iOS - 编码/解码枚举 - 重新启动后访问崩溃

Question

我做错了什么？我是否正确编码/解码枚举类型？

GameSettings 界面：

typedef enum {
    CatWhite = 0,
    CatBlack = 1,
    CatOrange = 2
} CatColor;

...
CatColor catColor;
...
@property CatColor catColor;

GameSettings 实现：

@synthesize catColor;

...

+ (GameSettings*)GetInstance
{
    if (sharedSingleton == nil) {
        sharedSingleton = [[super allocWithZone:NULL] init];
        sharedSingleton.catColor = CatWhite;
    }
    return sharedSingleton;
}
    -(void)encodeWithCoder:(NSCoder *)coder {
        [coder encodeInt:self.catColor forKey:@"CatColor"];
    }

    -(id)initWithCoder:(NSCoder *)coder {
        if((self = [super init])) {
            self.catColor = [coder decodeIntForKey:@"CatColor"];
        }
NSLog(@"initWithCoder: %d", self.catColor); //this logs the correct int
        return self;
    }

AppDidFinishLaunching:

    - (void)applicationDidFinishLaunching:(UIApplication *)application {    

        NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
        NSData *data = [defaults objectForKey:@"GameSettings"];
        GameSettings *gGameData = [NSKeyedUnarchiver unarchiveObjectWithData:data];
        if(gGameData != NULL) {
            GameSettings *settings = [GameSettings GetInstance];
            settings.catColor = gGameData.catColor;

        }else {
            GameSettings *settings = [GameSettings GetInstance];
            settings.catColor = CatWhite;
        }
        ...
    }

保存设置：

GameSettings* settings = [GameSettings GetInstance];

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:settings];
[defaults setObject:data forKey:@"GameSettings"];
[defaults synchronize];

当我重新启动应用程序并尝试访问游戏设置时，崩溃（程序收到信号：“EXC_BAD_ACCESS”）出现：

GameSettings* settings = [GameSettings GetInstance];
NSLog(@"settings: %d", settings); //EXC_BAD_ACCESS
NSLog(@"catColor: %d", settings.catColor); //EXC_BAD_ACCESS

为什么重新启动后我无法访问 GameSettings 单例？

Answer 1

您确定要在那里使用 applicationDidFinishLaunching 吗？当您恢复程序时，它可能会调用 awakeFromNib 而不是 applicationDidFinishLaunching （来源：http://www.cimgf.com/2008/03/26/cocoa-tutorial-awakefromnib-vs-applicationdidfinishlaunching/）。

Answer 2

终于明白了这一点。 GameSettings 被释放，因为 NSKeyedUnarchiver 正在自动释放它：

GameSettings *gGameData = [NSKeyedUnarchiver unarchiveObjectWithData:data];

修复：

GameSettings *gGameData = [[NSKeyedUnarchiver unarchiveObjectWithData:data] retain];