UIAction.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Layout/Visibility.h"
#include "Styling/SlateTypes.h"
 
DECLARE_DELEGATE(FExecuteAction);
 
DECLARE_DELEGATE_RetVal(bool, FCanExecuteAction);
 
DECLARE_DELEGATE_RetVal(bool, FIsActionChecked);
 
DECLARE_DELEGATE_RetVal(ECheckBoxState, FGetActionCheckState);
 
DECLARE_DELEGATE_RetVal(bool, FIsActionButtonVisible);
 
 
enum class EUIActionRepeatMode
{
    RepeatDisabled,
    RepeatEnabled,
};
 
 
struct FUIAction
{
    FExecuteAction ExecuteAction;
 
    FCanExecuteAction CanExecuteAction;
 
    FGetActionCheckState GetActionCheckState;
 
    FIsActionButtonVisible IsActionVisibleDelegate;
 
    EUIActionRepeatMode RepeatMode;
 
public:
 
    SLATE_API FUIAction();
 
    SLATE_API FUIAction(FExecuteAction InitExecuteAction, EUIActionRepeatMode InitRepeatMode = EUIActionRepeatMode::RepeatDisabled);
 
    SLATE_API FUIAction(FExecuteAction InitExecuteAction, FCanExecuteAction InitCanExecuteAction, EUIActionRepeatMode InitRepeatMode = EUIActionRepeatMode::RepeatDisabled);
 
    SLATE_API FUIAction(FExecuteAction InitExecuteAction, FCanExecuteAction InitCanExecuteAction, FIsActionChecked InitIsCheckedDelegate, EUIActionRepeatMode InitRepeatMode = EUIActionRepeatMode::RepeatDisabled);
 
    SLATE_API FUIAction(FExecuteAction InitExecuteAction, FCanExecuteAction InitCanExecuteAction, FGetActionCheckState InitGetActionCheckStateDelegate, EUIActionRepeatMode InitRepeatMode = EUIActionRepeatMode::RepeatDisabled);
 
    SLATE_API FUIAction(FExecuteAction InitExecuteAction, FCanExecuteAction InitCanExecuteAction, FIsActionChecked InitIsCheckedDelegate, FIsActionButtonVisible InitIsActionVisibleDelegate, EUIActionRepeatMode InitRepeatMode = EUIActionRepeatMode::RepeatDisabled);
 
    SLATE_API FUIAction(FExecuteAction InitExecuteAction, FCanExecuteAction InitCanExecuteAction, FGetActionCheckState InitGetActionCheckStateDelegate, FIsActionButtonVisible InitIsActionVisibleDelegate, EUIActionRepeatMode InitRepeatMode = EUIActionRepeatMode::RepeatDisabled);
 
public:
 
    bool CanExecute( ) const
    {
        // Fire the 'can execute' delegate if we have one, otherwise always return true
        return CanExecuteAction.IsBound() ? CanExecuteAction.Execute() : true;
    }
 
    bool Execute( ) const
    {
        // It's up to the programmer to ensure that the action is still valid by the time the user clicks on the
        // button.  Otherwise the user won't know why the action didn't take place!
        if( CanExecute() )
        {
            return ExecuteAction.ExecuteIfBound();
        }
 
        return false;
    }
 
    ECheckBoxState GetCheckState( ) const
    {
        if (GetActionCheckState.IsBound())
        {
            return GetActionCheckState.Execute();
        }
 
        return ECheckBoxState::Unchecked;
    }
 
    bool IsBound( ) const
    {
        return ExecuteAction.IsBound();
    }
 
    EVisibility IsVisible( ) const
    {
        if (IsActionVisibleDelegate.IsBound())
        {
            const bool bIsVisible = IsActionVisibleDelegate.Execute();
            return bIsVisible ? EVisibility::Visible : EVisibility::Collapsed;
        }
 
        return EVisibility::Visible;
    }
 
    bool CanRepeat( ) const
    {
        return RepeatMode == EUIActionRepeatMode::RepeatEnabled;
    }
 
    static ECheckBoxState IsActionCheckedPassthrough(FIsActionChecked InDelegate)
    {
        if (InDelegate.IsBound())
        {
            const bool bIsChecked = InDelegate.Execute();
            return bIsChecked ? ECheckBoxState::Checked : ECheckBoxState::Unchecked;
        }
 
        return ECheckBoxState::Unchecked;
    }
};
 
struct IUIActionContextBase
{
 
public:
    virtual FName GetContextName() const = 0;
};
 
struct FUIActionContext
{
public:
 
    SLATE_API TSharedPtr<IUIActionContextBase> FindContext(const FName InName) const;
 
    SLATE_API void AddContext(const TSharedPtr<IUIActionContextBase>& InContext);
 
private:
    TArray<TSharedPtr<IUIActionContextBase>> Contexts;
};