我正在使用Parse 1.7.1,Facebook SDK 4.0.1,Swift 1.2,Xcode 6.3.1

在执行此代码时,我得到一个零PFUser:

var permissions = [ "public_profile" ]

PFFacebookUtils.logInInBackgroundWithReadPermissions(permissions,  block: {  (user: PFUser?, error: NSError?) -> Void in
    if let user = user {
         if user.isNew {
             println("User signed up and logged in through Facebook!")
         } else {
             println("User logged in through Facebook!")
         }
    } else {
        println("Uh oh. The user cancelled the Facebook login.")
    }
})

返回的PFUser为零,因此我看到“哦哦 . 用户取消了Facebook登录 . ”在日志中 .

有人有主意吗?