---
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();
	}
}
```