注：此处使用版本是UE5.4，不爱看源码的朋友跳过往后翻就行，不影响使用

前言

为啥UE5要推CommonUI？

用过原生的UserWidget的朋友，应该都清楚，UE的UI输入都来自于Focus的UI，当遇到主机游戏上，要频繁切UI，切输入的时候，老会发现当前的UI没有Focus，导致界面按钮没输入，然后卡死。又或者鼠标上切到外部，再切回来的时候，会发现Focus又丢失掉了，当你点了Viewport时候，会发现输入跑到了GameViewPort上，整体UI也就丢失了输入。包括它的输入，蓝图WidgetTree里面的UI接收输入时候，它的WidgetTree拥有者，也会接收到输入，没有PlayerController里面的输入的Consume操作。当然，还有很多风格化（样式），手柄导航等诸多考校，大家可以去阅读官方文档：

官网

快速配置

配置Game Viewport Client Class

Project Setting->All Settings下搜索Game Viewport Client Class，将视口切换成CommonGameViewportClient（CommonGameViewportClient包含了有关输入内容）

CommonGameViewportClient源代码

跳过

.h

// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "Engine/GameViewportClient.h"
#include "CommonGameViewportClient.generated.h"

class FReply;

DECLARE_DELEGATE_FourParams(FOnRerouteInputDelegate, FInputDeviceId /* InputDeviceId */, FKey /* Key */, EInputEvent /* EventType */, FReply& /* Reply */);
DECLARE_DELEGATE_FourParams(FOnRerouteAxisDelegate, FInputDeviceId /* InputDeviceId */, FKey /* Key */, float /* Delta */, FReply& /* Reply */);
DECLARE_DELEGATE_FiveParams(FOnRerouteTouchDelegate, int32 /* ControllerId */, uint32 /* TouchId */, ETouchType::Type /* TouchType */, const FVector2D& /* TouchLocation */, FReply& /* Reply */);

/**
* CommonUI Viewport to reroute input to UI first. Needed to allow CommonUI to route / handle inputs.
*/
UCLASS(Within = Engine, transient, config = Engine)
class COMMONUI_API UCommonGameViewportClient : public UGameViewportClient
{
	GENERATED_BODY()

public:

	UCommonGameViewportClient(FVTableHelper& Helper);
	virtual ~UCommonGameViewportClient();

	// UGameViewportClient interface begin
	virtual bool InputKey(const FInputKeyEventArgs& EventArgs) override;
	virtual bool InputAxis(FViewport* InViewport, FInputDeviceId InputDevice, FKey Key, float Delta, float DeltaTime, int32 NumSamples, bool bGamepad) override;
	virtual bool InputTouch(FViewport* InViewport, int32 ControllerId, uint32 Handle, ETouchType::Type Type, const FVector2D& TouchLocation, float Force, FDateTime DeviceTimestamp, uint32 TouchpadIndex) override;
	// UGameViewportClient interface end

	FOnRerouteInputDelegate& OnRerouteInput() { return RerouteInput; }
	FOnRerouteAxisDelegate& OnRerouteAxis() { return RerouteAxis; }
	FOnRerouteTouchDelegate& OnRerouteTouch() { return RerouteTouch; }

	FOnRerouteInputDelegate& OnRerouteBlockedInput() { return RerouteBlockedInput; }

	/** Default Handler for Key input. */
	UE_DEPRECATED(5.1, "This version of HandleRerouteInput has been deprecated. Please use the version that takes an FInputDeviceId instead")
	virtual void HandleRerouteInput(int32 ControllerId, FKey Key, EInputEvent EventType, FReply& Reply);

	/** Default Handler for Key input. */
	virtual void HandleRerouteInput(FInputDeviceId DeviceId, FKey Key, EInputEvent EventType, FReply& Reply);

	/** Default Handler for Axis input. */
	UE_DEPRECATED(5.1, "This version of HandleRerouteAxis has been deprecated. Please use the version that takes an FInputDeviceId instead")
	virtual void HandleRerouteAxis(int32 ControllerId, FKey Key, float Delta, FReply& Reply);

	/** Default Handler for Axis input. */
	virtual void HandleRerouteAxis(FInputDeviceId DeviceId, FKey Key, float Delta, FReply& Reply);

	/** Default Handler for Touch input. */
	virtual void HandleRerouteTouch(int32 ControllerId, uint32 TouchId, ETouchType::Type TouchType, const FVector2D& TouchLocation, FReply& Reply);

protected:
	
	/** Console window & fullscreen shortcut have higher priority than UI */
	virtual bool IsKeyPriorityAboveUI(const FInputKeyEventArgs& EventArgs);

	FOnRerouteInputDelegate RerouteInput;
	FOnRerouteAxisDelegate RerouteAxis;
	FOnRerouteTouchDelegate RerouteTouch;

	FOnRerouteInputDelegate RerouteBlockedInput;
};

#if UE_ENABLE_INCLUDE_ORDER_DEPRECATED_IN_5_2
#include "CoreMinimal.h"
#include "Input/Reply.h"
#include "InputCoreTypes.h"
#include "InputKeyEventArgs.h"
#include "UObject/ObjectMacros.h"
#endif

.cpp

// Copyright Epic Games, Inc. All Rights Reserved.

