修复大小写切换后新输入字母不跟随转换，输入时根据当前大小写状态存储

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

LearnEnglish/LearnEnglish/Models/LearnedStore.swift

@@ -0,0 +1,90 @@
+import Foundation
+
+struct LearnedRecord: Codable {
+    let word: Word
+    var learnedAt: Date
+    var count: Int = 1
+    var correctCount: Int = 0
+
+    var accuracy: Int {
+        count > 0 ? Int(Double(correctCount) / Double(count) * 100) : 0
+    }
+}
+
+final class LearnedStore {
+    static let shared = LearnedStore()
+    private let key = "learned_records"
+
+    private(set) var records: [LearnedRecord] {
+        didSet {
+            guard let data = try? JSONEncoder().encode(records) else { return }
+            UserDefaults.standard.set(data, forKey: key)
+        }
+    }
+
+    private init() {
+        if let data = UserDefaults.standard.data(forKey: key),
+           let decoded = try? JSONDecoder().decode([LearnedRecord].self, from: data) {
+            records = decoded
+        } else {
+            records = []
+        }
+    }
+
+    func record(_ word: Word, correct: Bool) {
+        if let index = records.firstIndex(where: { $0.word.id == word.id }) {
+            records[index].learnedAt = Date()
+            records[index].count += 1
+            if correct { records[index].correctCount += 1 }
+        } else {
+            var rec = LearnedRecord(word: word, learnedAt: Date())
+            if correct { rec.correctCount = 1 }
+            records.append(rec)
+        }
+    }
+
+    func record(for word: Word) -> LearnedRecord? {
+        records.first { $0.word.id == word.id }
+    }
+
+    func isRecorded(_ word: Word) -> Bool {
+        records.contains { $0.word.id == word.id }
+    }
+
+    var sectioned: [(title: String, items: [LearnedRecord])] {
+        let sorted = records.sorted { $0.learnedAt > $1.learnedAt }
+        let formatter = DateFormatter()
+        formatter.locale = Locale(identifier: "zh_CN")
+        formatter.dateFormat = "yyyy-MM-dd"
+
+        var groups: [(String, [LearnedRecord])] = []
+        var seen: Set<String> = []
+        for record in sorted {
+            let dateStr = formatter.string(from: record.learnedAt)
+            let title = sectionTitle(dateStr)
+            if !seen.contains(title) {
+                groups.append((title, []))
+                seen.insert(title)
+            }
+            if let index = groups.firstIndex(where: { $0.0 == title }) {
+                groups[index].1.append(record)
+            }
+        }
+        return groups
+    }
+
+    private func sectionTitle(_ dateStr: String) -> String {
+        let today = DateFormatter()
+        today.locale = Locale(identifier: "zh_CN")
+        today.dateFormat = "yyyy-MM-dd"
+        let todayStr = today.string(from: Date())
+        if dateStr == todayStr { return "今天" }
+
+        let calendar = Calendar.current
+        if let yesterday = calendar.date(byAdding: .day, value: -1, to: Date()) {
+            let yesterdayStr = today.string(from: yesterday)
+            if dateStr == yesterdayStr { return "昨天" }
+        }
+        return dateStr
+    }
+}

LearnEnglish/LearnEnglish/Models/Quiz.swift

@@ -51,6 +51,27 @@ enum QuizGenerator {
         }
     }
 
+    static func recase(_ questions: [QuizQuestion], toUpper: Bool) -> [QuizQuestion] {
+        questions.map { q in
+            let word = q.word
+            let text = toUpper ? word.word.uppercased() : word.word.lowercased()
+            let recased = Word(categoryId: word.categoryId, word: text, phonetic: word.phonetic,
+                               meaning: word.meaning, example: word.example, exampleMeaning: word.exampleMeaning)
+            let blanked = q.blankedWord.map { ch -> String in
+                ch == "_" ? "_" : ch.uppercased()
+            }.joined()
+            let blankedWord = toUpper ? blanked.uppercased() : blanked.lowercased()
+            return QuizQuestion(
+                word: recased,
+                prompt: q.prompt,
+                options: q.options,
+                answer: text,
+                blankedWord: blankedWord,
+                blankPositions: q.blankPositions
+            )
+        }
+    }
+
     private static func promptText(_ word: Word, _ mode: QuizMode) -> String {
         switch mode {
         case .enToZh: return word.word

