主页 / coding / 问题 / 77056107
Accepted
BPDev
Asked: 2023-09-07 09:40:08 +0800 CST

如何在@AppStorage中存储字体？

  • 772

我想让用户选择自定义字体。

import SwiftUI

class FontPickerVM: ObservableObject {
    @AppStorage("custom_font") var font: Font? = nil
    // @Published var font: Font? = nil
}

extension Font: RawRepresentable {
    public typealias RawValue = String
    
    
    public init?(rawValue: RawValue) {
        
    }
    
    public var rawValue: RawValue {
        
    }
}

RawRepresentable我该如何实施Font？

我正在使用 aUIFontPickerViewController来选择字体。

import UIKit
import SwiftUI

public struct SUIFontPicker: UIViewControllerRepresentable {
    
    @Environment(\.presentationMode) var presentationMode
    private let onFontPick: (UIFontDescriptor) -> Void
    
    public init(onFontPick: @escaping (UIFontDescriptor) -> Void) {
        self.onFontPick = onFontPick
    }
    
    public func makeUIViewController(context: UIViewControllerRepresentableContext<SUIFontPicker>) -> UIFontPickerViewController {
        let configuration = UIFontPickerViewController.Configuration()
        configuration.includeFaces = true
        configuration.displayUsingSystemFont = false
        
        let vc = UIFontPickerViewController(configuration: configuration)
        vc.delegate = context.coordinator
        return vc
    }
    
    public func makeCoordinator() -> SUIFontPicker.Coordinator {
        return Coordinator(self, onFontPick: self.onFontPick)
    }
    
    public class Coordinator: NSObject, UIFontPickerViewControllerDelegate {
        
        var parent: SUIFontPicker
        private let onFontPick: (UIFontDescriptor) -> Void
        
        
        init(_ parent: SUIFontPicker, onFontPick: @escaping (UIFontDescriptor) -> Void) {
            self.parent = parent
            self.onFontPick = onFontPick
        }
        
        public func fontPickerViewControllerDidPickFont(_ viewController: UIFontPickerViewController) {
            guard let descriptor = viewController.selectedFontDescriptor else { return }
            onFontPick(descriptor)
            parent.presentationMode.wrappedValue.dismiss()
        }
        
        public func fontPickerViewControllerDidCancel(_ viewController: UIFontPickerViewController) {
            parent.presentationMode.wrappedValue.dismiss()
        }
    }
    
    public func updateUIViewController(_ uiViewController: UIFontPickerViewController,
                                       context: UIViewControllerRepresentableContext<SUIFontPicker>) {
        
    }
}

struct FontPicker: View {
    
    @State var isFontPickerPresented = false
    @Environment(\.font) var defaultFont
    
    @StateObject var vm = FontPickerVM()
    
    var body: some View {
        Button {
            isFontPickerPresented = true
            printDetails()
        } label: {
            Text("Select font")
        }
        .sheet(isPresented: $isFontPickerPresented) {
            SUIFontPicker { fontDescriptor in
                let newFont = UIFont(descriptor: fontDescriptor, size: 18)
                vm.font = Font(newFont as CTFont)
                printDetails()
            }
        }
        .font(vm.font)
    }
    
    func printDetails(){
        print("default font:", defaultFont ?? "")
        print("custom font:", vm.font ?? "")
    }
}



struct FontPicker_Previews: PreviewProvider {
    static var previews: some View {
        Form {
            FontPicker()
            FontPicker()
        }
    }
}

我必须指定大小UIFont(descriptor: fontDescriptor, size: 18)，但我只想更改字体系列。

ios

1 个回答

  1. Best Answer

    但我只想更改字体系列。

    如果是这种情况，那么您应该设置configuration.includeFaces为false，以便用户只能选择一个族，而不能选择该族中的面（粗体、斜体等）。

    之后，UIFontDescriptor由 返回 的UIFontPickerViewController应该始终NSFontFamilyAttribute在其 中有一个键fontAttributes。获取该键的值并将其存储在AppStorage.

    例子：

    @AppStorage("customFont") var fontFamily: String?

var customFont: Font {
    if let fontFamily {
        return Font.custom(fontFamily, size: 18)
    } else {
        return .body
    }
}

@State var showSheet = false

var body: some View {
    Text("Foo Bar Baz")
        .font(customFont)
        .onTapGesture {
            showSheet = true
        }
        .sheet(isPresented: $showSheet) {
            SUIFontPicker { desc in
                fontFamily = desc.fontAttributes[.family] as? String
            }
        }
}

    如果您还想保存字体描述符中的其他信息（尽管根据我的经验，a 中的字体描述符UIFontPickerViewController没有太多“其他信息”），您可以Data使用技术上将字体描述符转换为NSKeyedArchiver。然后您可以将其存储Data在@AppStorage.

    let fontData = try? NSKeyedArchiver.archivedData(withRootObject: someFontDescriptor, requiringSecureCoding: true)
// store fontData into AppStorage
    • 1

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