The document provides a comprehensive overview of iOS development, covering various implementations of user interface components and data management using Swift. It includes examples of handling user inputs, performing calculations, and managing view lifecycles with reactive programming approaches, including RxSwift. Additionally, it demonstrates how to create custom delegates and utilize iOS image picker functionality within a structured MVC framework.

1. .(
) . ..)

2. !

3. Disk Defragment
Code Defragment
→ →

4. Advantages
EASY to UNDERSTAND
READ
FOLLOW
FIND
MAINTENANCE

5. Goal
→

6. NO FREE LUNCH
CASE STUDY

7. CASE #1. Data + Logic + UI
class ViewController: UIViewController {
@IBOutlet var number1: UILabel!
@IBOutlet var number2: UILabel!
@IBOutlet var result: UILabel!
struct CalcData {
let num1: Int
let num2: Int
}
private func textToInt(_ text: String?) -> Int {
guard let text = text else { return 0 }
return Int(text) ?? 0
}
@IBAction func calcResult(_ sender: Any) {
let n1 = textToInt(number1.text)
let n2 = textToInt(number2.text)
let data = CalcData(num1: n1, num2: n2)
let res = calcPlus(data)
result.text = intToText(res)
}
private func intToText(_ num: Int) -> String {
return "(num)"
}
private func calcPlus(_ data: CalcData) -> Int {
return data.num1 + data.num2
}
}
❓

8. CASE #1. Data + Logic + UI
class ViewController: UIViewController {
// MARK: - DATA
struct CalcData {
let num1: Int
let num2: Int
}
// MARK: - LOGIC
private func textToInt(_ text: String?) -> Int {
guard let text = text else { return 0 }
return Int(text) ?? 0
}
private func intToText(_ num: Int) -> String {
return "(num)"
}
private func calcPlus(_ data: CalcData) -> Int {
return data.num1 + data.num2
}
// MARK: - UI
@IBOutlet var number1: UILabel!
@IBOutlet var number2: UILabel!
@IBOutlet var result: UILabel!
@IBAction func calcResult(_ sender: Any) {
let n1 = textToInt(number1.text)
let n2 = textToInt(number2.text)
let data = CalcData(num1: n1, num2: n2)
let res = calcPlus(data)
result.text = intToText(res)
}
}
❗

9. CASE #2. Data Setter ❓
class ViewController: UIViewController {
@IBOutlet var textLabel: UILabel!
var count: Int = 0
@IBAction func addOne() {
count += 1
textLabel.text = "(count)"
}
@IBAction func subOne() {
count -= 1
textLabel.text = "(count)" // duplicated
}
}

10. CASE #2. Data Setter ❗
class ViewController: UIViewController {
@IBOutlet var textLabel: UILabel!
var count: Int = 0 {
didSet {
textLabel.text = "(count)"
}
}
@IBAction func addOne() {
count += 1
}
@IBAction func subOne() {
count -= 1
}
}

11. CASE #3. Overrides
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
setupNavigationBar()
}
func setupNavigationBar() {
self.navigationController?.title = "App Title"
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.navigationController?.setNavigationBarHidden(false, animated: animated)
//Other Codes
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
self.navigationController?.setNavigationBarHidden(true, animated: animated)
//Other Codes
}
}
❓

12. class BaseViewController: UIViewController {
var viewWillAppearActions: [(Bool) -> ()] = []
var viewWillDisappearActions: [(Bool) -> ()] = []
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
viewWillAppearActions.forEach({ $0(animated) })
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
viewWillDisappearActions.forEach({ $0(animated) })
}
}
class ViewController: BaseViewController {
override func viewDidLoad() {
super.viewDidLoad()
setupNavigationBar()
}
func setupNavigationBar() {
self.navigationController?.title = "App Title"
viewWillAppearActions.append({ [weak self] anim in
self?.navigationController?.setNavigationBarHidden(false, animated: anim)
})
viewWillDisappearActions.append({ [weak self] anim in
self?.navigationController?.setNavigationBarHidden(true, animated: anim)
})
}
}
❗CASE #3. Overrides

