Advanced usage of UIAlertController and pickers Swift

Hello, In this blog we are going to learn about the Advanced usage of UIAlertController and pickers Swift

We can create multiple types using an alert controller like date picker, country picker, contact picker, phone code, etc

We will learn about 2 types and for rest please create by your own

1. Date picker

Create a date picker controller

final class DatePickerViewController: UIViewController {
    
    public typealias Action = (Date) -> Void
    
    fileprivate var action: Action?
    
    fileprivate lazy var datePicker: UIDatePicker = { [unowned self] in
        $0.addTarget(self, action: #selector(DatePickerViewController.actionForDatePicker), for: .valueChanged)
        return $0
    }(UIDatePicker())
    
    required init(mode: UIDatePicker.Mode, date: Date? = nil, minimumDate: Date? = nil, maximumDate: Date? = nil, action: Action?) {
        super.init(nibName: nil, bundle: nil)
        datePicker.datePickerMode = mode
        datePicker.date = date ?? Date()
        datePicker.minimumDate = minimumDate
        datePicker.maximumDate = maximumDate
        self.action = action
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    deinit {
        Log("has deinitialized")
    }
    
    override func loadView() {
        view = datePicker
    }
    
    @objc func actionForDatePicker() {
        action?(datePicker.date)
    }
    
    public func setDate(_ date: Date) {
        datePicker.setDate(date, animated: true)
    }
}

final class DatePickerViewController: UIViewController {

public typealias Action = (Date) -> Void

fileprivate var action: Action?

fileprivate lazy var datePicker: UIDatePicker = { [unowned self] in

$0.addTarget(self, action: #selector(DatePickerViewController.actionForDatePicker), for: .valueChanged)

return $0

}(UIDatePicker())

required init(mode: UIDatePicker.Mode, date: Date? = nil, minimumDate: Date? = nil, maximumDate: Date? = nil, action: Action?) {

super.init(nibName: nil, bundle: nil)

datePicker.datePickerMode = mode

datePicker.date = date ?? Date()

datePicker.minimumDate = minimumDate

datePicker.maximumDate = maximumDate

self.action = action

}

required init?(coder aDecoder: NSCoder) {

fatalError("init(coder:) has not been implemented")

}

deinit {

Log("has deinitialized")

}

override func loadView() {

view = datePicker

}

@objc func actionForDatePicker() {

action?(datePicker.date)

}

public func setDate(_ date: Date) {

datePicker.setDate(date, animated: true)

}

Next, please create a function in alert controller extension

extension UIAlertController {
    
    func addDatePicker(mode: UIDatePicker.Mode, date: Date?, minimumDate: Date? = nil, maximumDate: Date? = nil, action: DatePickerViewController.Action?) {
        let datePicker = DatePickerViewController(mode: mode, date: date, minimumDate: minimumDate, maximumDate: maximumDate, action: action)
        set(vc: datePicker, height: 217)
    }
}

extension UIAlertController {

func addDatePicker(mode: UIDatePicker.Mode, date: Date?, minimumDate: Date? = nil, maximumDate: Date? = nil, action: DatePickerViewController.Action?) {

let datePicker = DatePickerViewController(mode: mode, date: date, minimumDate: minimumDate, maximumDate: maximumDate, action: action)

set(vc: datePicker, height: 217)

}

Next, please call the alert from your view controller

let alert = UIAlertController(style: self.alertStyle, title: "Date Picker", message: "Select Date")
            alert.addDatePicker(mode: .dateAndTime, date: Date(), minimumDate: nil, maximumDate: nil) { date in
                Log(date)
            }
            alert.addAction(title: "Done", style: .cancel)
            alert.show()

let alert = UIAlertController(style: self.alertStyle, title: "Date Picker", message: "Select Date")

alert.addDatePicker(mode: .dateAndTime, date: Date(), minimumDate: nil, maximumDate: nil) { date in

Log(date)

}

alert.addAction(title: "Done", style: .cancel)

alert.show()

After using this you will get below type of view on your controller

2. Contact picker

Create a view controller to select the contacts from the device

final class ContactsPickerViewController: UIViewController {
    
    // MARK: UI Metrics
    
    struct UI {
        static let rowHeight: CGFloat = 58
        static let separatorColor: UIColor = UIColor.lightGray.withAlphaComponent(0.4)
    }
    
    // MARK: Properties
    
    public typealias Selection = (Contact?) -> ()
    
    fileprivate var selection: Selection?
    
