json - Swift:在国家和城市之间的两个pickerView中解析Json

Question

我有两个 JSON 网址。想要在两个 UIPickerView 之间进行解析。一个 UIPickerView 代表国家/地区，另一个 UIPickerView 代表城市。我已经能够在 Country 的第一个 UIPickerView 中解析 JSON，这里的数据非常完美。但是当单击城市的 UIPickerView 时，我在 DidSelectRow 函数中收到一条线程消息。请尝试解决这个问题

这是我的代码。

var arrCountryPicker = [CountryPicker]()

 var arrCitiPicker = [CityPicker]()

    var id = 0
    var country_id = 0

我的两个网址

let url = URL(string: "http://......./mobile-app/countries")

let url = URL(string: "http://......../mobile-app/city-by-country-id?country_id="+String(country_id))

PickerView代码

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {


    var country: Int = arrCountryPicker.count

    if pickerView == cityPickerView {

        country = self.arrCitiPicker.count
    }
    return country
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {

    if pickerView == countryPickerView {

        let titleRow = arrCountryPicker[row].name

        return titleRow

    } else if pickerView == cityPickerView{
        let titleRow = arrCitiPicker[row].name

        return titleRow
    }
    return ""
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

    countryTextField.text = arrCountryPicker[row].name

    if pickerView == countryPickerView {
        self.countryTextField.text = self.arrCountryPicker[row].name
        self.country_id = self.arrCountryPicker[row].id!
        self.countryPickerView.isHidden = true
    }
    else if pickerView == cityPickerView{

Thread about down code is "Thread 1: exc_bad_instruction(code=exc_1386_invop,subcode=0x0)

        self.cityTextField.text = self.arrCitiPicker[row].name

        self.cityPickerView.isHidden = true

    }
    self.view.endEditing(true)
}


func textFieldDidBeginEditing(_ textField: UITextField) {

    if (textField == countryTextField){
        self.countryPickerView.isHidden = false

    }
    else if (textField == cityTextField){
        self.cityPickerView.isHidden = false

    }

}

Answer 1

每当您更改国家/地区时，您都需要更新城市选择器数组。

在选择国家/地区选择器时，调用特定国家/地区 ID 的网络服务并更新城市数组。

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

    //Remove this line
    //txtCountry.text = self.arrCountries[row].name

    if pickerView == CountryPicker {
        self.txtCountry.text = self.arrCountries[row].name
        self.country_id = self.arrCountryPicker[row].id!

        //Update city array according selected country
        self.updateCitiesFor(id: row)

        self.CountryPicker.isHidden = true
    }  else if pickerView == cityPicker {
        self.txtCity.text = self.arrCities[row].name
        self.cityPicker.isHidden = true
    }
    self.view.endEditing(true)
}

更新arrCitiPicker的函数

func updateCitiesFor(id: Int) {

    let url = URL(string: "http://......../mobile-app/\(id)")

    //Call web service and store cities data of selected country into arrCitiPicker

    //Clear city textfield when country change
    self.txtCity.text = ""     

    //Update City Picker with new data
    cityPicker.reloadAllComponents()
}