10 little UIKit ideas you must know

Customized UIColor with darkish mode help

Darkish mode and lightweight mode should not comply with the very same design patterns, generally you need to make use of a border when your app is in gentle mode, however in darkish mode you would possibly wish to disguise the additional line.

One doable resolution is to outline a customized UIColor primarily based the given UITraitCollection. You’ll be able to verify the userInterfaceStyle property of a trait to verify for darkish look fashion.

extension UIColor {
    static var borderColor: UIColor {
        .init { (trait: UITraitCollection) -> UIColor in
            if trait.userInterfaceStyle == .darkish {
                return UIColor.clear
            }
            return UIColor.systemGray4
        }
    }
}

Primarily based on this situation you’ll be able to simply return totally different colours each for gentle and darkish mode. You’ll be able to create your personal set of static colour variables by extending the UIColor object. It is a will need to have little trick in case you are planning to help darkish mode and also you’d prefer to create customized colours. 🌈

Observing trait assortment adjustments

This subsequent one can also be associated to darkish mode help, generally you’d prefer to detect look adjustments of the consumer interface and that is the place the traitCollectionDidChange operate will be useful. It is accessible on views, controllers and cells too, so it is fairly an common resolution.

class MyCustomView: UIView {
    override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
        guard traitCollection.hasDifferentColorAppearance(comparedTo: previousTraitCollection) else {
            return
        }
        layer.borderColor = UIColor.borderColor.cgColor
    }
}

For instance, inside this operate you’ll be able to verify if the trait assortment has a unique look fashion and you’ll replace your CoreGraphics layers in line with that. The CoreGraphics framework is a low degree device and in case you work with layers and colours you must manually replace them if it involves darkish mode help, however the traitCollectionDidChange technique may help you numerous. 💡

UIButton with context menus

Creating buttons received loads simpler with iOS 15, however do you know that you may additionally use a button to show a context menu? It is very straightforward to current a UIMenu you simply must set the menu and the showsMenuAsPrimaryAction property of the button to true.

import UIKit

class TestViewController: UIViewController {
    
    weak var button: UIButton!

    override func loadView() {
        tremendous.loadView()
     
        let button = UIButton(body: .zero)
        button.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(button)
        self.button = button

        NSLayoutConstraint.activate([
            button.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            button.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            button.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            button.heightAnchor.constraint(equalToConstant: 44),
        ])
    }

    override func viewDidLoad() {
        tremendous.viewDidLoad()

        button.setTitle("Open menu", for: .regular)
        button.setTitleColor(.systemGreen, for: .regular)
        button.menu = getContextMenu()
        button.showsMenuAsPrimaryAction = true
    }

    func getContextMenu() -> UIMenu {
        .init(title: "Menu",
              kids: [
                UIAction(title: "Edit", image: UIImage(systemName: "square.and.pencil")) { _ in
                    print("edit button clicked")
                },
                UIAction(title: "Delete", image: UIImage(systemName: "trash"), attributes: .destructive) { _ in
                    print("delete action")
                },
              ])
    }
    
}

This fashion the UIButton will act as a menu button, you’ll be able to assign numerous actions to your menu merchandise. I imagine this API is particularly helpful in some instances, these days I desire to make use of context menus as an alternative of swipe-to-x-y actions, as a result of it’s kind of extra handy for the consumer if we visually present them (often with 3 dots) that there are extra actions accessible on a given UI component. 🧐

Do not be afraid of subclassing views

UIKit is an OOP framework and I extremely advocate to subclass customized views as an alternative of multi-line view configuration code snippets inside your view controller. The earlier code snippet is a superb instance for the other, so let’s repair that actual fast.

import UIKit

class MenuButton: UIButton {

    @accessible(*, unavailable)
    override init(body: CGRect) {
        tremendous.init(body: body)
        
        self.initialize()
    }

    @accessible(*, unavailable)
    required public init?(coder: NSCoder) {
        tremendous.init(coder: coder)
        
        self.initialize()
    }
   
    public init() {
        tremendous.init(body: .zero)
        
        self.initialize()
    }
    
    open func initialize() {
        self.translatesAutoresizingMaskIntoConstraints = false

        setTitle("Open menu", for: .regular)
        setTitleColor(.systemGreen, for: .regular)
        menu = getContextMenu()
        showsMenuAsPrimaryAction = true
    }
    
    func getContextMenu() -> UIMenu {
        .init(title: "Menu",
              kids: [
                UIAction(title: "Edit", image: UIImage(systemName: "square.and.pencil")) { _ in
                    print("edit button clicked")
                },
                UIAction(title: "Delete", image: UIImage(systemName: "trash"), attributes: .destructive) { _ in
                    print("delete action")
                },
              ])
    }

    func layoutConstraints(in view: UIView) -> [NSLayoutConstraint] {
        [
            centerYAnchor.constraint(equalTo: view.centerYAnchor),
            leadingAnchor.constraint(equalTo: view.leadingAnchor),
            trailingAnchor.constraint(equalTo: view.trailingAnchor),
            heightAnchor.constraint(equalToConstant: 44),
        ]
    }
}


class TestViewController: ViewController {
    
    weak var button: MenuButton!

