135 lines
5.4 KiB
Markdown
135 lines
5.4 KiB
Markdown
---
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title: UE5 Lyra学习笔记(6)—CommonUI
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date: 2024-03-22 15:03:59
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excerpt:
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tags:
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rating: ⭐
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---
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# 前言
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- 全局管理类
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- UGameUIManagerSubsystem：父类为UGameInstanceSubsystem，主要的功能是管理CurrentPolicy(UGameUIPolicy)。
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- UGameUIPolicy：将UPrimaryGameLayout添加到Viewport中。
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- UPrimaryGameLayout
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- Widgets
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使用[[#GameplayAbility]]检测玩家输入并且开启UI。
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# UPrimaryGameLayout
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父类为UCommonUserWidget。主要功能为UILayer以及Dormant状态管理。
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## UILayer
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使用`TMap<FGameplayTag, TObjectPtr<UCommonActivatableWidgetContainerBase>> Layers;`进行多UI层的管理，不同Layer使用GameplayTag进行区分。Lyra的UILayer分为以下4个层：
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- UI.Layer.Game
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- UI.Layer.GameMenu
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- UI.Layer.Menu
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- UI.Layer.Modal
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```c++
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template <typename ActivatableWidgetT = UCommonActivatableWidget>
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TSharedPtr<FStreamableHandle> PushWidgetToLayerStackAsync(FGameplayTag LayerName, bool bSuspendInputUntilComplete, TSoftClassPtr<UCommonActivatableWidget> ActivatableWidgetClass, TFunction<void(EAsyncWidgetLayerState, ActivatableWidgetT*)> StateFunc)
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{
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static_assert(TIsDerivedFrom<ActivatableWidgetT, UCommonActivatableWidget>::IsDerived, "Only CommonActivatableWidgets can be used here");
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static FName NAME_PushingWidgetToLayer("PushingWidgetToLayer");
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const FName SuspendInputToken = bSuspendInputUntilComplete ? UCommonUIExtensions::SuspendInputForPlayer(GetOwningPlayer(), NAME_PushingWidgetToLayer) : NAME_None;
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FStreamableManager& StreamableManager = UAssetManager::Get().GetStreamableManager();
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TSharedPtr<FStreamableHandle> StreamingHandle = StreamableManager.RequestAsyncLoad(ActivatableWidgetClass.ToSoftObjectPath(), FStreamableDelegate::CreateWeakLambda(this,
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[this, LayerName, ActivatableWidgetClass, StateFunc, SuspendInputToken]()
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{
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UCommonUIExtensions::ResumeInputForPlayer(GetOwningPlayer(), SuspendInputToken);
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ActivatableWidgetT* Widget = PushWidgetToLayerStack<ActivatableWidgetT>(LayerName, ActivatableWidgetClass.Get(), [StateFunc](ActivatableWidgetT& WidgetToInit) {
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StateFunc(EAsyncWidgetLayerState::Initialize, &WidgetToInit);
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});
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StateFunc(EAsyncWidgetLayerState::AfterPush, Widget);
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})
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);
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// Setup a cancel delegate so that we can resume input if this handler is canceled.
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StreamingHandle->BindCancelDelegate(FStreamableDelegate::CreateWeakLambda(this,
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[this, StateFunc, SuspendInputToken]()
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{
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UCommonUIExtensions::ResumeInputForPlayer(GetOwningPlayer(), SuspendInputToken);
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StateFunc(EAsyncWidgetLayerState::Canceled, nullptr);
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})
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);
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return StreamingHandle;
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}
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template <typename ActivatableWidgetT = UCommonActivatableWidget>
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ActivatableWidgetT* PushWidgetToLayerStack(FGameplayTag LayerName, UClass* ActivatableWidgetClass)
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{
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return PushWidgetToLayerStack<ActivatableWidgetT>(LayerName, ActivatableWidgetClass, [](ActivatableWidgetT&) {});
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}
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template <typename ActivatableWidgetT = UCommonActivatableWidget>
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ActivatableWidgetT* PushWidgetToLayerStack(FGameplayTag LayerName, UClass* ActivatableWidgetClass, TFunctionRef<void(ActivatableWidgetT&)> InitInstanceFunc)
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{
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static_assert(TIsDerivedFrom<ActivatableWidgetT, UCommonActivatableWidget>::IsDerived, "Only CommonActivatableWidgets can be used here");
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if (UCommonActivatableWidgetContainerBase* Layer = GetLayerWidget(LayerName))
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{
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return Layer->AddWidget<ActivatableWidgetT>(ActivatableWidgetClass, InitInstanceFunc);
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}
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return nullptr;
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}
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```
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### RegisterLayer
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用于向PrimaryGameLayout注册UILayer。（为了方便管理里面的CommonActivatabbleWidgetStack)
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```c++
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void RegisterLayer(UPARAM(meta = (Categories = "UI.Layer")) FGameplayTag LayerTag, UCommonActivatableWidgetContainerBase* LayerWidget);
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```
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Content/UI的W_OverallUILayout调用，它是一个根组件为Overlay，下面有4个子组件(CommonActivatabbleWidgetStack)：
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- GameLayer_Stack：游戏内UI，类似HUD。
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- GameMenu_Stack：游戏相关的 "菜单"，例如游戏中的库存用户界面。
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- Menu_Stack：设置界面等。
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- Model_Stack：游戏内的模态确认对话框、错误对话框。
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# GameplayAbility
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Lyra使用2个位于Plugins/ShooterCore/Content/Input/Abilites/
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- GAB_ShowWidget_WhenInputPressed
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- GAB_ShowWidget_WhileInputHeld
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GAB_ShowWidget_WhenInputPressed：![[GAB_ShowWidget_WhenInputPressed.png|800]]
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GAB_ShowWidget_WhileInputHeld，略微复杂一些会多一些：![[GAB_ShowWidget_WhileInputHeld.png|1200]]
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## GameplayTasks
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- UCancellableAsyncAction
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- [[#UAsyncAction_PushContentToLayerForPlayer]]
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核心函数逻辑如下，主要调用UPrimaryGameLayout::PushWidgetToLayerStackAsync()
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```c++
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void UAsyncAction_PushContentToLayerForPlayer::Activate()
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{
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if (UPrimaryGameLayout* RootLayout = UPrimaryGameLayout::GetPrimaryGameLayout(OwningPlayerPtr.Get()))
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{
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TWeakObjectPtr<UAsyncAction_PushContentToLayerForPlayer> WeakThis = this;
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StreamingHandle = RootLayout->PushWidgetToLayerStackAsync<UCommonActivatableWidget>(LayerName, bSuspendInputUntilComplete, WidgetClass, [this, WeakThis](EAsyncWidgetLayerState State, UCommonActivatableWidget* Widget) {
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if (WeakThis.IsValid())
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{
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switch (State)
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{
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case EAsyncWidgetLayerState::Initialize:
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BeforePush.Broadcast(Widget);
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break;
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case EAsyncWidgetLayerState::AfterPush:
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AfterPush.Broadcast(Widget);
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SetReadyToDestroy();
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break;
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case EAsyncWidgetLayerState::Canceled:
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SetReadyToDestroy();
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break;
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}
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}
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SetReadyToDestroy();
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});
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}
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else
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{
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SetReadyToDestroy();
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}
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}
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``` |