Iphone UIActivityViewController不使用Facebook登录

我正在Facebook股票期权的新应用程序中使用UIActivityViewController

但是如果用户没有登录到该设备，它将无法工作。。选择设置时，登录页面不显示

IActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:nil];
activityVC.excludedActivityTypes = @[UIActivityTypeAssignToContact, UIActivityTypePrint];
[self presentViewController:activityVC animated:TRUE completion:nil];

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这件事我能做什么。。？这是我的代码的问题还是一个常见错误？

这就是如何启动带有加载标签的ActivityIndicatorView

  UIActivityIndicatorView *tempSpinner = [[UIActivityIndicatorView alloc]     initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];


 lable =[[UILabel alloc]init];
 lable.center = self.view.center;
 lable.text = @"Loading...";

 lable.hidden=NO;

 lable.backgroundColor = [UIColor clearColor];

 lable.textColor = [UIColor blackColor];

 [lable sizeToFit];
 lable.center = CGPointMake(160, 255);

 tempSpinner.center = self.view.center;  


 [self.view addSubview:tempSpinner];

[self.view addSubview:lable];           
start where ever you want like this 
 [tempSpinner startAnimating]; 
stop it like this where ever you want
[tempSpinner stopAnimating]; 
hide unhide loading label as per requirement 

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iOS 6引入了UIActivityViewController类和社交框架，这两个类都可用于将Twitter、Facebook和新浪微博功能集成到iOS 6应用程序中。对于一般用途的需求，UIActivityViewController和SLComposeViewController类提供了一种易于实现的社交网络集成路径

UIActivityViewController *activityController =[[UIActivityViewController alloc]initWithActivityItems:activityItems applicationActivities:nil];

self-presentViewController:activityController已设置动画：是完成：无]

要使用SLComposeViewController类，应按顺序执行许多步骤。首先，应用程序可以选择性地检查以验证消息是否可以发送到指定的社交网络服务。这本质上等同于检查是否在设备上配置了有效的社交网络帐户，并使用isAvailableForServiceType:class方法实现，将以下选项中所需的服务类型作为参数传递：

SLServiceTypeFacebook

SLServiceTypeTwitter

SLServiceTypeSinaWeibo

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UIActivityViewController

与

UIActivityIndicatorView