ios - 如何在这种情况下管理 block

Question

我正在为 Instagram API 实现辅助类。

我有一个获取访问码的方法:

-(void) makeAuthenticateRequestWithBlock: (completionBlock) block {
  if (![self.viewController.view.subviews containsObject: self.webView]) {
    [self.viewController.view addSubview: self.webView];
  }
  if (!self.isUserAuthinticated && self.isAvailableAllRequredData) {
    NSString * fullURL = [NSString stringWithFormat: @ "%@?client_id=%@&redirect_uri=%@&response_type=token&scope=likes+comments+basic+public_content+follower_list", KAUTHURL, self.clientId, self.redirectURL];
    NSURL * url = [NSURL URLWithString: fullURL];
    NSURLRequest * request = [NSURLRequest requestWithURL: url];
    [self.webView loadRequest: request];
    self.block = block;
  }
} 

typedef void(^completionBlock) (BOOL success); 是一个 block ，我有:

@property (copy, nonatomic) completionBlock block ；

在 webview 委托(delegate)方法中。

-(BOOL) webView: (UIWebView * ) webView shouldStartLoadWithRequest: (NSURLRequest * ) request navigationType: (UIWebViewNavigationType) navigationType {
  NSString * urlString = [
    [request URL] absoluteString
  ];
  NSLog(@ "URL STRING : %@ ", urlString);
  NSArray * UrlParts = [urlString componentsSeparatedByString: [NSString stringWithFormat: @ "%@/", self.redirectURL]];
  if ([UrlParts count] > 1) {
    // do any of the following here
    urlString = [UrlParts objectAtIndex: 1];
    NSRange accessToken = [urlString rangeOfString: @ "#access_token="];
    if (accessToken.location != NSNotFound) {
      NSString * strAccessToken = [urlString substringFromIndex: NSMaxRange(accessToken)];
      NSLog(@ "access token = %@ ", strAccessToken);
      [self.webView removeFromSuperview];
      [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
      [
        [NSUserDefaults standardUserDefaults] setValue: strAccessToken forKey: kAccessToken
      ];
      [
        [NSUserDefaults standardUserDefaults] synchronize
      ];
      self.isUserAuthinticated = true;
      self.block(true);
    }
    return NO;
  }
  return YES;
}

一切正常。

现在，当我向 Instagram API 发送请求时，我会检查用户是否已通过身份验证。

-(void) getInformationOfOwnWithCompletionBlock: (dataTaskBlock) block {
  if (self.isUserAuthinticated) {
    NSString * urlString = [NSString stringWithFormat: @ "%@self/?access_token=%@", kUSERURL, [
      [NSUserDefaults standardUserDefaults] valueForKey: kAccessToken
    ]];
    [self makeRequestToServerWithUrl: urlString completionBlock: ^ (NSDictionary * data, NSError * error) {
      if (!error) {
        block(data, error);
      } else {
        block(nil, error);
      }
    }];
  } else {
    [self makeAuthenticateRequestWithBlock: ^ (BOOL success) {
      [self getinformationofOwnFollowsWithCompletionBlock: block];
    }];
    // block(nil,errorMsg);
  }
}

它将发送一个请求并使用返回 block 构建 webview。所有这些都工作正常。但是当我两次调用相同的方法时，我收到以下错误消息:

[self.instagramVC getInformationOfOwnWithCompletionBlock: ^ (NSDictionary * data, NSError * error) {
  NSLog(@ "%@", data);
}];
[self.instagramVC getInformationOfOwnWithCompletionBlock: ^ (NSDictionary * data, NSError * error) {
  NSLog(@ "DATA 2%@", data);
}];    

它返回最后调用的方法的 block ，如输出将是 DATA 2。我知道原因，这是因为 self.block。所以请给我一个建议，这样我就不必为每个请求都使用全局 block 。

Answer 1

正如您所说，您的问题是您对所有请求使用全局 block 。您需要设置一个数据结构来保存有关每个待处理请求的信息。也许是一个可变的字典数组，其中每个字典包含请求和该请求的完成 block 。然后，当请求完成时，将该请求与您的请求数组相匹配，并执行适当的完成 block 。