然后查找是否存在这个事件数组，如果为空说明目前没有这个事件，就重新添加一下，存在就直接添加事件进入到数组即可
-
AddEventListener函数完整代码逻辑
#include "EventManager.h"
#include "EventInterface.h"
//初始化监听器
TMap<FString, TArray<UObject*>> UEventManager::AllListeners;
void UEventManager::AddEventListener(FString EventName, UObject* Listener)
{
if (EventName == "" || Listener == nullptr || !Listener->IsValidLowLevel() ||
!Listener->GetClass()->ImplementsInterface(UEventInterface::StaticClass()))
{
return;
}
//查找是否存在这个事件数组
TArray<UObject*>* EventArr = UEventManager::AllListeners.Find(EventName);
//如果为空说明目前没有这个事件，就重新添加一下
if (EventArr == nullptr || EventArr->Num() == 0)
{
TArray<UObject*> NewEventArr = { Listener };
UEventManager::AllListeners.Add(EventName, NewEventArr);
}
//存在就直接添加事件进入到数组即可
else
{
EventArr->Add(Listener);
}
}
编写其他函数
RemoveEventListener函数编写
- 查询事件数组中是否有这个事件，如果有就删除这个事件
void UEventManager::RemoveEventListener(FString EventName, UObject* Listener)
{
TArray<UObject*>* EventArr = UEventManager::AllListeners.Find(EventName);
if (EventArr != nullptr && EventArr->Num() != 0)
{
EventArr->Remove(Listener);
}
}
DispatchEvent函数编写
- 分派事件，也是首先考虑事件是否存在，然后循环事件数组里事件，不存在的事件就直接剔除，存在的就进行派发事件通知，注意派发事件通知时也要进行安全检测
FString UEventManager::DispatchEvent(FString EventName, UObject* Data)
{
TArray<UObject*>* EventArr = UEventManager::AllListeners.Find(EventName);
//如果不存在此事件数组
if (EventArr == nullptr || EventArr->Num() == 0)
{
return "'" + EventName + "'No Listener.";
}
//使用UE_LOG换行，方便查看
FString ErrorInfo = "\n";
for (int i = 0; i < EventArr->Num(); i++)
{
UObject* Obj = (*EventArr)[i];
//安全判断一下事件是否存在
if (Obj == nullptr || !Obj->IsValidLowLevel() || !Obj->GetClass()->ImplementsInterface(UEventInterface::StaticClass()))
{
//不存在直接剔除
EventArr->RemoveAt(i);
//剔除后要i--,因为TArray删除一个元素后会自动补齐，这样会导致我们当前循环出现bug
i--;
}
//通过了安全检测就直接派遣事件通知
else
{
UFunction* FUN = Obj->FindFunction("OnReceiveEvent");
//安全检测这个FUN是否有效
if (FUN == nullptr || !FUN->IsValidLowLevel())
{
//打印错误信息
ErrorInfo += "'" + Obj->GetName() + "'No 'OnReceiveEvent' Function.\n";
}
else
{
//调用
Obj->ProcessEvent(FUN, &Data);
}
}
}
return ErrorInfo;
}
NameAsset函数编写
- 这个函数是方便我们在蓝图中去创建某一个新的指定类实例
- 加入头文件 #include “Engine.h”,使用NewObject函数来创建一个新的指定对象
- UObject* Obj =
NewObject;(GetTransientPackage(), ClassType) GetTransientPackage()：返回一个临时包（主要用于对象池）的指针ClassType：ClassType 是一个 UClass 指针，指定了新对象的类型。
UObject* UEventManager::NameAsset(UClass* ClassType)
{
UObject* Obj = NewObject<UObject>(GetTransientPackage(), ClassType);
return Obj;
}
EventManager.cpp
// Fill out your copyright notice in the Description page of Project Settings.
