Preview crash question in SwiftUI

[MMorit00]

I'm just starting out, this is a very simple application, the preview is having an issue, how should I resolve it? ( it can be successfully built)
import Dependencies
import Foundation
import GRDB
import SharingGRDB

// 全局数据库配置和初始化
func appDatabase() throws -> any DatabaseWriter {
var configuration = Configuration()
configuration.foreignKeysEnabled = true

#if DEBUG
configuration.prepareDatabase { db in
db.trace(options: .profile) { event in
// 使用 expandedDescription 获取完整信息
let description = event.expandedDescription
print("🗄️ Database Query: (description)")
print("---")
}
}
#endif

// 根据环境选择适当的数据库实现
@dependency(.context) var context
let database: any DatabaseWriter

if context == .live {
// 生产环境使用DatabasePool，支持并发读取
let path = URL.documentsDirectory.appending(component: "notes.sqlite").path
database = try DatabasePool(path: path, configuration: configuration)
} else {
// 测试环境使用DatabaseQueue，更轻量级
database = try DatabaseQueue(configuration: configuration)
}

// 数据库迁移
var migrator = DatabaseMigrator()

#if DEBUG
// 调试模式下，当模式变更时自动重置数据库
migrator.eraseDatabaseOnSchemaChange = true
#endif

// 注册迁移：创建notes表
migrator.registerMigration("Create notes table") { db in
try db.create(table: "notes") { t in
t.autoIncrementedPrimaryKey("id")
t.column("content", .text).notNull()
t.column("createdAt", .datetime).notNull()
t.column("updatedAt", .datetime).notNull()
t.column("isMarked", .boolean).notNull().defaults(to: false)
}
}

// 注册迁移：创建cards表
migrator.registerMigration("Create cards table") { db in
try db.create(table: "cards") { t in
t.autoIncrementedPrimaryKey("id")
t.column("title", .text).notNull()
t.column("description", .text).notNull()
t.column("startDate", .datetime).notNull()
t.column("upfrontFinishedDate", .datetime).notNull()
t.column("finishedDate", .datetime)
t.column("imagePath", .text)
t.column("messageForFinished", .text)
t.column("createdAt", .datetime).notNull()
t.column("updatedAt", .datetime).notNull()
}
}

// 注册迁移：添加笔记和卡片关联
migrator.registerMigration("addCardIdToNotes") { db in
try db.alter(table: "notes") { t in
t.add(column: "cardId", .integer).references("cards", onDelete: .setNull)

}

}

// 执行迁移
try migrator.migrate(database)
return database
}

// 创建测试数据库
func testDatabase() -> any DatabaseWriter {
let database = try! DatabaseQueue()
var migrator = DatabaseMigrator()

// 为测试环境创建相同的表结构
migrator.registerMigration("Create notes table") { db in
try! db.create(table: "notes") { t in
t.autoIncrementedPrimaryKey("id")
t.column("content", .text).notNull()
t.column("createdAt", .datetime).notNull()
t.column("updatedAt", .datetime).notNull()
t.column("isMarked", .boolean).notNull().defaults(to: false)
}
}

// 为测试环境创建cards表
migrator.registerMigration("Create cards table") { db in
try! db.create(table: "cards") { t in
t.autoIncrementedPrimaryKey("id")
t.column("title", .text).notNull()
t.column("description", .text).notNull()
t.column("startDate", .datetime).notNull()
t.column("upfrontFinishedDate", .datetime).notNull()
t.column("finishedDate", .datetime)
t.column("imagePath", .text)
t.column("messageForFinished", .text)
t.column("createdAt", .datetime).notNull()
t.column("updatedAt", .datetime).notNull()
}
}

// 测试环境添加笔记和卡片关联
migrator.registerMigration("addCardIdToNotes") { db in
try! db.alter(table: "notes") { t in
t.add(column: "cardId", .integer).references("cards", onDelete: .setNull)

}

}

try! migrator.migrate(database)
return database
}

// Creating the preview database
func previewDatabase() -> any DatabaseWriter {
let database = try! DatabaseQueue() // Using an in-memory queue for previews
var migrator = DatabaseMigrator()

// Create the same table structure for the preview environment
migrator.registerMigration("Create notes table") { db in
try! db.create(table: "notes") { t in
t.autoIncrementedPrimaryKey("id")
t.column("content", .text).notNull()
t.column("createdAt", .datetime).notNull()
t.column("updatedAt", .datetime).notNull()
t.column("isMarked", .boolean).notNull().defaults(to: false)
}
}

