如何跨设备共享已保存的游戏?

我在iOS游戏中实现了GameKit,包括保存的游戏功能。

下面是我如何保存和加载游戏的示例:

mobscvsavedgamedata.h

#ifndef MOBSVC_SAVEDGAMEDATA_H
#define MOBSVC_SAVEDGAMEDATA_H

#import <Foundation/Foundation.h>

@interface MobSvcSavedGameData : NSObject <NSCoding>

@property (readwrite, retain) NSString *data;

+(instancetype)sharedGameData;
-(void)reset;

@end


#endif /* MOBSVC_SAVEDGAMEDATA_H */

#import "MobSvcSavedGameData.h"
#import <Foundation/Foundation.h>

@interface MobSvcSavedGameData () <NSObject, NSCoding>

@end

@implementation MobSvcSavedGameData

#pragma mark MobSvcSavedGameData implementation

static NSString * const sgDataKey = @"data";

+ (instancetype)sharedGameData {
    static id sharedInstance = nil;

    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedInstance = [[self alloc] init];
    });

    return sharedInstance;
}

- (void)reset
{
    self.data = nil;
}

- (void)encodeWithCoder:(NSCoder *)encoder
{
    [encoder encodeObject:self.data forKey: sgDataKey];
}

- (nullable instancetype)initWithCoder:(nonnull NSCoder *)decoder {
    self = [self init];
    if (self) {
        self.data = [decoder decodeObjectForKey:sgDataKey];
    }
    return self;
}

@end

为了简单起见,我上面保存的游戏对象只有一个 NSString 它将被连载和上传如下:

void MobSvc::uploadSavedGameDataAwait(const char *name, const char *data)
{
    GKLocalPlayer *mobSvcAccount = [GKLocalPlayer localPlayer];

    if(mobSvcAccount.isAuthenticated)
    {
        MobSvcSavedGameData *savedGameData = [[MobSvcSavedGameData alloc] init];
        savedGameData.data = [NSString stringWithUTF8String:data];
        [mobSvcAccount saveGameData:[NSKeyedArchiver archivedDataWithRootObject:savedGameData] withName:[[NSString alloc] initWithUTF8String:name] completionHandler:^(GKSavedGame * _Nullable savedGame __unused, NSError * _Nullable error) {
            if(error == nil)
            {
                NSLog(@"Successfully uploaded saved game data");
            }
            else
            {
                NSLog(@"Failed to upload saved game data: %@", error.description);
            }
        }];
    }
}

这就是我如何在下一次游戏会话中再次下载最新保存的游戏:

void MobSvc::downloadSavedGameDataAwait(const char *name)
{
    GKLocalPlayer *mobSvcAccount = [GKLocalPlayer localPlayer];

    if(mobSvcAccount.isAuthenticated)
    {
        [mobSvcAccount fetchSavedGamesWithCompletionHandler:^(NSArray<GKSavedGame *> * _Nullable savedGames, NSError * _Nullable error) {
            if(error == nil)
            {
                GKSavedGame *savedGameToLoad = nil;
                for(GKSavedGame *savedGame in savedGames) {
                    const char *sname = savedGame.name.UTF8String;
                    if(std::strcmp(sname, name) == 0)
                    {
                        if (savedGameToLoad == nil || savedGameToLoad.modificationDate < savedGame.modificationDate) {
                            savedGameToLoad = savedGame;
                        }
                    }
                }
                if(savedGameToLoad != nil) {
                    [savedGameToLoad loadDataWithCompletionHandler:^(NSData * _Nullable data, NSError * _Nullable error) {
                        if(error == nil)
                        {
                            MobSvcSavedGameData *savedGameData = [NSKeyedUnarchiver unarchiveObjectWithData:data];
                            NSLog(@"Successfully downloaded saved game data: %@", [savedGameData.data cStringUsingEncoding:NSUTF8StringEncoding]);
                        }
                        else
                        {
                            NSLog(@"Failed to download saved game data: %@", error.description);
                        }
                    }];
                }
            }
            else
            {
                NSLog(@"Failed to prepare saved game data: %@", error.description);
            }
        }];
    }
}

我通过上传一个随机字符串并在下一个会话中使用相同的 name playerId 在 GKLocalPlayer 实例。