在tableView swift4中搜索JSON数据

Question

我正在尝试将jsondata显示到tableView并从searchBar搜索country ，但在textDidChange函数中error 。

我想用户输入三个字到searchBar ，然后tableView将打开和搜索数据。

struct country : Decodable {
    let name : String
    let capital : String
    let region : String
  }

class ViewController: UIViewController,UISearchBarDelegate {

    var isSearch : Bool = false
    var countries = [country]()
    var arrFilter:[String] = []

    @IBOutlet weak var tableview: UITableView!
    @IBOutlet weak var searchbar: UISearchBar!

    override func viewDidLoad() {
        super.viewDidLoad()

        tableview.dataSource = self
        tableview.delegate = self
        searchbar.delegate = self

        let jsonurl = "https://restcountries.eu/rest/v2/all"
        let url = URL(string: jsonurl)

        URLSession.shared.dataTask(with: url!) { (data, response, error) in

            do{
                self.countries = try JSONDecoder().decode([country].self, from: data!)

            }
            catch{
                print("Error")
            }
            DispatchQueue.main.async {
                self.tableview.reloadData()
            }
            }.resume()
}

在这部分显示错误。

func searchBar(searchBar: UISearchBar, textDidChange searchText: String) {

    if searchText.characters.count == 0 {
        isSearch = false;
        self.tableview.reloadData()
    } else {
        arrFilter = countries.filter({ (text) -> Bool in
            let tmp: NSString = text
            let range = tmp.rangeOfString(searchText, options: NSStringCompareOptions.CaseInsensitiveSearch)
            return range.location != NSNotFound
        })
        if(arrFilter.count == 0){
            isSearch = false;
        } else {
            isSearch = true;
        }
        self.tableview.reloadData()
    }
  }

}

我的表视图部分

extension ViewController : UITableViewDelegate, UITableViewDataSource{
  func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    if(isSearch){
       return arrFilter.count
    }
    else{
      return countries.coun
    }
}

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

    let cell = tableview.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
    if(isSearch){    
         cell.textLabel?.text = arrFilter[indexPath.row]    
    }else{
         cell.textLabel?.text = countries[indexPath.row].name.capitalized
    }
    return cell
  }
}

Answer 1

• 首先不要在 Swift和Foundation rangeOfString API 中使用NSString ，使用原生String和原生range(of .
• 其次，永远不要检查空字符串和.count == 0的空数组。 有isEmpty 。
• 第三，请以大写字母开头命名结构和类。 struct Country ... .

---

发生错误是因为您正在过滤Country实例，而实际上您正在寻找它的name或它的region 。

这是您代码的纯 Swift 版本

func searchBar(searchBar: UISearchBar, textDidChange searchText: String) {

    if searchText.isEmpty {
        isSearch = false
    } else {
        arrFilter = countries.filter( $0.name.range(of: searchText, options: .caseInsensitive) != nil }
        isSearch = !arrFilter.isEmpty 
    }
    self.tableview.reloadData()
}

如果要过滤name和region写入

arrFilter = countries.filter( $0.name.range(of: searchText, options: .caseInsensitive) != nil 
                              || $0.region.range(of: searchText, options: .caseInsensitive) != nil }

使用此语法声明arrFilter

var arrFilter = [Country]()

并在cellForRow写入

let dataArray = isSearch ? arrFilter : countries
cell.textLabel?.text = dataArray[indexPath.row].name.capitalized 

Answer 2

您正在以字符串形式获取数组的国家/地区对象，因此发生了这样的错误。请按以下步骤操作

    var arrFilter:[country] = [country]()

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

        let cell = tableview.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        if(isSearch){    
        cell.textLabel?.text = arrFilter[indexPath.row].name.capitalized    
        }else{
             cell.textLabel?.text = countries[indexPath.row].name.capitalized
        }
        return cell
    }


    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
            if searchText.characters.count == 0 {
                isSearch = false;
                self.tableview.reloadData()
            } else {
                arrFilter = countries.filter({ (country) -> Bool in

                    let tmp: NSString = NSString.init(string: country.name)
                    let range = tmp.range(of: searchText, options: NSString.CompareOptions.caseInsensitive)

                    return range.location != NSNotFound
                })
                if(arrFilter.count == 0){
                    isSearch = false;
                } else {
                    isSearch = true;
                }
                self.tableview.reloadData()
            }
     }

Answer 3

首先，您不能将值类型 [Country] 分配给 [String]。例如，当分配 arrFilter 时 country.filter 始终返回国家类型值而不是字符串类型。

使用下面的代码来帮助你，

var countries = [country]()
var arrFilter:[country] = [country]()

在 viewdidLoad 里面

override func viewDidLoad() {

    self.countries.append(country(name: "India", capital: "New Delhi", region: "Asia"))
    self.countries.append(country(name: "Indonesia", capital: "Jakarta", region: "region"))
    self.countries.append(country(name: "Australia", capital: "Canberra", region: "Austrialia"))
    // Do any additional setup after loading the view.
}

和

 self.arrFilter = self.countries.filter({ (country) -> Bool in
        let temp : NSString  = country.name as NSString //or you can use country.capital or country.region
        let range = temp.range(of: "ind", options: .caseInsensitive)
        print(range.location)
        print(range.length)
        print(temp)
        return range.location != NSNotFound
    })

谢谢