U++ Slate学习笔记 ------ Editor Standalone Window

创建成功效果如下（我名字为Test）：

插件名叫SimpleWindow,所以生成4个文件夹名为：Test.h、TestCommand.h、TestStyle.h及其cpp，记忆Test.Build.cs

Test类：为插件主类，插件的入口和出口都在此类中

TestCommand类：注册一个OpenPluginWindow的命令

TestStyle类：定义UI样式的类

// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.
 
#include "Test.h"
#include "TestStyle.h"
#include "TestCommands.h"
#include "LevelEditor.h"
#include "Widgets/Docking/SDockTab.h"
#include "Widgets/Layout/SBox.h"
#include "Widgets/Text/STextBlock.h"
#include "Framework/MultiBox/MultiBoxBuilder.h"
 
static const FName TestTabName("Test");
 
#define LOCTEXT_NAMESPACE "FTestModule"
 
void FTestModule::StartupModule()
{
	// This code will execute after your module is loaded into memory; the exact timing is specified in the .uplugin file per-module
	
	FTestStyle::Initialize();//初始化UI样式
	FTestStyle::ReloadTextures();//初始化UI样式
 
	FTestCommands::Register();//注册命令
	
	PluginCommands = MakeShareable(new FUICommandList);//实例化一个命令
 
	PluginCommands->MapAction(//将实例化的命令进行绑定，且绑定到函数FTestModule::PluginButtonClicked
		FTestCommands::Get().OpenPluginWindow,
		FExecuteAction::CreateRaw(this, &FTestModule::PluginButtonClicked),
		FCanExecuteAction());
		
	FLevelEditorModule& LevelEditorModule = FModuleManager::LoadModuleChecked<FLevelEditorModule>("LevelEditor");//获取LevelEditor模块的引用
	
	{
		TSharedPtr<FExtender> MenuExtender = MakeShareable(new FExtender());//创建一个菜单扩展，并把它添加到场景编辑器中
		MenuExtender->AddMenuExtension("WindowLayout", EExtensionHook::After, PluginCommands, FMenuExtensionDelegate::CreateRaw(this, &FTestModule::AddMenuExtension));
 
		LevelEditorModule.GetMenuExtensibilityManager()->AddExtender(MenuExtender);
	}
	
	{
		TSharedPtr<FExtender> ToolbarExtender = MakeShareable(new FExtender);//创建一个菜单扩展，并添加到工具栏
		ToolbarExtender->AddToolBarExtension("Settings", EExtensionHook::After, PluginCommands, FToolBarExtensionDelegate::CreateRaw(this, &FTestModule::AddToolbarExtension));
		
		LevelEditorModule.GetToolBarExtensibilityManager()->AddExtender(ToolbarExtender);
	}
	
	FGlobalTabmanager::Get()->RegisterNomadTabSpawner(TestTabName, FOnSpawnTab::CreateRaw(this, &FTestModule::OnSpawnPluginTab))//注册一个Tab容器
		.SetDisplayName(LOCTEXT("FTestTabTitle", "Test"))
		.SetMenuType(ETabSpawnerMenuType::Hidden);
}
 
void FTestModule::ShutdownModule()
{
	// This function may be called during shutdown to clean up your module.  For modules that support dynamic reloading,
	// we call this function before unloading the module.
	FTestStyle::Shutdown();
 
	FTestCommands::Unregister();
 