#include "CommonGameViewportClient.h"
#include "Engine/Console.h"
#include "Engine/GameInstance.h"
#include "Engine/LocalPlayer.h"
#include "InputKeyEventArgs.h"

#if WITH_EDITOR
#endif // WITH_EDITOR

#include "Input/CommonUIActionRouterBase.h"

#include UE_INLINE_GENERATED_CPP_BY_NAME(CommonGameViewportClient)

#define LOCTEXT_NAMESPACE ""

static const FName NAME_Typing = FName(TEXT("Typing"));
static const FName NAME_Open = FName(TEXT("Open"));

UCommonGameViewportClient::UCommonGameViewportClient(FVTableHelper& Helper) : Super(Helper)
{
}

UCommonGameViewportClient::~UCommonGameViewportClient()
{
}

bool UCommonGameViewportClient::InputKey(const FInputKeyEventArgs& InEventArgs)
{
	FInputKeyEventArgs EventArgs = InEventArgs;

	if (IsKeyPriorityAboveUI(EventArgs))
	{
		return true;
	}

	// Check override before UI
	if (OnOverrideInputKey().IsBound())
	{
		if (OnOverrideInputKey().Execute(EventArgs))
		{
			return true;
		}
	}

	// The input is fair game for handling - the UI gets first dibs
#if !UE_BUILD_SHIPPING
	if (ViewportConsole && !ViewportConsole->ConsoleState.IsEqual(NAME_Typing) && !ViewportConsole->ConsoleState.IsEqual(NAME_Open))
#endif
	{		
		FReply Result = FReply::Unhandled();
		if (!OnRerouteInput().ExecuteIfBound(EventArgs.InputDevice, EventArgs.Key, EventArgs.Event, Result))
		{
			HandleRerouteInput(EventArgs.InputDevice, EventArgs.Key, EventArgs.Event, Result);
		}

		if (Result.IsEventHandled())
		{
			return true;
		}
	}

	return Super::InputKey(EventArgs);
}

bool UCommonGameViewportClient::InputAxis(FViewport* InViewport, FInputDeviceId InputDevice, FKey Key, float Delta, float DeltaTime, int32 NumSamples, bool bGamepad)
{
	FReply RerouteResult = FReply::Unhandled();

	if (!OnRerouteAxis().ExecuteIfBound(InputDevice, Key, Delta, RerouteResult))
	{
		HandleRerouteAxis(InputDevice, Key, Delta, RerouteResult);
	}

	if (RerouteResult.IsEventHandled())
	{
		return true;
	}
	return Super::InputAxis(InViewport, InputDevice, Key, Delta, DeltaTime, NumSamples, bGamepad);
}

bool UCommonGameViewportClient::InputTouch(FViewport* InViewport, int32 ControllerId, uint32 Handle, ETouchType::Type Type, const FVector2D& TouchLocation, float Force, FDateTime DeviceTimestamp, uint32 TouchpadIndex)
{
#if !UE_BUILD_SHIPPING
	if (ViewportConsole != NULL && (ViewportConsole->ConsoleState != NAME_Typing) && (ViewportConsole->ConsoleState != NAME_Open))
#endif
	{
		FReply Result = FReply::Unhandled();
		if (!OnRerouteTouch().ExecuteIfBound(ControllerId, Handle, Type, TouchLocation, Result))
		{
			HandleRerouteTouch(ControllerId, Handle, Type, TouchLocation, Result);
		}

		if (Result.IsEventHandled())
		{
			return true;
		}
	}

	return Super::InputTouch(InViewport, ControllerId, Handle, Type, TouchLocation, Force, DeviceTimestamp, TouchpadIndex);
}

void UCommonGameViewportClient::HandleRerouteInput(FInputDeviceId DeviceId, FKey Key, EInputEvent EventType, FReply& Reply)
{
	FPlatformUserId OwningPlatformUser = IPlatformInputDeviceMapper::Get().GetUserForInputDevice(DeviceId);
	ULocalPlayer* LocalPlayer = GameInstance->FindLocalPlayerFromPlatformUserId(OwningPlatformUser);
	Reply = FReply::Unhandled();

	if (LocalPlayer)
	{
		UCommonUIActionRouterBase* ActionRouter = LocalPlayer->GetSubsystem<UCommonUIActionRouterBase>();
		if (ensure(ActionRouter))
		{
			ERouteUIInputResult InputResult = ActionRouter->ProcessInput(Key, EventType);
			if (InputResult == ERouteUIInputResult::BlockGameInput)
			{
				// We need to set the reply as handled otherwise the input won't actually be blocked from reaching the viewport.
				Reply = FReply::Handled();
				// Notify interested parties that we blocked the input.
				OnRerouteBlockedInput().ExecuteIfBound(DeviceId, Key, EventType, Reply);
			}
			else if (InputResult == ERouteUIInputResult::Handled)
			{
				Reply = FReply::Handled();
			}
		}
	}	
}

