facebook-ios-sdk - FBLoginView : login isn't performed

Question

我将 FBLoginView 添加到我的 ViewController < FBLoginViewDelegate >:

FBLoginView *loginview = [[FBLoginView alloc] init];    
loginview.frame = CGRectOffset(loginview.frame, 5, 5);
loginview.delegate = self;    
[self.view addSubview:loginview];    
[loginview sizeToFit];

plist 中所有必要的字段(FacebookAppID、FacebookDisplayName、URL Schemes)都根据教程设置。 facebook app也是按照教程配置的(设置bundle ID，启用facebook登录)。

但是登录仍然没有执行。当我按下“登录”时，我被重定向到使用 facebook 登录的浏览器，但是当它完成时，我没有登录应用程序(loginViewFetchedUserInfo:user: 没有被调用，“登录”没有改变以“注销”)。
可能是什么问题？

Answer 1

在 AppDelegate.m 中实现以下内容后，一切正常(取自官方示例之一):

- (void)sessionStateChanged:(FBSession *)session
                      state:(FBSessionState) state
                      error:(NSError *)error
{
    switch (state) {
        case FBSessionStateOpen:
            if (!error) {
                // We have a valid session
                //NSLog(@"User session found");
                [FBRequestConnection
                 startForMeWithCompletionHandler:^(FBRequestConnection *connection,
                                                   NSDictionary<FBGraphUser> *user,
                                                   NSError *error) {
                     if (!error) {
                         self.loggedInUserID = user.id;
                         self.loggedInSession = FBSession.activeSession;
                     }
                 }];
            }
            break;
        case FBSessionStateClosed:
        case FBSessionStateClosedLoginFailed:
            [FBSession.activeSession closeAndClearTokenInformation];
            break;
        default:
            break;
    }

    [[NSNotificationCenter defaultCenter]
     postNotificationName:FBSessionStateChangedNotification
     object:session];

    if (error) {
        UIAlertView *alertView = [[UIAlertView alloc]
                                  initWithTitle:@"Error"
                                  message:error.localizedDescription
                                  delegate:nil
                                  cancelButtonTitle:@"OK"
                                  otherButtonTitles:nil];
        [alertView show];
    }
}

/*
 * Opens a Facebook session and optionally shows the login UX.
 */
- (BOOL)openSessionWithAllowLoginUI:(BOOL)allowLoginUI {
    return [FBSession openActiveSessionWithReadPermissions:nil
                                              allowLoginUI:allowLoginUI
                                         completionHandler:^(FBSession *session,
                                                             FBSessionState state,
                                                             NSError *error) {
                                             [self sessionStateChanged:session
                                                                 state:state
                                                                 error:error];
                                         }];
}

/*
 *
 */
- (void) closeSession {
    [FBSession.activeSession closeAndClearTokenInformation];
}

/*
 * If we have a valid session at the time of openURL call, we handle
 * Facebook transitions by passing the url argument to handleOpenURL
 */
- (BOOL)application:(UIApplication *)application
            openURL:(NSURL *)url
  sourceApplication:(NSString *)sourceApplication
         annotation:(id)annotation {
    // attempt to extract a token from the url
    return [FBAppCall handleOpenURL:url sourceApplication:sourceApplication];
}