As I found a solution for the indicated problem:
1) Previously, I created a button and gave the FBLoginButton class, and in action I wrote as
FBSDKLoginManager *login = [[FBSDKLoginManager alloc] init];
[login logInWithReadPermissions:@[@"email",@"public_profile"] fromViewController:self handler:^(FBSDKLoginManagerLoginResult *result, NSError *error) {
}];
Modification of the solution: Removed the FBLoginButton class and placed only UIButton
2) Use the ios 8 and ios 9 methods as described below in AppDelegate.
- (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<NSString*, id> *)options {
return [[FBSDKApplicationDelegate sharedInstance] application:app
openURL:url
sourceApplication:options[UIApplicationOpenURLOptionsSourceApplicationKey]
annotation:options[UIApplicationOpenURLOptionsAnnotationKey]];
}
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
{
return [[FBSDKApplicationDelegate sharedInstance] application:application
openURL:url
sourceApplication:sourceApplication
annotation:annotation
];
}