13. class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
setupKeyboardEvent()
}
func setupKeyboardEvent() {
NotificationCenter.default.addObserver(self,
selector: #selector(onKeyboardWillShow),
name: .UIKeyboardWillShow,
object: nil)
NotificationCenter.default.addObserver(self,
selector: #selector(onKeyboardWillHide),
name: .UIKeyboardWillHide,
object: nil)
}
@objc func onKeyboardWillShow(notification: Notification) {
print("Keyboard will show")
}
@objc func onKeyboardWillHide(notification: Notification) {
print("Keyboard will hide")
}
}
CASE #4. Selector ❓

14. class KeyboardEventWrapper {
var onKeyboardWillShowCallBack: (Notification) -> () = { _ in }
init() {
NotificationCenter.default.addObserver(self,
selector: #selector(onKeyboardWillShow),
name: .UIKeyboardWillShow,
object: nil)
}
@objc func onKeyboardWillShow(notification: Notification) {
onKeyboardWillShowCallBack(notification)
}
deinit {
NotificationCenter.default.removeObserver(self)
}
}
class ViewController: UIViewController {
var keyboardEventWrapper: KeyboardEventWrapper!
override func viewDidLoad() {
super.viewDidLoad()
setupKeyboardEvent()
}
func setupKeyboardEvent() {
keyboardEventWrapper = KeyboardEventWrapper()
keyboardEventWrapper.onKeyboardWillShowCallBack = { _ in
print("Keyboard will show")
}
}
}
❗CASE #4. Selector

15. class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate
{
@IBAction func onLoadImage() {
let picker = UIImagePickerController()
picker.delegate = self
present(picker, animated: true, completion: nil)
}
// MARK: - UIImagePickerControllerDelegate
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [String: Any]) {
let originalInfo = info[UIImagePickerControllerOriginalImage]
guard let originalImage = originalInfo as? UIImage else { return }
// ...
picker.dismiss(animated: true, completion: nil)
}
}
CASE #5. Delegate ❓

16. class ImagePickerWrapper: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
var onImagePicked: (UIImage?) -> () = { _ in }
func showImagePicker(on vc: UIViewController) {
let picker = UIImagePickerController()
picker.delegate = self
vc.present(picker, animated: true, completion: nil)
}
// MARK: - UIImagePickerControllerDelegate
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [String: Any]) {
let originalInfo = info[UIImagePickerControllerOriginalImage]
guard let originalImage = originalInfo as? UIImage else { return }
onImagePicked(originalImage)
picker.dismiss(animated: true, completion: nil)
}
}
class ViewController: UIViewController {
var imagePicker: ImagePickerWrapper!
@IBAction func onLoadImage() {
imagePicker = ImagePickerWrapper()
imagePicker.showImagePicker(on: self)
imagePicker.onImagePicked = { image in
guard let image = image else { return }
// ...
}
}
}
❗CASE #5. Delegate

17. ELEGANT WAY
feat. RxSwift

18. CASE #1. Data + Logic + UI
struct CalcData {
let num1: Int
let num2: Int
}
func textToInt(_ text: String?) -> Int {
guard let text = text else { return 0 }
return Int(text) ?? 0
}
func intToText(_ num: Int) -> String {
return "(num)"
}
func calcPlus(_ data: CalcData) -> Int {
return data.num1 + data.num2
}
class ViewController: UIViewController {
@IBOutlet var number1: UILabel!
@IBOutlet var number2: UILabel!
@IBOutlet var result: UILabel!
@IBAction func calcResult(_ sender: Any) {
let n1 = textToInt(number1.text)
let n2 = textToInt(number2.text)
let data = CalcData(num1: n1, num2: n2)
let res = calcPlus(data)
result.text = intToText(res)
}
}
Model.swift
Context.swift
ViewController.swift
❗❗

19. CASE #2. Data Setter
import RxSwift
import RxCocoa
// Common Functions
let intToText = { (i: Int) in "(i)" }
///
class ViewController: UIViewController {
@IBOutlet var textLabel: UILabel!
let disposeBag = DisposeBag()
let count = BehaviorRelay<Int>(value: 0)
override func viewDidLoad() {
super.viewDidLoad()
count.map(intToText)
.bind(to: textLabel.rx.text)
.disposed(by: disposeBag)
}
@IBAction func addOne() {
count.accept(count.value + 1)
}
@IBAction func subOne() {
count.accept(count.value - 1)
}
}
❗❗

