(商店版引擎的实用方案，源码版的去改源码实现更快)

1.准备工作：

• UE4C++项目中创建新的C++异步任务类继承自：BlueprintAsyncActionBase

2.添加模块并编写代码：

• 项目Build.cs中添加模块：HTTP，ImageWrapper，RHI(未使用可不添加)

.h头文件中：

#pragma once

#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "Interfaces/IHttpRequest.h"
#include "Kismet/BlueprintAsyncActionBase.h"
#include "Modules/ModuleManager.h"
#include "Engine/Texture2D.h"
#include "Engine/Texture2DDynamic.h"
#include "IImageWrapper.h"
#include "IImageWrapperModule.h"
#include "RuntimeOnlineHTTPPublicInterfacesIHttpResponse.h"
#include "RuntimeOnlineHTTPPublicHttpModule.h"
#include "RuntimeEngineClassesKismetKismetStringLibrary.h"
#include 
#include 
#include "BAATask.generated.h"

class UTexture2DDynamic;//useless

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FDownloadImageDelegateMY, UTexture2D*, Texture);

UCLASS()
class CQSHUILINEW_API UBAATask : public UBlueprintAsyncActionBase
{
	GENERATED_BODY()
public:
	UBAATask(const FObjectInitializer& ObjectInitializer);

	UFUNCTION(BlueprintCallable, meta = (BlueprintInternalUseOnly = "true"))
		static UBAATask* DownloadImage(FString URL,FString Token);

public:
	UPROPERTY(BlueprintAssignable)
		FDownloadImageDelegateMY Success;
	UPROPERTY(BlueprintAssignable)
		FDownloadImageDelegateMY Fail;
public:

	FString IMGurl="";

	void Start(FString URL,FString Token);

	UTexture2D* GetTexture(TSharedPtr ImageWrapper, FHttpResponsePtr HttpResponse);
	
	void HandleImageRequest(FHttpRequestPtr HttpRequest, FHttpResponsePtr HttpResponse, bool bSucceeded);
};

• .cpp中：

  #include "BAATask.h"
  #include 
  #include 
  #include 
  #include 
  
  using namespace std;
  
  UBAATask::UBAATask(const FObjectInitializer& ObjectInitializer)
  	: Super(ObjectInitializer)
  {
  	if (HasAnyFlags(RF_ClassDefaultObject) == false)
  	{
  		AddToRoot();
  	}
  }
  
  UBAATask* UBAATask::DownloadImage(FString URL,FString Token)
  {
  	UBAATask* DownloadTask = NewObject();
  	DownloadTask->Start(URL,Token);
  	return DownloadTask;
  }
  
  void UBAATask::Start(FString URL,FString Token)
  {
  #if !UE_SERVER
  	TSharedRef HttpRequest = FHttpModule::Get().CreateRequest();
  
  	HttpRequest->OnProcessRequestComplete().BindUObject(this, &UBAATask::HandleImageRequest);
  	FString Lurl="";
  	FString Rurl="";
  	FString Unuse="";//useless value
  	UKismetStringLibrary::Split(URL, "/", Lurl, Rurl, ESearchCase::IgnoreCase, ESearchDir::FromEnd);
  	UKismetStringLibrary::Split(Rurl, "/", Unuse, Rurl, ESearchCase::IgnoreCase, ESearchDir::FromEnd);
  
  	//URL encode For Chinese(UTF-8)
  	ostringstream escaped;
  	escaped.fill('0');
  	escaped << hex;
  	string vaule= TCHAR_TO_UTF8(*Rurl);
  	for (string::const_iterator i = vaule.begin(), n = vaule.end(); i != n; ++i) {
  		string::value_type c = (*i);
  		if (isalnum(c) || c == '-' || c == '_' || c == '.' || c == '~') {
  			escaped << c;
  			continue;
  		}
  		escaped << uppercase;
  		escaped << '%' << setw(2) << int((unsigned char)c);
  		escaped << nouppercase;
  	}
  
  	HttpRequest->SetURL(Lurl + "/" + FString(escaped.str().c_str()));//urlencode2fstring
  	IMGurl =URL;//For bool if jpg or png
  	HttpRequest->SetVerb(TEXT("GET"));
  	HttpRequest->SetHeader(TEXT("X-Access-Token"), Token);//in Token
  	HttpRequest->ProcessRequest();
  #else
  	RemoveFromRoot();
  #endif
  }
  
  void UBAATask::HandleImageRequest(FHttpRequestPtr HttpRequest, FHttpResponsePtr HttpResponse, bool bSucceeded)
  {
  	UTexture2D* Texture = nullptr;//create Texture2D
  	
  	IImageWrapperModule& module = FModuleManager::LoadModuleChecked(FName("ImageWrapper"));
  	if(UKismetStringLibrary::Contains(*IMGurl,TEXT(".jpg"),ESearchCase::IgnoreCase,ESearchDir::FromStart)|| UKismetStringLibrary::Contains(*IMGurl, TEXT(".jpeg"), ESearchCase::IgnoreCase, ESearchDir::FromStart))
  	{
  		TSharedPtr ImageWrapper = module.CreateImageWrapper(EImageFormat::JPEG);
  		Texture = GetTexture(ImageWrapper,HttpResponse);
  		Success.Broadcast(Texture);//success return texture2d
  		return;
  	}else if(UKismetStringLibrary::Contains(*IMGurl, TEXT(".png"), ESearchCase::IgnoreCase, ESearchDir::FromStart))
  	{
  		TSharedPtr ImageWrapper = module.CreateImageWrapper(EImageFormat::PNG);
  		Texture = GetTexture(ImageWrapper, HttpResponse);
  		Success.Broadcast(Texture);//success return texture2d
  		return;
  	}
  	Fail.Broadcast(nullptr);//fail nullptr
  }
  
  UTexture2D* UBAATask::GetTexture(TSharedPtr ImageWrapper, FHttpResponsePtr HttpResponse)
  {
  	if (ImageWrapper->SetCompressed(HttpResponse->GetContent().GetData(), HttpResponse->GetContentLength()))
  	{
  		TArray UncompressedRGBA;
  		if (ImageWrapper->GetRaw(ERGBFormat::RGBA, 8, UncompressedRGBA))
  		{
  			UTexture2D* Texture = UTexture2D::CreateTransient(ImageWrapper->GetWidth(), ImageWrapper->GetHeight(), PF_R8G8B8A8);
  			if (Texture != nullptr)
  			{
  				//int OutWidth = ImageWrapper->GetWidth();//w&h
  				//int OutHeight = ImageWrapper->GetHeight();
  				void* TextureData = Texture->PlatformData->Mips[0].BulkData.Lock(LOCK_READ_WRITE);
  				FMemory::Memcpy(TextureData, UncompressedRGBA.GetData(), UncompressedRGBA.Num());
  				Texture->PlatformData->Mips[0].BulkData.Unlock();
  				Texture->UpdateResource();
  				return Texture;
  			}
  		}
  	}
  	return nullptr;
  }

  3.编译后蓝图传入地址与Token处理成功设置笔刷：

   

  ---

   后言：考虑到验证访问地址图片时URL中带有中文时需要urlencode进行转码后转回Fstring才能正常访问地址，把图片处理单独写成一个函数便于处理不同格式的图片；
• 希望这篇文章能帮到你！