10 little UIKit ideas you must know

Customized UIColor with darkish mode help

Darkish mode and light-weight mode should not comply with the very same design patterns, typically you need to make use of a border when your app is in mild mode, however in darkish mode you may need to disguise the additional line.

One doable answer is to outline a customized UIColor primarily based the given UITraitCollection. You may examine the userInterfaceStyle property of a trait to examine for darkish look model.

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

Based mostly on this situation you possibly can simply return totally different colours each for mild and darkish mode. You may create your personal set of static shade variables by extending the UIColor object. It is a should have little trick if you’re 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, typically you’d prefer to detect look adjustments of the person interface and that is the place the traitCollectionDidChange operate may be useful. It is accessible on views, controllers and cells too, so it is fairly an common answer.

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 possibly can examine if the trait assortment has a special look model and you’ll replace your CoreGraphics layers in line with that. The CoreGraphics framework is a low stage device and if you happen to work with layers and colours it’s a must to manually replace them if it involves darkish mode help, however the traitCollectionDidChange methodology may help you numerous. 💡

UIButton with context menus

Creating buttons bought lots simpler with iOS 15, however do you know that you could additionally use a button to show a context menu? It’s totally straightforward to current a UIMenu you simply should 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",
              youngsters: [
                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 manner the UIButton will act as a menu button, you possibly can assign numerous actions to your menu merchandise. I imagine this API is particularly helpful in some circumstances, these days I choose to make use of context menus as a substitute of swipe-to-x-y actions, as a result of it is a bit extra handy for the person if we visually present them (often with 3 dots) that there are extra actions accessible on a given UI ingredient. 🧐

Do not be afraid of subclassing views

UIKit is an OOP framework and I extremely suggest to subclass customized views as a substitute 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",
              youngsters: [
                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 possibly can see the code contained in the view controller is closely diminished and many of the button configuration associated logic is now encapsulated contained in the MenuButton subclass. This strategy is nice as a result of you possibly can focus much less on view configuration and extra on your enterprise logic contained in the view controller. It’s going to additionally show you how to to assume in reusable elements.

One extra be aware right here is that I are likely 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 staff cannot name them by accident, however that is only a private desire. 😅

At all times massive navigation title

I do not find out about you, however for me all of the apps have glitches if it involves the massive title characteristic within the navigation bar. For private initiatives I’ve bought sick and uninterested in this and I merely power the massive title show mode. It is comparatively easy, this is easy 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 should set two properties (you possibly can subclass UINavigationController or set these inside your view controller, however I choose subclassing) plus it’s a must to add an empty view to your view hierarchy to forestall collapsing if you’re 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 desire, I’ve additionally included a couple of extra customization choices within the snippet. In the event you check out the initialize methodology you possibly can see easy methods to change the tint shade and the background shade of the navigation bar. 👍

Customized separators for navigation and tab bars

Since many apps choose to have a custom-made navigation bar and tab bar look it is fairly a standard observe when it’s a must to additionally add a separator line to tell apart person interface components a bit extra. That is how one can clear up it through the use of 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 manner you possibly can 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 ought 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: "Residence", picture: UIImage(systemName: "home"), selectedImage: nil)

I would additionally like to say that SF Symbols are wonderful. If you’re not utilizing these sort of icons simply but I extremely suggest to have a look. Apple made a very nice job with this assortment, there are such a lot of pretty icons that you need to use 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 methodology and configure your views contained in the viewDidLoad operate.

I all the time use implicitly unwrapped weak elective 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 need 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 would go along with a customized subclass for the gathering view right here as effectively and possibly outline a configure methodology then name that one as a substitute of inserting every little thing on to the controller. The choice is all the time up-to-you, I am simply making an attempt to indicate you the some doable options. 😉

Stack views & auto-layout anchors

Make the most of stack views and auto structure anchors as a lot as doable. If you will create person interfaces programmatically in Swift with the assistance of UIKit, then it’ll be a necessary talent to grasp these methods in any other case you are going to battle lots.

I have already got a tutorial about utilizing auto structure programmatically and one other one about mastering auto-layout anchors, they had been revealed a couple of years in the past, however the ideas are nonetheless legitimate and the code nonetheless works. I even have another article that you must learn if you wish to study about constructing varieties utilizing stack views. Studying these sort of issues helped me lots to create complicated screens hassle-free. I am additionally utilizing another “finest observe” to create assortment views.

When SwiftUI got here out I had the sensation that ultimately I would do the identical with UIKit, however in fact Apple had the mandatory tooling to help the framework with view builders and property wrappers. Now that we’ve got SwiftUI I am nonetheless not utilizing it as a result of I really feel prefer it lacks various 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 fancy software my intestine tells me that I ought to nonetheless go along with UIKit. 🤐

Create a reusable elements library

My remaining recommendation on this tutorial is that you must construct a customized Swift bundle and transfer all of your elements there. Possibly for the primary time it’ll eat various time however if you’re engaged on a number of initiatives it can velocity up improvement course of on your second, third, and so on. app.

You may transfer all of your customized base courses right into a separate library and create particular ones on your software. You simply should mark them open, you need to use the provision API to handle what can be utilized and what ought to be marked as unavailable.

I’ve various tutorials in regards to the Swift Bundle Supervisor on my weblog, it is a nice approach to get conversant in it and you can begin constructing your personal library step-by-step. 😊