DanielNo

   
@objc var closureInitialization : UIButton = {
      // Cannot use self in closure initialization
        let btn = UIButton()
        return btn
    }()

    // Lazy property closure init
let textColor : UIColor
@objc lazy var errorMsgLabel : UILabel = {

DanielNo

1. Set and hit a breakpoint in the app, and write the following in the Xcode Console (next to the Variables View):
2. po NSHomeDirectory()
3. open terminal and change directory
4. run command in terminal
open .

DanielNo

/*
  Using Swift code inside an Objective-C file
*/

// In a project :
// Use product module name found in build settings
#import "ProductModuleName-Swift.h"

// Within a Framework
#import <FrameworkName/FrameworkName-Swift.h>

DanielNo

    func testNextVC() {
        
        // Can query elements by accessibility identifier or accessibility label
        // Use Accessibility Identifier instead of accessibility label for ui tests!
        let button = app.buttons["btnAccessibiityLabel"]
        XCTAssertTrue(button.exists)
        button.tap()
        
        // Find ui element by accessibility identifer
        let vcLabel = app.staticTexts["labelAccessibilityIdentifier"]

DanielNo

// In a view subclass's layoutSubviews()

let roundPAth = UIBezierPath(roundedRect: bounds, cornerRadius: bounds.height / 2)
let maskLayer = CAShapeLayer()
maskLayer.path = roundPath.cgPath
layer.mask = maskLayer

DanielNo

extension UIStackView {
    
    convenience init(labelTitles: [String]) {
        self.init()
        
        for title in labelTitles {
            let label = UILabel()
            label.text = title
            addArrangedSubview(label)
        }

DanielNo

import UIKit

extension UIScrollView{

    func currentPage() -> Int{
        let page = Int((self.contentOffset.x / self.frame.size.width).rounded())
        print("page num : \(page)")
        return page
    }
}

DanielNo

extension String{
    func charAtIndex(index : Int) -> Character{
        let i = self.index (self.startIndex, offsetBy: index)
        return self[i]
    }
    
    func stringAtIndex(index : Int) -> String{
        let i = self.index (self.startIndex, offsetBy: index)
        return String(self[i])
    }

DanielNo

struct GenericQueue<Element>{
    fileprivate var elements : [Element] = []
    
    mutating func enqueue(newElement : Element){
        elements.append(newElement)
    }
    
    mutating func dequeue(){
        guard !elements.isEmpty else {
            print("queue is empty")

DanielNo

struct GenericStack<Element>{
    fileprivate var elements : [Element] = []
    
    mutating func pop(){
        guard !elements.isEmpty else{
            return
        }
        elements.removeLast(1)
    }