UE5 C++（五）— UPROPERTY宏（属性说明符和元数据说明符）

前提

创建一个继承自Pawn类的C++类 MyPawn 和 蓝图对象 BP_MyPawn

属性说明符

这里只介绍几个常用的，具体的可以参考官方文档

• UPROPERTY(VisibleDefaultsOnly)： 仅在默认设置下可见
  

• UPROPERTY(VisibleInstanceOnly)：仅在实例化细节面板可见
  

• UPROPERTY(VisibleAnywhere)：类默认设置和实例化细节面板都可见
  

• UPROPERTY(EditDefaultsOnly)：仅在默认设置下可编辑
  

• UPROPERTY(EditInstanceOnly)：仅在实例化细节面板可编辑
  

• UPROPERTY(EditAnywhere) ：类默认设置和实例化细节面板都可编辑
  

• UPROPERTY(EditAnywhere,BlueprintReadOnly)：仅在蓝图中可读

• UPROPERTY(EditAnywhere,BlueprintReadWrite)：在蓝图中可读、可写 可以获取和设置变量
  

• Category目录
  UPROPERTY(EditAnywhere,BlueprintReadWrite,Category =“MyIntValue”)
  
  UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = “MyIntValue|MySubIntValue”)
  

元数据说明符

这里只介绍几个常用的，具体的可以参考官方文档

• DisplayName别名
  UPROPERTY(EditAnywhere,BlueprintReadWrite, meta=(DisplayName=“MyValue3DisplayName”))
  

• 条件控制编辑：
  UPROPERTY(EditAnywhere, BlueprintReadWrite,meta = (DisplayName = “Controller”))
  UPROPERTY(EditAnywhere, BlueprintReadWrite, meta = (EditCondition = “isController”))
  float ControllerValueInt32;
  

• ToolTip提示 解释说明变量
  UPROPERTY(EditAnywhere, BlueprintReadWrite, meta = (ToolTip = “isControllerTrue”))
  bool isControllerTrue;
  

函数在蓝图中使用

	 // 函数在蓝图中调用
	UFUNCTION(BlueprintCallable, Category = "MyFunction")
	void MyFunction1();
	// 纯虚函数在蓝图中调用 BlueprintPure
	UFUNCTION(BlueprintCallable, BlueprintPure, Category = "MyFunction")
	bool MyFunction2();

BlueprintImplementableEvent

BuleprintImplementableEvent在C++中声明，不能定义,蓝图可重载

声明带有BuleprintImplementableEvent函数在.h文件中声明，不需要在.cpp文件中实现

不带返回值：

	// BuleprintImplementableEvent在C++中声明，不能定义,蓝图可重载
	UFUNCTION(BlueprintImplementableEvent, Category = "BIEFunction")
	void MyFunction3();
	UFUNCTION(BlueprintImplementableEvent, Category = "BIEFunction")
	void MyFunction5(const FString &str);

带返回值：

	// BuleprintImplementableEvent在C++中声明，不能定义,蓝图可重载
	UFUNCTION(BlueprintImplementableEvent, Category = "BIEFunction")
	bool MyFunction4();
	UFUNCTION(BlueprintImplementableEvent, Category = "BIEFunction")
	bool MyFunction7(const FString &str);

BlueprintNativeEvent

BlueprintNativeEvent在C++中声明，可以定义,蓝图可重载、不可重载都可以。

声明带有BuleprintImplementableEvent函数在.h文件中声明，需要在.cpp文件中实现。实现时在函数末尾添加_Implementation

不带返回值：

	// BlueprintNativeEvent在C++中声明，可以定义,蓝图可重载或不可重载
	UFUNCTION(BlueprintNativeEvent, Category = "BNEFunction")
	void MyFunction8();
	UFUNCTION(BlueprintNativeEvent, Category = "BNEFunction")
	void MyFunction10(const FString &str);

void AMyPawn::MyFunction8_Implementation()
{
}
void AMyPawn::MyFunction10_Implementation(const FString &str)
{
}

带返回值：

	// BlueprintNativeEvent在C++中声明，可以定义,蓝图可重载或不可重载
	UFUNCTION(BlueprintNativeEvent, Category = "BNEFunction")
	bool MyFunction9();
	UFUNCTION(BlueprintNativeEvent, Category = "BNEFunction")
	bool MyFunction11(const FString &str);

bool AMyPawn::MyFunction9_Implementation()
{
	return true;
}
bool AMyPawn::MyFunction11_Implementation(const FString &str)
{
	return true;
}

元数据说明符meta 别名作用

	//元数据说明符meta
	UFUNCTION(BlueprintCallable, Category = "MyFunction", meta = (DisplayName = "PrintString"))
	void MyPrintString(const FString &str);