2021-09-25 权限控制 改名 代码清理 类型推断

权限控制 private private(set)
改名 command+左键
代码清理 typealias Card = MemoryGame<String>.Card
类型推断 1，保留函数 -> 的类型 其他做推断 2，保留变量里的类型 下面做推断
计算属性

MemorizeApp.swift -------------

import SwiftUI

@main
struct MemorizeApp: App {
   private let game = EmojiMemoryGame()
    var body: some Scene {
        WindowGroup {
            EmojiMemoryGameView(game: game)
        }
    }
}

EmojiMemoryGameView.swift------------------------

import SwiftUI

struct EmojiMemoryGameView: View {

    @ObservedObject var game: EmojiMemoryGame
    var body: some View {
        
        ScrollView {
            LazyVGrid(columns: [GridItem(.adaptive(minimum: 65))]){
                ForEach(game.cards) { card in
                    CardView(card).aspectRatio(2/3, contentMode: .fit)
                        .onTapGesture {
                            game.choose(card)
                        }
                }
            }
        }
        .foregroundColor(.red)
        
        .padding(.horizontal)
        
    }

}

struct CardView: View {
    private let card: EmojiMemoryGame.Card
    
    //这里如果有init 则可以把card设置为private，通过init访问，CardView(card: card) 则成CardView(card)
//    private var card: EmojiMemoryGame.Card
    init(_ card: EmojiMemoryGame.Card) {
        self.card = card //后参前变，my card = 传过来的card
    }
    
    var body: some View {
        ZStack {
            let shape = RoundedRectangle(cornerRadius: 20)
            if card.isFaceUp {
                shape.fill().foregroundColor(.white)
                shape.strokeBorder(lineWidth: 3)
                Text(card.content).font(.largeTitle)
                
            } else if card.isMatched {
                shape.opacity(0)
            }
            else {
                shape.fill()
            }
        }
    }
}


struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        let game = EmojiMemoryGame()
        EmojiMemoryGameView(game: game)
            .preferredColorScheme(/*@START_MENU_TOKEN@*/.dark/*@END_MENU_TOKEN@*/)
        EmojiMemoryGameView(game: game)
            .preferredColorScheme(.light)
    }
}

MemoryGame.swift -------------------

import Foundation

struct MemoryGame<CardContent> where CardContent: Equatable {
    private(set) var cards: Array<Card>
    
    private var indexOfTheOneAndOnlyFaceUpCard: Int?
    
    mutating func choose(_ card: Card) {
        if let chosenIndex = cards.firstIndex(where: { $0.id == card.id }),
           !cards[chosenIndex].isMatched,
           !cards[chosenIndex].isFaceUp
           {
            if let potentialIndex = indexOfTheOneAndOnlyFaceUpCard {
                if cards[chosenIndex].content == cards[potentialIndex].content {
                    cards[chosenIndex].isMatched = true
                    cards[potentialIndex].isMatched = true
                }
                indexOfTheOneAndOnlyFaceUpCard = nil
            } else {
                for index in cards.indices {
                    cards[index].isFaceUp = false
                }
                indexOfTheOneAndOnlyFaceUpCard = chosenIndex
            }
            cards[chosenIndex].isFaceUp.toggle()
        }
    }
    
    init(numberOfPairOfCards: Int, createCardContent: (Int) -> CardContent) {
        cards = []
        for pairIndex in 0..<numberOfPairOfCards {
            let content = createCardContent(pairIndex)
            cards.append(Card(content: content, id: pairIndex*2))
            cards.append(Card(content: content, id: pairIndex*2+1))
        }
    }
    
    struct Card:Identifiable {
        var isFaceUp = false
        var isMatched = false
        let content: CardContent
        let id: Int
    }
}

EmojiMemoryGame.swift -------------------

import SwiftUI

class EmojiMemoryGame: ObservableObject {
    typealias Card = MemoryGame<String>.Card
    
    private static var emojis = ["🪓", "🚙", "🚗", "⛱", "🎡", "🪝", "🗿", "🛖", "⏱", "☎️", "🎰","🚜","🛴", "✈️"]
    
    private static func createMemoryGame() -> MemoryGame<String> {
        MemoryGame<String>(numberOfPairOfCards: 4){ pairIndex in emojis[pairIndex]}
    }
    @Published private var model = createMemoryGame()
    
    var cards: Array<Card> {
        return model.cards
    }
    
    func choose(_ card: Card) {
        return model.choose(card)
    }
}