Xcode Swift UITableView：表格不出现

Posted 2023-02-23

【中文标题】Xcode Swift UITableView：表格不出现

【英文标题】：Xcode Swift UITableView: Table Doesn't appear

【发布时间】：2020-05-19 04:49:41

【问题描述】：

我正在尝试制作一个包含国家/地区列表的表格，我已经完成了所有编码，但是当我运行模拟器并按下按钮时，没有出现任何内容，请帮助，这是我的故事板和代码 Image 选择国家是我应该点击的按钮，但是当我按下时什么都没有出现

这是我的个人资料 vc

    import UIKit
import Firebase
import FirebaseAuth
import FirebaseDatabase

class SetUpProfileViewController: UIViewController 


    @IBOutlet weak var userNameTextField: UITextField!
    @IBOutlet weak var adressTextField: UITextField!
    @IBOutlet weak var phoneNumberTextField: UITextField!
    @IBOutlet weak var selectCountryButton: UIButton!
    @IBOutlet weak var errorLabel: UILabel!

    override func viewDidLoad() 
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        setUpElements()

        // To move to the countries table after the button is tapped
        selectCountryButton.addTarget(self, action: #selector(tapForCountry), for: .touchUpInside)
    

    func setUpElements() 


        // hide the error label
        errorLabel.alpha = 0

        // style the elements
        Utilities.styleTextField(userNameTextField)
        Utilities.styleTextField(adressTextField)
        Utilities.styleTextField(phoneNumberTextField)


    

    @IBAction func NextTapped(_ sender: Any) 
    

    // To move to the countries table
    @objc func tapForCountry() 
        let story = UIStoryboard(name:"Main", bundle: nil)
        guard let controller = story.instantiateViewController(identifier: "Countries") as? CountriesViewController else 
            return
        
        self.navigationController?.pushViewController(controller, animated: true)
    

这是我的国家 VC

    import UIKit

class CountriesViewController: UIViewController 

    @IBOutlet weak var searchBar: UISearchBar!
    @IBOutlet weak var tableView: UITableView!


    override func viewDidLoad() 
        super.viewDidLoad()

        // Do any additional setup after loading the view.

        // Show up The Countries
        self.navigationItem.title = "Select Country"
        self.tableView.separatorStyle = .none

        self.tableView.delegate = self
        self.tableView.dataSource = self
        configuration()
    

    var list : [Countries] = [Countries]()
    func configuration() 
        for code in NSLocale.isoCountryCodes 
            let id = NSLocale.localeIdentifier(fromComponents: [NSLocale.Key.countryCode.rawValue: code])

            let name = NSLocale(localeIdentifier: "en_US").displayName(forKey: NSLocale.Key.identifier, value: id)

            let locale = NSLocale.init(localeIdentifier: id)

            let countryCode = locale.object(forKey: NSLocale.Key.countryCode)

            let currencyCode = locale.object(forKey: NSLocale.Key.currencyCode)

            let currencySymbol = locale.object(forKey: NSLocale.Key.currencySymbol)




            if name != nil 
                let model = Countries()
                model.name = name
                model.countryCode = countryCode as? String
                model.currencyCode = currencyCode as? String
                model.currencySymbol = currencySymbol as? String
                model.flag = String.flag(for: code)
                model.extensionCode = NSLocale().extensionCode(countryCode: model.countryCode)
                list.append(model)


            

        

        self.tableView.reloadData()

    



extension CountriesViewController : UITableViewDelegate, UITableViewDataSource 
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int 
        return list.count
    

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell 
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell")
        cell?.textLabel?.text = "\(list[indexPath.row].flag!) \(list[indexPath.row].name!)"

        return cell!
    




extension String 
    static func flag(for code: String) -> String? 
        func isLowercaseASCIIScaler( scaler: Unicode.Scalar) -> Bool 
            return scaler.value >= 0x61 && scaler.value <= 0x7A
        

        func regionalIndicatorSymbol(for scaler: Unicode.Scalar) -> Unicode.Scalar 
            precondition(isLowercaseASCIIScaler(scaler: scaler))
            return Unicode.Scalar(scaler.value + (0x1F1E6 - 0x61))!
        

        let lowercasedCode = code.lowercased()
        guard lowercasedCode.count == 2 else return nil 
        guard lowercasedCode.unicodeScalars.reduce(true,  accum, scaler in accum && isLowercaseASCIIScaler(scaler: scaler) ) else  return nil 
        let indicatorSymbols = lowercasedCode.unicodeScalars.map( regionalIndicatorSymbol(for: $0) )
        return String(indicatorSymbols.map( Character($0) ))

