UE4新手常用C++API

//C++暴露给蓝图可编辑
UCLASS(Blueprintable)

//创建FString
FString::Printf(TEXT("aa bb"));

//蓝图调用变量
UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )

//限制条件范围
meta = (ClampMin=0.1,ClampMax = 100)

//蓝图识别组件
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "XXX")

//返回物理材质
EPhysicalSurface SurfaceType = UPhysicalMaterial::DetermineSurfaceType(Hit.PhysMaterial.Get());

//开放给编辑器时的类型，而不是某一个引用
TSubClassOf

//软引用
TSoftObjectPtr
TSoftClassPtr 

//蓝图调用函数
UFUNCTION(BlueprintCallable, Category = "XXX")

//设置子Actor
HandObject->SetChildActorClass(ASlAiHandObject::StaticClass());

//继承父类
Super::Xxx();  

//获取组件
GetComponentByClass(UXXXComponent::StaticClass());

//调整Tick间隔为1秒
PrimaryActorTick.TickInterval = 1.0f;

//循环输出
ForEachLoop   FStringaa 
for(FString xx : FStringaa){}

//设置鼠标点击输入模式（controlelr）
FInputModeGameOnly InputMode;
InputMode.SetConsumeCaptureMouseDown(true);
SetInputMode(InputMode);

//碰撞体物理旋转锁定
BoxCollision->GetBodyInstance()->bLockZRotation = true;

//播放音效
UGameplayStatics::SpawnSoundAttached(soundcue,RootComponent);

//向量长度
Fvector.size();

//Widget的初始化函数
public:
    virtual bool Initialize() override;

protected:
    //Widget的tick函数
    virtual void NativeTick(const FGeometry& MyGeometry, float InDeltaTime) override;

//例：
void BeginDestroy() override;

void AmyActor::BeginDestroy()
{
Super::BeginDestroy();
UE_LOG(LogTemp, Warning, TEXT("Game exit!"));
}

//C++调用蓝图函数

//首先创建C++为基类，蓝图继承后创建一个函数Test

#include "OutputDevice.h"

FString cmd = FString::Printf(TEXT("BB CD"));

//BB函数名，CD参数

FOutputDeviceDebug device;
CallFunctionByNameWithArguments(*cmd, device, NULL, true);

//蓝图重载C++函数(可以在C++中其他位置调用一个目前没有任何功能的函数（事件），而该函数的具体实现交给蓝图实现)

UFUNCTION(BlueprintImplementableEvent)       

void OnTest(); 

//在蓝图中Add Event，找到对应的函数名，创建后即可实现具体逻辑

//然后也可以在自己的C++代码中调用该方法

void MyActor::OnPressed()
{
OnTest();
}

//蓝图添加默认的C++实现（C++在调用了SomeFunction()的地方先调用SomeFunction_Implementation的实现，但如果在蓝图中定义了SomeFunction事件（即使后面不连接任何内容），则会忽略C++中SomeFunction_Implementation中的实现，只采用蓝图中的实现）

UFUNCTION(BlueprintNativeEvent, Category = "SomeCategory")

 void SomeFunction();

void AMyActor::SomeFunction_Implementation() 

{ 

UE_LOG(LogTemp, Warning, TEXT("Implenetaion in C++")); 

}

//loadstreamlevel的百分比调用
GetAsyncLoadPercentage(PackageName)

//获取控制器
UGameplayStatics::GetPlayerController(GWorld, 0)；(->GetWorld())

//获取默认蓝图类
HUDClass = AXXXHUD::StaticClass();

//判断Actor是蓝图还是C++
Actor->GetClass.IsNative();

//按键
GetWorld()->GetFirstPlayerController()->WasInputKeyJustPressed(Key)
GetWorld()->GetFirstPlayerController()->WasInputKeyJustReleased(Key) 

//确保内容存在，否则中断代码
ensure(XX)

//鼠标在屏幕中的位置
#include "Engine/GameEngine.h"
#include "Engine/Engine.h"

FVector2D MousePosition;

