iOS 13 中推出了暗黑模式，可以给用户沉浸式的体验。其主要原理：
一个资源创建两种样式。系统根据当前的UserInterfaceStyle 获取对应的样式资源;
每次系统更新样式时，应用会调用当前所有存在的元素调用对应的一些重新方法，进行重绘视图，可以在对应的方法做相应的改动;
UserInterfaceStyle 共有3中状态,如果不设置跟随系统，默认的初始状态是：unspecified
@available(iOS 12.0, *)
public enum UIUserInterfaceStyle : Int {
case unspecified = 0
case light = 1
case dark = 2
}
系统调用更新方法，自定义重绘视图
UIView
traitCollectionDidChange(_:)
layoutSubviews()
draw(_:)
updateConstraints()
tintColorDidChange()
UIViewController
traitCollectionDidChange(_:)
updateViewConstraints()
viewWillLayoutSubviews()
viewDidLayoutSubviews()
UIPresentationController
traitCollectionDidChange(_:)
containerViewWillLayoutSubviews()
containerViewDidLayoutSubviews()
颜色适配
在iOS 13中提供了以下方法：
+ (UIColor *)colorWithDynamicProvider:(UIColor * (^)(UITraitCollection *))dynamicProvider API_AVAILABLE(ios(13.0), tvos(13.0)) API_UNAVAILABLE(watchos);
- (UIColor *)initWithDynamicProvider:(UIColor * (^)(UITraitCollection *))dynamicProvider API_AVAILABLE(ios(13.0), tvos(13.0)) API_UNAVAILABLE(watchos);
可以根据对应的 UserInterfaceStyle 调用不同的颜色
我们可以根据这两个方法，创建对应的分类 UIColor+Extension.swift
extension UIColor {
static func dynamicColor(_ lightColor: UIColor, darkColor: UIColor? = UIColor.white) -> UIColor {
if #available(iOS 13.0, *) {
return UIColor.init { (traitCollection) -> UIColor in
if traitCollection.userInterfaceStyle == .light {
return lightColor
}else{
return darkColor!
}
}
} else {
return lightColor
}
}
}
图片适配
打开 Assets.xcassets
找到对应的图片
图片
我们在右侧工具栏中点击最后一栏，点击 Appearances 选择 Any, Dark，如图所示
右侧工具栏
把 DarkMode 的图片拖进去，如图所示
dark Image
富文本适配
基于颜色适配的方法，对应修改
let attrLabel = UILabel.init(frame: .init(x: 30, y: 200, width: 200, height: 30))
view.addSubview(attrLabel)
let attr = NSMutableAttributedString.init(string: "这是", attributes: [NSAttributedString.Key.foregroundColor : UIColor.dynamicColor(UIColor.red, darkColor: UIColor.orange)])
attr.append(NSAttributedString.init(string: "富文本", attributes: [NSAttributedString.Key.foregroundColor : UIColor.dynamicColor(UIColor.black, darkColor: UIColor.white)]))
attrLabel.attributedText = attr
Light Mode
Dark Mode
导航栏适配
适配返回按钮
返回按钮使用自定义图片，对应的图片做好Dark Mode 适配.
根据返回按钮图片设置对应的按钮 UIButton
使用 UIBarButtonItem.init(customView: button) 设置导航栏的 leftBarButtonItem
import UIKit
class SSNavigationController: UINavigationController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func pushViewController(_ viewController: UIViewController, animated: Bool) {
if self.viewControllers.count > 0 {
let button = UIButton.init(type: .custom)
button.setImage(UIImage.init(named: "back"), for: .normal)
button.setImage(UIImage.init(named: "back"), for: .highlighted)
button.frame = .init(x: 0, y: 0, width: 30, height: 30)
button.addTarget(self, action: #selector(clickBack), for: .touchUpInside)
viewController.navigationItem.leftBarButtonItem = UIBarButtonItem.init(customView: button)
viewController.hidesBottomBarWhenPushed = true
}
super.pushViewController(viewController, animated: animated)
self.interactivePopGestureRecognizer?.delegate = nil
}
@objc
private func clickBack() -> () {
self.popViewController(animated: true)
}
}
标签栏适配
UITabBarController 的适配，并不适用于上面的 颜色适配、图片适配，标签栏上每个 tabBarItem, 要有对应的4张图片，dark 模式下的: dark, dark_selected; light 模式下的：light，light_selected；
import UIKit
class SSTabBarVC: UITabBarController {
override func viewDidLoad() {
super.viewDidLoad()
// let home = SSNavigationController.init(rootViewController: HomeVC())
// home.tabBarItem.image = UIImage.init(named: "home_light")?.withRenderingMode(.alwaysOriginal)
// home.tabBarItem.selectedImage = UIImage.init(named: "home_selected_light")?.withRenderingMode(.alwaysOriginal)
// home.title = "Home"
//// home.tabBarItem.imageInsets = UIEdgeInsets(top: 8, left: 0, bottom: -6, right: 0)
// home.tabBarItem.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.red], for: .selected)
// home.tabBarItem.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.lightGray], for: .normal)
// addChild(home)
addChildController(viewController: HomeVC(), title: "home", imageName: "home", selectedImageName: "home_selected", textColor: UIColor.lightGray, selectedTextColor: UIColor.red, darkTextColor: UIColor.white, darkSelectedTextColor: UIColor.green)
