UE4官网针对热更新有较为详细的步骤，但是其中漏掉的几个问题导致实现不了效果。

总的来说可以分为四大步。

第一步：自己的项目设置好插件ChunkDownloader

1.新建第三人称c 项目工程，设置分块打包

2.勾选插件ChunkDownloader

3.修改项目的 Build.cs 文件

PrivateDependencyModuleNames.AddRange(

new string[] { "ChunkDownloader" }

4.保存后重新生成项目文件。操作：右键点击你的 .uproject 文件，然后点击 生成项目文件（Generate Project Files）。

第二步：资源分块，然后打包。为了测试方便，新建三个map，分别放在不同的文件夹。我的是Test，Test2，Test3.

1. 添加资源分块标签。

标签设置如图：红框内需必备

属性解释：

依次对自己的测试资源添加标签。

2.打包默认设置即可。这样你可以在打出的包里看到分好的pak文件。红框ID与你的标签ID对应。

第三步：构建资源清单与托管本地测试服务器

1.构建资源清单。这里注意，英文字符下 TAB建进行属性空格。

我的清单如下：

资源文件夹结构，其中Windows文件夹中放的是分块后的pak文件

稍作解释：

第1行是需要下载更新的pak数目

第2行理解为资源和清单所在的文件夹

后面的几行就是pak资源相关的。共5个属性。资源名字，资源大小（右键资源看其属性字节数），版本号，ChunkID，资源所在位置。

2.文件托管到本地测试服务器

如何创建本地测试服务器这里不啰嗦，可以参考ue4官网。

但是这里要注意：新建文件夹PatchingDemoCDN，除了上传我们前面准备好的资源和清单即PatchingDemoKey文件夹。我们还需要在PatchingDemoCDN文件夹中新建表单

这个表单中我们要写上$BUILD_ID对应的也就是资源和清单所在的文件夹PatchingDemoKey

最后我们还需要在项目的配置表DefaultGame.ini中添加用来下载资源的网站地址。这里我们是用本地服务器测试的。

[/Script/Plugins.ChunkDownloader PatchingDemoLive]

CdnBaseUrls=127.0.0.1/PatchingDemoCDN

第三步：编辑代码和逻辑。（开始不必扩展，实现基本功能即可）

1.GameInstance不仅具有可以绑定的相应初始化和关闭函数，而且还可以在游戏运行时持续访问ChunkDownloader。

所以使用 GameInstance 作为基类创建 新C 类。将其命名为 PatchingDemoGameInstance。

最后代码为：

.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"

#include "Engine/GameInstance.h"

#include "PatchingDemoGameInstance.generated.h"

/**

*

*/

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FPatchCompleteDelegate, bool, Succeeded);

UCLASS()

class UPatchingDemoGameInstance : public UGameInstance

{

GENERATED_BODY()

public:

/** Overrides */

virtual void Init() override;

virtual void Shutdown() override;

/** Delegates */

/** Fired when the patching process succeeds or fails */

UPROPERTY(BlueprintAssignable, Category = "Patching")

FPatchCompleteDelegate OnPatchComplete;

/** Starts the game patching process. Returns false if the patching manifest is not up to date. */

UFUNCTION(BlueprintCallable, Category = "Patching")

bool PatchGame();

UFUNCTION(BlueprintPure, Category = "Patching|Stats")

void GetLoadingProgress(int32& FilesDownloaded, int32& TotalFilesToDownload, float& DownloadPercent, int32& ChunksMounted, int32& TotalChunksToMount, float& MountPercent) const;

protected:

//Tracks Whether or not our local manifest file is up to date with the one hosted on our website

bool bIsDownloadManifestUpToDate;

void OnManifestUpdateComplete(bool bSuccess);

/** List of Chunk IDs to try and download */

UPROPERTY(EditDefaultsOnly, Category = "Patching")

TArray<int32> ChunkDownloadList;

/** Called when the chunk download process finishes */

void OnDownloadComplete(bool bSuccess);

/** Called whenever ChunkDownloader's loading mode is finished*/

void OnLoadingModeComplete(bool bSuccess);

/** Called when ChunkDownloader finishes mounting chunks */

void OnMountComplete(bool bSuccess);

};

.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "PatchingDemoGameInstance.h"

#include "ChunkDownloader.h"

#include "Misc/CoreDelegates.h"

#include "AssetRegistryModule.h"

void UPatchingDemoGameInstance::Init()

{

Super::Init();

const FString DeploymentName = "PatchingDemoLive";

const FString ContentBuildId = "PatchingDemoKey";

// initialize the chunk downloader

TSharedRef<FChunkDownloader> Downloader = FChunkDownloader::GetOrCreate();

// TODO 安卓下载方式

// Downloader->Initialize("Android", 8);

Downloader->Initialize("Windows", 8);

// load the cached build ID

Downloader->LoadCachedBuild(DeploymentName);

// update the build manifest file

TFunction<void(bool bSuccess)> UpdateCompleteCallback = [&](bool bSuccess){bIsDownloadManifestUpToDate = true;};