    //Contacts ordered in dicitonary alphabetically
    fileprivate var orderedContacts = [String: [CNContact]]()
    fileprivate var sortedContactKeys = [String]()
    fileprivate var filteredContacts: [CNContact] = []
    
    fileprivate var selectedContact: Contact?
    
    fileprivate lazy var searchView: UIView = UIView()
    
    fileprivate lazy var searchController: UISearchController = {
        $0.searchResultsUpdater = self
        $0.searchBar.delegate = self
        $0.dimsBackgroundDuringPresentation = false
        /// true if search bar in tableView header
        $0.hidesNavigationBarDuringPresentation = true
        $0.searchBar.searchBarStyle = .minimal
        $0.searchBar.textField?.textColor = .black
        $0.searchBar.textField?.clearButtonMode = .whileEditing
        return $0
    }(UISearchController(searchResultsController: nil))
    
    fileprivate lazy var tableView: UITableView = { [unowned self] in
        $0.dataSource = self
        $0.delegate = self
        //$0.allowsMultipleSelection = true
        $0.rowHeight = UI.rowHeight
        $0.separatorColor = UI.separatorColor
        $0.bounces = true
        $0.backgroundColor = nil
        $0.tableFooterView = UIView()
        $0.sectionIndexBackgroundColor = .clear
        $0.sectionIndexTrackingBackgroundColor = .clear
        $0.register(ContactTableViewCell.self,
                    forCellReuseIdentifier: ContactTableViewCell.identifier)
        return $0
        }(UITableView(frame: .zero, style: .plain))
    
    // MARK: Initialize
    
    required init(selection: Selection?) {
        self.selection = selection
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    deinit {

        let _ = searchController.view
        Log("has deinitialized")
    }
    
    override func loadView() {
        view = tableView
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        if UIDevice.current.userInterfaceIdiom == .pad {
            preferredContentSize.width = UIScreen.main.bounds.width / 2
        }
        
        searchView.addSubview(searchController.searchBar)
        tableView.tableHeaderView = searchView
        
        extendedLayoutIncludesOpaqueBars = true
        edgesForExtendedLayout = .bottom
        definesPresentationContext = true

        updateContacts()
    }
    
    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        tableView.tableHeaderView?.height = 57
        searchController.searchBar.sizeToFit()
        searchController.searchBar.frame.size.width = searchView.frame.size.width
        searchController.searchBar.frame.size.height = searchView.frame.size.height
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        preferredContentSize.height = tableView.contentSize.height
        Log("preferredContentSize.height = \(preferredContentSize.height), tableView.contentSize.height = \(tableView.contentSize.height)")
    }
    
    func updateContacts() {
        checkStatus { [unowned self] orderedContacts in
            
            self.orderedContacts = orderedContacts
            self.sortedContactKeys = Array(self.orderedContacts.keys).sorted(by: <)
            
            if self.sortedContactKeys.first == "#" {
                self.sortedContactKeys.removeFirst()
                self.sortedContactKeys.append("#")
            }
            
            DispatchQueue.main.async {
                self.tableView.reloadData()
            }
        }
    }
    
    func checkStatus(completionHandler: @escaping ([String: [CNContact]]) -> ()) {
        Log("status = \(CNContactStore.authorizationStatus(for: .contacts))")
        switch CNContactStore.authorizationStatus(for: .contacts) {
            
        case .notDetermined:
            /// This case means the user is prompted for the first time for allowing contacts
            Contacts.requestAccess { [unowned self] bool, error in
                self.checkStatus(completionHandler: completionHandler)
            }
            
        case .authorized:
            /// Authorization granted by user for this app.
            DispatchQueue.main.async {
                self.fetchContacts(completionHandler: completionHandler)
            }

        case .denied, .restricted:
            /// User has denied the current app to access the contacts.
            let productName = Bundle.main.infoDictionary!["CFBundleName"]!
            let alert = UIAlertController(style: .alert, title: "Permission denied", message: "\(productName) does not have access to contacts. Please, allow the application to access to your contacts.")
            alert.addAction(title: "Settings", style: .destructive) { action in
                if let settingsURL = URL(string: UIApplication.openSettingsURLString) {
                    UIApplication.shared.open(settingsURL)
                }
            }
            alert.addAction(title: "OK", style: .cancel) { [unowned self] action in
                self.alertController?.dismiss(animated: true)
            }
            alert.show()
        }
    }
    
    func fetchContacts(completionHandler: @escaping ([String: [CNContact]]) -> ()) {
        Contacts.fetchContactsGroupedByAlphabets { [unowned self] result in
            switch result {
                
            case .success(let orderedContacts):
                completionHandler(orderedContacts)
                
            case .error(let error):
                Log("------ error")
                let alert = UIAlertController(style: .alert, title: "Error", message: error.localizedDescription)
                alert.addAction(title: "OK") { [unowned self] action in
                    self.alertController?.dismiss(animated: true)
                }
                alert.show()
            }
        }
    }
    
