关闭应用程序时,IOS会丢失FBSession

我正在努力实现这项工作.我有一个 IOS应用程序,我正在尝试集成到Facebook SDK 3.1.用户可以选择登录Facebook,如果他们正在缓存令牌.返回的令牌到期日期是提前几周,我让一切正常,登录/退出,返回前台.但是,每次关闭应用程序时,都不会保留FBSession.我知道这一点,因为当应用程序重新启动时,app委托执行[self openSessionWithAllowLoginUI：NO]并尝试刷新会话,但是这总是返回null.我已经关注了其他教程和其他帖子,似乎无法在我的应用委托中看到我做错了什么. @H_419_7@

@H_419_7@我正在敲打我的头,因为我在应用程序关闭时失去了这个会话.我已经附上了我的appDelegate.

@H_419_7@AppDelegate.m

@H_419_7@

#import "AppDelegate.h"
@implementation AppDelegate

NSString *const FBSessionStateChangedNotification=@"ro.Tag:FBSessionStateChangedNotification";


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.

    [self openSessionWithAllowLoginUI:NO];
    NSLog(@"%@",[[FBSession activeSession] accessToken]);

    return YES;
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was prevIoUsly in the background,optionally refresh the user interface.

    // We need to properly handle activation of the application with regards to SSO
    // (e.g.,returning from iOS 6.0 authorization dialog or from fast app switching).
    [FBSession.activeSession handleDidBecomeActive];
}

/*
 * Callback for session changes.
 */
- (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");
                NSLog(@"session %@",session);
            }
            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 {
    NSArray *permissions = [[NSArray alloc] initWithObjects:
                            @"email",@"user_games_activity",@"user_location",@"user_likes",@"user_birthday",nil];

    //NSLog(@"permissions: %@",permissions);

    return [FBSession openActiveSessionWithReadPermissions:permissions
                                              allowLoginUI:allowLoginUI
                                         completionHandler:^(FBSession *session,FBSessionState state,NSError *error) {
                                             [self sessionStateChanged:session
                                                                 state:state
                                                                 error:error];
                                         }];
}

/*
 * 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 [FBSession.activeSession handleOpenURL:url];
}
/*
  *logout
  *
 */
 - (void) closeSession {
    [FBSession.activeSession closeAndClearTokenInformation];
 }
 @end