Extensions¶

Swift plays a great role in terms of extending current functionality in a clean code aspect and not cluttering the main class code implementation.

So with extensions you could just extend specific functionality to a specific class by just defining extension className

Colors¶

You could define your colors extension in a separate folder and class file. That would better define your codebase in a cleaner approach. So it could be used anywhere in the project where it takes UIColor or Color class object of any sort.

// Extension Define
import UIKit
extension UIColor {
    static let kautilyaPrimaryColor = #colorLiteral(red: 0.6220935889, green: 0.9803921569, blue: 0.3810976606, alpha: 1)
}

// Utilize
 view.backgroundColor = .kautilyaPrimaryColor

You would get clean code and also direct shorthand autocompletion. Rather than writing verbose code like this

// Define
struct HSColors {
    // Colors
    static let sensehackDarkGrey = UIColor(red: 69/255, green: 69/255, blue: 69/255, alpha: 1)
}

// Utilize
view.backgroundColor = HSColors.sensehackDarkGrey;
// OR
view.backgroundColor = UIColor(red: 0.6220935889, green: 0.9803921569, blue: 0.3810976606, alpha: 1);

Note you can use #colorLiteral(r:g:b:a:); to hide the values of the color itself. Xcode just interprets and abstracts these values with a colored square. Double tap to edit it using the color dialog view or you can see its actual values in git.

Alerts¶

Keyboard¶

Keyboard Dismiss

String Format¶

Value Conversion¶

UIView¶

Gradient Layer¶

Adding a gradient layer to the background UIView object.

import UIKit
extension UIView {
    func addGradient(color1: CGColor,
                 color2: CGColor) {
        let gradientLayer = CAGradientLayer()
        gradientLayer.frame = bounds
        gradientLayer.colors = [color1, color2]
        layer.addSublayer(gradientLayer)
    }
}

https://www.advancedswift.com/gradient-view-background-in-swift/#override-layerclass-to-add-a-cagradientlayer

Class approach which is better due to dynamic layout orientation updates

class GradientView: UIView {
    let gradientLayer: CAGradientLayer = .init()
    init(_ colors: UIColor...) {
        super.init(frame: .zero)
        gradientLayer.frame = bounds
        gradientLayer.colors = colors.map(\.cgColor)
        layer.addSublayer(gradientLayer)
    }
    override func layoutSubviews() {
        super.layoutSubviews()
        gradientLayer.frame = bounds
    }
}

The func layoutSubviews() in my opinion would appropriately deal with framing when the UI is in the process of laying out subviews. Which would be when the user is changing orientation on its physical devices.

Limiting conformance¶

I need to understand the difference between : Type & == Type Would have to check some articles around protocol conformance or extension conformance. I know that one is a protocol type and one is element reference check or something which is more expensive on CPU.

: Type

extension Assert where TestValueType: Collection {
    public func isEmpty(message: @autoclosure () -> String = "", file: StaticString = #filePath, line: UInt = #line) {

        XCTAssertTrue(testValue.isEmpty, message(), file: file, line: line)

    }
}

== Type

extension Assert where TestValueType == Array<Any> {
    public func isEmpty(message: @autoclosure () -> String = "", file: StaticString = #filePath, line: UInt = #line) {

        XCTAssertTrue(testValue.isEmpty, message(), file: file, line: line)

    }
}