iOS应用程序中的Facebook连接

在我的新iOS应用程序中，我必须登录Facebook并获取用户详细信息。我已经阅读了这里的教程，并研究了美味和其他样品。但我无法理解流程

我创建了一个用于Facebook登录的示例项目（代码如下）——但有以下主要问题：

• 当我再次点击登录按钮时，为什么应用程序会要求授权？在我在Facebook上点击一次“OK”之后

下面是我的代码-

@实现AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // See if the app has a valid token for the current state.
    if (FBSession.activeSession.state == FBSessionStateCreatedTokenLoaded)
    {
        // To-do, show logged in view --- LOGGED IN : Already Login
        // Yes, so just open the session (this won't display any UX).
        UIWindow *window = [UIApplication sharedApplication].keyWindow;
        ViewController *rootViewController = (ViewController *)window.rootViewController;
        [rootViewController openSession];        
    }

    return YES;
}

- (BOOL)application:(UIApplication *)application
            openURL:(NSURL *)url
  sourceApplication:(NSString *)sourceApplication
         annotation:(id)annotation
{
    return [FBSession.activeSession handleOpenURL:url];
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    [FBSession.activeSession handleDidBecomeActive];
}


@implementation ViewController

@synthesize lblStatus;

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    lblStatus.text = @"Login Now";
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)login:(id)sender
{
    [self openSession];
}

- (void)sessionStateChanged:(FBSession *)session
                      state:(FBSessionState) state
                      error:(NSError *)error
{
    switch (state) {
        case FBSessionStateOpen:
        {
            // Connection is Open
            lblStatus.text = @"FBSessionStateOpen";
        }
            break;
        case FBSessionStateClosed:
        case FBSessionStateClosedLoginFailed:
        {
            [FBSession.activeSession closeAndClearTokenInformation];

            // Connection is Closed / Login Failed
            lblStatus.text = @"FBSessionStateClosed";
        }
            break;
        default:
            break;
    }
}

- (void)openSession
{
    [FBSession openActiveSessionWithReadPermissions:nil
                                       allowLoginUI:YES
                                  completionHandler:
     ^(FBSession *session,
       FBSessionState state, NSError *error)
     {
         [self sessionStateChanged:session state:state error:error];
     }];
}

答案-->

谢谢nerowolfe的建议

下面是我连接到Facebook的完整解决方案。我的下一个任务是现在获取用户数据

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application
            openURL:(NSURL *)url
  sourceApplication:(NSString *)sourceApplication
         annotation:(id)annotation
{
    return [FBSession.activeSession handleOpenURL:url];
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    [FBSession.activeSession handleDidBecomeActive];
}

--------------------------

@implementation ViewController

@synthesize lblStatus;

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    lblStatus.text = @"Login Now";
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)login:(id)sender
{
    [self openSession];
}

- (void)sessionStateChanged:(FBSession *)session
                      state:(FBSessionState) state
                      error:(NSError *)error
{
    switch (state) {
        case FBSessionStateOpen:
        {
            // Connection is Open
            lblStatus.text = @"FBSessionStateOpen";
        }
            break;
        case FBSessionStateClosed:
        case FBSessionStateClosedLoginFailed:
        {
            [FBSession.activeSession closeAndClearTokenInformation];

            // Connection is Closed / Login Failed
            lblStatus.text = @"FBSessionStateClosed";
        }
            break;
        default:
            break;
    }
}

- (void)openSession
{
    if(FBSession.activeSession.isOpen)
    {
        [FBSession openActiveSessionWithReadPermissions:nil
                                           allowLoginUI:NO
                                      completionHandler:
         ^(FBSession *session,
           FBSessionState state, NSError *error)
         {
             [self sessionStateChanged:session state:state error:error];
         }];
    }
    else
    {
        [FBSession openActiveSessionWithReadPermissions:nil
                                           allowLoginUI:YES         
                                      completionHandler:
         ^(FBSession *session,
           FBSessionState state, NSError *error)
         {
             [self sessionStateChanged:session state:state error:error];
         }];
    }
}

- (IBAction)logout:(id)sender
{
    [FBSession.activeSession closeAndClearTokenInformation];

    if(FBSession.activeSession.isOpen)
        lblStatus.text = @"Open Still";
    else
        lblStatus.text = @"Close";

}

---

只是没有显示登录

 - (void)openSession
{
 if(FBSession.activeSession.isOpen)
 {

       [FBSession openActiveSessionWithReadPermissions:nil
                                   allowLoginUI:NO
                              completionHandler:
                     ^(FBSession *session,
                         FBSessionState state, NSError *error)
       {
        [self sessionStateChanged:session state:state error:error];
       }];
    }

 }

---

只是没有显示登录

 - (void)openSession
{
 if(FBSession.activeSession.isOpen)
 {

       [FBSession openActiveSessionWithReadPermissions:nil
                                   allowLoginUI:NO
                              completionHandler:
                     ^(FBSession *session,
                         FBSessionState state, NSError *error)
       {
        [self sessionStateChanged:session state:state error:error];
       }];
    }

 }

---

是的，这很有帮助。现在，当会话打开时，我不再看到登录屏幕/授权屏幕。另一件事是-如果我想使用其他用户登录-如何注销或终止当前会话-在您发布的代码上有两件事-1。FBSession.activeSession.isOpen：这意味着我们正在检查会话是否处于活动状态，然后只进入内部。我们是否应该检查“会话是否未激活”？2.“allowLoginUI:是”和“allowLoginUI:否”-这有什么影响？当然，正如你所希望的。我只是给你指路。。。顺便说一句，当然，对于使用facebook sdk方法，您需要在FBRequest*postLocRequest=[FBRequest RequestForPlacesArchatCoordination:currentLocation radiusInMeters:1000结果限制：1搜索文本：self.location.name]；postLocRequest.session=FBSession.activeSession；是的，这很有帮助。现在，当会话打开时，我不再看到登录屏幕/授权屏幕。另一件事是-如果我想使用其他用户登录-如何注销或终止当前会话-在您发布的代码上有两件事-1。FBSession.activeSession.isOpen：这意味着我们正在检查会话是否处于活动状态，然后只进入内部。我们是否应该检查“会话是否未激活”？2.“allowLoginUI:是”和“allowLoginUI:否”-这有什么影响？当然，正如你所希望的。我只是给你指路。。。顺便说一句，当然，对于使用facebook sdk方法，您需要在FBRequest*postLocRequest=[FBRequest RequestForPlacesArchatCoordination:currentLocation radiusInMeters:1000结果限制：1搜索文本：self.location.name]；postLocRequest.session=FBSession.activeSession；