#include "EventManager.h"
#include "EventInterface.h"
#include "Engine.h"
//初始化监听器
TMap<FString, TArray<UObject*>> UEventManager::AllListeners;
void UEventManager::AddEventListener(FString EventName, UObject* Listener)
{
if (EventName == "" || Listener == nullptr || !Listener->IsValidLowLevel() ||
!Listener->GetClass()->ImplementsInterface(UEventInterface::StaticClass()))
{
return;
}
//查找是否存在这个事件数组
TArray<UObject*>* EventArr = UEventManager::AllListeners.Find(EventName);
//如果为空说明目前没有这个事件，就重新添加一下
if (EventArr == nullptr || EventArr->Num() == 0)
{
TArray<UObject*> NewEventArr = { Listener };
UEventManager::AllListeners.Add(EventName, NewEventArr);
}
//存在就直接添加事件进入到数组即可
else
{
EventArr->Add(Listener);
}
}
void UEventManager::RemoveEventListener(FString EventName, UObject* Listener)
{
TArray<UObject*>* EventArr = UEventManager::AllListeners.Find(EventName);
if (EventArr != nullptr && EventArr->Num() != 0)
{
EventArr->Remove(Listener);
}
}
FString UEventManager::DispatchEvent(FString EventName, UObject* Data)
{
TArray<UObject*>* EventArr = UEventManager::AllListeners.Find(EventName);
//如果不存在此事件数组
if (EventArr == nullptr || EventArr->Num() == 0)
{
return "'" + EventName + "'No Listener.";
}
//使用UE_LOG换行，方便查看
FString ErrorInfo = "\n";
for (int i = 0; i < EventArr->Num(); i++)
{
UObject* Obj = (*EventArr)[i];
//安全判断一下事件是否存在
if (Obj == nullptr || !Obj->IsValidLowLevel() || !Obj->GetClass()->ImplementsInterface(UEventInterface::StaticClass()))
{
//不存在直接剔除
EventArr->RemoveAt(i);
//剔除后要i--,因为TArray删除一个元素后会自动补齐，这样会导致我们当前循环出现bug
i--;
}
//通过了安全检测就直接派遣事件通知
else
{
UFunction* FUN = Obj->FindFunction("OnReceiveEvent");
//安全检测这个FUN是否有效
if (FUN == nullptr || !FUN->IsValidLowLevel())
{
//打印错误信息
ErrorInfo += "'" + Obj->GetName() + "'No 'OnReceiveEvent' Function.\n";
}
else
{
//调用
Obj->ProcessEvent(FUN, &Data);
}
}
}
return ErrorInfo;
}
UObject* UEventManager::NameAsset(UClass* ClassType)
{
UObject* Obj = NewObject<UObject>(GetTransientPackage(), ClassType);
return Obj;
}
自定义事件分发广播事件
- 因为我们的自定义事件系统里面发布数据只有一个参数，所以我们新建一个Object类专门来放数据，需要传递数据时就通过这个Object类
- 然后创建一个Pawn类作为SenderEvent发起者，开始广播事件
// Called when the game starts or when spawned
void AMyBPAndCpp_Sender::BeginPlay()
{
Super::BeginPlay();
FTimerHandle TimerHandle;
auto Lambda = []()
{
//开始广播事件
UMyData* Data = Cast<UMyData>(UEventManager::NameAsset(UMyData::StaticClass()));
Data->Param = FMath::RandRange(0, 100);
//委派事件
UEventManager::DispatchEvent("MyBPAndCpp_DispatchEvent", Data);
};
GetWorld()->GetTimerManager().SetTimer(TimerHandle, FTimerDelegate::CreateLambda(Lambda), 3.f, true);
}
MyBPAndCpp_Sender.h
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "GameFramework/Pawn.h"
#include "MyBPAndCpp_Sender.generated.h"
UCLASS()
class DISTRIBUTE_API AMyBPAndCpp_Sender : public APawn
{
GENERATED_BODY()
public:
// Sets default values for this pawn's properties
AMyBPAndCpp_Sender();
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Properties")
class UStaticMeshComponent* StaticMesh;
protected:
// Called when the game starts or when spawned
virtual void BeginPlay() override;
public:
// Called every frame
virtual void Tick(float DeltaTime) override;
// Called to bind functionality to input
virtual void SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent) override;
};
MyBPAndCpp_Sender.cpp
// Fill out your copyright notice in the Description page of Project Settings.
