单词详情页新增历史记录入口，可查看单个单词的学习统计

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

LearnEnglish/LearnEnglish/Models/LearnedStore.swift

@@ -43,6 +43,10 @@ final class LearnedStore {
         }
     }
 
+    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 }
     }

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(image: UIImage(systemName: "clock.arrow.circlepath"), style: .plain, target: self, action: #selector(showHistory)),
+            UIBarButtonItem(title: "学习", style: .plain, target: self, action: #selector(startSpelling))
+        ]
         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"
+        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
+    }
+}