// Create cards table for preview environment
migrator.registerMigration("Create cards table") { db in
try! db.create(table: "cards") { t in
t.autoIncrementedPrimaryKey("id")
t.column("title", .text).notNull()
t.column("description", .text).notNull()
t.column("startDate", .datetime).notNull()
t.column("upfrontFinishedDate", .datetime).notNull()
t.column("finishedDate", .datetime)
t.column("imagePath", .text)
t.column("messageForFinished", .text)
t.column("createdAt", .datetime).notNull()
t.column("updatedAt", .datetime).notNull()
}
}

// 预览环境添加笔记和卡片关联
migrator.registerMigration("addCardIdToNotes") { db in
try! db.alter(table: "notes") { t in
t.add(column: "cardId", .integer).references("cards", onDelete: .setNull)

}

}

print("🗄️ Preview Database: (database)")
try! migrator.migrate(database)

// Add some sample data for the preview environment
try! database.write { db in
var note1 = Note(
id: nil, content: "示例笔记 1 📝", createdAt: Date().addingTimeInterval(-3600),
updatedAt: Date().addingTimeInterval(-3600), isMarked: false)
try note1.insert(db) // Call insert on the mutable variable

var note2 = Note(
  id: nil, content: "示例笔记 2 ✨", createdAt: Date(), updatedAt: Date(), isMarked: true)
try note2.insert(db)

var note3 = Note(
  id: nil, content: "这是一个置顶的预览笔记 📌", createdAt: Date().addingTimeInterval(-7200),
  updatedAt: Date().addingTimeInterval(3600), isMarked: true)
try note3.insert(db)

var note4 = Note(
  id: nil, content: "买牛奶 🥛", createdAt: Date().addingTimeInterval(-10800),
  updatedAt: Date().addingTimeInterval(-100), isMarked: false)
try note4.insert(db)

// Add sample card data
var card1 = Card(
  id: nil,
  title: "旅行计划",
  description: "计划去日本的旅行",
  startDate: Date(),
  upfrontFinishedDate: Date().addingTimeInterval(60 * 60 * 24 * 30),  // 30天后
  finishedDate: nil,
  imagePath: nil,
  messageForFinished: nil,
  createdAt: Date(),
  updatedAt: Date()
)
try card1.insert(db)

var card2 = Card(
  id: nil,
  title: "学习Swift",
  description: "完成Swift编程的学习",
  startDate: Date().addingTimeInterval(-60 * 60 * 24 * 15),  // 15天前
  upfrontFinishedDate: Date().addingTimeInterval(60 * 60 * 24 * 15),  // 15天后
  finishedDate: nil,
  imagePath: nil,
  messageForFinished: nil,
  createdAt: Date().addingTimeInterval(-60 * 60 * 24 * 15),
  updatedAt: Date().addingTimeInterval(-60 * 60 * 24 * 15)
)
try card2.insert(db)

var card3 = Card(
  id: nil,
  title: "健身目标",
  description: "达到理想体重",
  startDate: Date().addingTimeInterval(-60 * 60 * 24 * 60),  // 60天前
  upfrontFinishedDate: Date().addingTimeInterval(-60 * 60 * 24 * 15),  // 15天前
  finishedDate: Date().addingTimeInterval(-60 * 60 * 24 * 10),  // 10天前完成
  imagePath: nil,
  messageForFinished: "感觉很棒！坚持锻炼真的有效果",
  createdAt: Date().addingTimeInterval(-60 * 60 * 24 * 60),
  updatedAt: Date().addingTimeInterval(-60 * 60 * 24 * 10)
)
try card3.insert(db)

// 添加带有卡片关联的示例笔记
var noteWithCard1 = Note(
  id: nil,
  content: "日本旅行准备清单 ✈️",
  createdAt: Date().addingTimeInterval(-1800),
  updatedAt: Date().addingTimeInterval(-1800),
  isMarked: true,
  cardId: 1  // 关联到"旅行计划"卡片
)
try noteWithCard1.insert(db)

var noteWithCard2 = Note(
  id: nil,
  content: "Swift学习资源链接 📚",
  createdAt: Date().addingTimeInterval(-2000),
  updatedAt: Date().addingTimeInterval(-2000),
  isMarked: false,
  cardId: 2  // 关联到"学习Swift"卡片
)
try noteWithCard2.insert(db)

