I'm new in Swift! and I'm learning from several sources.
I'm building a small app with only 2 elements ( PickerView and label )
I want to know how to let the PickerView row contents to be displayed into a label?
also is there a way to show more information for the row content?
import UIKit
class ViewController: UIViewController {
#IBOutlet var picker: UIPickerView!
let names = ["Sara", "Ali", "Joy"]
override func viewDidLoad() {
super.viewDidLoad()
picker.dataSource = self
picker.delegate = self
}
}
extension ViewController : UIPickerViewDataSource {
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return names.count
}
}
extension ViewController : UIPickerViewDelegate {
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return names[row]
}
}
For example : when Ali is chosen, I want to display "He scores 90" in the label
but I don't want the "He scores 90" sentence to be shown next to Ali in PickerView itself
Thank you
Thank you El Tomato for your hint
it's one of the delegate methods - didSelectRow
and it worked great
import UIKit
class ViewController: UIViewController {
#IBOutlet var picker: UIPickerView!
#IBOutlet var label: UILabel!
let names = ["Sara", "Ali", "Joy"]
override func viewDidLoad() {
super.viewDidLoad()
picker.dataSource = self
picker.delegate = self
}
}
extension ViewController : UIPickerViewDataSource {
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return names.count
}
}
extension ViewController : UIPickerViewDelegate {
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return names[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
label.text = names[row]
}
}
Related
I'm trying to create a second UIPickerView delegate so I can control them individually instead of using if blocks. Below is an example I put together, I'm unsure of how to connect the second UIPickerView outlet to the second UIPickerView delegate (assuming that is all I am missing).
import UIKit
protocol secondDelegate {
func secondPickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int
func secondNumberOfComponents(in pickerView: UIPickerView) -> Int
}
protocol secondDelegateDataSource {
func secondPickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String?
}
class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, secondDelegate, secondDelegateDataSource {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
p1.delegate = self
p1.dataSource = self
p2.delegate = self
p2.dataSource = self
}
#IBOutlet weak var p1: UIPickerView!
#IBOutlet weak var p2: UIPickerView!
var delegate2: secondDelegate?
var dataSource2: secondDelegateDataSource?
let picker1 = ["1","3","5"]
let picker2 = ["2","4","6"]
// first picker
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return picker1.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return picker1[row]
}
// second picker
func secondNumberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func secondPickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return picker2.count
}
func secondPickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return picker2[row]
}
}
So here's the problem: you are saying the words "second delegate", but in fact you still have just one delegate — the view controller.
That's your mistake. Make your deeds match your words. Get all the delegate code out of the view controller. Instead, give your view controller two helper objects — the two picker delegates. Route the dataSource and delegate properties of the two pickers correctly, one to each delegate. Now the messages are coming and going to completely separate places, and you will not have any single bottleneck with if clauses everywhere as you do now.
Here's a simplified example where the two helpers are instance of one class — naturally, nothing requires that you do it that way:
class Helper: NSObject, UIPickerViewDataSource, UIPickerViewDelegate {
let data: [String]
init(data: [String]) {
self.data = data
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
data.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
data[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
print(data[row])
}
}
class ViewController: UIViewController {
#IBOutlet weak var p1: UIPickerView!
#IBOutlet weak var p2: UIPickerView!
let helper1 = Helper(data:["Manny", "Moe", "Jack"])
let helper2 = Helper(data:["Harpo", "Chico", "Groucho"])
override func viewDidLoad() {
super.viewDidLoad()
p1.delegate = helper1
p1.dataSource = helper1
p2.delegate = helper2
p2.dataSource = helper2
}
}
If the two picker views do very different kinds of thing, then you would want two separate Helper classes, each of which acts as a picker view delegate in its own way. Again, the goal here is to avoid having to examine the pickerView in the datasource and delegate methods and decide with an if clause what to do; each Helper type would do just one thing.