    func contact(at indexPath: IndexPath) -> Contact? {
        if searchController.isActive {
            return Contact(contact: filteredContacts[indexPath.row])
        }
        let key: String = sortedContactKeys[indexPath.section]
        if let contact = orderedContacts[key]?[indexPath.row] {
            return Contact(contact: contact)
        }
        return nil
    }
    
    func indexPathOfSelectedContact() -> IndexPath? {
        guard let selectedContact = selectedContact else { return nil }
        if searchController.isActive {
            for row in 0 ..< filteredContacts.count {
                if filteredContacts[row] == selectedContact.value {
                    return IndexPath(row: row, section: 0)
                }
            }
        }
        for section in 0 ..< sortedContactKeys.count {
            if let orderedContacts = orderedContacts[sortedContactKeys[section]] {
                for row in 0 ..< orderedContacts.count {
                    if orderedContacts[row] == selectedContact.value {
                        return IndexPath(row: row, section: section)
                    }
                }
            }
        }
        return nil
    }
}

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final class ContactsPickerViewController: UIViewController {

// MARK: UI Metrics

struct UI {

static let rowHeight: CGFloat = 58

static let separatorColor: UIColor = UIColor.lightGray.withAlphaComponent(0.4)

}

// MARK: Properties

public typealias Selection = (Contact?) -> ()

fileprivate var selection: Selection?

//Contacts ordered in dicitonary alphabetically

fileprivate var orderedContacts = [String: [CNContact]]()

fileprivate var sortedContactKeys = [String]()

fileprivate var filteredContacts: [CNContact] = []

fileprivate var selectedContact: Contact?

fileprivate lazy var searchView: UIView = UIView()

fileprivate lazy var searchController: UISearchController = {

$0.searchResultsUpdater = self

$0.searchBar.delegate = self

$0.dimsBackgroundDuringPresentation = false

/// true if search bar in tableView header

$0.hidesNavigationBarDuringPresentation = true

$0.searchBar.searchBarStyle = .minimal

$0.searchBar.textField?.textColor = .black

$0.searchBar.textField?.clearButtonMode = .whileEditing

return $0

}(UISearchController(searchResultsController: nil))

fileprivate lazy var tableView: UITableView = { [unowned self] in

$0.dataSource = self

$0.delegate = self

//$0.allowsMultipleSelection = true

$0.rowHeight = UI.rowHeight

$0.separatorColor = UI.separatorColor

$0.bounces = true

$0.backgroundColor = nil

$0.tableFooterView = UIView()

$0.sectionIndexBackgroundColor = .clear

$0.sectionIndexTrackingBackgroundColor = .clear

$0.register(ContactTableViewCell.self,

forCellReuseIdentifier: ContactTableViewCell.identifier)

return $0

}(UITableView(frame: .zero, style: .plain))

// MARK: Initialize

required init(selection: Selection?) {

self.selection = selection

super.init(nibName: nil, bundle: nil)

}

required init?(coder aDecoder: NSCoder) {

fatalError("init(coder:) has not been implemented")

}

deinit {

let _ = searchController.view

Log("has deinitialized")

}

override func loadView() {

view = tableView

}

override func viewDidLoad() {

super.viewDidLoad()

if UIDevice.current.userInterfaceIdiom == .pad {

preferredContentSize.width = UIScreen.main.bounds.width / 2

}

searchView.addSubview(searchController.searchBar)

tableView.tableHeaderView = searchView

extendedLayoutIncludesOpaqueBars = true

edgesForExtendedLayout = .bottom

definesPresentationContext = true

updateContacts()

}

override func viewWillLayoutSubviews() {

super.viewWillLayoutSubviews()

tableView.tableHeaderView?.height = 57

searchController.searchBar.sizeToFit()

searchController.searchBar.frame.size.width = searchView.frame.size.width

searchController.searchBar.frame.size.height = searchView.frame.size.height

}

override func viewDidLayoutSubviews() {

super.viewDidLayoutSubviews()

preferredContentSize.height = tableView.contentSize.height

Log("preferredContentSize.height = \(preferredContentSize.height), tableView.contentSize.height = \(tableView.contentSize.height)")

}

func updateContacts() {

checkStatus { [unowned self] orderedContacts in

self.orderedContacts = orderedContacts

self.sortedContactKeys = Array(self.orderedContacts.keys).sorted(by: <)

if self.sortedContactKeys.first == "#" {

self.sortedContactKeys.removeFirst()

self.sortedContactKeys.append("#")

}

DispatchQueue.main.async {

self.tableView.reloadData()

}

func checkStatus(completionHandler: @escaping ([String: [CNContact]]) -> ()) {

Log("status = \(CNContactStore.authorizationStatus(for: .contacts))")

switch CNContactStore.authorizationStatus(for: .contacts) {

case .notDetermined:

/// This case means the user is prompted for the first time for allowing contacts

Contacts.requestAccess { [unowned self] bool, error in

self.checkStatus(completionHandler: completionHandler)

}

case .authorized:

/// Authorization granted by user for this app.