LearnEnglish/LearnEnglish/Views/CategoryListViewController.swift

@@ -14,6 +14,12 @@ final class CategoryListViewController: UITableViewController {
     override func viewDidLoad() {
         super.viewDidLoad()
         title = "背单词"
+        navigationItem.rightBarButtonItem = UIBarButtonItem(
+            image: UIImage(systemName: "list.bullet.clipboard"),
+            style: .plain,
+            target: self,
+            action: #selector(showHistory)
+        )
         tableView.register(CategoryCardCell.self, forCellReuseIdentifier: "cell")
         tableView.separatorStyle = .none
         tableView.backgroundColor = .systemBackground
@@ -23,6 +29,10 @@ final class CategoryListViewController: UITableViewController {
         }
     }
 
+    @objc private func showHistory() {
+        navigationController?.pushViewController(HistoryViewController(), animated: true)
+    }
+
     private func showError(_ message: String) {
         let label = UILabel()
         label.text = "词库加载失败\n\(message)"

LearnEnglish/LearnEnglish/Views/HistoryViewController.swift

@@ -0,0 +1,101 @@
+import UIKit
+
+final class HistoryViewController: UITableViewController {
+    private var sections: [(title: String, items: [LearnedRecord])] = []
+    private var speechObserver: NSObjectProtocol?
+    private let timeFormatter: DateFormatter = {
+        let f = DateFormatter()
+        f.locale = Locale(identifier: "zh_CN")
+        f.dateFormat = "HH:mm:ss"
+        return f
+    }()
+
+    init() {
+        super.init(style: .plain)
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) { fatalError() }
+
+    deinit {
+        if let speechObserver {
+            NotificationCenter.default.removeObserver(speechObserver)
+        }
+    }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        title = "学习记录"
+        navigationItem.largeTitleDisplayMode = .never
+        tableView.register(WordCardCell.self, forCellReuseIdentifier: "cell")
+        tableView.separatorStyle = .none
+        tableView.backgroundColor = .systemBackground
+        tableView.contentInset.top = 8
+
+        speechObserver = NotificationCenter.default.addObserver(
+            forName: SpeechService.speakingDidChangeNotification, object: nil, queue: .main
+        ) { [weak self] _ in
+            for cell in self?.tableView.visibleCells ?? [] {
+                (cell as? WordCardCell)?.updateSpeakerState()
+            }
+        }
+    }
+
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+        sections = LearnedStore.shared.sectioned
+        if sections.isEmpty {
+            let label = UILabel()
+            label.text = "暂无学习记录"
+            label.textAlignment = .center
+            label.textColor = .secondaryLabel
+            label.font = .preferredFont(forTextStyle: .body)
+            let bg = UIView()
+            bg.addSubview(label)
+            label.translatesAutoresizingMaskIntoConstraints = false
+            NSLayoutConstraint.activate([
+                label.centerXAnchor.constraint(equalTo: bg.centerXAnchor),
+                label.centerYAnchor.constraint(equalTo: bg.centerYAnchor)
+            ])
+            tableView.backgroundView = bg
+        } else {
+            tableView.backgroundView = nil
+        }
+        tableView.reloadData()
+    }
+
+    override func numberOfSections(in tableView: UITableView) -> Int {
+        sections.count
+    }
+
+    override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
+        sections[section].title
+    }
+
+    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
+        sections[section].items.count
+    }
+
+    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
+        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! WordCardCell
+        let record = sections[indexPath.section].items[indexPath.row]
+        let time = timeFormatter.string(from: record.learnedAt)
+        cell.configure(with: record.word, count: record.count, accuracy: record.accuracy, time: time)
+        cell.onSpeak = { word in
+            SpeechService.shared.speak(word.word)
+        }
+        cell.onLearn = { [weak self] word in
+            guard let self else { return }
+            let config = QuizConfig(mode: .spelling, words: [word], isStudyMode: true)
+            navigationController?.pushViewController(QuizViewController(config: config), animated: true)
+        }
+        return cell
+    }
+
+    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
+        Haptics.selection()
+        let record = sections[indexPath.section].items[indexPath.row]
+        let detail = WordDetailViewController(word: record.word, categoryName: "")
+        navigationController?.pushViewController(detail, animated: true)
+    }
+}