	FGlobalTabmanager::Get()->UnregisterNomadTabSpawner(TestTabName);
}
 
TSharedRef<SDockTab> FTestModule::OnSpawnPluginTab(const FSpawnTabArgs& SpawnTabArgs)
{
	FText WidgetText = FText::Format(
		LOCTEXT("WindowWidgetText", "Add code to {0} in {1} to override this window's contents"),
		FText::FromString(TEXT("FTestModule::OnSpawnPluginTab")),
		FText::FromString(TEXT("Test.cpp"))
		);
 
	return SNew(SDockTab)
		.TabRole(ETabRole::NomadTab)
		[
			// Put your tab content here!
			SNew(SBox)
			.HAlign(HAlign_Center)
			.VAlign(VAlign_Center)
			[
				SNew(STextBlock)
				.Text(WidgetText)
			]
		];
}
 
void FTestModule::PluginButtonClicked()
{
	FGlobalTabmanager::Get()->InvokeTab(TestTabName);
}
 
void FTestModule::AddMenuExtension(FMenuBuilder& Builder)
{
	Builder.AddMenuEntry(FTestCommands::Get().OpenPluginWindow);
}
 
void FTestModule::AddToolbarExtension(FToolBarBuilder& Builder)
{
	Builder.AddToolBarButton(FTestCommands::Get().OpenPluginWindow);
}
 
#undef LOCTEXT_NAMESPACE
	
IMPLEMENT_MODULE(FTestModule, Test)

在工具栏点击按钮时，因为以下代码让ToolbarExtension与PluginCommands关联，PluginCommands执行的函数是&FTestModule::PluginButtonClicked，所以当点击按钮后，执行的是该函数

    FTestCommands::Register();//注册命令
	
	PluginCommands = MakeShareable(new FUICommandList);//实例化一个命令
 
	PluginCommands->MapAction(//将实例化的命令进行绑定，且绑定到函数FTestModule::PluginButtonClicked
	FTestCommands::Get().OpenPluginWindow,
	FExecuteAction::CreateRaw(this, &FTestModule::PluginButtonClicked),
	FCanExecuteAction());
 
    FLevelEditorModule& LevelEditorModule = FModuleManager::LoadModuleChecked<FLevelEditorModule>("LevelEditor");//获取LevelEditor模块的引用
 
    TSharedPtr<FExtender> ToolbarExtender = MakeShareable(new FExtender);//创建一个菜单扩展，并添加到工具栏
	ToolbarExtender->AddToolBarExtension("Settings", EExtensionHook::After, PluginCommands, FToolBarExtensionDelegate::CreateRaw(this, &FTestModule::AddToolbarExtension));
		
	LevelEditorModule.GetToolBarExtensibilityManager()->AddExtender(ToolbarExtender);

PluginButtonClicked里调用了FGlobalTabmanager的Invoke函数，因为在StartupModule里，已经注册了Tab了，InvokeTab函数会启动这个Tab，而Tab在注册时已经绑定了&FTestModule::OnSpawnPluginTab这个函数，所以InvokeTab去调用该函数去了

FGlobalTabmanager::Get()->RegisterNomadTabSpawner(TestTabName, FOnSpawnTab::CreateRaw(this, &FTestModule::OnSpawnPluginTab))//注册一个Tab容器
		.SetDisplayName(LOCTEXT("FTestTabTitle", "Test"))
		.SetMenuType(ETabSpawnerMenuType::Hidden);
 
void FTestModule::PluginButtonClicked()
{
	FGlobalTabmanager::Get()->InvokeTab(TestTabName);
}

在OnSpawnPluginTab内部，实现了具体UI

TSharedRef<SDockTab> FTestModule::OnSpawnPluginTab(const FSpawnTabArgs& SpawnTabArgs)
{
	FText WidgetText = FText::Format(
		LOCTEXT("WindowWidgetText", "Add code to {0} in {1} to override this window's contents"),
		FText::FromString(TEXT("FTestModule::OnSpawnPluginTab")),
		FText::FromString(TEXT("Test.cpp"))
		);
 
	return SNew(SDockTab)
		.TabRole(ETabRole::NomadTab)
		[
			// Put your tab content here!
			SNew(SBox)
			.HAlign(HAlign_Center)
			.VAlign(VAlign_Center)
			[
				SNew(STextBlock)
				.Text(WidgetText)
			]
		];
}