void UCommonGameViewportClient::HandleRerouteInput(int32 ControllerId, FKey Key, EInputEvent EventType, FReply& Reply)
{
	// Remap the old int32 ControllerId to the new platform user and input device ID
	FPlatformUserId UserId = FGenericPlatformMisc::GetPlatformUserForUserIndex(ControllerId);
	FInputDeviceId DeviceID = INPUTDEVICEID_NONE;
	IPlatformInputDeviceMapper::Get().RemapControllerIdToPlatformUserAndDevice(ControllerId, UserId, DeviceID);
	return HandleRerouteInput(DeviceID, Key, EventType, Reply);
}

void UCommonGameViewportClient::HandleRerouteAxis(FInputDeviceId DeviceId, FKey Key, float Delta, FReply& Reply)
{
	// Get the ownign platform user for this input device and their local player
	FPlatformUserId OwningPlatformUser = IPlatformInputDeviceMapper::Get().GetUserForInputDevice(DeviceId);
	ULocalPlayer* LocalPlayer = GameInstance->FindLocalPlayerFromPlatformUserId(OwningPlatformUser);
	
	Reply = FReply::Unhandled();

	if (LocalPlayer)
	{
		UCommonUIActionRouterBase* ActionRouter = LocalPlayer->GetSubsystem<UCommonUIActionRouterBase>();
		if (ensure(ActionRouter))
		{
			// We don't actually use axis inputs that reach the game viewport UI land for anything, we just want block them reaching the game when they shouldn't
			if (!ActionRouter->CanProcessNormalGameInput())
			{
				Reply = FReply::Handled();
			}
		}
	}
}

void UCommonGameViewportClient::HandleRerouteAxis(int32 ControllerId, FKey Key, float Delta, FReply& Reply)
{
	// Remap the old int32 ControllerId to the new platform user and input device ID
	FPlatformUserId UserId = FGenericPlatformMisc::GetPlatformUserForUserIndex(ControllerId);
	FInputDeviceId DeviceID = INPUTDEVICEID_NONE;
	IPlatformInputDeviceMapper::Get().RemapControllerIdToPlatformUserAndDevice(ControllerId, UserId, DeviceID);
	
	return HandleRerouteAxis(DeviceID, Key, Delta, Reply);
}

void UCommonGameViewportClient::HandleRerouteTouch(int32 ControllerId, uint32 TouchId, ETouchType::Type TouchType, const FVector2D& TouchLocation, FReply& Reply)
{
	ULocalPlayer* LocalPlayer = GameInstance->FindLocalPlayerFromControllerId(ControllerId);
	Reply = FReply::Unhandled();

	if (LocalPlayer && TouchId < EKeys::NUM_TOUCH_KEYS)
	{
		FKey KeyPressed = EKeys::TouchKeys[TouchId];
		if (KeyPressed.IsValid())
		{
			UCommonUIActionRouterBase* ActionRouter = LocalPlayer->GetSubsystem<UCommonUIActionRouterBase>();
			if (ensure(ActionRouter))
			{
				EInputEvent SimilarInputEvent = IE_MAX;
				switch (TouchType)
				{
				case ETouchType::Began:
					SimilarInputEvent = IE_Pressed;
					break;
				case ETouchType::Ended:
					SimilarInputEvent = IE_Released;
					break;
				default:
					SimilarInputEvent = IE_Repeat;
					break;
				}

				if (ActionRouter->ProcessInput(KeyPressed, SimilarInputEvent) != ERouteUIInputResult::Unhandled)
				{
					Reply = FReply::Handled();
				}
			}
		}
	}
}

bool UCommonGameViewportClient::IsKeyPriorityAboveUI(const FInputKeyEventArgs& EventArgs)
{
#if !UE_BUILD_SHIPPING
	// First priority goes to the viewport console regardless any state or setting
	if (ViewportConsole && ViewportConsole->InputKey(EventArgs.InputDevice, EventArgs.Key, EventArgs.Event, EventArgs.AmountDepressed, EventArgs.IsGamepad()))
	{
		return true;
	}
#endif

	// We'll also treat toggling fullscreen as a system-level sort of input that isn't affected by input filtering
	if (TryToggleFullscreenOnInputKey(EventArgs.Key, EventArgs.Event))
	{
		return true;
	}

	return false;
}

#undef LOCTEXT_NAMESPACE

创建CommonInputAction表

Common UI使用输入InputAction表来创建能够与各种平台的输入所关联的Action。

选用CommonInputActionDataBase 结构体来创建DataTable：

打开新建的DataTable，进行简单的输入配置

Common UI控件将这些抽象的Action映射到实际的输入。比如，你可以将数据表和RowName名称参考添加到 CommonButtonBase 控件中的 触发InputAction。之后，按下该Action所关联的按钮会触发Common UI按钮。

默认导航Action设置

虚幻引擎原生支持指向导航。但是这里，Common UI使用 CommonUIInputData来定义所有平台通用的 点击（Click） 和 返回（Back） 输Input Action。
（简单来说，就是实现多个界面打开关闭时候使用的，比如按A键打开某个界面，按B键关闭某个界面）