GEngine->GameViewport->GetMousePosition(MousePosition);

MousePosition=MousePosition/DPIScale;

//判断当前游戏运行模式
GetWorld()->WorldType

//失焦后声音还能播放
GConfig->GetFloat(TEXT("Audio"), TEXT("UnfocusedVolumeMultiplier"), UnfocusedVolumeMultiplier, GEngineIni);

//或者在DefaultEngine.ini中添加

[Audio]

UnfocusedVolumeMultiplier=1.0

//加载地图
UGameplayStatics::OpenLevel(GetWorld(), *mapName);

//获取角色位置和方向
GetWorld()->GetFirstPlayerController()->GetPlayerViewPoint(PawnLocation,PawnRotation);//面朝的方向

//当前帧
#include "Engine/World.h"

GetWorld()->DeltaTimeSeconds

//当前旋转量
this->GetActorForwardVector().Rotation()

//单位向量
PawnRotation.Vector();

PawnVector.GetSafeNormal();

//获取速度
auto ForwardSpeed = FVector::DotProduct(MoveVelocityNormal, AIForwardNormal);

//运行命令行
GetWorld()->GetFirstPlayerController()->ConsoleCommand("quit");

//打印
GEngine->AddOnScreenDebugMessage(-1, 5.0f, FColor::Yellow, FString::Printf(TEXT("%s"),*FString));
#include "Misc/OutputDevice.h"
GLog->Logf(TEXT("%s"), *Filepath);

//限制函数
FMath::Clamp(A1 + A2, 0.0, 1.0);

//设置位置
SetActorLocation(FVector(0.0f, 0.0f, 250.0f));

//打开EXE

FPlatformProcess::ExecProcess(*QQ, nullptr, nullptr, nullptr, nullptr);

FPlatformProcess::CreateProc(*QQ, nullptr, true, false, false, nullptr, -1, nullptr, nullptr);

//添加到控制台函数
UFUNCTION(Exec, Category = "AActor")

//覆盖Actor控制台函数
virtual bool ProcessConsoleExec(const TCHAR* Cmd, FOutputDevice& Ar, UObject* Executor) override;

bool UMyGameInstance::ProcessConsoleExec(const TCHAR* Cmd, FOutputDevice& Ar, UObject* Executor)
{
    bool Res = Super::ProcessConsoleExec(Cmd, Ar, Executor);
    if (!Res)
    {
        //获取场景对象方法一: 
        for (TActorIterator It(GetWorld()); It; ++It)
        {
            Res = It->ProcessConsoleExec(Cmd, Ar, Executor);
        }
        //获取场景对象方法二:
        /*TArray ActArray;
        UGameplayStatics::GetAllActorsOfClass(GetWorld(), AMyCharacter::StaticClass(), ActArray);
        for(AActor* Act : ActArray) Act->ProcessConsoleExec(Cmd, Ar, Executor);*/
    }
    return Res;
}

//判断exe是那个端
ENetMode netMode = GetNetMode();

switch(netMode)

{

case NM_Standalone :

print //单独端, 单机游戏

NM_DedicatedServer //专用服务器

NM_ListenServer //监听服务器

NM_Client //客户端

NM_MAX

}

//MD5加密
FMD5::HashAnsiString(TEXT("someStuff"));

//蓝图打印
#include"MessageLog.h"
FMessageLog("DebugLog_FMessageLog").Warning(FText::FromString(MyString));

//生成类
TestObjectActor = GWorld->SpawnActor(TestBlueprint);
UWorld* const World = GetWorld();
AActor* GridCube = World->SpawnActor(GridCubeClass2, FVector(0.0f, 90.0f, 50.0f), FRotator(0.0f, 0.0f, 0.0f));

//读取Texture2D
UTexture2D* texture22 = Cast(StaticLoadObject(UTexture2D::StaticClass(), NULL, *(Path)));

//获得名字
Actor->GetName() == TEXT("FloatActor_1")

//获取相机
GetWorld()->GetFirstPlayerController()->PlayerCameraManager

//强制转换
PTGameInstance = Cast(World->GetGameInstance());

