如何阻止Swift中的segue发生？

Question

当用户单击登录按钮时,我有一个登录到另一个场景的登录场景,但是,当我尝试在用户电子邮件和密码不正确时阻止它发生.我正在使用Firebase,下面的这个功能会检查用户名和密码是否正确,但我想在不正确时阻止发生这种情况.

 func userLogin (user: String!, pass: String!){
    ref.authUser(user, password: pass,
                 withCompletionBlock: { error, authData in
                    if error != nil {
                        print("user account doesnt exist")
                    } else {
                        print("You're logged in Fam")
                    }
    })
}

Answer 1

试试这个:

override func shouldPerformSegueWithIdentifier(identifier: String, sender: AnyObject?) -> Bool {
    if password incorrect {
        return false
    }else {
        return true
    }
}

或者在auth成功后预先形成segue:

func userLogin (user: String!, pass: String!){
ref.authUser(user, password: pass,
             withCompletionBlock: { error, authData in
                if error != nil {
                    print("user account doesnt exist")
                } else {
                    print("You're logged in Fam")
                    performSegueWithIdentifier("Your identifier", sender: AnyObject?)
                }
})

}