How to make picker view to display from a particular row in swift 3?

Question

How to make picker view to display from default country but it is displaying from first but I need it from default country that is united states but here it is showing from first country but I need it to display from United States can anyone help me how to implement this ?

here are the images shown below here picker view displaying from first country but I need it to display from United States because it is my default selected country

func countryListDownloadJsonwithURL(countryAPI: String) {
        let url = NSURL(string: countryAPI)
        URLSession.shared.dataTask(with: (url as URL?)!, completionHandler: {(data, response, error) -> Void in
            if let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [[String:Any]] {
                for item in jsonObj! {
                    let dict = Country(dict: item)
                    self.countryArray.append(dict)
                }
                print(self.countryArray)
                OperationQueue.main.addOperation({
                     self.countryPickerView.selectRow(self.i, inComponent: 0, animated: true)
                     self.countryPickerView.reloadAllComponents()
                     self.statePickerView.reloadAllComponents()
                })
            }
        }).resume()
    }  


    func numberOfComponents(in pickerView: UIPickerView) -> Int{
        if pickerView.tag == 1 {
            return 1
        }else {
            return 1
        }
    }


    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
        if pickerView.tag == 1 {
            return countryArray.count
        }
        else {
            return countryArray[countrySelectedIndex!].state.count
        }
    }
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        if pickerView.tag == 1 {
            return countryArray[row].country
        }
        else {
            return countryArray[countrySelectedIndex!].state[row].state
        }
    }
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        if pickerView.tag == 1 {
            countryTextField.text = countryArray[row].country
            for item in countryArray {
                print(item.country)
                print(countryArray[row].country)
                if item.country == countryArray[row].country {
                    self.countryId = item.countryId
                    if item.state.count == 0 {
                        self.stateTextfield.isHidden = false
                        self.stateLabel.isHidden = true
                        self.selectedCountryTextField.isHidden = true
                        self.imageArrow.isHidden = true
                        break
                    }
                    else {
                        if let i = countryArray.index(where: { $0.country == countryArray[row].country }) {
                            countrySelectedIndex = i
                        }
                        self.countryId = item.countryId
                        if self.countryId?.isEmpty == true {
                            self.countryId = countryTextField.text
                        }
                        UserDefaults.standard.set(self.countryId, forKey: "guestCountryId")
                        self.statePickerView.delegate = self
                        self.statePickerView.dataSource = self
                        selectedCountryTextField.inputView = statePickerView
                        self.statePickerView.reloadAllComponents()
                        selectedCountryTextField.text = "Select state/province"
                        self.stateLabel.isHidden = false
                        self.stateTextfield.isHidden = true
                        self.selectedCountryTextField.isHidden = false
                        self.imageArrow.isHidden = false
                        break
                    }
                }
                else {
                    self.stateTextfield.isHidden = false
                    self.stateLabel.isHidden = true
                    self.selectedCountryTextField.isHidden = true
                    self.imageArrow.isHidden = true
                }
            }
        }
        else {
            self.selectedCountryTextField.text = countryArray[countrySelectedIndex!].state[row].state
            self.stateCode = countryArray[countrySelectedIndex!].state[row].stateValue as! Int
            print(self.stateCode)
            UserDefaults.standard.set(self.stateCode, forKey: "statecode")
        }
    }

Answer 1

Have class variables to track selection. It should be updated by your picker delegate function func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int). Instead of updating in viewDidLoad() you will have to update the selection in func viewWillAppear(_ animated: Bool) for the values to be updated each time. viewDidLoad() is executed only the first time the view is loaded, not every time it is visited.

In swift 4, it would look like this :

//class variable
var selectedCountry:Int = 0
var column : Int = 0

    // Catpure the picker view selection
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
            selectedCountry = row
            column = component 
    }

    override func viewWillAppear(_ animated: Bool) {
            super.viewWillAppear(animated);
            countryPickerView.selectRow(selectedCountry, inComponent: column, animated: true))
    }

Answer 2

you can use ActionSheetPicker which in fact reduces the code of all picker methods & you can get your selected country as default in picker view using else condition

if txtCountry.text == ""
    {
        let countryPicker = ActionSheetStringPicker(title: "Select a country", rows: pickerData, initialSelection: 0, doneBlock: { (pickerSheet, selectedIndex, selectedValue) in    
            self.txtCountry.text = selectedValue! as? String
            self.selectedCountry = selectedIndex
        }, cancel: {pickerSheet in return }, origin: (sender as AnyObject).superview!)
        countryPicker?.show();
    }
    else
    {
        let countryPicker = ActionSheetStringPicker(title: "Select a country", rows: pickerData, initialSelection: selectedCountry, doneBlock: { (pickerSheet, selectedIndex, selectedValue) in
            self.txtCountry.text = selectedValue! as? String
            self.selectedCountry = selectedIndex

        }, cancel: {pickerSheet in return }, origin: (sender as AnyObject).superview!)
        countryPicker?.show();
    }

Here self.selectedCountry = selectedIndex helps you to manage selectedCountry Index dynamically

Answer 3

First thing you need to know what is the index of United States. So store it's index in variable selectedCountry when you are calling the api. After that call the pickers delegate method selectedRow.

var selectedCountry:Int = 0

func countryListDownloadJsonwithURL(countryAPI: String) {
        let url = NSURL(string: countryAPI)
        URLSession.shared.dataTask(with: (url as URL?)!, completionHandler: {(data, response, error) -> Void in
            if let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [[String:Any]] {
                for itemNumber in 0..<jsonObj!.count {
                    let dict = Country(dict:jsonObj![itemNumber])
                    if dict.countryName == "United States" {
                        self.selectedCountry = itemNumber
                        self.countryPickerView.selectRow(self.selectedCountry, inComponent: 0, animated: true)
                    }
                    self.countryArray.append(dict)
                }
                print(self.countryArray)
                OperationQueue.main.addOperation({
                    self.countryPickerView.reloadAllComponents()
                    self.statePickerView.reloadAllComponents()
                })
            }
        }).resume()
    }

Hope this will be help.