how to updatePickerView Data according to previous picker view selection

Question

I have 2 pickerView. one is showing courses and other is showing courses sections according to courses id(Response is going from Json) now the problem is when I choose course(lets say calculus) and then select the sectionPickerView it gives me list of corresponding sections(A,B,C,D) but when I change the course again to (English) the section PickerView still shows the same section and doesn't update sections according to Course Pickerview.

Here is my Code :

let coursesPicker = UIPickerView()
let sectionsPicker = UIPickerView()

var countryId = 0

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

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    if pickerView == coursesPicker {
        return GetCourses.instance.getCoursesInstance.count
    } else {
        return GetSectionService.sectionsServiceinstance.sectionModelInstance.count  
    }
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    if pickerView == coursesPicker {
        return GetCourses.instance.getCoursesInstance[row].courseName
    } else {
        return GetSectionService.sectionsServiceinstance.sectionModelInstance[row].sectionName
    }        
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    if pickerView == coursesPicker {
        coursesTextField.text = GetCourses.instance.getCoursesInstance[row].courseName
        countryId = GetCourses.instance.getCoursesInstance[row].id
        self.callSectioApi(id: countryId)
        self.coursesPicker.isHidden = true
    } else {
        sectionTextField.text =  GetSectionService.sectionsServiceinstance.sectionModelInstance[row].sectionName
        self.sectionsPicker.isHidden = true
    }
    self.view.endEditing(true)
}

function to update Url according to course Id

func callSectioApi(id : Int) {

    let Idurl = String(id)
    let url1 = getSectionUrl+Idurl
    print(url1)

    GetSectionService.sectionsServiceinstance.getSectionsName(url: url1) { (success) in
        if success {
        let status = GetSectionService.sectionsServiceinstance.status
            if status == 400 {
                print("400")
            } else if status == 500 {
                print("500")
            } else if status == 404 {
                print("404")
            } else if status == 200 {
                print("200")
                self.sectionTextField.text = ""
                self.sectionsPicker.reloadAllComponents()
            } else {
                print("Error")
            }
        } else {
            let status = GetSectionService.sectionsServiceinstance.status
            print(status)
        }
    }
}

Answer 1

You need to reload sectionPicker after course selection.

So, change your didSelect like below

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

    if pickerView == coursesPicker {

        coursesTextField.text = GetCourses.instance.getCoursesInstance[row].courseName
        countryId = GetCourses.instance.getCoursesInstance[row].id
        self.callSectioApi(id: countryId)

        //Reload sectionPicker
        self.sectionsPicker.reloadAllComponents()
        self.sectionsPicker.selectRow(0, inComponent: 0, animated: false)

        self.coursesPicker.isHidden = true

    } else {

        sectionTextField.text =  GetSectionService.sectionsServiceinstance.sectionModelInstance[row].sectionName
        self.sectionsPicker.isHidden = true

    }
    self.view.endEditing(true)
}