    override func loadView() {
        tremendous.loadView()
     
        let button = MenuButton()
        view.addSubview(button)
        self.button = button
        NSLayoutConstraint.activate(button.layoutConstraints(in: view))
    }

    override func viewDidLoad() {
        tremendous.viewDidLoad()
        
    }
}

As you’ll be able to see the code contained in the view controller is closely lowered and a lot of the button configuration associated logic is now encapsulated contained in the MenuButton subclass. This strategy is nice as a result of you’ll be able to focus much less on view configuration and extra on your corporation logic contained in the view controller. It will additionally enable you to assume in reusable parts.

One extra observe right here is that I are inclined to create my interfaces from code that is why I mark the pointless init strategies with the @accessible(*, unavailable) flag so different individuals in my group cannot name them by accident, however that is only a private choice. 😅

At all times massive navigation title

I do not learn about you, however for me all of the apps have glitches if it involves the massive title function within the navigation bar. For private tasks I’ve received sick and bored with this and I merely pressure the massive title show mode. It is comparatively easy, here is methods to do it.

import UIKit

class TestNavigationController: UINavigationController {

    override init(rootViewController: UIViewController) {
        tremendous.init(rootViewController: rootViewController)
        
        initialize()
    }

    @accessible(*, unavailable)
    required init?(coder aDecoder: NSCoder) {
        tremendous.init(coder: aDecoder)

        initialize()
    }
    
    open func initialize() {
        navigationBar.prefersLargeTitles = true
        navigationItem.largeTitleDisplayMode = .all the time
        
        
        navigationBar.tintColor = .systemGreen
        
        let navBarAppearance = UINavigationBarAppearance()
        navBarAppearance.backgroundColor = .systemBackground
        navigationBar.standardAppearance = navBarAppearance
        navigationBar.scrollEdgeAppearance = navBarAppearance
    }
}

class TestViewController: UIViewController {
    
    override func loadView() {
        tremendous.loadView()
        
        
        view.addSubview(UIView(body: .zero))
        
        
    }
}

let controller = TestNavigationController(rootViewController: TestViewController())

You simply must set two properties (you’ll be able to subclass UINavigationController or set these inside your view controller, however I desire subclassing) plus you must add an empty view to your view hierarchy to forestall collapsing in case you are planning to make use of a UIScrollView, UITableView or UICollectionView contained in the view controller.

Since this tip can also be primarily based on my private choice, I’ve additionally included a couple of extra customization choices within the snippet. When you check out the initialize technique you’ll be able to see methods to change the tint colour and the background colour of the navigation bar. 👍

Customized separators for navigation and tab bars

Since many apps desire to have a personalized navigation bar and tab bar look it is fairly a typical observe when you must additionally add a separator line to differentiate consumer interface components a bit extra. That is how one can remedy it by utilizing a single bar separator class.

import UIKit 

class BarSeparator: UIView {
    
    let peak: CGFloat = 0.3

    init() {
        tremendous.init(body: CGRect(x: 0, y: 0, width: 0, peak: peak))
        
        translatesAutoresizingMaskIntoConstraints = false
        backgroundColor = .systemGray4
    }
    
    @accessible(*, unavailable)
    required init?(coder: NSCoder) {
        tremendous.init(coder: coder)
    }
    
    func layoutConstraints(for navigationBar: UINavigationBar) -> [NSLayoutConstraint] {
        [
            widthAnchor.constraint(equalTo: navigationBar.widthAnchor),
            heightAnchor.constraint(equalToConstant: CGFloat(height)),
            centerXAnchor.constraint(equalTo: navigationBar.centerXAnchor),
            topAnchor.constraint(equalTo: navigationBar.bottomAnchor),
        ]
    }
    
    func layoutConstraints(for tabBar: UITabBar) -> [NSLayoutConstraint] {
        [
            widthAnchor.constraint(equalTo: tabBar.widthAnchor),
            heightAnchor.constraint(equalToConstant: CGFloat(height)),
            centerXAnchor.constraint(equalTo: tabBar.centerXAnchor),
            topAnchor.constraint(equalTo: tabBar.topAnchor),
        ]
    }
}

class MyNavigationController: UINavigationController {
    
   override func viewDidLoad() {
        tremendous.viewDidLoad()
        
        let separator = BarSeparator()
        navigationBar.addSubview(separator)
        NSLayoutConstraint.activate(separator.layoutConstraints(for: navigationBar))
    }
}

class MyTabBarController: UITabBarController {
    
    override func viewDidLoad() {
        tremendous.viewDidLoad()
        
        let separator = BarSeparator()
        tabBar.addSubview(separator)
        NSLayoutConstraint.activate(separator.layoutConstraints(for: tabBar))
    }   
}