创建一个CommonUIInputData。

打开其ClassDefault，配置默认的点击与返回Action

此前我在DataTable里创建了俩测试按键配置

ProjectSetting下搜索InputData，并配置自己的刚创建的测试的CommonUIInputData

CommonUIInputData源码

跳过
.h

UCLASS(Abstract, Blueprintable, ClassGroup = Input, meta = (Category = "Common Input"))
class COMMONINPUT_API UCommonUIInputData : public UObject
{
	GENERATED_BODY()

public:
	virtual bool NeedsLoadForServer() const override;

public:
	UPROPERTY(EditDefaultsOnly, Category = "Properties", meta = (RowType = "/Script/CommonUI.CommonInputActionDataBase"))
	FDataTableRowHandle DefaultClickAction;

	UPROPERTY(EditDefaultsOnly, Category = "Properties", meta = (RowType = "/Script/CommonUI.CommonInputActionDataBase"))
	FDataTableRowHandle DefaultBackAction;

	/**
    * Newly created CommonButton widgets will use these hold values by default if bRequiresHold is true.
    * Inherits from UCommonUIHoldData.
    */
    UPROPERTY(EditDefaultsOnly, Category = "Properties")
    TSoftClassPtr<UCommonUIHoldData> DefaultHoldData;

	UPROPERTY(EditDefaultsOnly, Category = "Properties", meta = (EditCondition = "CommonInput.CommonInputSettings.IsEnhancedInputSupportEnabled", EditConditionHides))
	TObjectPtr<UInputAction> EnhancedInputClickAction;

	UPROPERTY(EditDefaultsOnly, Category = "Properties", meta = (EditCondition = "CommonInput.CommonInputSettings.IsEnhancedInputSupportEnabled", EditConditionHides))
	TObjectPtr<UInputAction> EnhancedInputBackAction;
};

.cpp

bool UCommonUIInputData::NeedsLoadForServer() const
{
	const UUserInterfaceSettings* UISettings = GetDefault<UUserInterfaceSettings>();
	return UISettings->bLoadWidgetsOnDedicatedServer;
}

Bind CommonInputBaseControllerData

新建CommonInputBaseControllerData


将你的资产配置到Platform Input里面，对应平台配置对应平台内容

很可惜，我只看到Android、IOS、Linux、LinuxArm64、Mac、TVOS、Windows，其他平台还是需要自己写（比如Ps5、XBox，看了一圈源代码，也没找到有哪可以新增平台，虚幻会通过FProjectManager查询支持注册好的平台，如果有哪位朋友找到添加平台的方式，可以分享一波）。

查引用时候，会发现就是获取InputInfo时候会使用它，通俗来说，就是切平台时候，我们有按键提示，不同平台里面的按键不同，意味着显示不同的按键提醒图片，这时候，我们就可以考虑用它来处理。

bool FCommonInputActionDataBase::IsKeyBoundToInputActionData(const FKey& Key) const
{
	if (Key == KeyboardInputTypeInfo.GetKey() || Key == TouchInputTypeInfo.GetKey())
	{
		return true;
	}

	for (const FName& GamepadName : UCommonInputBaseControllerData::GetRegisteredGamepads())
	{
		const FCommonInputTypeInfo& TypeInfo = GetInputTypeInfo(ECommonInputType::Gamepad, GamepadName);
		if (Key == TypeInfo.GetKey())
		{
			return true;
		}
	}

	return false;
}

CommonInputBaseControllerData源码

跳过
.h

UCLASS(Abstract, Blueprintable, ClassGroup = Input, meta = (Category = "Common Input"))
class COMMONINPUT_API UCommonInputBaseControllerData : public UObject
{
	GENERATED_BODY()

public:
	virtual bool NeedsLoadForServer() const override;
	virtual bool TryGetInputBrush(FSlateBrush& OutBrush, const FKey& Key) const;
	virtual bool TryGetInputBrush(FSlateBrush& OutBrush, const TArray<FKey>& Keys) const;

	virtual void PreSave(FObjectPreSaveContext ObjectSaveContext) override;
	virtual void PostLoad() override;

private:
#if WITH_EDITORONLY_DATA
	UPROPERTY(Transient, EditAnywhere, Category = "Editor")
	int32 SetButtonImageHeightTo = 0;
#endif

public:
	UPROPERTY(EditDefaultsOnly, Category = "Default")
	ECommonInputType InputType;
	
	UPROPERTY(EditDefaultsOnly, Category = "Gamepad", meta=(EditCondition="InputType == ECommonInputType::Gamepad", GetOptions = GetRegisteredGamepads))
	FName GamepadName;

	UPROPERTY(EditDefaultsOnly, Category = "Gamepad", meta = (EditCondition = "InputType == ECommonInputType::Gamepad"))
	FText GamepadDisplayName;

	UPROPERTY(EditDefaultsOnly, Category = "Gamepad", meta=(EditCondition="InputType == ECommonInputType::Gamepad"))
	FText GamepadCategory;

	UPROPERTY(EditDefaultsOnly, Category = "Gamepad", meta = (EditCondition = "InputType == ECommonInputType::Gamepad"))
	FText GamepadPlatformName;

	UPROPERTY(EditDefaultsOnly, Category = "Gamepad", meta=(EditCondition="InputType == ECommonInputType::Gamepad"))
	TArray<FInputDeviceIdentifierPair> GamepadHardwareIdMapping;

