ios – 如何使我的单例类可扩展？

static UseRMANager *_sharedInstance = nil;

+ (id)sharedInstance {
    @synchronized([UseRMANager class]) {
        if(!_sharedInstancE){
            id temp = [[self alloc] init];
            [temp class];
        }
        return _sharedInstance;
    }
    return nil;
}

+ (id)alloc {
    @synchronized([UseRMANager class]) {
        NSAssert(_sharedInstance == nil,@"Attempted to allocate a second instance of a singleton");
        _sharedInstance = [super alloc];
        return _sharedInstance;
    }
    return nil;
}

Beter设计将使用COR_864_11845@position然后继承.声明协议AuthenticationDelegate

@protocol AuthenticationDelegate
@optional
-(void) authenticateUser:(User*)inUser;
@end

在UseRMANager中有一个属性,默认情况下指向UseRMANager.

@class UseRMANager : NSObject <AuthenticationDelegate> {
    ......
} 

@property (assign) id<AuthenticationDelegate>  authenticator

+ (id)sharedInstance;

如果您的客户希望通过他们的方法进行身份验证,那么他们必须向AuthenticationDelegate协议确认并实现其方法.他们必须将authenticator属性设置为其所限定的类.然而它的单身人士.因此,只要对象被实例化,他们就可以设置它.因此他们可以使用他们的身份验证器

但要确保验证者剂量指向零.您可以实现setAuthenticator：方法,以便当客户端将此设置为nil时,authenticator将指向UseRMANager.

static UseRMANager *_sharedInstance = nil;

@implementation UseRMANager

@synthasize authenticator;

+ (id)sharedInstance {
    @synchronized([UseRMANager class]) {
        if(!_sharedInstancE){
            id temp = [[self alloc] init];
            [temp class];
        }
        return _sharedInstance;
    }
    return nil;
}

+ (id)alloc {
    @synchronized([UseRMANager class]) {
        NSAssert(_sharedInstance == nil,@"Attempted to allocate a second instance of a     singleton");
        _sharedInstance = [super alloc];
        return _sharedInstance;
    }
    return nil;
}

-(void)init {
    self = [super init];
    if (self) {
        self.authenticator = nil;
    }
}

-(void)setAuthenticator:(id<AuthenticationDelegate>)inAuthenticator {
    if (!inAuthenticator) {
        __authenticator = self;
    } else {
        __authenticator = inAuthenticator;
    }
}

#pragma mark - AuthenticationDelegate

-(void) authenticateUser:(User*)inUser
{
    // Your Authentication Code.
}

希望这可以帮助…