How to make button for Dark Mode - swift

Question

I want to make possibility to switching between dark and light mode on my main screen. I don't want to make it with UISlider, but with just a button. You tap once and its dark mode, you tap again and its light. Is it possible to do?

Answer 1

UIKit
UPDATE
The updated version is more reliable, it checks the overrideUserInterfaceStyle and if it is .unspecified there is a fallback to UIScreen.main.traitCollection.userInterfaceStyle
//
// ViewController.swift
// ToggleInterfaceStyle
//
// Created by Sebastian on 23.09.22.
//
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Here is the button
let toggleInterfaceStyleButton = UIButton()
toggleInterfaceStyleButton.setTitle("Toggle Color Scheme", for: .normal)
toggleInterfaceStyleButton.setTitleColor(.tintColor, for: .normal)
toggleInterfaceStyleButton.frame = CGRect(x: 15, y: -50, width: 250, height: 500)
toggleInterfaceStyleButton.addTarget(self, action: #selector(toggleInterfaceStyle), for: .touchUpInside)
self.view.addSubview(toggleInterfaceStyleButton)
}
#objc func toggleInterfaceStyle() {
let scenes = UIApplication.shared.connectedScenes
let windowScene = scenes.first as? UIWindowScene
let window = windowScene?.windows.first
let interfaceStyle = window?.overrideUserInterfaceStyle == .unspecified ? UIScreen.main.traitCollection.userInterfaceStyle : window?.overrideUserInterfaceStyle
if interfaceStyle != .dark {
window?.overrideUserInterfaceStyle = .dark
} else {
window?.overrideUserInterfaceStyle = .light
}
}
}
SwiftUI
For SwiftUI, you can change the appearance (light mode / dark mode) with .preferredColorScheme, it changes the appearance for the entire app. In this example I added a second view and a navigationLink to show that the styles stays as selected:
import SwiftUI
struct ContentView: View {
#State private var scheme: ColorScheme = .light
#State private var isShowingNewAccountView = false
func toggleScheme() {
if scheme == .light {
scheme = .dark
} else {
scheme = .light
}
}
var body: some View {
NavigationView() {
VStack {
Image(systemName: "globe")
.imageScale(.large)
.foregroundColor(.accentColor)
.padding()
Text("Hello, world!")
.padding()
NavigationLink(destination: SecondView()) {
Text("Second View")
}
Button(action: {
self.toggleScheme()
}) {
Text("Toggle Scheme")
}
.padding()
}
}
.preferredColorScheme(scheme)
}
}
struct SecondView: View {
var body: some View {
VStack {
Image(systemName: "airplane")
.imageScale(.large)
.foregroundColor(.accentColor)
.padding()
Text("Hello, second view!")
.padding()
}
}
}