Swift 隐藏搜索栏也会隐藏导航栏标题

我有

导航栏

和

搜索

按钮。单击它会显示

搜索栏

，单击取消按钮会隐藏它。但由于某种原因，如果

搜索栏

被隐藏，则导航栏标题视图也会隐藏。这是什么原因造成的？起初我真的想让它从右边滑到标题视图，但我没能做到，所以我就这样做了

这是显示和隐藏它的代码：

//Create searchbar
    func createSearchBar(){

        searchBar.showsCancelButton = true
        searchBar.tintColor = UIColor(red:0.184, green:0.996, blue:0.855, alpha:1.00)
        searchBar.placeholder = "Search brands"
        searchBar.delegate = self



        searchBar.hidden =  false
        searchBar.alpha = 0

        navigationItem.titleView = searchBar
        navigationItem.setLeftBarButtonItem(menuButton, animated: true)
        navigationItem.setRightBarButtonItem(searchButtton, animated: true)


        UIView.animateWithDuration(0.5, animations: {
            self.searchBar.alpha = 1
            }, completion: { finished in
                self.searchBar.becomeFirstResponder()
        })


    }

    //Searchbar hide
    func hideSearchBar() {


        navigationItem.setLeftBarButtonItem(menuButton, animated: true)
        navigationItem.setRightBarButtonItem(searchButtton, animated: true)
        searchBar.alpha = 0
        UIView.animateWithDuration(1, animations: {


            }, completion: { finished in

        })
    }

    //Searchbar cancel button
    func searchBarCancelButtonClicked(searchBar: UISearchBar) {
        hideSearchBar()
        searchBar.endEditing(true)
        snusBrandsTableView.reloadData()
    }

---

如果要在隐藏

搜索栏时设置
导航项的
标题
，则需要将
标题视图
设置为零，然后设置标题

func hideSearchBar() {
    navigationItem.setLeftBarButtonItem(menuButton, animated: true)
    navigationItem.setRightBarButtonItem(searchButtton, animated: true)
    searchBar.alpha = 0
    self.navigationItem.titleView = nil
    self.navigationItem.title = "YourTitle"
}

如果要在隐藏
搜索栏时设置
导航项的
标题
，则需要将
标题视图
设置为零，然后设置标题

func hideSearchBar() {
    navigationItem.setLeftBarButtonItem(menuButton, animated: true)
    navigationItem.setRightBarButtonItem(searchButtton, animated: true)
    searchBar.alpha = 0
    self.navigationItem.titleView = nil
    self.navigationItem.title = "YourTitle"
}

如果可能，请选择屏幕截图；如果您想显示标题，请选择隐藏标题视图；如果可能，请选择屏幕截图；如果您想显示标题，请选择隐藏标题视图