UnrealEngineUWP/Engine/Source/Runtime/UMG/Private/UWidgetNavigation.cpp

// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.

#include "CoreMinimal.h"
#include "Types/SlateEnums.h"
#include "Input/NavigationReply.h"
#include "Types/NavigationMetaData.h"
#include "Blueprint/WidgetNavigation.h"
#include "Blueprint/WidgetTree.h"

/////////////////////////////////////////////////////
// UWidgetNavigation

UWidgetNavigation::UWidgetNavigation(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
}

#if WITH_EDITOR

FWidgetNavigationData& UWidgetNavigation::GetNavigationData(EUINavigation Nav)
{
	switch ( Nav )
	{
	case EUINavigation::Up:
		return Up;
	case EUINavigation::Down:
		return Down;
	case EUINavigation::Left:
		return Left;
	case EUINavigation::Right:
		return Right;
	case EUINavigation::Next:
		return Next;
	case EUINavigation::Previous:
		return Previous;
	default:
		break;
	}

	// Should never happen
	check(false);

	return Up;
}

EUINavigationRule UWidgetNavigation::GetNavigationRule(EUINavigation Nav)
{
	switch ( Nav )
	{
	case EUINavigation::Up:
		return Up.Rule;
	case EUINavigation::Down:
		return Down.Rule;
	case EUINavigation::Left:
		return Left.Rule;
	case EUINavigation::Right:
		return Right.Rule;
	case EUINavigation::Next:
		return Next.Rule;
	case EUINavigation::Previous:
		return Previous.Rule;
		break;
	}
	return EUINavigationRule::Escape;
}

#endif

void UWidgetNavigation::ResolveExplictRules(UWidgetTree* WidgetTree)
{
	if ( Up.Rule == EUINavigationRule::Explicit )
	{
		Up.Widget = WidgetTree->FindWidget(Up.WidgetToFocus);
	}
	if ( Down.Rule == EUINavigationRule::Explicit )
	{
		Down.Widget = WidgetTree->FindWidget(Down.WidgetToFocus);
	}
	if ( Left.Rule == EUINavigationRule::Explicit )
	{
		Left.Widget = WidgetTree->FindWidget(Left.WidgetToFocus);
	}
	if ( Right.Rule == EUINavigationRule::Explicit )
	{
		Right.Widget = WidgetTree->FindWidget(Right.WidgetToFocus);
	}
	if ( Next.Rule == EUINavigationRule::Explicit )
	{
		Next.Widget = WidgetTree->FindWidget(Next.WidgetToFocus);
	}
	if ( Previous.Rule == EUINavigationRule::Explicit )
	{
		Previous.Widget = WidgetTree->FindWidget(Previous.WidgetToFocus);
	}
}

void UWidgetNavigation::UpdateMetaData(TSharedRef<FNavigationMetaData> MetaData)
{
	UpdateMetaDataEntry(MetaData, Up, EUINavigation::Up);
	UpdateMetaDataEntry(MetaData, Down, EUINavigation::Down);
	UpdateMetaDataEntry(MetaData, Left, EUINavigation::Left);
	UpdateMetaDataEntry(MetaData, Right, EUINavigation::Right);
	UpdateMetaDataEntry(MetaData, Next, EUINavigation::Next);
	UpdateMetaDataEntry(MetaData, Previous, EUINavigation::Previous);
}

bool UWidgetNavigation::IsDefault() const
{
	return Up.Rule == EUINavigationRule::Escape &&
		Down.Rule == EUINavigationRule::Escape &&
		Left.Rule == EUINavigationRule::Escape &&
		Right.Rule == EUINavigationRule::Escape &&
		Next.Rule == EUINavigationRule::Escape &&
		Previous.Rule == EUINavigationRule::Escape;
}

void UWidgetNavigation::UpdateMetaDataEntry(TSharedRef<FNavigationMetaData> MetaData, const FWidgetNavigationData & NavData, EUINavigation Nav)
{
	switch ( NavData.Rule )
	{
	case EUINavigationRule::Escape:
		MetaData->SetNavigationEscape(Nav);
		break;
	case EUINavigationRule::Stop:
		MetaData->SetNavigationStop(Nav);
		break;
	case EUINavigationRule::Wrap:
		MetaData->SetNavigationWrap(Nav);
		break;
	case EUINavigationRule::Explicit:
		if ( NavData.Widget.IsValid() )
		{
			MetaData->SetNavigationExplicit(Nav, NavData.Widget.Get()->GetCachedWidget());
		}
		break;
	case EUINavigationRule::Custom:
		break;
	}
}