如果自定义搜索栏中的字符串与swift不匹配，想在表格视图中显示消息

Question

我已经使用UITextField创建了自定义搜索栏，并在其下方显示了UITableView，它将显示结果。如何显示消息，即在搜索栏中键入的字符串不匹配时找不到记录

我用于搜索控制器的情节提要图像：

我的搜索控制器文件代码：

class SearchPageController: UIViewController {

    @IBOutlet weak var searchTxtBar: UITextField!
    @IBOutlet weak var searchTblView: UITableView!
    @IBOutlet weak var helpMessageView: UIView!


    var CatStoreData:[String] = Array()
    var filteredData:[String] = Array()

    override func viewDidLoad() {
        super.viewDidLoad()

        self.hideKeyboardWhenTappedAround()
        self.helpMessageView.isHidden = true

        // Do any additional setup after loading the view.
        searchTxtBar.delegate = self

        //append data to catstoredata array
        CatStoreData.append("costco.com.au")
        CatStoreData.append("au.kogan.com")
        CatStoreData.append("rebelsport.com.au")
        CatStoreData.append("ebgames.com.au")
        CatStoreData.append("computeralliance.com.au")
        CatStoreData.append("harveynorman-com-au")
        CatStoreData.append("binglee.com.au")
        CatStoreData.append("iwantthatflight.com.au")
        CatStoreData.append("mobileciti.com.au")
        CatStoreData.append("Electronics and Gadgets")
        CatStoreData.append("Baby Care")
        CatStoreData.append("Computers")
        CatStoreData.append("Computers and Laptops")
        CatStoreData.append("Entertainment")
        CatStoreData.append("Eyewear")
        CatStoreData.append("Flights")
        CatStoreData.append("Home & Kitchen")

        for data in CatStoreData {
            filteredData.append(data)
        }

        searchTxtBar.addTarget(self, action: #selector(searchRecords(_ :)), for: .editingChanged)

    }

    override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }

    @objc func searchRecords(_ textfield: UITextField) {

        self.CatStoreData.removeAll()
        if searchTxtBar.text?.count != 0 {
            for data in filteredData {

                if let dataToSearch = self.searchTxtBar.text {
                    let range = data.lowercased().range(of: dataToSearch, options: .caseInsensitive, range: nil, locale: nil)
                    if range != nil {
                        CatStoreData.append(data)
                    }
                }
            }
        }else {
            for data in filteredData {
                CatStoreData.append(data)
            }
        }

        searchTblView.reloadData()
    }

    //MARK: IBActions
    @IBAction func toHomeScreen(_ sender: UIButton) {
        self.navigationController?.popViewController(animated: true)
    }

    @IBAction func clearSearchData(_ sender: UIButton) {

        self.CatStoreData.removeAll()
        self.searchTxtBar.text = ""
        for data in filteredData {
            CatStoreData.append(data)
        }
        searchTblView.reloadData()
    }

}

Tableview委托和数据源方法

 extension SearchPageController: UITableViewDelegate, UITableViewDataSource{

        func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
            return CatStoreData.count
        }

        func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

            var cell = tableView.dequeueReusableCell(withIdentifier: "catstoredata")

            if cell == nil {
                cell = UITableViewCell(style: .default, reuseIdentifier: "catstoredata")
            }

            cell?.selectionStyle = .none
            cell?.textLabel?.text = CatStoreData[indexPath.row]
            return cell!
        }

        func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

            tableView.deselectRow(at: indexPath, animated: true)
            self.navigationController?.popViewController(animated: true)
        }
    }

文本字段委托方法

 extension SearchPageController: UITextFieldDelegate{

        func textFieldShouldReturn(_ textField: UITextField) -> Bool {

            self.searchTxtBar.resignFirstResponder()
            return false
        }

    }