我正在尝试使用Facebook登录，但登录成功，但没有返回到应用程序

Step-1. Download latest Facebook SDK (it includes major changes).

Step-2. Add FBSDKCoreKit.framework and FBSDKLoginKit.framework to 
        your project.

Step-3. Now go to Project > Build Phases > add 
        SafariServices.framework

Step-4. There are three changes in info.plist we need to verify.

4.1 Make sure you have below in your info.plist file



 <key>CFBundleURLTypes</key>
<array>
  <dict>
  <key>CFBundleURLSchemes</key>
  <array>
    <string><your fb id here eg. fbxxxxxx></string>
  </array>
  </dict>
</array>
  <key>FacebookAppID</key>
  <string><your FacebookAppID></string>
  <key>FacebookDisplayName</key>
<string><Your_App_Name_Here></string>

4.2 Now add below for White-list Facebook Servers, this is must for     iOS 9

    <key>NSAppTransportSecurity</key>
<dict>
  <key>NSExceptionDomains</key>
  <dict>
    <key>facebook.com</key>
    <dict>
      <key>NSIncludesSubdomains</key>
      <true/>
      <key>NSExceptionRequiresForwardSecrecy</key>
      <false/>
    </dict>
    <key>fbcdn.net</key>
    <dict>
      <key>NSIncludesSubdomains</key>
      <true/>
      <key>NSExceptionRequiresForwardSecrecy</key>
      <false/>
    </dict>
    <key>akamaihd.net</key>
    <dict>
      <key>NSIncludesSubdomains</key>
      <true/>
      <key>NSExceptionRequiresForwardSecrecy</key>
      <false/>
    </dict>
  </dict>
</dict>

4.3 Add URL schemes
    <key>LSApplicationQueriesSchemes</key>
  <array>
      <string>fbapi</string>
      <string>fb-messenger-api</string>
      <string>fbauth2</string>
      <string>fbshareextension</string>
  </array>
Step-5. Now open AppDelegate.m file

5.1 Add below import statements

#import <FBSDKLoginKit/FBSDKLoginKit.h>
#import <FBSDKCoreKit/FBSDKCoreKit.h>

5.2 update following following methods



 - (BOOL)application:(UIApplication *)application
            openURL:(NSURL *)url
  sourceApplication:(NSString *)sourceApplication
         annotation:(id)annotation {
  return [[FBSDKApplicationDelegate sharedInstance] application:application
                                                         openURL:url
                                               sourceApplication:sourceApplication
                                                      annotation:annotation];
}

- (void)applicationDidBecomeActive:(UIApplication *)application {
  [FBSDKAppEvents activateApp];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  return [[FBSDKApplicationDelegate sharedInstance] application:application
                                    didFinishLaunchingWithOptions:launchOptions];
}

Step-6. Now we need to modify our Login Controller, where we do Login task

6.1 Add these imports in Login ViewController.m

#import <FBSDKCoreKit/FBSDKCoreKit.h>
#import <FBSDKLoginKit/FBSDKLoginKit.h>

6.2 Add Facebook Login Button

    FBSDKLoginButton *loginButton = [[FBSDKLoginButton alloc] init];
loginButton.center = self.view.center;
[self.view addSubview:loginButton];

6.3 Handle Login button click



 -(IBAction)facebookLogin:(id)sender
{
    FBSDKLoginManager *login = [[FBSDKLoginManager alloc] init];

    if ([FBSDKAccessToken currentAccessToken])
    {
        NSLog(@"Token is available : %@",[[FBSDKAccessToken currentAccessToken]tokenString]);
        [self fetchUserInfo];
    }
    else
    {
        [login logInWithReadPermissions:@[@"email"] fromViewController:self handler:^(FBSDKLoginManagerLoginResult *result, NSError *error)
         {
             if (error)
             {
                 NSLog(@"Login process error");
             }
             else if (result.isCancelled)
             {
                 NSLog(@"User cancelled login");
             }
             else
             {
                 NSLog(@"Login Success");

                 if ([result.grantedPermissions containsObject:@"email"])
                 {
                     NSLog(@"result is:%@",result);
                     [self fetchUserInfo];
                 }
                 else
                 {
                     [SVProgressHUD showErrorWithStatus:@"Facebook email permission error"];

                 }
             }
         }];
    }
}
6.4 Get user info (name, email etc.)

    -(void)fetchUserInfo
{
    if ([FBSDKAccessToken currentAccessToken])
    {
        NSLog(@"Token is available : %@",[[FBSDKAccessToken currentAccessToken]tokenString]);

        [[[FBSDKGraphRequest alloc] initWithGraphPath:@"me" parameters:@{@"fields": @"id, name, email"}]
         startWithCompletionHandler:^(FBSDKGraphRequestConnection *connection, id result, NSError *error) {
             if (!error)
             {
                 NSLog(@"results:%@",result);

                 NSString *email = [result objectForKey:@"email"];
                 NSString *userId = [result objectForKey:@"id"];

                 if (email.length >0 )
                 {
                     //Start you app Todo
                 }
                 else
                 {
                    NSLog(@“Facebook email is not verified");
                 }
             }
             else
             {
                 NSLog(@"Error %@",error);
            }
         }];
    }
}