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03-UnrealEngine/Gameplay/Lyra/UE5 Lyra学习笔记(6)—CommonUI.md

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+---
+title: UE5 Lyra学习笔记(6)—CommonUI
+date: 2024-03-22 15:03:59
+excerpt: 
+tags: 
+rating: ⭐
+---
+# 前言
+- 全局管理类
+	- [[#UGameUIManagerSubsystem]]
+		- [[#UGameUIPolicy]]
+			- UPrimaryGameLayout
+- Widgets
+使用[[#GameplayAbility]]检测玩家输入并且开启UI。
+
+# UGameUIManagerSubsystem
+父类为：UGameInstanceSubsystem，主要的功能是管理CurrentPolicy(UGameUIPolicy)。
+
+# UGameUIPolicy
+
+
+
+# GameplayAbility
+Lyra使用2个位于Plugins/ShooterCore/Content/Input/Abilites/ 
+- GAB_ShowWidget_WhenInputPressed
+- GAB_ShowWidget_WhileInputHeld
+
+ GAB_ShowWidget_WhenInputPressed：![[GAB_ShowWidget_WhenInputPressed.png|800]]
+ GAB_ShowWidget_WhileInputHeld，略微复杂一些会多一些：![[GAB_ShowWidget_WhileInputHeld.png|1200]]
+
+## GameplayTasks
+- UCancellableAsyncAction
+	- [[#UAsyncAction_PushContentToLayerForPlayer]]
+
+核心函数逻辑如下，主要调用UPrimaryGameLayout::PushWidgetToLayerStackAsync()
+```c++
+void UAsyncAction_PushContentToLayerForPlayer::Activate()
+{
+	if (UPrimaryGameLayout* RootLayout = UPrimaryGameLayout::GetPrimaryGameLayout(OwningPlayerPtr.Get()))
+	{
+		TWeakObjectPtr<UAsyncAction_PushContentToLayerForPlayer> WeakThis = this;
+		StreamingHandle = RootLayout->PushWidgetToLayerStackAsync<UCommonActivatableWidget>(LayerName, bSuspendInputUntilComplete, WidgetClass, [this, WeakThis](EAsyncWidgetLayerState State, UCommonActivatableWidget* Widget) {
+			if (WeakThis.IsValid())
+			{
+				switch (State)
+				{
+					case EAsyncWidgetLayerState::Initialize:
+						BeforePush.Broadcast(Widget);
+						break;
+					case EAsyncWidgetLayerState::AfterPush:
+						AfterPush.Broadcast(Widget);
+						SetReadyToDestroy();
+						break;
+					case EAsyncWidgetLayerState::Canceled:
+						SetReadyToDestroy();
+						break;
+				}
+			}
+			SetReadyToDestroy();
+		});
+	}
+	else
+	{
+		SetReadyToDestroy();
+	}
+}
+```