UE4之Slate编程的常见宏

Slate框架结合了声明式语法，并且提供了一套完整的宏来简化声明及创建新控件的过程。下面就来学习一下slate矿建中一些常见的宏：

这些宏声明在以下头文件中：Engine\Source\Runtime\SlateCore\Public\Widgets\DeclarativeSyntaxSuppot.h

SLATE_BEGIN_ARGS(WidgetType):带参宏

Widgets的创建者可以使用SLATE_BEGIN_ARGS和SLATE_END_ARGS来声明和构建一个Widget,使得Widget可以通过SNew()和SAssignNew()来创建一个Widget,从而可以添加到用户视口.

其中参数WidgetType是你正在构建的Widget的类型;

SLATE_BEGIN_ARGS的声明
#define SLATE_BEGIN_ARGS( WidgetType ) \
    public: \
    struct FArguments : public TSlateBaseNamedArgs<WidgetType> \
    { \
        typedef FArguments WidgetArgsType; \
        FORCENOINLINE FArguments()

SLATE_END_ARGS():无参宏

SLATE_END_ARGS的声明
#define SLATE_END_ARGS() \
    };

SLATE_ATTRIBUTE（AttrType,AttrName）:

Use this macro to add a attribute to the declaration of your widget.使用这个宏可以为你正在声明的Widget添加一个属性(TAttribute<>类型).
* An attribute can be a value or a function.一个属性可以是一个值或者方法

