呈现 activityViewController 时 UINavigationBar 隐藏

Question

我的项目在 Storyboard 中是完整的，我在 NavigationController 中嵌入了一个 UITableViewController，并且在每个单元格上我都有一个共享通知的按钮。

   @IBAction  func shareSheetButtonFeed(sender: AnyObject) {
        let btnPos: CGPoint = sender.convertPoint(CGPointZero, toView: self.tableView)
        let indexPath: NSIndexPath = self.tableView.indexPathForRowAtPoint(btnPos)!
        passaValor = Int(indexPath.row)
        let printtestess = (objects?[passaValor] as! PFObject)

        let textToShare: AnyObject = (printtestess.objectForKey("subject")! as! String) + " - Cheque agora em:"


        let myWebsite = NSURL(string:"http://www.mysite.com.br/")
        let img: UIImage = UIImage(named: "myLogo-1024x1024")!

        guard let url = myWebsite else {
            print("nothing found")
            return
        }
        self.navigationController?.setNavigationBarHidden(false, animated: true)
        let shareItems:Array = [img, textToShare, url]
        let activityViewController:UIActivityViewController = UIActivityViewController(activityItems: shareItems, applicationActivities: nil)
        activityViewController.excludedActivityTypes = [UIActivityTypePrint, UIActivityTypePostToWeibo, UIActivityTypeCopyToPasteboard, UIActivityTypeAddToReadingList, UIActivityTypePostToVimeo]
        self.presentViewController(activityViewController, animated: true, completion: nil)  
        }

问题是，当我单击按钮时，会显示 shareSheet，在我选择社交网络（如 Twitter 或 Facebook）后，我之前的 NavigationBar 就会消失。

我尝试在按钮内使用这条线解决问题，当我再次单击按钮时，导航栏重新出现：

self.navigationController?.setNavigationBarHidden(false, animated: true)

所以我尝试将这一行放在ViewWillAppear 中，但没有成功。

Obs：我正在使用自动布局

谢谢。

Answer 1

尝试等到共享表关闭以显示导航栏。为此，请在UIActivityViewController 上设置completionWithItemsHandler 属性。

activityViewController.completionWithItemsHandler = { _ in
    self.navigationController?.setNavigationBarHidden(false, animated: true)
}