20. CASE #2. Data Setter
import RxSwift
import RxCocoa
// Common Functions
let intToText = { (i: Int) in "(i)" }
///
class ViewController: UIViewController {
@IBOutlet var textLabel: UILabel!
@IBOutlet var textLabelx10: UILabel!
let disposeBag = DisposeBag()
let count = BehaviorRelay<Int>(value: 0)
override func viewDidLoad() {
super.viewDidLoad()
count.map(intToText)
.bind(to: textLabel.rx.text)
.disposed(by: disposeBag)
count.map({ $0 * 10 })
.map(intToText)
.bind(to: textLabelx10.rx.text)
.disposed(by: disposeBag)
}
@IBAction func addOne() {
count.accept(count.value + 1)
}
@IBAction func subOne() {
count.accept(count.value - 1)
}
}
❗❗

21. import RxSwift
import RxCocoa
import RxViewController // <==
class ViewController: UIViewController {
let disposeBag = DisposeBag()
override func viewDidLoad() {
super.viewDidLoad()
setupNavigationBar()
}
func setupNavigationBar() {
self.navigationController?.title = "App Title"
self.rx.viewWillAppear.subscribe(onNext: { [weak self] anim in
self?.navigationController?.setNavigationBarHidden(false, animated: anim)
}).disposed(by: disposeBag)
self.rx.viewWillDisappear.subscribe(onNext: { [weak self] anim in
self?.navigationController?.setNavigationBarHidden(true, animated: anim)
}).disposed(by: disposeBag)
}
}
CASE #3. Overrides ❗❗

22. import UIKit
import RxSwift
import RxCocoa
class ViewController: UIViewController {
let disposeBag = DisposeBag()
override func viewDidLoad() {
super.viewDidLoad()
setupKeyboardEvent()
}
func setupKeyboardEvent() {
NotificationCenter.default.rx.notification(.UIKeyboardWillShow)
.subscribe(onNext: { notifiaction in
print("Keyboard will show")
})
.disposed(by: disposeBag)
NotificationCenter.default.rx.notification(.UIKeyboardWillHide)
.subscribe(onNext: { notifiaction in
print("Keyboard will hide")
})
.disposed(by: disposeBag)
}
}
CASE #4. Selector ❗❗

23. import UIKit
import RxSwift
import RxCocoa
class ViewController: UIViewController {
let disposeBag = DisposeBag()
@IBOutlet weak var imageView: UIImageView!
@IBAction func onLoadImage() {
let picker = UIImagePickerController()
present(picker, animated: true, completion: nil)
picker.rx.didFinishPickingMediaWithInfo
.map({ info -> UIImage? in
info[UIImagePickerControllerOriginalImage] as? UIImage
})
.bind(to: imageView.rx.image)
.disposed(by: disposeBag)
}
}
CASE #5. Delegate ❗❗

24. // MARK:- UIImagePickerController.rx
// picker.rx.didFinishPickingMediaWithInfo
// ~~~~~~ ~~
// Base Reactive
extension Reactive where Base: UIImagePickerController {
public var didFinishPickingMediaWithInfo: Observable<[String : Any]> {
return RxImagePickerProxy.proxy(for: base)
.didFinishPickingMediaWithInfoSubject
.asObservable()
.do(onCompleted: {
self.base.dismiss(animated: true, completion: nil)
})
}
public var didCancel: Observable<Void> {
return RxImagePickerProxy.proxy(for: base)
.didCancelSubject
.asObservable()
.do(onCompleted: {
self.base.dismiss(animated: true, completion: nil)
})
}
}
CASE #5. Delegate ❗❗

25. import UIKit
import RxSwift
import RxCocoa
public typealias ImagePickerDelegate = UIImagePickerControllerDelegate & UINavigationControllerDelegate
extension UIImagePickerController: HasDelegate {
public typealias Delegate = ImagePickerDelegate
}
class RxImagePickerProxy: DelegateProxy<UIImagePickerController, ImagePickerDelegate>,
DelegateProxyType, UIImagePickerControllerDelegate, UINavigationControllerDelegate
{
public init(imagePicker: UIImagePickerController) {
super.init(parentObject: imagePicker, delegateProxy: RxImagePickerProxy.self)
}
//MARK:- DelegateProxyType
public static func registerKnownImplementations() {
self.register { RxImagePickerProxy(imagePicker: $0) }
}
static func currentDelegate(for object: UIImagePickerController) -> ImagePickerDelegate? {
return object.delegate
}
static func setCurrentDelegate(_ delegate: ImagePickerDelegate?, to object: UIImagePickerController)
{
object.delegate = delegate
}
//MARK:- Proxy Subject
//MARK:- UIImagePickerControllerDelegate
//MARK:- Completed
}
CASE #5. Delegate ❗❗

