Objective c 在异步请求完成之前返回self

嘿，到目前为止我有这个代码

- (id)initWithDictionary:(NSDictionary *)aDictionary {
    self = [super init];
    if (!self) {
        return nil;
    }

    _userAvatar = [self getUserAvatar:[aDictionary objectForKey:@"user_avatar"]];
    _userId = [aDictionary objectForKey:@"user_id"];
    _username = [aDictionary objectForKey:@"username"];
    _userEmail = [aDictionary objectForKey:@"user_email"];
    return self;
}


- (UIImage *)getUserAvatar:(NSString *)avatarPath {

    __block UIImage *avatarImage = [[UIImage alloc]init];
    if ([avatarPath length] != 0) {
        [[AFFnBAPIClient sharedClient] setDefaultHeader:@"Accept" value:@"image/png"];
        [[AFFnBAPIClient sharedClient] getPath:FNB_DOWNLOAD_PATH parameters:[NSDictionary dictionaryWithObject:avatarPath forKey:@"avatar"] success:^(AFHTTPRequestOperation *operation, id image) {
            avatarImage = image;
        } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
            NSLog(@"Error");
        }];
    } else {
        UIImage *placeholderImage = [UIImage imageNamed:@"placeholder.png"];
        avatarImage = placeholderImage;
    }
    return avatarImage;
}

我的问题是在异步请求完成之前调用return self，如何在没有同步请求的情况下在请求完成的情况下返回self

- (id)initWithDictionary:(NSDictionary *)aDictionary {
    self = [super init];
    if (self) {

        // for starters, it's a placeholder
        self.userAvatar = [UIImage imageNamed:@"placeholder.png"];

        // now go get the avatar, fill it in whenever the get finishes.
        // notice there's no return value.
        [self getUserAvatar:[aDictionary objectForKey:@"user_avatar"]];

        // make sure these are retained (or strong in ARC) properties.
        // your code looked like it was releasing these
        self.userId = [aDictionary objectForKey:@"user_id"];
        self.username = [aDictionary objectForKey:@"username"];
        self.userEmail = [aDictionary objectForKey:@"user_email"];
    }
    return self;
}

// see - no return value.  it's asynch
- (void)getUserAvatar:(NSString *)avatarPath {

    // don't need a __block var here
    if ([avatarPath length] != 0) {
        [[AFFnBAPIClient sharedClient] setDefaultHeader:@"Accept" value:@"image/png"];
        [[AFFnBAPIClient sharedClient] getPath:FNB_DOWNLOAD_PATH parameters:[NSDictionary dictionaryWithObject:avatarPath forKey:@"avatar"] success:^(AFHTTPRequestOperation *operation, id image) {

            // self got a retain+1 while this was running.
            self.userAvatar = image;

        } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
            NSLog(@"Error");
        }];
    }
}

---

如果您不希望它在请求完成之前返回，这不是同步请求的定义吗？您的问题似乎是“如何在不阻塞的情况下进行阻塞？”或者您的意思是“如何将make AFFnBAPIClient转换为同步请求？”因此，我猜在这种情况下，如果没有同步请求，就不可能返回self？主要问题是我调用的是

User*User=[[User alloc]initWithDictionary:forUser]；[userDic setObject:user forKey:@“user”]

因此userDic在用户对象获得必须发生的AvataRimage之前已经拥有该用户对象。阿凡达将在之后某个时候出现。我提供的代码将在图像到达时更新userAvatar。也许你在更新用户界面时遇到了问题？现在，在块self.userAvatar=image中的行上放置一个断点；检查您是否拥有良好的自我和良好的图像。图像已设置，但在我将userDic传递给另一个控制器后，因此我无法通过

[[userDic objectForKey@“user”]userAvatar]

访问真实图像，因为它已设置为占位符图像，我想这有点复杂；）。上面的整个代码都在一个类User.m中，它用我上面注释中的代码初始化，并传递给它的委托方法

[self.delegate loadUserData:userDic]@daiikota，对不起，没有代码很难理解。也许你可以勾选这个答案，然后用相关代码打开一个新问题？这里的方法将初始化该对象，为userAvatar设置占位符并返回它。稍后，它会将化身设置为获取的图像（覆盖占位符）。无论该对象去哪里，在其他词典中，或者在任何地方，它都应该有一个占位符或者在它到达后获取的图像。您的UI可能需要意识到映像已更改并自行更新，但这是一个不同的问题/问题。它最终需要向新控制器添加一个观察者并观察映像：）