    



extension NSLocale 
    func extensionCode(countryCode : String?) -> String? 
        let prefixCodes = ["AC" : "247", "AF": "93", "AE": "971", "AL": "355", "AN": "599", "AS":"1", "AD": "376", "AO": "244", "AI": "1", "AG":"1", "AR": "54","AM": "374", "AW": "297", "AU":"61", "AT": "43","AZ": "994", "BS": "1", "BH":"973", "BF": "226","BI": "257", "BD": "880", "BB": "1", "BY": "375", "BE":"32","BZ": "501", "BJ": "229", "BM": "1", "BT":"975", "BA": "387", "BW": "267", "BR": "55", "BG": "359", "BO": "591", "BL": "590", "BN": "673", "CC": "61", "CD":"243","CI": "225", "KH":"855", "CM": "237", "CA": "1", "CV": "238", "KY":"345", "CF":"236", "CH": "41", "CL": "56", "CN":"86","CX": "61", "CO": "57", "KM": "269", "CG":"242", "CK": "682", "CR": "506", "CU":"53", "CY":"537","CZ": "420", "DE": "49", "DK": "45", "DJ":"253", "DM": "1", "DO": "1", "DZ": "213", "EC": "593", "EG":"20", "ER": "291", "EE":"372","ES": "34", "ET": "251", "FM": "691", "FK": "500", "FO": "298", "FJ": "679", "FI":"358", "FR": "33", "GB":"44", "GF": "594", "GA":"241", "GS": "500", "GM":"220", "GE":"995","GH":"233", "GI": "350", "GQ": "240", "GR": "30", "GG": "44", "GL": "299", "GD":"1", "GP": "590", "GU": "1", "GT": "502", "GN":"224","GW": "245", "GY": "595", "HT": "509", "HR": "385", "HN":"504", "HU": "36", "HK": "852", "IR": "98", "IM": "44", "IL": "972", "IO":"246", "IS": "354", "IN": "91", "ID":"62", "IQ":"964", "IE": "353","IT":"39", "JM":"1", "JP": "81", "JO": "962", "JE":"44", "KP": "850", "KR": "82","KZ":"77", "KE": "254", "KI": "686", "KW": "965", "KG":"996","KN":"1", "LC": "1", "LV": "371", "LB": "961", "LK":"94", "LS": "266", "LR":"231", "LI": "423", "LT": "370", "LU": "352", "LA": "856", "LY":"218", "MO": "853", "MK": "389", "MG":"261", "MW": "265", "MY": "60","MV": "960", "ML":"223", "MT": "356", "MH": "692", "MQ": "596", "MR":"222", "MU": "230", "MX": "52","MC": "377", "MN": "976", "ME": "382", "MP": "1", "MS": "1", "MA":"212", "MM": "95", "MF": "590", "MD":"373", "MZ": "258", "NA":"264", "NR":"674", "NP":"977", "NL": "31","NC": "687", "NZ":"64", "NI": "505", "NE": "227", "NG": "234", "NU":"683", "NF": "672", "NO": "47","OM": "968", "PK": "92", "PM": "508", "PW": "680", "PF": "689", "PA": "507", "PG":"675", "PY": "595", "PE": "51", "PH": "63", "PL":"48", "PN": "872","PT": "351", "PR": "1","PS": "970", "QA": "974", "RO":"40", "RE":"262", "RS": "381", "RU": "7", "RW": "250", "SM": "378", "SA":"966", "SN": "221", "SC": "248", "SL":"232","SG": "65", "SK": "421", "SI": "386", "SB":"677", "SH": "290", "SD": "249", "SR": "597","SZ": "268", "SE":"46", "SV": "503", "ST": "239","SO": "252", "SJ": "47", "SY":"963", "TW": "886", "TZ": "255", "TL": "670", "TD": "235", "TJ": "992", "TH": "66", "TG":"228", "TK": "690", "TO": "676", "TT": "1", "TN":"216","TR": "90", "TM": "993", "TC": "1", "TV":"688", "UG": "256", "UA": "380", "US": "1", "UY": "598","UZ": "998", "VA":"379", "VE":"58", "VN": "84", "VG": "1", "VI": "1","VC":"1", "VU":"678", "WS": "685", "WF": "681", "YE": "967", "YT": "262","ZA": "27" , "ZM": "260", "ZW":"263", "AQ" : "672", "AX" : "358", "BQ" : "599", "BV": "55"]

        let countryDialingCode = prefixCodes[countryCode ?? "IN"] ?? nil
        return countryDialingCode
    

&

import Foundation

struct ToCountries 

    struct Storyboard 
        static let CountriesViewController = "Countries"
    

【问题讨论】：

什么都没有出现是什么意思？ CountryViewController 是不显示还是显示为空的 tableView？

您是否将情节提要中的原型单元格标识符设置为“单元格”？您是否尝试在return list.count 设置断点以查看是否有要显示的内容？

@sats 国家视图控制器不显示

@SwissMark 是的，没有帮助

@SwissMark 仍然不起作用，我嵌入了导航控制器，但它不起作用，我尝试在另一个项目中使用相同的编码和步骤，它起作用但没有显示国家（空单元格），是的，我确实将原型单元格标识符设置为“单元格”

【参考方案1】：

通过查看您的故事板，我没有看到任何 NavigationController。

这意味着当您调用self.navigationController?.pushViewController(controller, animated: true) 时，navigationController 为 nil。

尝试将 SetUpProfileViewController 嵌入到 NavigationController 中。

在情节提要中选择 SetUpProfielViewController，然后转到编辑器 > 嵌入 > 导航控制器