	UPROPERTY(EditDefaultsOnly, Category = "Display")
	TSoftObjectPtr<UTexture2D> ControllerTexture;

	UPROPERTY(EditDefaultsOnly, Category = "Display")
	TSoftObjectPtr<UTexture2D> ControllerButtonMaskTexture;

	UPROPERTY(EditDefaultsOnly, Category = "Display", Meta = (TitleProperty = "Key"))
	TArray<FCommonInputKeyBrushConfiguration> InputBrushDataMap;

	UPROPERTY(EditDefaultsOnly, Category = "Display", Meta = (TitleProperty = "Keys"))
	TArray<FCommonInputKeySetBrushConfiguration> InputBrushKeySets;

	UFUNCTION()
	static const TArray<FName>& GetRegisteredGamepads();

private:
#if WITH_EDITOR
	virtual void PostEditChangeProperty(struct FPropertyChangedEvent& PropertyChangedEvent) override;
#endif
};

.cpp

 bool UCommonInputBaseControllerData::NeedsLoadForServer() const
{
	const UUserInterfaceSettings* UISettings = GetDefault<UUserInterfaceSettings>();
	return UISettings->bLoadWidgetsOnDedicatedServer;
}

bool UCommonInputBaseControllerData::TryGetInputBrush(FSlateBrush& OutBrush, const FKey& Key) const
{
	const FCommonInputKeyBrushConfiguration* DisplayConfig = InputBrushDataMap.FindByPredicate([&Key](const FCommonInputKeyBrushConfiguration& KeyBrushPair) -> bool
	{
		return KeyBrushPair.Key == Key;
	});

	if (DisplayConfig)
	{
		OutBrush = DisplayConfig->GetInputBrush();
		return true;
	}

	return false;
}

bool UCommonInputBaseControllerData::TryGetInputBrush(FSlateBrush& OutBrush, const TArray<FKey>& Keys) const
{
	if (Keys.Num() == 0)
	{
		return false;
	}

	if (Keys.Num() == 1)
	{
		return TryGetInputBrush(OutBrush, Keys[0]);
	}

	const FCommonInputKeySetBrushConfiguration* DisplayConfig = InputBrushKeySets.FindByPredicate([&Keys](const FCommonInputKeySetBrushConfiguration& KeyBrushPair) -> bool
	{
		if (KeyBrushPair.Keys.Num() < 2)
		{
			return false;
		}

		if (Keys.Num() == KeyBrushPair.Keys.Num())
		{
			for (const FKey& Key : Keys)
			{
				if (!KeyBrushPair.Keys.Contains(Key))
				{
					return false;
				}
			}

			return true;
		}

		return false;
	});

	if (DisplayConfig)
	{
		OutBrush = DisplayConfig->GetInputBrush();
		return true;
	}

	return false;
}

void UCommonInputBaseControllerData::PreSave(FObjectPreSaveContext ObjectSaveContext)
{
	Super::PreSave(ObjectSaveContext);

	if (!ObjectSaveContext.IsProceduralSave())
	{
		// These have been organized by a human already, better to sort using this array.
		TArray<FKey> AllKeys;
		EKeys::GetAllKeys(AllKeys);

		// Organize the keys so they're nice and clean
		InputBrushDataMap.Sort([&AllKeys](const FCommonInputKeyBrushConfiguration& A, const FCommonInputKeyBrushConfiguration& B) {
			return AllKeys.IndexOfByKey(A.Key) < AllKeys.IndexOfByKey(B.Key);
		});

		// Delete any brush data where we have no image assigned
		InputBrushDataMap.RemoveAll([](const FCommonInputKeyBrushConfiguration& A) {
			return A.GetInputBrush().GetResourceObject() == nullptr;
		});
	}
}

void UCommonInputBaseControllerData::PostLoad()
{
	Super::PostLoad();

#if WITH_EDITOR
	// Have to clear it even though it's transient because it's saved into the CDO.
	SetButtonImageHeightTo = 0;
#endif
}

const TArray<FName>& UCommonInputBaseControllerData::GetRegisteredGamepads()
{
	auto GenerateRegisteredGamepads = []()
	{
		TArray<FName> RegisteredGamepads;
		RegisteredGamepads.Add(FCommonInputDefaults::GamepadGeneric);

		for (const TPair<FName, FDataDrivenPlatformInfo>& Platform : FDataDrivenPlatformInfoRegistry::GetAllPlatformInfos())
		{
			const FName PlatformName = Platform.Key;
			const FDataDrivenPlatformInfo& PlatformInfo = Platform.Value;

			// Don't add fake platforms that are used to group real platforms to make configuration for groups of platforms
			// simpler.
			if (PlatformInfo.bIsFakePlatform)
			{
				continue;
			}

			// If the platform uses the standard keyboard for default input, ignore it, all of those platforms will use "PC"
			// as their target, so Windows, Linux, but not Mac.
			if (PlatformInfo.bDefaultInputStandardKeyboard)
			{
				continue;
			}

			// Only add platforms with dedicated gamepads.
			if (PlatformInfo.bHasDedicatedGamepad)
			{
				RegisteredGamepads.Add(PlatformName);
			}
		}
		return RegisteredGamepads;
	};
	static TArray<FName> RegisteredGamepads = GenerateRegisteredGamepads();
	return RegisteredGamepads;
}