//设置碰撞类型
SetCollisionEnabled(ECollisionEnabled::QueryAndPhysics);

//设置碰撞属性
SetCollisionProfileName(FName("NoCollision"));

//设置碰撞属性
MeshFirst->SetCollisionObjectType(ECC_Pawn);
MeshFirst->SetCollisionEnabled(ECollisionEnabled::NoCollision);
MeshFirst->SetCollisionResponseToAllChannels(ECR_Ignore);

//构造函数添加组件
RootComponent = CreateDefaultSubobject(TEXT("Center"));

//动态创建UObject
UMyObject*NewObj=NewObject();

//动态创建Object
FMyObject*NewObj= new FMyObject();

//屏幕大小
GetWorld()->GetFirstPlayerController()->GetViewportSize(ViewportSizeX,ViewportSizeY);

//重力
SetEnableGravity(false);

//随机数
FRandomStream Stream;

//产生新的随机种子
Stream.GenerateNewSeed();
int RandIndex = Stream.RandRange(0, ResourcePath.Num() - 1);

//删除AIController
DetachFromControllerPendingDestroy();

//进入观察者模式
StartSpectatingOnly();

//复制资源
UBehaviorTree* myBehaviorTree = DuplicateObject(object,NULL)

//退出游戏
UKismetSystemLibrary::QuitGame(this, nullptr, EQuitPreference::Quit);

GEngine->Exec(GWorld, *FString("Exit"));

//获取游戏时间
double MyTime = FPlatformTime::Seconds;

//获取时间
FDateTime::Now().ToString();

//链接URL
FString TheURL = "xxxxxxxx";
FPlatformProcess::LaunchURL(*TheURL, nullptr, nullptr);

//创建UI   
"Media", "MediaAssets"
if (nullptr == MainMenuWidget)    
{        
UClass* aa = LoadClass( NULL, TEXT( "Blueprint'/Game/UMG/MainMenu.MainMenu_C'" ) );        
MainMenuWidget = CreateWidget( GetWorld()->GetFirstPlayerController(), aa ); 
}    
MainMenuWidget->AddToViewport(); 

//OR：

UPROPERTY(EditAnywhere, Category = "AA")
        TSubclassOf HUDWidgetClass;

UMyHUDWidget* HUDWidget = CreateWidget(GetWorld(), HUDWidgetClass);

//绘制射线
#include "DrawDebugHelpers.h"

DrawDebugLine(
GetWorld(),
StartLocation1,
EndLocation1,
FColor(255, 0, 0),
false,
0.0f,
0.0f,
10.0f

);

FCollisionQueryParams QueryParameter = FCollisionQueryParams("", false, GetOwner());
FHitResult HitResult;
GetWorld()->LineTraceSingleByChannel(
HitResult,
StartLocation2,
EndLocation2,
FCollisionObjectQueryParams(ECollisionChannel::ECC_PhysicsBody),
QueryParameter
)


//获取IP地址
//需要在build.cs添加Sockets模块
#include "SocketSubsystem.h"
#include "IPAddress.h"
FString IpAddr("NONE");
  bool canBind = false;
  TSharedRef LocalIp = ISocketSubsystem::Get(PLATFORM_SOCKETSUBSYSTEM)->GetLocalHostAddr(*GLog, canBind);
  if (LocalIp->IsValid())
  {
IpAddr = LocalIp->ToString(false); //（如果想附加端口就写 ture）
}
return IpAddr;

//添加标签
MyActor.Tags.AddUnique(TEXT("MyTag"));  