DispatchQueue.main.async {

self.fetchContacts(completionHandler: completionHandler)

}

case .denied, .restricted:

/// User has denied the current app to access the contacts.

let productName = Bundle.main.infoDictionary!["CFBundleName"]!

let alert = UIAlertController(style: .alert, title: "Permission denied", message: "\(productName) does not have access to contacts. Please, allow the application to access to your contacts.")

alert.addAction(title: "Settings", style: .destructive) { action in

if let settingsURL = URL(string: UIApplication.openSettingsURLString) {

UIApplication.shared.open(settingsURL)

}

alert.addAction(title: "OK", style: .cancel) { [unowned self] action in

self.alertController?.dismiss(animated: true)

}

alert.show()

}

func fetchContacts(completionHandler: @escaping ([String: [CNContact]]) -> ()) {

Contacts.fetchContactsGroupedByAlphabets { [unowned self] result in

switch result {

case .success(let orderedContacts):

completionHandler(orderedContacts)

case .error(let error):

Log("------ error")

let alert = UIAlertController(style: .alert, title: "Error", message: error.localizedDescription)

alert.addAction(title: "OK") { [unowned self] action in

self.alertController?.dismiss(animated: true)

}

alert.show()

}

func contact(at indexPath: IndexPath) -> Contact? {

if searchController.isActive {

return Contact(contact: filteredContacts[indexPath.row])

}

let key: String = sortedContactKeys[indexPath.section]

if let contact = orderedContacts[key]?[indexPath.row] {

return Contact(contact: contact)

}

return nil

}

func indexPathOfSelectedContact() -> IndexPath? {

guard let selectedContact = selectedContact else { return nil }

if searchController.isActive {

for row in 0 ..< filteredContacts.count {

if filteredContacts[row] == selectedContact.value {

return IndexPath(row: row, section: 0)

}

for section in 0 ..< sortedContactKeys.count {

if let orderedContacts = orderedContacts[sortedContactKeys[section]] {

for row in 0 ..< orderedContacts.count {

if orderedContacts[row] == selectedContact.value {

return IndexPath(row: row, section: section)

}

return nil

}

Please create a function to add contact view contact view controller in alert extension

extension UIAlertController {
    
    /// Add Contacts Picker
    ///
    /// - Parameters:
    ///   - selection: action for selection of contact
    
    func addContactsPicker(selection: @escaping ContactsPickerViewController.Selection) {
        let selection: ContactsPickerViewController.Selection = selection
        var contact: Contact?
        
        let addContact = UIAlertAction(title: "Add Contact", style: .default) { action in
            selection(contact)
        }
        addContact.isEnabled = false
        
        let vc = ContactsPickerViewController { new in
            addContact.isEnabled = new != nil
            contact = new
        }
        
        set(vc: vc)
        addAction(addContact)
    }
}

extension UIAlertController {

/// Add Contacts Picker

///

/// - Parameters:

/// - selection: action for selection of contact

func addContactsPicker(selection: @escaping ContactsPickerViewController.Selection) {

let selection: ContactsPickerViewController.Selection = selection

var contact: Contact?

let addContact = UIAlertAction(title: "Add Contact", style: .default) { action in

selection(contact)

}

addContact.isEnabled = false

let vc = ContactsPickerViewController { new in

addContact.isEnabled = new != nil

contact = new

}

set(vc: vc)

addAction(addContact)

}

Then create an alert view in your contact

let alert = UIAlertController(style: self.alertStyle)
            alert.addContactsPicker { contact in Log(contact) }
            alert.addAction(title: "Cancel", style: .cancel)
            alert.show()

let alert = UIAlertController(style: self.alertStyle)

alert.addContactsPicker { contact in Log(contact) }

alert.addAction(title: "Cancel", style: .cancel)

alert.show()

After that you will get below screen

And for the other types Please do it on your own

Thank you for reading this article. I hope this article helped you to implement Advanced usage of UIAlertController and pickers Swift,

After that, if you want to read more articles regarding iOS Development click here or if you want to read more about advance alert click here.

For other technical blogs, please click here.

Ranjit kumar 2 May 2022

. . .

Advanced usage of UIAlertController and pickers Swift

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