USaveGame

存档，读档。

惯例，先上文档链接

USaveGame - 5.3

保存和加载游戏 - 5.3

USaveGame是UObject的派生类，当我们需要缓存一个UObject对象时，使对象类型派生自USaveGame

头文件

Copy1#include "GameFramework/SaveGame.h"

创建UObject对象和USaveGame对象的区别

• 创建UObject对象
  

  Copy1// UTestObject派生自UObject
  2UTestObject *Obj = NewObject<UTestObject>();

• 创建USaveGame对象
  

  Copy1#include "Kismet/GameplayStatics.h"
  2
  3// UTestSaveGame派生自USaveGame
  4UTestSaveGame *SaveGame = Cast<UTestSaveGame>(UGameplayStatics::CreateSaveGameObject(UTestSaveGame::StaticClass());

异步缓存

SaveSlotName和UnserIndex是USaveGame逻辑相关的，作为派生类的数据成员，在执行存/读档操作时使用

其中，UserIndex我只用了0，SaveSlotName用以缓存的标识，以及缓存文件的名称

Copy 1UCLASS()
 2class [PROJECTNAME]_API UMySaveGame : public USaveGame
 3{
 4    GENERATED_BODY()
 5
 6public:
 7    UPROPERTY(VisibleAnywhere, Category = Basic)
 8    FString SaveSlotName;
 9
10    UPROPERTY(VisibleAnywhere, Category = Basic)
11    uint32 UserIndex;
12
13    //...
14};

异步操作即订阅委托，在缓存结束后收到通知

• 纯C++委托
  

• 回调函数声明
  
  通过SlotName和UserIndex确定缓存为何
  

  Copy1void CallFunc(const FString &SlotName, const int32 UserIndex, bool bSuccess);

• 注意到，绑定回调函数时，回调函数作为指针类型的成员函数
  

• 同样，回调函数的执行不在主进程
  

Copy1UMySaveGame* SaveGameObj = Cast<UMySaveGame>(UGameplayStatics::CreateSaveGameObject(UMySaveGame::StaticClass())));
2if (SaveGameObj)
3{
4    FAsyncSaveGameToSlotDelegate SavedDelegate;
5    // USomeUObjectClass *SomeUObjectPointer;
6    SavedDelegate.BindUObject(SomeUObjectPointer, &USomeUObjectClass::SaveGameDelegateFunction);
7    UGameplayStatics::AsyncSaveGameToSlot(SaveGameObj, SaveSlotName, UserIndex, SavedDelegate);
8}

确实有对应的缓存文件

[项目路径]/Saved/SaveGame/[SaveSlotName].sav

异步加载

同样，订阅委托，在加载结束后收到通知

• 回调函数声明
  

  Copy1void CallFunc(const FString &SlotName, const int32 UserIndex, USaveGame *LoadedGameData);

• 此时，回调函数的第三个参数为USaveGame派生类对象，所需参数自行取出
  

Copy1FAsyncLoadGameFromSlotDelegate LoadedDelegate;
2LoadedDelegate.BindUObject(SomeUObjectPointer, &USomeUObjectClass::LoadGameDelegateFunction);
3UGameplayStatics::AsyncLoadGameFromSlot(SlotName, UserIndex, LoadedDelegate);

注意

USaveGame只缓存使用UPROPERTY宏标记了的数据成员