This fashion you’ll be able to reuse the BarSeparator element so as to add a line to the underside of a navigation bar and to the highest of a tab bar. This snippet follows the very same rules that I confirmed you earlier than, so you need to be conversant in the subclassing ideas by now. 🤓

Customized tab bar objects

I struggled rather a lot with tab bar merchandise icon alignment, however this the way in which I can simply present / disguise the title and align the icons to the middle of the bar if there are not any labels.

import UIKit

class MyTabBarItem: UITabBarItem {
    
    override var title: String? {
        get { hideTitle ? nil : tremendous.title }
        set { tremendous.title = newValue }
    }
        
    non-public var hideTitle: Bool {
        true
    }

    non-public func offset(_ picture: UIImage?) -> UIImage? {
        if hideTitle {
            return picture?.withBaselineOffset(fromBottom: 12)
        }
        return picture
    }
    
    
    
    public comfort init(title: String?, picture: UIImage?, selectedImage: UIImage?) {
        self.init()

        self.title = title
        self.picture = offset(picture)
        self.selectedImage = offset(selectedImage)
    }

    override init() {
        tremendous.init()
    }

    @accessible(*, unavailable)
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been applied")
    }
}


tabBarItem = MyTabBarItem(title: "Dwelling", picture: UIImage(systemName: "home"), selectedImage: nil)

I might additionally like to say that SF Symbols are superb. If you’re not utilizing these type of icons simply but I extremely advocate to have a look. Apple made a very nice job with this assortment, there are such a lot of beautiful icons that you should utilize to visually enrich your app, so do not miss out. 😊

loadView vs viewDidLoad

Lengthy story quick, you must all the time instantiate and place constraints to your views contained in the loadView technique and configure your views contained in the viewDidLoad operate.

I all the time use implicitly unwrapped weak non-compulsory variables for customized views, because the addSubview operate will create a robust reference to the view when it’s added to the view hierarchy. We do not wish to have retain cycles, proper? That’d be actual dangerous for our software. 🙃

import UIKit

class MyCollectionViewController: ViewController {
    
    weak var assortment: UICollectionView!

    override func loadView() {
        tremendous.loadView()
        
        view.addSubview(UIView(body: .zero))
        
        let assortment = UICollectionView(body: .zero, collectionViewLayout: UICollectionViewFlowLayout())
        assortment.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(assortment)
        self.assortment = assortment
        NSLayoutConstraint.activate([
            
        ])
    }
    
    override func viewDidLoad() {
        tremendous.viewDidLoad()
        
        assortment.backgroundColor = .systemBackground
        assortment.alwaysBounceVertical = true
        assortment.dragInteractionEnabled = true
        assortment.dragDelegate = self
        assortment.dropDelegate = self

        if let flowLayout = assortment.collectionViewLayout as? UICollectionViewFlowLayout {
            flowLayout.sectionHeadersPinToVisibleBounds = true
        }
        
        assortment.register(MyCell.self,
                            forCellWithReuseIdentifier: MyCell.identifier)
    }

Anyway, I might go together with a customized subclass for the gathering view right here as nicely and possibly outline a configure technique then name that one as an alternative of inserting every thing on to the controller. The choice is all the time up-to-you, I am simply attempting to indicate you the some doable options. 😉

Stack views & auto-layout anchors

Reap the benefits of stack views and auto structure anchors as a lot as doable. If you’ll create consumer interfaces programmatically in Swift with the assistance of UIKit, then it is going to be a vital ability to grasp these methods in any other case you are going to battle loads.

I have already got a tutorial about utilizing auto structure programmatically and one other one about mastering auto-layout anchors, they had been printed a couple of years in the past, however the ideas are nonetheless legitimate and the code nonetheless works. I even have yet one more article that you must learn if you wish to be taught about constructing types utilizing stack views. Studying these type of issues helped me loads to create advanced screens hassle-free. I am additionally utilizing yet one more “greatest observe” to create assortment views.

When SwiftUI got here out I had the sensation that ultimately I might do the identical with UIKit, however after all Apple had the mandatory tooling to help the framework with view builders and property wrappers. Now that now we have SwiftUI I am nonetheless not utilizing it as a result of I really feel prefer it lacks numerous options even in 2022. I do know it is nice and I’ve created a number of prototypes for screens utilizing it, but when it involves a posh software my intestine tells me that I ought to nonetheless go together with UIKit. 🤐

Create a reusable parts library

My closing recommendation on this tutorial is that you must construct a customized Swift bundle and transfer all of your parts there. Possibly for the primary time it is going to eat numerous time however in case you are engaged on a number of tasks it would velocity up growth course of to your second, third, and many others. app.

You’ll be able to transfer all of your customized base lessons right into a separate library and create particular ones to your software. You simply must mark them open, you should utilize the provision API to handle what can be utilized and what needs to be marked as unavailable.

I’ve numerous tutorials concerning the Swift Package deal Supervisor on my weblog, this can be a nice method to get conversant in it and you can begin constructing your personal library step-by-step. 😊