在回顾了几篇文章后，我为Swift 4创建了自己的字体转换，它涵盖了大多数情况，例如：
1st将字体添加到项目结构和.plist文件（具有相同名称）：
<key>UIAppFonts</key>
<array>
<string>Typo-Light.ttf</string>
<string>Typo-Regular.ttf</string>
<string>Typo-Semibold.ttf</string>
<string>Typo-LightItalic.ttf</string>
</array>
然后
struct Resources {
struct Fonts {
//struct is extended in Fonts
}
}
extension Resources.Fonts {
enum Weight: String {
case light = "Typo-Light"
case regular = "Typo-Regular"
case semibold = "Typo-Semibold"
case italic = "Typo-LightItalic"
}
}
extension UIFontDescriptor.AttributeName {
static let nsctFontUIUsage = UIFontDescriptor.AttributeName(rawValue: "NSCTFontUIUsageAttribute")
}
extension UIFont {
@objc class func mySystemFont(ofSize: CGFloat, weight: UIFont.Weight) -> UIFont {
switch weight {
case .semibold, .bold, .heavy, .black:
return UIFont(name: Resources.Fonts.Weight.semibold.rawValue, size: ofSize)!
case .medium, .regular:
return UIFont(name: Resources.Fonts.Weight.regular.rawValue, size: ofSize)!
default:
return UIFont(name: Resources.Fonts.Weight.light.rawValue, size: ofSize)!
}
}
@objc class func mySystemFont(ofSize size: CGFloat) -> UIFont {
return UIFont(name: Resources.Fonts.Weight.light.rawValue, size: size)!
}
@objc class func myBoldSystemFont(ofSize size: CGFloat) -> UIFont {
return UIFont(name: Resources.Fonts.Weight.semibold.rawValue, size: size)!
}
@objc class func myItalicSystemFont(ofSize size: CGFloat) -> UIFont {
return UIFont(name: Resources.Fonts.Weight.italic.rawValue, size: size)!
}
@objc convenience init(myCoder aDecoder: NSCoder) {
guard
let fontDescriptor = aDecoder.decodeObject(forKey: "UIFontDescriptor") as? UIFontDescriptor,
let fontAttribute = fontDescriptor.fontAttributes[.nsctFontUIUsage] as? String else {
self.init(myCoder: aDecoder)
return
}
var fontName = ""
switch fontAttribute {
case "CTFontRegularUsage", "CTFontMediumUsage":
fontName = Resources.Fonts.Weight.regular.rawValue
case "CTFontEmphasizedUsage", "CTFontBoldUsage", "CTFontSemiboldUsage","CTFontHeavyUsage", "CTFontBlackUsage":
fontName = Resources.Fonts.Weight.semibold.rawValue
case "CTFontObliqueUsage":
fontName = Resources.Fonts.Weight.italic.rawValue
default:
fontName = Resources.Fonts.Weight.light.rawValue
}
self.init(name: fontName, size: fontDescriptor.pointSize)!
}
class func overrideDefaultTypography() {
guard self == UIFont.self else { return }
if let systemFontMethodWithWeight = class_getClassMethod(self, #selector(systemFont(ofSize: weight:))),
let mySystemFontMethodWithWeight = class_getClassMethod(self, #selector(mySystemFont(ofSize: weight:))) {
method_exchangeImplementations(systemFontMethodWithWeight, mySystemFontMethodWithWeight)
}
if let systemFontMethod = class_getClassMethod(self, #selector(systemFont(ofSize:))),
let mySystemFontMethod = class_getClassMethod(self, #selector(mySystemFont(ofSize:))) {
method_exchangeImplementations(systemFontMethod, mySystemFontMethod)
}
if let boldSystemFontMethod = class_getClassMethod(self, #selector(boldSystemFont(ofSize:))),
let myBoldSystemFontMethod = class_getClassMethod(self, #selector(myBoldSystemFont(ofSize:))) {
method_exchangeImplementations(boldSystemFontMethod, myBoldSystemFontMethod)
}
if let italicSystemFontMethod = class_getClassMethod(self, #selector(italicSystemFont(ofSize:))),
let myItalicSystemFontMethod = class_getClassMethod(self, #selector(myItalicSystemFont(ofSize:))) {
method_exchangeImplementations(italicSystemFontMethod, myItalicSystemFontMethod)
}
if let initCoderMethod = class_getInstanceMethod(self, #selector(UIFontDescriptor.init(coder:))),
let myInitCoderMethod = class_getInstanceMethod(self, #selector(UIFont.init(myCoder:))) {
method_exchangeImplementations(initCoderMethod, myInitCoderMethod)
}
}
}
最后Appdelegate在下一个调用创建的方法：
class AppDelegate: UIResponder, UIApplicationDelegate {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
UIFont.overrideDefaultTypography()
return true
}
}