26. class RxImagePickerProxy: DelegateProxy<UIImagePickerController, ImagePickerDelegate>,
DelegateProxyType, UIImagePickerControllerDelegate, UINavigationControllerDelegate
{
//MARK:- DelegateProxyType
//MARK:- Proxy Subject
internal lazy var didFinishPickingMediaWithInfoSubject = PublishSubject<[String : Any]>()
internal lazy var didCancelSubject = PublishSubject<Void>()
//MARK:- UIImagePickerControllerDelegate
func imagePickerController(_ picker: UIImagePickerController,
didFinishPickingMediaWithInfo info: [String: Any]) {
didFinishPickingMediaWithInfoSubject.onNext(info)
didFinishPickingMediaWithInfoSubject.onCompleted()
didCancelSubject.onCompleted()
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
didCancelSubject.onNext(())
didCancelSubject.onCompleted()
didFinishPickingMediaWithInfoSubject.onCompleted()
}
//MARK:- Completed
deinit {
self.didFinishPickingMediaWithInfoSubject.onCompleted()
self.didCancelSubject.onCompleted()
}
}
CASE #5. Delegate ❗❗

27. import UIKit
import RxSwift
import RxCocoa
class ViewController: UIViewController {
let disposeBag = DisposeBag()
@IBOutlet weak var imageView: UIImageView!
@IBAction func onLoadImage() {
let picker = UIImagePickerController()
present(picker, animated: true, completion: nil)
picker.rx.didFinishPickingMediaWithInfo
.map({ info -> UIImage? in
info[UIImagePickerControllerOriginalImage] as? UIImage
})
.bind(to: imageView.rx.image)
.disposed(by: disposeBag)
}
}
CASE #5. Delegate ❗❗

28. ALL TOGETHER
SUMMARY

29. UI

30. Model.swift
struct CalcData {
let n1: Int?
let n2: Int?
let result: Int?
}
extension CalcData {
static func empty() -> CalcData {
return CalcData(n1: nil, n2: nil, result: nil)
}
}

31. Context.swift (Business Logic)
let i2s = { (i: Int?) in "(i ?? 0)" }
let s2i = { (s: String?) in Int(s ?? "0") }
class Context {
let model = BehaviorRelay<CalcData>(value: CalcData.empty())
func doCalc(data: CalcData) -> CalcData {
guard let n1 = data.n1 else { return data }
guard let n2 = data.n2 else { return data }
let result = n1 + n2
return CalcData(n1: n1, n2: n2, result: result)
}
}

32. ViewController.swift
class ViewController: UIViewController {
@IBOutlet weak var n1Field: UITextField! // Input
@IBOutlet weak var n2Field: UITextField! // Input
@IBOutlet weak var resultLabel: UILabel! // Output
@IBOutlet weak var calcButton: UIButton! // Event
let context = Context()
let disposeBag = DisposeBag()
override func viewDidLoad() {
super.viewDidLoad()
bindUI()
bindEvent()
}
func bindUI() {
// ...
}
func bindEvent() {
// …
}
}

33. ViewController.swift
class ViewController: UIViewController {
func bindUI() {
//n1 input
n1Field.rx.text.map(s2i)
.withLatestFrom(context.model) { (n1, dat) in
CalcData(n1: n1, n2: dat.n2, result: dat.result)
}
.bind(to: context.model)
.disposed(by: disposeBag)
//n2 input
n2Field.rx.text.map(s2i)
.withLatestFrom(context.model) { (n2, dat) in
CalcData(n1: dat.n1, n2: n2, result: dat.result)
}
.bind(to: context.model)
.disposed(by: disposeBag)
//result output
viewModel.model.map({ $0.result })
.map(i2s)
.bind(to: resultLabel.rx.text)
.disposed(by: disposeBag)
}
func bindEvent() {
//event
calcButton.rx.tap
.withLatestFrom(context.model)
.map(context.doCalc)
.bind(to: context.model)
.disposed(by: disposeBag)
}
}