#if WITH_EDITOR
void UCommonInputBaseControllerData::PostEditChangeProperty(struct FPropertyChangedEvent& PropertyChangedEvent)
{
	Super::PostEditChangeProperty(PropertyChangedEvent);

	if (PropertyChangedEvent.ChangeType == EPropertyChangeType::ValueSet)
	{
		if (PropertyChangedEvent.GetPropertyName() == GET_MEMBER_NAME_CHECKED(UCommonInputBaseControllerData, SetButtonImageHeightTo))
		{
			if (SetButtonImageHeightTo != 0)
			{
				for (FCommonInputKeyBrushConfiguration& BrushConfig : InputBrushDataMap)
				{
					FVector2D NewBrushSize = BrushConfig.KeyBrush.GetImageSize();
					if (NewBrushSize.X != 0 && NewBrushSize.Y != 0)
					{
						NewBrushSize.X = FMath::RoundToInt(SetButtonImageHeightTo * (NewBrushSize.X / NewBrushSize.Y));
						NewBrushSize.Y = SetButtonImageHeightTo;

						BrushConfig.KeyBrush.SetImageSize(NewBrushSize);
					}
				}

				for (FCommonInputKeySetBrushConfiguration& BrushConfig : InputBrushKeySets)
				{
					FVector2D NewBrushSize = BrushConfig.KeyBrush.GetImageSize();
					if (NewBrushSize.X != 0 && NewBrushSize.Y != 0)
					{
						NewBrushSize.X = FMath::RoundToInt(SetButtonImageHeightTo * (NewBrushSize.X / NewBrushSize.Y));
						NewBrushSize.Y = SetButtonImageHeightTo;

						BrushConfig.KeyBrush.SetImageSize(NewBrushSize);
					}
				}
			}

			SetButtonImageHeightTo = 0;
		}
	}
}
#endif

Common UI控件库和控件样式

CommonUI带了一些Style，在它自己的控件里面可以使用这些

一样的ProjectSetting里面配置Style

支持的控件类型：

CommonUIl有俩种主要有UserWdiget，一个CommonActivatableWidget，一个CommonUserWidget 。CommonUserWidget接管了原生虚幻的输入（也像PlayerController一样的方式，采用Consume的方式）。CommonActivatableWidget是继承自CommonUserWidget，它比起原生的CommonUserWidget添加了，激活的一些内容。CommonUserWidget接管了原生虚幻的输入（也像PlayerController一样的方式，采用Consume的方式）
当然，还有其他子控件:

CommonActivatableWidget里面带是带堆栈的，方便用于新旧界面之间的交互

之前的Button，也得继承CommonButtonBase使用

CommonUserWidget 源码

// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "Blueprint/UserWidget.h"
#include "Input/UIActionBindingHandle.h"

#include "CommonUserWidget.generated.h"

class UCommonInputSubsystem;
class UCommonUISubsystemBase;
class FSlateUser;

struct FUIActionTag;
struct FBindUIActionArgs;
enum class ECommonInputMode : uint8;

UCLASS(ClassGroup = UI, meta = (Category = "Common UI", DisableNativeTick))
class COMMONUI_API UCommonUserWidget : public UUserWidget
{
	GENERATED_UCLASS_BODY()

public:
	/** Sets whether or not this widget will consume ALL pointer input that reaches it */
	UFUNCTION(BlueprintCallable, Category = CommonUserWidget)
	void SetConsumePointerInput(bool bInConsumePointerInput);

	/** Add a widget to the list of widgets to get scroll events for this input root node */
	UFUNCTION(BlueprintCallable, Category = CommonUserWidget)
	void RegisterScrollRecipientExternal(const UWidget* AnalogScrollRecipient);

	/** Remove a widget from the list of widgets to get scroll events for this input root node */
	UFUNCTION(BlueprintCallable, Category = CommonUserWidget)
	void UnregisterScrollRecipientExternal(const UWidget* AnalogScrollRecipient);

public:

	const TArray<FUIActionBindingHandle>& GetActionBindings() const { return ActionBindings; }
	const TArray<TWeakObjectPtr<const UWidget>> GetScrollRecipients() const { return ScrollRecipients; }

	/**
	 * Convenience methods for menu action registrations (any UWidget can register via FCommonUIActionRouter directly, though generally that shouldn't be needed).
	 * Persistent bindings are *always* listening for input while registered, while normal bindings are only listening when all of this widget's activatable parents are activated.
	 */
	FUIActionBindingHandle RegisterUIActionBinding(const FBindUIActionArgs& BindActionArgs);

	void RemoveActionBinding(FUIActionBindingHandle ActionBinding);
	void AddActionBinding(FUIActionBindingHandle ActionBinding);

protected:
	virtual void OnWidgetRebuilt() override;
	virtual void NativeDestruct() override;
	
	virtual FReply NativeOnMouseButtonDown(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent) override;
	virtual FReply NativeOnMouseButtonUp(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent) override;
	virtual FReply NativeOnMouseWheel(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent) override;
	virtual FReply NativeOnMouseButtonDoubleClick(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent) override;
	virtual FReply NativeOnTouchGesture(const FGeometry& InGeometry, const FPointerEvent& InGestureEvent) override;
	virtual FReply NativeOnTouchStarted(const FGeometry& InGeometry, const FPointerEvent& InGestureEvent) override;
	virtual FReply NativeOnTouchMoved(const FGeometry& InGeometry, const FPointerEvent& InGestureEvent) override;
	virtual FReply NativeOnTouchEnded(const FGeometry& InGeometry, const FPointerEvent& InGestureEvent) override;
	