LearnEnglish/LearnEnglish/Views/QuizViewController.swift

@@ -218,6 +218,7 @@ final class QuizViewController: UIViewController {
 
         if isSpelling {
             spellingHintLabel.text = "\(question.word.word.count) 个字母，补全空缺部分"
+            spellingView.isUppercase = isUppercase
             spellingView.configure(blankedWord: question.blankedWord, blankPositions: question.blankPositions)
             if config.isStudyMode {
                 nextButton.isHidden = true
@@ -358,6 +359,7 @@ final class QuizViewController: UIViewController {
         guard selectedOption == nil else { return }
         selectedOption = typed
         let correct = typed.lowercased() == question.answer.lowercased()
+        LearnedStore.shared.record(question.word, correct: correct)
         if !correct {
             wrongWords.append(question.word)
         }
@@ -424,7 +426,9 @@ final class QuizViewController: UIViewController {
         isUppercase.toggle()
         UserDefaults.standard.set(isUppercase, forKey: "spelling_uppercase")
         updateCaseButton()
-        restart()
+        spellingView.isUppercase = isUppercase
+        questions = QuizGenerator.recase(questions, toUpper: isUppercase)
+        spellingView.updateCase(toUpper: isUppercase)
     }
 
     private func updateCaseButton() {

LearnEnglish/LearnEnglish/Views/SpellingInputView.swift

@@ -17,6 +17,8 @@ final class SpellingInputView: UIView, UITextFieldDelegate {
     private var cursorView: UIView?
     private var inputEnabled = true
 
+    var isUppercase = false
+
     var isComplete: Bool {
         !filledBlanks.isEmpty && filledBlanks.allSatisfy { !$0.isEmpty }
     }
@@ -55,6 +57,7 @@ final class SpellingInputView: UIView, UITextFieldDelegate {
         hiddenField.autocapitalizationType = .none
         hiddenField.spellCheckingType = .no
         hiddenField.keyboardType = .asciiCapable
+        hiddenField.returnKeyType = .done
         hiddenField.frame = .zero
         addSubview(hiddenField)
 
@@ -132,6 +135,20 @@ final class SpellingInputView: UIView, UITextFieldDelegate {
         hiddenField.inputAccessoryView = nil
     }
 
+    func updateCase(toUpper: Bool) {
+        chars = chars.map {
+            guard $0 != "_" else { return $0 }
+            return toUpper ? $0.uppercased() : $0.lowercased()
+        }
+        filledBlanks = filledBlanks.map {
+            $0.isEmpty ? $0 : (toUpper ? $0.uppercased() : $0.lowercased())
+        }
+        for (index, box) in boxViews.enumerated() where chars[index] != "_" {
+            (box.viewWithTag(100) as? UILabel)?.text = chars[index]
+        }
+        refreshBoxes()
+    }
+
     func showResultState(correct: Bool) {
         let color = correct ? Theme.Color.correct : Theme.Color.wrong
         for position in blankPositions {
@@ -168,7 +185,8 @@ final class SpellingInputView: UIView, UITextFieldDelegate {
                 onChange?()
             }
         } else if let char = string.last, char.isLetter, cursorIndex < blankPositions.count {
-            filledBlanks[cursorIndex] = String(char).lowercased()
+            let converted = isUppercase ? char.uppercased() : char.lowercased()
+            filledBlanks[cursorIndex] = converted
             cursorIndex += 1
             refreshBoxes()
             popBox(atBlank: cursorIndex - 1)
@@ -178,6 +196,12 @@ final class SpellingInputView: UIView, UITextFieldDelegate {
         return false
     }
 
+    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
+        guard isComplete else { return false }
+        onSubmit?()
+        return false
+    }
+
     // MARK: - Boxes
 
     private func rebuildBoxes() {

LearnEnglish/LearnEnglish/Views/WordCardCell.swift

@@ -5,6 +5,7 @@ final class WordCardCell: UITableViewCell {
     private let wordLabel = UILabel()
     private let phoneticLabel = UILabel()
     private let meaningLabel = UILabel()
+    private let countLabel = UILabel()
     private let learnButton = UIButton(type: .system)
     private let speakerButton = UIButton(type: .system)
     private var word: Word?
@@ -37,6 +38,10 @@ final class WordCardCell: UITableViewCell {
         meaningLabel.font = .preferredFont(forTextStyle: .subheadline)
         meaningLabel.textColor = .secondaryLabel
 