let mine = SSNavigationController.init(rootViewController: MineVC())
mine.title = "Mine"
addChild(mine)
self.selectedIndex = 0
}
private
func addChildController(viewController: UIViewController, title: String? = "" ,imageName: String, selectedImageName: String, textColor: UIColor? = UIColor.white, selectedTextColor: UIColor? = UIColor.black, darkTextColor: UIColor? = UIColor.white, darkSelectedTextColor: UIColor? = UIColor.black) {
let nav = SSNavigationController.init(rootViewController: viewController)
nav.title = title
if #available(iOS 13.0, *), UIApplication.shared.keyWindow?.overrideUserInterfaceStyle == UIUserInterfaceStyle.dark{
setupNaviagtionController(naviagtionController: nav, imageName: "\(imageName)_dark", selectedImageName: "\(selectedImageName)_dark", textColor: darkTextColor, selectedTextColor: darkSelectedTextColor)
}else{
setupNaviagtionController(naviagtionController: nav, imageName: "\(imageName)_light", selectedImageName: "\(selectedImageName)_light", textColor: textColor, selectedTextColor: selectedTextColor)
}
self.addChild(nav)
}
private
func setupNaviagtionController(naviagtionController: UIViewController, imageName: String, selectedImageName: String, textColor: UIColor? = UIColor.white, selectedTextColor: UIColor? = UIColor.black){
naviagtionController.tabBarItem.image = UIImage.init(named: imageName)?.withRenderingMode(.alwaysOriginal)
naviagtionController.tabBarItem.selectedImage = UIImage.init(named: selectedImageName)?.withRenderingMode(.alwaysOriginal)
naviagtionController.tabBarItem.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: selectedTextColor ?? UIColor.black], for: .selected)
naviagtionController.tabBarItem.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: textColor ?? UIColor.white], for: .normal)
naviagtionController.tabBarItem.imageInsets = UIEdgeInsets(top: 8, left: 0, bottom: -6, right: 0)
}
}
TabBarController 动态修改颜色：
override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
super.traitCollectionDidChange(previousTraitCollection)
for nav in children {
let index = children.firstIndex(of: nav)
if index == 0 {
if #available(iOS 12.0, *) {
/// 先前的是 dark mode
if previousTraitCollection?.userInterfaceStyle == .dark {
setupNaviagtionController(naviagtionController: nav, imageName: "home_light", selectedImageName: "home_selected_light", textColor: UIColor.lightGray, selectedTextColor: UIColor.red)
}else {
setupNaviagtionController(naviagtionController: nav, imageName: "home_dark", selectedImageName: "home_selected_dark", textColor: UIColor.white, selectedTextColor: UIColor.green)
}
}else {
// Fallback on earlier versions
}
}
}
}
在这里面也尝试了使用：
naviagtionController.tabBarItem.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: textColor ?? UIColor.white], for: .normal)
来设置对应的文字颜色，但是效果并不理想，仍然会出现系统的蓝色字体
因此，建议：tabBarItem 全部使用切图，切图中放入对应文字。
App 内全局修改 userInterfaceStyle
func tapForSwitch() {
if #available(iOS 13.0, *) {
if UIApplication.shared.keyWindow?.overrideUserInterfaceStyle == UIUserInterfaceStyle.dark {
UIApplication.shared.keyWindow?.overrideUserInterfaceStyle = .light
SSUserDefaultsConfig.currentUserInterfaceStyle = "light"
}else if UIApplication.shared.keyWindow?.overrideUserInterfaceStyle == UIUserInterfaceStyle.light {
UIApplication.shared.keyWindow?.overrideUserInterfaceStyle = .dark
SSUserDefaultsConfig.currentUserInterfaceStyle = "dark"
}else{
UIApplication.shared.keyWindow?.overrideUserInterfaceStyle = .light
SSUserDefaultsConfig.currentUserInterfaceStyle = "light"
}
} else {
}
}
某个 ViewController 不遵循暗黑模式
class HomeVC: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor.dynamicColor(.white, darkColor: .gray)
if #available(iOS 13.0, *) {
self.overrideUserInterfaceStyle = .light
} else {
// Fallback on earlier versions
}
}
}
DarkMode跟随系统
/// 跟随系统的dark Mode
window?.overrideUserInterfaceStyle = UITraitCollection.current.userInterfaceStyle
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