	UCommonInputSubsystem* GetInputSubsystem() const;
	UCommonUISubsystemBase* GetUISubsystem() const;
	TSharedPtr<FSlateUser> GetOwnerSlateUser() const;

	template <typename GameInstanceT = UGameInstance>
	GameInstanceT& GetGameInstanceChecked() const
	{
		GameInstanceT* GameInstance = GetGameInstance<GameInstanceT>();
		check(GameInstance);
		return *GameInstance;
	}

	template <typename PlayerControllerT = APlayerController>
	PlayerControllerT& GetOwningPlayerChecked() const
	{
		PlayerControllerT* PC = GetOwningPlayer<PlayerControllerT>();
		check(PC);
		return *PC;
	}

	void RegisterScrollRecipient(const UWidget& AnalogScrollRecipient);
	void UnregisterScrollRecipient(const UWidget& AnalogScrollRecipient);

	/** True to generally display this widget's actions in the action bar, assuming it has actions. */
	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Input, meta = (AllowPrivateAccess = true))
	bool bDisplayInActionBar = false;

private:

	/** Set this to true if you don't want any pointer (mouse and touch) input to bubble past this widget */
	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = Input, meta = (AllowPrivateAccess = true))
	bool bConsumePointerInput = false;

private:

	TArray<FUIActionBindingHandle> ActionBindings;
	TArray<TWeakObjectPtr<const UWidget>> ScrollRecipients;
};

#if UE_ENABLE_INCLUDE_ORDER_DEPRECATED_IN_5_2
#include "CommonUITypes.h"
#endif

// Copyright Epic Games, Inc. All Rights Reserved.

#include "CommonUserWidget.h"

#include "Engine/GameInstance.h"
#include "CommonInputSubsystem.h"
#include "CommonUISubsystemBase.h"
#include "Input/CommonUIActionRouterBase.h"
#include "Input/CommonUIInputTypes.h"

#include UE_INLINE_GENERATED_CPP_BY_NAME(CommonUserWidget)

UCommonUserWidget::UCommonUserWidget(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{	
#if WITH_EDITORONLY_DATA
	PaletteCategory = FText::FromString(TEXT("Common UI"));
#endif
}

void UCommonUserWidget::SetConsumePointerInput(bool bInConsumePointerInput)
{
	bConsumePointerInput = bInConsumePointerInput;
}

UCommonInputSubsystem* UCommonUserWidget::GetInputSubsystem() const
{
	return UCommonInputSubsystem::Get(GetOwningLocalPlayer());
}

UCommonUISubsystemBase* UCommonUserWidget::GetUISubsystem() const
{
	return UGameInstance::GetSubsystem<UCommonUISubsystemBase>(GetGameInstance());
}

TSharedPtr<FSlateUser> UCommonUserWidget::GetOwnerSlateUser() const
{
	ULocalPlayer* LocalPlayer = GetOwningLocalPlayer();
	return LocalPlayer ? LocalPlayer->GetSlateUser() : nullptr;
}

FReply UCommonUserWidget::NativeOnMouseButtonDown(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent)
{
	return bConsumePointerInput ? FReply::Handled() : Super::NativeOnMouseButtonDown(InGeometry, InMouseEvent);
}

FReply UCommonUserWidget::NativeOnMouseButtonUp(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent)
{
	return bConsumePointerInput ? FReply::Handled() : Super::NativeOnMouseButtonUp(InGeometry, InMouseEvent);
}

FReply UCommonUserWidget::NativeOnMouseWheel(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent)
{
	return bConsumePointerInput ? FReply::Handled() : Super::NativeOnMouseWheel(InGeometry, InMouseEvent);
}

FReply UCommonUserWidget::NativeOnMouseButtonDoubleClick(const FGeometry& InGeometry, const FPointerEvent& InMouseEvent)
{
	return bConsumePointerInput ? FReply::Handled() : Super::NativeOnMouseButtonDoubleClick(InGeometry, InMouseEvent);
}

FReply UCommonUserWidget::NativeOnTouchGesture(const FGeometry& InGeometry, const FPointerEvent& InGestureEvent)
{
	return bConsumePointerInput ? FReply::Handled() : Super::NativeOnTouchGesture(InGeometry, InGestureEvent);
}

FReply UCommonUserWidget::NativeOnTouchStarted(const FGeometry& InGeometry, const FPointerEvent& InGestureEvent)
{
	return bConsumePointerInput ? FReply::Handled() : Super::NativeOnTouchStarted(InGeometry, InGestureEvent);
}