参数：

AttrType：属性类型，可以是任意数据类型

AttrType：属性名

SLATE_ATTRIBUTE的声

#define SLATE_ATTRIBUTE( AttrType, AttrName ) \

        TAttribute< AttrType > _##AttrName; \
        WidgetArgsType& AttrName( const TAttribute< AttrType >& InAttribute ) \
        { \
            _##AttrName = InAttribute; \
            return this->Me(); \
        } \
    \
        /* Bind attribute with delegate to a global function
         * NOTE: We use a template here to avoid 'typename' issues when hosting attributes inside templated classes */ \
        template< typename StaticFuncPtr > \
        WidgetArgsType& AttrName##_Static( StaticFuncPtr InFunc )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateStatic( InFunc ) ); \
            return this->Me(); \
        } \
        template< typename Var1Type > \
        WidgetArgsType& AttrName##_Static( typename TAttribute< AttrType >::FGetter::template TStaticDelegate_OneVar< Var1Type >::FFuncPtr InFunc, Var1Type Var1 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateStatic( InFunc, Var1 ) ); \
            return this->Me(); \
        } \
        template< typename Var1Type, typename Var2Type > \
        WidgetArgsType& AttrName##_Static( typename TAttribute< AttrType >::FGetter::template TStaticDelegate_TwoVars< Var1Type, Var2Type >::FFuncPtr InFunc, Var1Type Var1, Var2Type Var2 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateStatic( InFunc, Var1, Var2 ) ); \
            return this->Me(); \
        } \
        template< typename Var1Type, typename Var2Type, typename Var3Type > \
        WidgetArgsType& AttrName##_Static( typename TAttribute< AttrType >::FGetter::template TStaticDelegate_ThreeVars< Var1Type, Var2Type, Var3Type >::FFuncPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateStatic( InFunc, Var1, Var2, Var3 ) ); \
            return this->Me(); \
        } \
        template< typename Var1Type, typename Var2Type, typename Var3Type, typename Var4Type > \
        WidgetArgsType& AttrName##_Static( typename TAttribute< AttrType >::FGetter::template TStaticDelegate_FourVars< Var1Type, Var2Type, Var3Type, Var4Type >::FFuncPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3, Var4Type Var4 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateStatic( InFunc, Var1, Var2, Var3, Var4 ) ); \
            return this->Me(); \
        } \
    \
        /* Bind attribute with delegate to a lambda
         * technically this works for any functor types, but lambdas are the primary use case */ \
        WidgetArgsType& AttrName##_Lambda(TFunction< AttrType(void) >&& InFunctor) \
        { \
            _##AttrName = TAttribute< AttrType >::Create(Forward<TFunction< AttrType(void) >>(InFunctor)); \
            return this->Me(); \
        } \
    \
        /* Bind attribute with delegate to a raw C++ class method */ \
        template< class UserClass >    \
        WidgetArgsType& AttrName##_Raw( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TRawMethodDelegate_Const< UserClass >::FMethodPtr InFunc )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateRaw( InUserObject, InFunc ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type >    \
        WidgetArgsType& AttrName##_Raw( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TRawMethodDelegate_OneVar_Const< UserClass, Var1Type  >::FMethodPtr InFunc, Var1Type Var1 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateRaw( InUserObject, InFunc, Var1 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type >    \
        WidgetArgsType& AttrName##_Raw( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TRawMethodDelegate_TwoVars_Const< UserClass, Var1Type, Var2Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateRaw( InUserObject, InFunc, Var1, Var2 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type, typename Var3Type >    \
        WidgetArgsType& AttrName##_Raw( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TRawMethodDelegate_ThreeVars_Const< UserClass, Var1Type, Var2Type, Var3Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateRaw( InUserObject, InFunc, Var1, Var2, Var3 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type, typename Var3Type, typename Var4Type >    \
        WidgetArgsType& AttrName##_Raw( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TRawMethodDelegate_FourVars_Const< UserClass, Var1Type, Var2Type, Var3Type, Var4Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3, Var4Type Var4 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateRaw( InUserObject, InFunc, Var1, Var2, Var3, Var4 ) ); \
            return this->Me(); \
        } \
    \
        /* Bind attribute with delegate to a shared pointer-based class method.  Slate mostly uses shared pointers so we use an overload for this type of binding. */ \
        template< class UserClass >    \
        WidgetArgsType& AttrName( TSharedRef< UserClass > InUserObjectRef, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_Const< UserClass >::FMethodPtr InFunc )    \
        { \
            _##AttrName = TAttribute< AttrType >( InUserObjectRef, InFunc ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type >    \
        WidgetArgsType& AttrName( TSharedRef< UserClass > InUserObjectRef, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_OneVar_Const< UserClass, Var1Type >::FMethodPtr InFunc, Var1Type Var1 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObjectRef, InFunc, Var1 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type >    \
        WidgetArgsType& AttrName( TSharedRef< UserClass > InUserObjectRef, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_TwoVars_Const< UserClass, Var1Type, Var2Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObjectRef, InFunc, Var1, Var2 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type, typename Var3Type >    \
        WidgetArgsType& AttrName( TSharedRef< UserClass > InUserObjectRef, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_ThreeVars_Const< UserClass, Var1Type, Var2Type, Var3Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObjectRef, InFunc, Var1, Var2, Var3 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type, typename Var3Type, typename Var4Type >    \
        WidgetArgsType& AttrName( TSharedRef< UserClass > InUserObjectRef, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_FourVars_Const< UserClass, Var1Type, Var2Type, Var3Type, Var4Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3, Var4Type Var4 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObjectRef, InFunc, Var1, Var2, Var3, Var4 ) ); \
            return this->Me(); \
        } \
    \
        /* Bind attribute with delegate to a shared pointer-based class method.  Slate mostly uses shared pointers so we use an overload for this type of binding. */ \
        template< class UserClass >    \
        WidgetArgsType& AttrName( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_Const< UserClass >::FMethodPtr InFunc )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObject, InFunc ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type >    \
        WidgetArgsType& AttrName( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_OneVar_Const< UserClass, Var1Type >::FMethodPtr InFunc, Var1Type Var1 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObject, InFunc, Var1 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type >    \
        WidgetArgsType& AttrName( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_TwoVars_Const< UserClass, Var1Type, Var2Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObject, InFunc, Var1, Var2 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type, typename Var3Type >    \
        WidgetArgsType& AttrName( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_ThreeVars_Const< UserClass, Var1Type, Var2Type, Var3Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObject, InFunc, Var1, Var2, Var3 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type, typename Var3Type, typename Var4Type >    \
        WidgetArgsType& AttrName( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TSPMethodDelegate_FourVars_Const< UserClass, Var1Type, Var2Type, Var3Type, Var4Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3, Var4Type Var4 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateSP( InUserObject, InFunc, Var1, Var2, Var3, Var4 ) ); \
            return this->Me(); \
        } \
    \
        /* Bind attribute with delegate to a UObject-based class method */ \
        template< class UserClass >    \
        WidgetArgsType& AttrName##_UObject( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TUObjectMethodDelegate_Const< UserClass >::FMethodPtr InFunc )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateUObject( InUserObject, InFunc ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type >    \
        WidgetArgsType& AttrName##_UObject( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TUObjectMethodDelegate_OneVar_Const< UserClass, Var1Type >::FMethodPtr InFunc, Var1Type Var1 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateUObject( InUserObject, InFunc, Var1 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type  >    \
        WidgetArgsType& AttrName##_UObject( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TUObjectMethodDelegate_TwoVars_Const< UserClass, Var1Type, Var2Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateUObject( InUserObject, InFunc, Var1, Var2 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type, typename Var3Type >    \
        WidgetArgsType& AttrName##_UObject( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TUObjectMethodDelegate_ThreeVars_Const< UserClass, Var1Type, Var2Type, Var3Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateUObject( InUserObject, InFunc, Var1, Var2, Var3 ) ); \
            return this->Me(); \
        } \
        template< class UserClass, typename Var1Type, typename Var2Type, typename Var3Type, typename Var4Type >    \
        WidgetArgsType& AttrName##_UObject( UserClass* InUserObject, typename TAttribute< AttrType >::FGetter::template TUObjectMethodDelegate_FourVars_Const< UserClass, Var1Type, Var2Type, Var3Type, Var4Type >::FMethodPtr InFunc, Var1Type Var1, Var2Type Var2, Var3Type Var3, Var4Type Var4 )    \
        { \
            _##AttrName = TAttribute< AttrType >::Create( TAttribute< AttrType >::FGetter::CreateUObject( InUserObject, InFunc, Var1, Var2, Var3, Var4 ) ); \
            return this->Me(); \
        }

SLATE_ARGUMENT(ArgType, ArgName):

/**
* Use this macro to declare a slate argument.使用这个宏可以为你的正在构建的Widget声明一个参数，这个参数不是一个TAttribute<>类型（属性），只是一个一般数据类型的变量
* Arguments differ from attributes in that they can only be values.Argumet和Attribute的区别在于Argument只能是一个值，而Attitude可以是一个值或者方法，并且可以为其绑定代理。
*/

ArgType: 参数类型

ArgName:参数名

 */
#define SLATE_ARGUMENT( ArgType, ArgName ) \
        ArgType _##ArgName; \
        WidgetArgsType& ArgName( ArgType InArg ) \
        { \
            _##ArgName = InArg; \
            return this->Me(); \
        }