#include "MyBPAndCpp_Sender.h"
#include "Components/StaticMeshComponent.h"
#include "UObject/ConstructorHelpers.h"
#include "EventDistributeTool/EventManager.h"
#include "Public/TimerManager.h"
#include "MyData.h"
// Sets default values
AMyBPAndCpp_Sender::AMyBPAndCpp_Sender()
{
// 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;
StaticMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("StaticMesh"));
RootComponent = StaticMesh;
static ConstructorHelpers::FObjectFinder<UStaticMesh> StaticMeshAsset(TEXT("StaticMesh'/Engine/BasicShapes/Sphere.Sphere'"));
static ConstructorHelpers::FObjectFinder<UMaterialInterface> MaterialAsset(TEXT("Material'/Engine/BasicShapes/BasicShapeMaterial.BasicShapeMaterial'"));
if (StaticMeshAsset.Succeeded() && MaterialAsset.Succeeded())
{
StaticMesh->SetStaticMesh(StaticMeshAsset.Object);
StaticMesh->SetMaterial(0, MaterialAsset.Object);
}
}
// Called when the game starts or when spawned
void AMyBPAndCpp_Sender::BeginPlay()
{
Super::BeginPlay();
FTimerHandle TimerHandle;
auto Lambda = []()
{
//开始广播事件
UMyData* Data = Cast<UMyData>(UEventManager::NameAsset(UMyData::StaticClass()));
Data->Param = FMath::RandRange(0, 100);
//委派事件
UEventManager::DispatchEvent("MyBPAndCpp_DispatchEvent", Data);
};
GetWorld()->GetTimerManager().SetTimer(TimerHandle, FTimerDelegate::CreateLambda(Lambda), 3.f, true);
}
// Called every frame
void AMyBPAndCpp_Sender::Tick(float DeltaTime)
{
Super::Tick(DeltaTime);
}
// Called to bind functionality to input
void AMyBPAndCpp_Sender::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{
Super::SetupPlayerInputComponent(PlayerInputComponent);
}
自定义事件分发订阅事件
- 新建一个Actor基类，然后派生三个子类来订阅事件测试，这三个子类需要继承EventInterface这个接口类，父类接口中方法有
BlueprintNativeEvent反射参数，所以在这实现加后缀_Implementation
Actor_Receive_R.h
// Fill out your copyright notice in the Description page of Project Settings.
#pragma once
#include "CoreMinimal.h"
#include "EventDistributeTool/EventInterface.h"
#include "BPAndCpp/Actor_Receive.h"
#include "Actor_Receive_R.generated.h"
/**
*
*/
UCLASS()
class DISTRIBUTE_API AActor_Receive_R : public AActor_Receive, public IEventInterface
{
GENERATED_BODY()
protected:
virtual void BeginPlay() override;
public:
virtual void OnReceiveEvent_Implementation(UObject* Data) override;
};
Actor_Receive_R.cpp
// Fill out your copyright notice in the Description page of Project Settings.
#include "Actor_Receive_R.h"
#include "Engine/Engine.h"
#include "MyData.h"
#include "EventDistributeTool/EventManager.h"
void AActor_Receive_R::BeginPlay()
{
Super::BeginPlay();
//订阅事件
UEventManager::AddEventListener("MyBPAndCpp_DispatchEvent", this);
}
void AActor_Receive_R::OnReceiveEvent_Implementation(UObject* Data)
{
//打印到屏幕
GEngine->AddOnScreenDebugMessage(INDEX_NONE, 10.f, FColor::Red, FString::Printf(TEXT("%i"), Cast<UMyData>(Data)->Param));
}
- 运行结果
- 触发错误打印log的原因是因为，EventManager类中的都是静态方法，静态方法只有到下次编译之后才会被释放，所以在调试中就会这样触发log
- 使用在视口中播放就不会触发log，在正式游戏中也不会触发，或者有正常的解绑事件也不会有问题
自定义事件分发蓝图订阅与解绑事件
蓝图订阅事件
- 蓝图订阅事件，创建一个Actor蓝图然后派生三个子蓝图，注意调用接口类中的事件时要添加接口后编译才能找到
OnReceiveEvent，然后委派事件时的名字记得填写
- 运行结果
解绑事件
- 解绑调用RemoveEventListener函数即可
- C++中也是差不多调用RemoveEventListener函数即可
- 运行结果，只会播放一轮了
当播放结束时自动移除事件
- 这样也能解决C++中的触发错误打印log
- 蓝图中结束后自动移除事件
- C++中是重写BeginDestroy函数，调用移除函数即可
- 运行结果，这样就不会有log错误了
自定义事件之蓝图广播事件
- 将MyBPAndCpp_Sender类转换为蓝图，首先调用一下父类的BeginPlay这样C++那边的事件才会生效
- 编写蓝图逻辑，发布广播
- 然后找个Actor蓝图接收事件，测试，订阅一下这个事件名即可
- 运行结果