}

return database
}

// 配置测试数据库依赖的辅助函数
public func configureTestDatabase() {
prepareDependencies { dependencies in
dependencies.defaultDatabase = testDatabase()
}
}

// 配置预览数据库依赖的辅助函数
public func configurePreviewDatabase() {
prepareDependencies { dependencies in
dependencies.defaultDatabase = previewDatabase()
}
}

public func configureDatabase() {
// 使用prepareDependencies函数配置defaultDatabase依赖
prepareDependencies { dependencies in
dependencies.defaultDatabase = try! appDatabase()
}
}
import ComposableArchitecture
import SwiftUI

// 主视图
public struct NotesView: View {
@bindable var store: StoreOf

public var body: some View {
ZStack {
// 黄色背景
BG.yellow
.ignoresSafeArea()

  ScrollView(.vertical, showsIndicators: false) {
    VStack(spacing: 24) {
      headerView
      statisticsView
      weekCalendarView
      noteInputView
    }
    .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .top)
    .padding(.top, 20)
  }
  .onAppear {
    // 视图出现时加载笔记数据
    store.send(.loadNotes)
  }
}
//    .sheet(
//      item: $store.scope(
//        state: \.presentedNote,
//        action: \.presentedNote
//      )
//    ) { noteStore in
//      NoteFormView(store: noteStore)
//    }

}
}

// MARK: - 子视图
extension NotesView {
fileprivate var headerView: some View {
HStack {
HStack {
Text("2024")
.font(.system(.title2, design: .rounded))
Text("-")
Text("2")
.foregroundColor(.primary700)
}
.font(.system(.title, design: .rounded))

  Spacer()

  HStack(spacing: 18) {
    Button {
      // 搜索功能
    } label: {
      Image(systemName: "sparkle.magnifyingglass")
      
    }
    Button {
      // 图片功能
    } label: {
      Image(systemName: "photo.artframe")
    
    }
    Button {
      // 亮度调节
    } label: {
      Image(systemName: "sparkles")
       
    }
  }
  .font(.title3)
  .foregroundColor(.primary)
}
.padding(.horizontal, 18)

}

fileprivate var statisticsView: some View {
HStack(spacing: 12) {
// 左侧统计
statisticItem(
title: "记录",
subtitle: "今年",
iconName: "sparkles.rectangle.stack.fill",
value: "24"
)

  Spacer()

  statisticItem(
    title: "天数",
    subtitle: "总计",
    iconName: "calendar",
    value: "9"
  )
}
.overlay {
  Rectangle()
    .frame(width: 1, height: 40)
    .foregroundColor(.gray.opacity(0.3))
}
.padding(.vertical, 20)
.padding(.horizontal, 16)
.background(
  RoundedRectangle(cornerRadius: 16, style: .continuous)
    .fill(Color.white)
    .shadow(color: Color.black.opacity(0.1), radius: 2, y: 1)
)
.padding(.horizontal, 12)

}

fileprivate func statisticItem(title: String, subtitle: String, iconName: String, value: String)
-> some View
{
HStack {
VStack(alignment: .center) {
Text(title)
.font(.system(.callout, design: .rounded))
Text(subtitle)
.font(.system(.caption, design: .rounded))
.foregroundColor(.gray300)
}

  Button {
    // 功能按钮
  } label: {
    Image(systemName: iconName)
      .font(.title3)
      .foregroundColor(.secondary300)
  }

  Text(value)
    .font(.system(.headline, design: .rounded))
    .foregroundColor(.primary700)
    .padding(.horizontal, 16)
    .padding(.vertical, 6)
    .background(
      RoundedRectangle(cornerRadius: 8, style: .continuous)
        .fill(Color.primary100)
    )
}

}

fileprivate var weekCalendarView: some View {
VStack(spacing: 8) {
weekdayHeader
dateRow
}
.padding(.vertical, 12)
.padding(.horizontal)
}

fileprivate var weekdayHeader: some View {
let weekdays = ["日", "一", "二", "三", "四", "五", "六"]

return HStack {
  ForEach(weekdays, id: \.self) { day in
    Text(day)
      .frame(maxWidth: .infinity)
      .foregroundColor(.gray700)
      .font(.system(size: 14, weight: .medium, design: .rounded))
  }
}

