在tableView swift4中搜索JSON数据

Question

I am trying to show jsondata in to the tableView and search country from the searchBar but getting error in to the textDidChange function.

I want the user to enter three words into the searchBar then tableView will open and search data.

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()
}

shows error into this part.

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()
    }
  }

}

my table view part

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

• First of all do not use NSString in Swift and the Foundation rangeOfString API, use native String and native range(of .
• Second of all never check for an empty string and for an empty array with .count == 0 . There is isEmpty .
• Third of all please name structs and classes with a starting capital letter. struct Country ... .

---

The error occurs because you are filtering Country instances and actually you are looking for its name or its region .

This is a pure Swift version of your code

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()
}

If you want to filter for name and region write

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

With this syntax declare arrFilter

var arrFilter = [Country]()

and in cellForRow write

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

Answer 2

You are getting country object of your array as a string so such an error occured.. Please do as below

    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

First you can not assign a value type [Country] to [String].For example when assign a arrFilter at that time country.filter always return country type value not a string type.

use below code to helping you,

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

inside the viewdidLoad

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.
}

And

 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
    })

Thanks