+        countLabel.font = .preferredFont(forTextStyle: .caption2)
+        countLabel.textColor = Theme.Color.accent
+        countLabel.setContentHuggingPriority(.required, for: .horizontal)
+
         let textStack = UIStackView(arrangedSubviews: [wordLabel, phoneticLabel, meaningLabel])
         textStack.axis = .vertical
         textStack.spacing = 8
@@ -57,7 +62,7 @@ final class WordCardCell: UITableViewCell {
         }, for: .touchUpInside)
         speakerButton.setContentHuggingPriority(.required, for: .horizontal)
 
-        let row = UIStackView(arrangedSubviews: [textStack, learnButton, speakerButton])
+        let row = UIStackView(arrangedSubviews: [textStack, countLabel, learnButton, speakerButton])
         row.axis = .horizontal
         row.alignment = .center
         row.spacing = 8
@@ -83,9 +88,16 @@ final class WordCardCell: UITableViewCell {
         wordLabel.text = word.word
         phoneticLabel.text = word.phonetic
         meaningLabel.text = word.meaning
+        countLabel.isHidden = true
         updateSpeakerState()
     }
 
+    func configure(with word: Word, count: Int, accuracy: Int, time: String) {
+        configure(with: word)
+        countLabel.text = "\(time) · \(count)次 · \(accuracy)%"
+        countLabel.isHidden = false
+    }
+
     func updateSpeakerState() {
         guard let word else { return }
         let speaking = SpeechService.shared.isSpeaking(word.word)

LearnEnglish/LearnEnglish/Views/WordDetailViewController.swift

@@ -31,7 +31,10 @@ final class WordDetailViewController: UIViewController {
         view.backgroundColor = .systemBackground
         title = categoryName
         navigationItem.largeTitleDisplayMode = .never
-        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "学习", style: .plain, target: self, action: #selector(startSpelling))
+        navigationItem.rightBarButtonItems = [
+            UIBarButtonItem(title: "学习", style: .plain, target: self, action: #selector(startSpelling)),
+            UIBarButtonItem(image: UIImage(systemName: "clock.arrow.circlepath"), style: .plain, target: self, action: #selector(showHistory))
+        ]
         buildLayout()
         updateSpeakState()
         speechObserver = NotificationCenter.default.addObserver(
@@ -187,6 +190,10 @@ final class WordDetailViewController: UIViewController {
         return card
     }
 
+    @objc private func showHistory() {
+        navigationController?.pushViewController(WordHistoryViewController(word: word), animated: true)
+    }
+
     @objc private func startSpelling() {
         Haptics.selection()
         let config = QuizConfig(mode: .spelling, words: [word], isStudyMode: true)