34. Summary
class ViewController: UIViewController {
@IBOutlet weak var n1Field: UITextField! // Input
@IBOutlet weak var n2Field: UITextField! // Input
@IBOutlet weak var resultLabel: UILabel! // Output
@IBOutlet weak var calcButton: UIButton! // Event
let context = Context()
let disposeBag = DisposeBag()
override func viewDidLoad() {
super.viewDidLoad()
bindUI()
bindEvent()
}
func bindUI() {
//n1 input
n1Field.rx.text.map(s2i)
.withLatestFrom(context.model) { (n1, dat) in
CalcData(n1: n1, n2: dat.n2, result: dat.result)
}
.bind(to: context.model)
.disposed(by: disposeBag)
//n2 input
n2Field.rx.text.map(s2i)
.withLatestFrom(context.model) { (n2, dat) in
CalcData(n1: dat.n1, n2: n2, result: dat.result)
}
.bind(to: context.model)
.disposed(by: disposeBag)
//result output
viewModel.model.map({ $0.result })
.map(i2s)
.bind(to: resultLabel.rx.text)
.disposed(by: disposeBag)
}
func bindEvent() {
//event
calcButton.rx.tap
.withLatestFrom(context.model)
.map(context.doCalc)
.bind(to: context.model)
.disposed(by: disposeBag)
}
}
struct CalcData {
let n1: Int?
let n2: Int?
let result: Int?
}
extension CalcData {
static func empty() -> CalcData {
return CalcData(n1: nil, n2: nil, result: nil)
}
}
View
ViewController
Context
Model
let i2s = { (i: Int?) in "(i ?? 0)" }
let s2i = { (s: String?) in Int(s ?? "0") }
class Context {
let model = BehaviorRelay<CalcData>(value: CalcData.empty())
func doCalc(data: CalcData) -> CalcData {
guard let n1 = data.n1 else { return data }
guard let n2 = data.n2 else { return data }
let result = n1 + n2
return CalcData(n1: n1, n2: n2, result: result)
}
}

35. struct CalcData {
let n1: Int?
let n2: Int?
let result: Int?
}
extension CalcData {
static func empty() -> CalcData {
return CalcData(n1: nil, n2: nil, result: nil)
}
}
View
ViewController
Context
Model
ViewModel
Summary
class ViewController: UIViewController {
@IBOutlet weak var n1Field: UITextField! // Input
@IBOutlet weak var n2Field: UITextField! // Input
@IBOutlet weak var resultLabel: UILabel! // Output
@IBOutlet weak var calcButton: UIButton! // Event
let viewModel = ViewModel()
let disposeBag = DisposeBag()
override func viewDidLoad() {
super.viewDidLoad()
bindUI()
bindEvent()
}
func bindUI() {
//n1 input
n1Field.rx.text.map(s2i)
.withLatestFrom(viewModel.model) { (n1, dat) in
CalcData(n1: n1, n2: dat.n2, result: dat.result)
}
.bind(to: viewModel.model)
.disposed(by: disposeBag)
//n2 input
n2Field.rx.text.map(s2i)
.withLatestFrom(viewModel.model) { (n2, dat) in
CalcData(n1: dat.n1, n2: n2, result: dat.result)
}
.bind(to: viewModel.model)
.disposed(by: disposeBag)
//result output
viewModel.model.map({ $0.result })
.map(i2s)
.bind(to: resultLabel.rx.text)
.disposed(by: disposeBag)
}
func bindEvent() {
//event
calcButton.rx.tap
.withLatestFrom(viewModel.model)
.map(viewModel.doCalc)
.bind(to: viewModel.model)
.disposed(by: disposeBag)
}
}
let i2s = { (i: Int?) in "(i ?? 0)" }
let s2i = { (s: String?) in Int(s ?? "0") }
class ViewModel {
let model = BehaviorRelay<CalcData>(value: CalcData.empty())
func doCalc(data: CalcData) -> CalcData {
guard let n1 = data.n1 else { return data }
guard let n2 = data.n2 else { return data }
let result = n1 + n2
return CalcData(n1: n1, n2: n2, result: result)
}
}