I would like to show a user different screens depending on what they choose in a UIPickerView. What would be the best way to implement this? Thanks!
import UIKit
class SelectKitViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
#IBOutlet weak var kitPickerView: UIPickerView!
let kits = ["Kit 1", "Kit 2"]
var chosenKit: String?
override func viewDidLoad() {
super.viewDidLoad()
kitPickerView.delegate = self
kitPickerView.dataSource = self
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return kits[row]
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return kits.count
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
let value = kits[row]
chosenKit = value
}
#IBAction func continuePressed(_ sender: Any) {
performSegue(withIdentifier: "SelectReactionVolume", sender: nil)
}
}
I would like to perform a segue to another View Controller when continue is pressed. Once the user chooses a kit they will have to enter additional info about the kit selected.
I am trying to set accessibility label for UIPickerView component, but the delegate method is never called. What's more, UIInspector shows the pickerView is not accessible, but it has the label actually set.
The dataSource/delegate methods are fired. Only the UIAccessibilityDelegate is not.
Tested on xcode 10.1 iOS 12.1 simulator
class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate, UIPickerViewAccessibilityDelegate {
#IBOutlet weak var pickerView: UIPickerView!
override func viewDidLoad() {
super.viewDidLoad()
pickerView.isAccessibilityElement = true
pickerView.accessibilityLabel = "TESTAccLabel"
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return 5
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 2
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return "\(component) - \(row)"
}
func pickerView(_ pickerView: UIPickerView, accessibilityLabelForComponent component: Int) -> String? {
return "TODO:JS"
}
}
this code makes me really mad. I already read thousands of tutorials and stack overflow comments....
Please help me. The Picker just contains a blank grey screen.
Code here:
GenderPickerModel.swift
import UIKit
class GenderPickerModel: NSObject, UIPickerViewDataSource, UIPickerViewDelegate {
let genderPickerData: [String] = ["male", "female"]
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1;
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return genderPickerData.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return genderPickerData[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
}
}
and used in a Controller:
#IBOutlet weak var gender: UITextField!
private var genderPickerView: UIPickerView?
override func viewDidLoad() {
super.viewDidLoad()
loadProfile()
prepareView()
}
func prepareView() {
genderPickerView = UIPickerView.init()
let gpModel = GenderPickerModel()
genderPickerView?.delegate = gpModel
genderPickerView?.dataSource = gpModel
gender.inputView = genderPickerView;
genderPickerView?.selectRow(0, inComponent: 0, animated: true)
genderPickerView?.reloadAllComponents()
}
First, you do not need to do the separate array of gender in pickerview class and you don't need to create the instance of pickerview.
From this, you can see your datasource in your custompickerview
/**
Controller code where you can create instantiate picker assign data
*/
class ViewController: UIViewController {
#IBOutlet weak var textField: UITextField!
let genderPickerData : [String] = ["male", "female"]
override func viewDidLoad() {
super.viewDidLoad()
prepareView()
}
func prepareView() {
genderPickerView = UIPickerView()
let gpModel = GenderPickerModel()
gpModel.data = genderPickerData
gpModel.dataSource = gpModel
gpModel.delegate = gpModel
textField.inputView = gpModel
}
}
/**
Custom pickerview class where you can handle data
*/
import UIKit
class GenderPickerModel: UIPickerView, UIPickerViewDataSource, UIPickerViewDelegate {
var data = [String]()
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return data.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return data[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
}
}
For some reason I can't seem to get both selector lines in my pickers to show. They only seem to show one but the date picker is fine.
class HomeViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
#IBOutlet weak var linePicker: UIPickerView!
#IBOutlet weak var skuPicker: UIPickerView!
override func viewDidLoad() {
super.viewDidLoad()
linePicker.delegate = self
linePicker.dataSource = self
skuPicker.delegate = self
skuPicker.dataSource = self
//passed over from previous view
var plantInfo = plantInformation
let totalNumberOfLines = plantInfo!["lines"].count
//populated the data
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if (pickerView.isEqual(linePicker)){
return lineInfo.count
} else {
return skusForPickerLine.count
}
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
if pickerView.isEqual(linePicker) {
return lineInfo[row].lineNumber
} else {
return skusForPickerLine[row].sku_value
}
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
let selectedValue = linePicker.selectedRow(inComponent: 0)
skusForPickerLine = lineInfo[selectedValue].skuInfo
skuPicker.reloadComponent(0)
}
func pickerView(_ pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat {
// height of picker is 50
return CGFloat(50)
}
}