Downloader->UpdateBuild(DeploymentName, ContentBuildId, UpdateCompleteCallback);

}

void UPatchingDemoGameInstance::Shutdown()

{

Super::Shutdown();

// Shut down ChunkDownloader

FChunkDownloader::Shutdown();

}

void UPatchingDemoGameInstance::OnManifestUpdateComplete(bool bSuccess)

{

bIsDownloadManifestUpToDate = bSuccess;

}

void UPatchingDemoGameInstance::GetLoadingProgress(int32& BytesDownloaded, int32& TotalBytesToDownload, float& DownloadPercent, int32& ChunksMounted, int32& TotalChunksToMount, float& MountPercent) const

{

//Get a reference to ChunkDownloader

TSharedRef<FChunkDownloader> Downloader = FChunkDownloader::GetChecked();

//Get the loading stats struct

FChunkDownloader::FStats LoadingStats = Downloader->GetLoadingStats();

//Get the bytes downloaded and bytes to download

BytesDownloaded = LoadingStats.BytesDownloaded;

TotalBytesToDownload = LoadingStats.TotalBytesToDownload;

//Get the number of chunks mounted and chunks to download

ChunksMounted = LoadingStats.ChunksMounted;

TotalChunksToMount = LoadingStats.TotalChunksToMount;

//Calculate the download and mount percent using the above stats

DownloadPercent = ((float)BytesDownloaded / (float)TotalBytesToDownload)*100.0f;

MountPercent = ((float)ChunksMounted / (float)TotalChunksToMount)*100.0f;

}

void UPatchingDemoGameInstance::OnLoadingModeComplete(bool bSuccess)

{

OnDownloadComplete(bSuccess);

}

void UPatchingDemoGameInstance::OnMountComplete(bool bSuccess)

{

OnPatchComplete.Broadcast(bSuccess);

}

bool UPatchingDemoGameInstance::PatchGame()

{

// make sure the download manifest is up to date

if (bIsDownloadManifestUpToDate)

{

// get the chunk downloader

TSharedRef<FChunkDownloader> Downloader = FChunkDownloader::GetChecked();

// report current chunk status

for (int32 ChunkID : ChunkDownloadList)

{

int32 ChunkStatus = static_cast<int32>(Downloader->GetChunkStatus(ChunkID));

UE_LOG(LogTemp, Display, TEXT("Chunk %i status: %i"), ChunkID, ChunkStatus);

}

TFunction<void(bool bSuccess)> DownloadCompleteCallback = [&](bool bSuccess) {OnDownloadComplete(bSuccess); };

Downloader->DownloadChunks(ChunkDownloadList, DownloadCompleteCallback, 1);

// start loading mode

TFunction<void(bool bSuccess)> LoadingModeCompleteCallback = [&](bool bSuccess) {OnLoadingModeComplete(bSuccess); };

Downloader->BeginLoadingMode(LoadingModeCompleteCallback);

return true;

}

// we couldn't contact the server to validate our manifest, so we can't patch

UE_LOG(LogTemp, Display, TEXT("Manifest Update Failed. Can't patch the game"));

return false;

}

void UPatchingDemoGameInstance::OnDownloadComplete(bool bSuccess)

{

if (bSuccess)

{

UE_LOG(LogTemp, Display, TEXT("Download complete"));

// get the chunk downloader

TSharedRef<FChunkDownloader> Downloader = FChunkDownloader::GetChecked();

FJsonSerializableArrayInt DownloadedChunks;

for (int32 ChunkID : ChunkDownloadList)

{

DownloadedChunks.Add(ChunkID);

}

//Mount the chunks

TFunction<void(bool bSuccess)> MountCompleteCallback = [&](bool bSuccess) {OnMountComplete(bSuccess); };

Downloader->MountChunks(DownloadedChunks, MountCompleteCallback);

OnPatchComplete.Broadcast(true);

}

else

{

UE_LOG(LogTemp, Display, TEXT("Load process failed"));

// call the delegate

OnPatchComplete.Broadcast(false);

}

}

2.使用 PatchingDemoGameInstance 作为基类创建 新蓝图，命名为 CDGameInstance

3.打开CDGameInstance，添加chunk列表

4.创建名为 PatchingGameMode 的新游戏模式 蓝图

5.项目做如下设置。

6.第三人称游戏map设置gamemode为PatchingGameMode

7.打开PatchingGameMode，添加如下蓝图逻辑。

beginPlay后添加：patchGame返回值为true则进入tick即开始下载资源。否则根据资源数进行进一步检测。

tick后添加：大概意思就是资源下载并且装载完打开Test3地图。

到此代码，逻辑都写好了。

第四步：打包测试

1.直接打包。

结果是包文件夹里的Content中的paks文件夹有四个pak文件。删掉ID为1001-1003的pak。

2.运行.exe

结果如下：

下载中

下载完成，3秒后进入Test3地图。

下载的文件：

,