LearnEnglish/LearnEnglish/Views/WordHistoryViewController.swift

@@ -0,0 +1,146 @@
+import UIKit
+
+final class WordHistoryViewController: UIViewController {
+    private let word: Word
+    private let record: LearnedRecord?
+
+    init(word: Word) {
+        self.word = word
+        record = LearnedStore.shared.record(for: word)
+        super.init(nibName: nil, bundle: nil)
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) { fatalError() }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        title = "学习记录"
+        navigationItem.largeTitleDisplayMode = .never
+        view.backgroundColor = .systemBackground
+        buildLayout()
+    }
+
+    private func buildLayout() {
+        guard let record else {
+            let label = UILabel()
+            label.text = "暂无学习记录"
+            label.textAlignment = .center
+            label.textColor = .secondaryLabel
+            label.font = .preferredFont(forTextStyle: .body)
+            view.addSubview(label)
+            label.translatesAutoresizingMaskIntoConstraints = false
+            NSLayoutConstraint.activate([
+                label.centerXAnchor.constraint(equalTo: view.centerXAnchor),
+                label.centerYAnchor.constraint(equalTo: view.centerYAnchor)
+            ])
+            return
+        }
+
+        let wordCard = makeWordCard(record)
+        let statsCard = makeStatsCard(record)
+
+        let stack = UIStackView(arrangedSubviews: [wordCard, statsCard])
+        stack.axis = .vertical
+        stack.spacing = 20
+
+        let scrollView = UIScrollView()
+        scrollView.alwaysBounceVertical = true
+        view.addSubview(scrollView)
+        scrollView.addSubview(stack)
+        scrollView.translatesAutoresizingMaskIntoConstraints = false
+        stack.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            scrollView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
+            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
+            stack.topAnchor.constraint(equalTo: scrollView.contentLayoutGuide.topAnchor, constant: 20),
+            stack.leadingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.leadingAnchor, constant: 16),
+            stack.trailingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.trailingAnchor, constant: -16),
+            stack.bottomAnchor.constraint(equalTo: scrollView.contentLayoutGuide.bottomAnchor, constant: -16),
+            stack.widthAnchor.constraint(equalTo: scrollView.frameLayoutGuide.widthAnchor, constant: -32)
+        ])
+    }
+
+    private func makeWordCard(_ record: LearnedRecord) -> UIView {
+        let card = UIView()
+        card.backgroundColor = Theme.Color.cardBackground
+        card.layer.cornerRadius = Theme.Metrics.cardRadius
+
+        let wordLabel = UILabel()
+        wordLabel.text = record.word.word
+        wordLabel.font = .preferredFont(forTextStyle: .headline)
+
+        let phoneticLabel = UILabel()
+        phoneticLabel.text = record.word.phonetic
+        phoneticLabel.font = .preferredFont(forTextStyle: .caption1)
+        phoneticLabel.textColor = .secondaryLabel
+
+        let meaningLabel = UILabel()
+        meaningLabel.text = record.word.meaning
+        meaningLabel.font = .preferredFont(forTextStyle: .subheadline)
+        meaningLabel.textColor = .secondaryLabel
+
+        let textStack = UIStackView(arrangedSubviews: [wordLabel, phoneticLabel, meaningLabel])
+        textStack.axis = .vertical
+        textStack.spacing = 8
+
+        card.addSubview(textStack)
+        textStack.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            textStack.topAnchor.constraint(equalTo: card.topAnchor, constant: 14),
+            textStack.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 14),
+            textStack.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -14),
+            textStack.bottomAnchor.constraint(equalTo: card.bottomAnchor, constant: -14)
+        ])
+        return card
+    }
+
+    private func makeStatsCard(_ record: LearnedRecord) -> UIView {
+        let card = UIView()
+        card.backgroundColor = Theme.Color.cardBackground
+        card.layer.cornerRadius = Theme.Metrics.cardRadius
+
+        let title = UILabel()
+        title.text = "学习统计"
+        title.font = .preferredFont(forTextStyle: .caption1)
+        title.textColor = .secondaryLabel
+
+        let countLabel = UILabel()
+        countLabel.text = "\(record.count) 次"
+        countLabel.font = .systemFont(ofSize: 36, weight: .bold)
+
+        let accuracyLabel = UILabel()
+        accuracyLabel.text = "正确率 \(record.accuracy)%"
+        accuracyLabel.font = .preferredFont(forTextStyle: .subheadline)
+        accuracyLabel.textColor = Theme.Color.correct
+
+        let formatter = DateFormatter()
+        formatter.locale = Locale(identifier: "zh_CN")
+        formatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
+        let dateLabel = UILabel()
+        dateLabel.text = "最近学习：\(formatter.string(from: record.learnedAt))"
+        dateLabel.font = .preferredFont(forTextStyle: .caption1)
+        dateLabel.textColor = .tertiaryLabel
+
+        let statsStack = UIStackView(arrangedSubviews: [countLabel, accuracyLabel])
+        statsStack.axis = .horizontal
+        statsStack.spacing = 16
+        statsStack.alignment = .lastBaseline
+
+        let stack = UIStackView(arrangedSubviews: [title, statsStack, dateLabel])
+        stack.axis = .vertical
+        stack.spacing = 12
+
+        card.addSubview(stack)
+        stack.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            stack.topAnchor.constraint(equalTo: card.topAnchor, constant: 16),
+            stack.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: 16),
+            stack.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -16),
+            stack.bottomAnchor.constraint(equalTo: card.bottomAnchor, constant: -16)
+        ])
+        return card
+    }
+}