FReply UCommonUserWidget::NativeOnTouchMoved(const FGeometry& InGeometry, const FPointerEvent& InGestureEvent)
{
	return bConsumePointerInput ? FReply::Handled() : Super::NativeOnTouchMoved(InGeometry, InGestureEvent);
}

FReply UCommonUserWidget::NativeOnTouchEnded(const FGeometry& InGeometry, const FPointerEvent& InGestureEvent)
{
	return bConsumePointerInput ? FReply::Handled() : Super::NativeOnTouchEnded(InGeometry, InGestureEvent);
}

FUIActionBindingHandle UCommonUserWidget::RegisterUIActionBinding(const FBindUIActionArgs& BindActionArgs)
{
	if (UCommonUIActionRouterBase* ActionRouter = UCommonUIActionRouterBase::Get(*this))
	{
		FBindUIActionArgs FinalBindActionArgs = BindActionArgs;
		if (bDisplayInActionBar && !BindActionArgs.bDisplayInActionBar)
		{
			FinalBindActionArgs.bDisplayInActionBar = true;
		}
		FUIActionBindingHandle BindingHandle = ActionRouter->RegisterUIActionBinding(*this, FinalBindActionArgs);
		ActionBindings.Add(BindingHandle);
		return BindingHandle;
	}

	return FUIActionBindingHandle();
}

void UCommonUserWidget::RemoveActionBinding(FUIActionBindingHandle ActionBinding)
{
	ActionBindings.Remove(ActionBinding);
	if (UCommonUIActionRouterBase* ActionRouter = UCommonUIActionRouterBase::Get(*this))
	{
		ActionRouter->RemoveBinding(ActionBinding);
	}
}

void UCommonUserWidget::AddActionBinding(FUIActionBindingHandle ActionBinding)
{
	ActionBindings.Add(ActionBinding);
	if (UCommonUIActionRouterBase* ActionRouter = UCommonUIActionRouterBase::Get(*this))
	{
		ActionRouter->AddBinding(ActionBinding);
	}
}

void UCommonUserWidget::RegisterScrollRecipient(const UWidget& AnalogScrollRecipient)
{
	if (!ScrollRecipients.Contains(&AnalogScrollRecipient))
	{
		ScrollRecipients.Add(&AnalogScrollRecipient);
		if (GetCachedWidget())
		{
			if (UCommonUIActionRouterBase* ActionRouter = UCommonUIActionRouterBase::Get(*this))
			{
				ActionRouter->RegisterScrollRecipient(AnalogScrollRecipient);
			}
		}
	}
}

void UCommonUserWidget::UnregisterScrollRecipient(const UWidget& AnalogScrollRecipient)
{
	if (ScrollRecipients.Remove(&AnalogScrollRecipient) && GetCachedWidget())
	{
		if (UCommonUIActionRouterBase* ActionRouter = UCommonUIActionRouterBase::Get(*this))
		{
			ActionRouter->UnregisterScrollRecipient(AnalogScrollRecipient);
		}
	}
}

void UCommonUserWidget::RegisterScrollRecipientExternal(const UWidget* AnalogScrollRecipient)
{
	if (AnalogScrollRecipient != nullptr)
	{
		RegisterScrollRecipient(*AnalogScrollRecipient);
	}
}

void UCommonUserWidget::UnregisterScrollRecipientExternal(const UWidget* AnalogScrollRecipient)
{
	if (AnalogScrollRecipient != nullptr)
	{
		UnregisterScrollRecipient(*AnalogScrollRecipient);
	}
}

void UCommonUserWidget::OnWidgetRebuilt()
{
	// Using OnWidgetRebuilt instead of NativeConstruct to ensure we register ourselves with the ActionRouter before the child receives NativeConstruct
	if (!IsDesignTime())
	{
		// Clear out any invalid bindings before we bother trying to register them
		for (int32 BindingIdx = ActionBindings.Num() - 1; BindingIdx >= 0; --BindingIdx)
		{
			if (!ActionBindings[BindingIdx].IsValid())
			{
				ActionBindings.RemoveAt(BindingIdx);
			}
		}

		if (ActionBindings.Num() > 0)
		{
			if (UCommonUIActionRouterBase* ActionRouter = UCommonUIActionRouterBase::Get(*this))
			{
				ActionRouter->NotifyUserWidgetConstructed(*this);
			}
		}
	}

	Super::OnWidgetRebuilt();

	if (UCommonUIActionRouterBase* ActionRouter = UCommonUIActionRouterBase::Get(*this))
	{
		for (const TWeakObjectPtr<const UWidget>& WidgetPtr : GetScrollRecipients())
		{
			if (const UWidget* Widget = WidgetPtr.Get())
			{
				ActionRouter->RegisterScrollRecipient(*Widget);
			}
		}
	}
}

void UCommonUserWidget::NativeDestruct()
{
	if (ActionBindings.Num() > 0)
	{
		if (UCommonUIActionRouterBase* ActionRouter = UCommonUIActionRouterBase::Get(*this))
		{
			ActionRouter->NotifyUserWidgetDestructed(*this);
		}
	}

	Super::NativeDestruct();
}

小结

总体来说，CommonUI的使用不是很理想，相关联的配置内容也比较繁琐，使用的成本较高，支持的也不够全面，大家根据自己的需求来看把。