Wei Wang onevcat

用户体验和布局进阶

PokeMaster app 现在已经是一个具有完整功能的 SwiftUI app 了。麻雀虽小，五脏俱全，在这个示例 app 里，我们涉及到了一个一般性的 iOS app 所需要的大部分内容：


	import SwiftUI

	struct ContentView: View {

	@State var offset: CGFloat = 0.0
	@State var previousOffset: CGFloat = 0.0

	init() {
	let appearance = UINavigationBarAppearance()

	```swift
	actor GiftCache {
	private(set) var cachedGifts: [GiftId: CachedGift] = [:]

	// this method would be caller by other parts
	func add(gift: CachedGift) {
	cachedGifts[gift.giftId] = gift
	//...
	}

	// https://github.com/pointfreeco/swift-composable-architecture/discussions/488#discussioncomment-591715

	@propertyWrapper
	public struct CoW<T> {
	private final class Ref {
	var val: T
	init(_ v: T) { val = v }
	}
	private var ref: Ref

	protocol P: AnyObject { }
	class A: P {}

	Runtime.classes(conformTo: P.Type.self) // [MyApp.A]

	class Runtime {

	public static func allClasses() -> [AnyClass] {
	let numberOfClasses = Int(objc_getClassList(nil, 0))
	if numberOfClasses > 0 {

	import UIKit

	protocol DefaultValue {
	associatedtype Value: Decodable
	static var defaultValue: Value { get }
	}

	@propertyWrapper
	struct Default<T: DefaultValue> {
	var wrappedValue: T.Value

	//: A UIKit based Playground for presenting user interface

	import UIKit
	import PlaygroundSupport

	public protocol TrafficLightOption {
	associatedtype Value

	/// 默认的选项值
	static var defaultValue: Value { get }

	import Combine
	import Foundation

	extension Publishers {
	struct ZipAll<Collection: Swift.Collection>: Publisher
	where Collection.Element: Publisher
	{
	typealias Output = [Collection.Element.Output]
	typealias Failure = Collection.Element.Failure

	class CabalInstall < Formula
	desc "Command-line interface for Cabal and Hackage"
	homepage "https://www.haskell.org/cabal/"
	url "https://hackage.haskell.org/package/cabal-install-2.4.1.0/cabal-install-2.4.1.0.tar.gz"
	sha256 "69bcb2b54a064982412e1587c3c5c1b4fada3344b41b568aab25730034cb21ad"
	head "https://github.com/haskell/cabal.git", :branch => "2.4"

	bottle do
	cellar :any_skip_relocation
	sha256 "4c9ad9914b483ffb64f4449bd6446cb8c0ddfeeff42eddde9137884af3471825" => :mojave