UIActivityViewController无法使用Facebook登录

iOS 6引入了UIActivityViewController类和Social Framework,这两个类都可以用于将Twitter、Facebook和新浪微博功能集成到iOS 6应用程序中。对于通用需求,UIActivityViewController和SLComposeViewController类提供了一个易于实现的社交网络集成路径。

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

self-presentViewController:activityController动画:YES完成:nil];

为了使用SLComposeViewController类,应该按顺序执行许多步骤。首先,应用程序可以可选地进行检查以验证消息是否可以发送到指定的社交网络服务。这基本上等同于检查是否已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:

1. SL服务类型Facebook
2. SL服务类型推特
3. SL服务类型新浪微博

这就是如何启动ActivityIndicatorView和Loading标签

  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