SwiftUI 学习笔记 31：项目 5-3 挑战

巨石强森（Dwayne“ The Rock” Johnson）曾经说过：“成功并不总是与伟大有关，而是与一致性有关。一贯的努力导致成功；伟大将会来临。”

挑战

不允许答案少于三个字母或与我们的起始单词相同。对于三字母检查，最简单的操作是将一个检查放入isReal()，如果单词长度在三个字母以下，则返回false。对于第二部分，只需将起始词与输入词进行比较，如果相同则返回false。
添加一个称为的左键按钮项startGame()，以便用户可以在需要时以一个新单词重新启动。
在下方放置一个文本视图，List以便你可以跟踪并显示给定根词的玩家得分。如何计算分数取决于你，但是涉及单词数量及其字母数的内容是合理的。

自定的得分规则

拼写的单词所含字母数量	3	4	5	6	7	8	超过8
得分	1	2	4	8	12	20	40

并且在拼写第4个单词开始，每拼写成功一次额外加5分

代码

import SwiftUI

struct ContentView: View {
    @State private var usedWords = [String]()
    @State private var rootWord = ""
    @State private var newWord = ""
    
    @State private var errorTitle = ""
    @State private var errorMessage = ""
    @State private var showingError = false
    
    @State private var sumscore: Int = 0
    @State private var score: Int = 0
    
    var body: some View {
        NavigationView {
            VStack {
                TextField("Enter your word", text: $newWord, onCommit: addNewWord)
                    .autocapitalization(.none)
                    .textFieldStyle(RoundedBorderTextFieldStyle())
                    .padding()
                List(usedWords, id: \.self){
                    Image(systemName: "\($0.count).circle")
                    Text($0)
                }
                Text("You get \(sumscore)")
            }
            .navigationBarTitle(rootWord)
        .navigationBarItems(trailing: Button(action: startGame) {
            Image(systemName: "goforward")
                .foregroundColor(.black)
        })
            .onAppear(perform: startGame)
        }.alert(isPresented: $showingError){
            Alert(---
title: Text(errorTitle), message: Text(errorMessage), dismissButton: .default(Text("OK")))
            
        
        }
        
    }
    func addNewWord() {
        //将单词全部小写并删除空格和换行符
        let answer = newWord.lowercased().trimmingCharacters(in: .whitespacesAndNewlines)
        guard isOriginal(word: answer) else {
            wordError(---
title: "word used already", message: "Be more original")
            return
        }
        guard isPossible(word: answer) else {
            wordError(---
title: "Word not recongnized", message: "You can't just make them up, you know!")
            return
        }
        guard isReal(word: answer) else {
            wordError(---
title: "Word not possible", message: "That isn't a real word.")
            return
        }
        //判断是否有字符，没有则退出
        guard answer.count > 0 else {
            return
        }
        
        //计算得分
        caculationScore(answer: answer)
        

        //将输入的文本加入到数组
        usedWords.insert(answer, at: 0)
        newWord = ""
    }
    
    func startGame(){
        // 获取资源库中的文件
        if let startWordsURL = Bundle.main.url(forResource: "start", withExtension: "txt"){
            // 将文件中的内容加入字符串
            if let startWords = try? String(contentsOf: startWordsURL){
                // 通过换行符将字符串分割为数组
                let allWords = startWords.components(separatedBy: "\n")
                rootWord = allWords.randomElement() ?? "sillkworm"
                //初始化得分和数组
                sumscore = 0
                usedWords = [String]()
                // 执行到这里就可以返回了
                return
            }
        }
        //如果产生问题则报错
        fatalError("Could not load start.txt form bundle.")
    }
    
    func isOriginal(word: String) -> Bool {
        !usedWords.contains(word)
    }
    
    func isPossible(word: String) -> Bool {
        var tempWord = rootWord
        
        for letter in word {
            if let pos = tempWord.firstIndex(of: letter) {
                tempWord.remove(at: pos)
            }else {
                return false
            }
            
        }
        return true
    }
    
    func isReal(word: String) -> Bool {
        // 检查是否小于三个字母
        let threewordslim = word.count >= 3
        
        // 检查与游戏词语是否相同
        let samewordlim = !(word == rootWord)
        
        let checker = UITextChecker()
        let range = NSRange(location: 0, length: word.utf16.count)
        let misspelledRange = checker.rangeOfMisspelledWord(in: word, range: range, startingAt: 0, wrap: false, language: "en")
        
        return misspelledRange.location == NSNotFound && threewordslim && samewordlim
    }
    
    func wordError(---
title: String, message: String) {
        errorTitle = title
        errorMessage = message
        showingError = true
    
        
    }
    func caculationScore(answer: String){
        //计算得分
        let wordnum = answer.count
        let wordsnum = usedWords.count
        
        switch wordnum {
        case 3:
            score = 1
        case 4:
            score = 2
        case 5:
            score = 4
        case 6:
            score = 8
        case 7:
            score = 12
        case 8:
            score = 20
        default:
            score = 40
        }
        
        //因为是添加之前，所以从第4的单词开始不是-3而是-2
        let addscore = (wordsnum - 2) * 5
        
        if addscore > 0 {
            score += addscore
        }
        
        sumscore += score
        score = 0
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}