}

fileprivate var dateRow: some View {
let dates = ["05", "06", "07", "08", "09", "10", "11"]

return HStack(spacing: 0) {
  ForEach(dates, id: \.self) { date in
    dateItem(date: date, isSelected: date == "10")
  }
}

}

fileprivate func dateItem(date: String, isSelected: Bool) -> some View {
VStack(spacing: 0) {
Text(date)
.font(.system(.callout, design: .rounded))
.fontWeight(isSelected ? .medium : .light)
.foregroundColor(isSelected ? .primary : .gray700)
.frame(width: 40, height: 40)
.overlay {
if isSelected {
Circle()
.fill(.secondary300)
.frame(width: 4, height: 4)
.offset(y: 14)
}
}
.background {
RoundedRectangle(cornerRadius: 16)
.fill(Color.white)
.shadow(color: Color.black.opacity(0.1), radius: 1)

      if isSelected {
        RoundedRectangle(cornerRadius: 16)
          .fill(.primary100)
      }
    }
}
.frame(maxWidth: .infinity)
.contentShape(Rectangle())
.onTapGesture {
  // 处理日期点击
}

}

fileprivate var noteInputView: some View {
VStack(alignment: .center) {
noteToolbar
emptyStateNote
}
.padding(.bottom, 32)
.background {
RoundedRectangle(cornerRadius: 12, style: .continuous)
.foregroundStyle(.white)
.frame(maxWidth: .infinity)
.padding(.horizontal, 12)
.shadow(color: .black.opacity(0.1), radius: 5, x: 0, y: 3)
}
}

fileprivate var noteToolbar: some View {
HStack(alignment: .top, spacing: 12) {
Spacer()

  Button {
    // 添加图片
  } label: {
    Image(systemName: "photo.badge.plus.fill")
      .foregroundColor(.primary)
      .font(.system(size: 20))
  }

  Button {
    // 添加更多
  } label: {
    Image(systemName: "plus.rectangle.fill")
      .foregroundColor(.primary)
      .font(.system(size: 20))
  }
}
.padding(.top, 12)
.padding(.horizontal, 30)

}

fileprivate var emptyStateNote: some View {
VStack {
Text("✨想记点什么？😊✨")
.font(.system(size: 16, weight: .semibold))
.frame(maxWidth: .infinity)
.foregroundColor(.gray700)
.padding(.vertical, 16)

  Image(systemName: "lightbulb.fill")
    .foregroundColor(.gray700)
    .font(.system(size: 24))
    .padding(.bottom, 20)
}

}
}

#Preview("NotesView") {
return NotesView(
store: Store(
initialState: NotesFeature.State()
) {
NotesFeature()
}
)
}

[mbrandonw]

Hi @MMorit00, can you please provide a full project that demonstrates the problem? It's difficult to know what is happening by this partial code snippet alone.

[MMorit00]

Of course!!!, I would be even more grateful if you could point out any issues I have in the project, in addition to the preview. Sent from my iPhone

…

------------------ Original ------------------ From: Brandon Williams ***@***.***> Date: Sat,Jul 5,2025 5:15 AM To: pointfreeco/sharing-grdb ***@***.***> Cc: MOOZA ***@***.***>, Mention ***@***.***> Subject: Re: [pointfreeco/sharing-grdb] Preview crash question in SwiftUI(Discussion #86) Hi @MMorit00, can you please provide a full project that demonstrates the problem? It's difficult to know what is happening by this partial code snippet alone. — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you were mentioned.Message ID: ***@***.***> 从QQ邮箱发来的超大附件 LumiNote.zip (1.5GB, 2025年8月5日 12:30) 进入下载页面 ：https://wx.mail.qq.com/ftn/download?func=3&k=c7c70c316da554d0f5b44a313a346331bec3206e383463311017095717050500095e5c09081902080f0c49050b02511c015d5c54155602045c0c0155090d00035d34647d4d590a7f574c011f425d13259a82886ceed358e05532a038a9b2f47503ab5f743934633138386431&key=c7c70c316da554d0f5b44a313a346331bec3206e383463311017095717050500095e5c09081902080f0c49050b02511c015d5c54155602045c0c0155090d00035d34647d4d590a7f574c011f425d13259a82886ceed358e05532a038a9b2f47503ab5f743934633138386431&code=88d184c1&from=