Facebook應用程序邀請的iOS SDK無法顯示邀請VC

Question

所以這是我的應用程序代碼的邀請：

private func inviteFriends() { 

    let content = FBSDKAppInviteContent() 
    content.appLinkURL = URL(string: "...") 
    content.appInvitePreviewImageURL = URL(string: "...") 
    FBSDKAppInviteDialog.show(from: self, with: content, delegate: nil) 
} 

此代碼工作正常，但如果我嘗試添加促銷代碼：

private func inviteFriends() { 

    let content = FBSDKAppInviteContent() 
    content.appLinkURL = URL(string: "...") 
    content.appInvitePreviewImageURL = URL(string: "...") 
    content.promotionCode = "preview" 
    content.promotionText = "Use the *preview* code to unlock the app" 
    FBSDKAppInviteDialog.show(from: self, with: content, delegate: nil) 
} 

邀請VC不再顯示（該函數被調用，但沒有顯示）。我在這裏錯過了什麼？

Answer 1

的問題是，我用特殊字符像*所以刪除它使應用程序正常工作我最終的代碼是這樣的：

private func inviteFriends() { 

    let content = FBSDKAppInviteContent() 
    content.appLinkURL = URL(string: "...") 
    content.appInvitePreviewImageURL = URL(string: "...") 
    content.promotionCode = "preview" 
    content.promotionText = "Use the preview code to unlock the app" 
    FBSDKAppInviteDialog.show(from: self, with: content, delegate: nil) 
}