//销毁物体
MyActor->Destroy();
MyActor->SetLifeSpan(1);//延迟1S

//截图
FString UMyBlueprintFunctionLibrary::TakeScreenShoot(FString picName, bool bUnique /*= true*/)
{
FString inStr;
FString Filename;
FScreenshotRequest::RequestScreenshot(picName + ".png", false, bUnique);
FString ResultStr = FScreenshotRequest::GetFilename();
ResultStr = FPaths::GetBaseFilename(ResultStr, true);
return ResultStr + ".png";
}

void UMyBlueprintFunctionLibrary::Screenshot(const FString InFilename, bool bInShowUI)
{
FScreenshotRequest SR = FScreenshotRequest();
FString savelocation = FPaths::ConvertRelativePathToFull(FPaths::GameDir());
FString filename = savelocation + FString(TEXT("/Saved/Screenshotss/")) + InFilename + FString(TEXT(".png"));
SR.RequestScreenshot(filename, bInShowUI, false);
}

//写入配置文件，有GEditorIni,GEditorProjectIni,GCompatIni,GlightmassIni,GScalabilityIni,GHardwareIni,GInputIni,GGameIni,GGameUserSettingsIni等(查找CoreGlobals.h)
//写的数据会写到 YourGame\Saved\Config\Windows\Game.ini 中
    const FString WriteSection = "MyCustomSection";
    //String
    GConfig->SetString(
        *WriteSection,
        TEXT("key1"),
        TEXT("Hello world"),
        GGameIni
    );
    GConfig->Flush(false, GGameIni);
//读取配置
if (!GConfig) return 0;
float ValueReceived ;
GConfig->GetFloat(
TEXT("MyCustomSection"),
TEXT("key1"),
ValueReceived,
GGameIni
);
return ValueReceived;

//服务器：

//判断是否在服务端运行

GetWorld()->IsServer()

//网络更新频率

NetUpdateFrequency = 66.0f;

MinNetUpdateFrequency = 33.0f;

//枚举字节化

TEnumAsByte AA;

//让矢量服务器传输不用那么精确

FVector_NetQuantize   vectorr；

//复制变量到服务器

UPROPERTY(Replicated)

//在服务器上运行函数

UFUNCTION(Server, Reliable, WithValidation)//NetMulticast

void Server();

void XXX::ServerFire_Implementation(){}

bool XXX::ServerFire_Validate(){return true;}//完整性检查才用到

//判断是否在服务器上运行（Actor是否主机）

Role == ROLE_Authority

//判断是否在客户端上运行

Role < ROLE_Authority

//服务器变量改了通知客户端调用函数

UPROPERTY(ReplicatedUsing=OnRep_GuardState)

UFUNCTION()
    void OnRep_GuardState();

//规则：所有的客户端  
#include "Net/UnrealNetwork.h"
void XXX::GetLifetimeReplicatedProps(TArray< FLifetimeProperty > & OutLifetimeProps) const
{
    Super::GetLifetimeReplicatedProps(OutLifetimeProps);

    DOREPLIFETIME(XXX（AActor）, 变量);

//DOREPLIFETIME_CONDITION(XXX（AActor）, 变量,COND_SkipOwner);
}


/// Slate：/


//创建slate

TSharedPtr MenuHUDWidget;

ASlAiMenuHUD::ASlAiMenuHUD()
{
    if (GEngine && GEngine->GameViewport) {

        SAssignNew(MenuHUDWidget, SSlAiMenuHUDWidget);

        GEngine->GameViewport->AddViewportWidgetContent(SNew(SWeakWidget).PossiblyNullContent(MenuHUDWidget.ToSharedRef()));

    }
}

//播放动画

MenuAnimation = FCurveSequence();
MenuCurve = MenuAnimation.AddCurve(StartDelay, AnimDuration, ECurveEaseFunction::QuadInOut);

MenuAnimation.Play(this->AsShared());

//把图片导入ImageSlot

SOverlay::FOverlaySlot* ImageSlot;

.Expose(ImageSlot)

//点击事件

.OnClicked(this, &XXX::OnClick)

//设置锚点

.Anchors(FAnchors(0.f))

//创建按钮

+ SOverlay::Slot()

[

SNew(SButton)

]

//布局

.HAlign(HAlign_Left)
.VAlign(VAlign_Top)

//创建外部调用Slate

TSharedPtr ZhCheckBox;//.h
SAssignNew(ZhCheckBox,SCheckBox)