版本記錄
版本號 | 時間 |
---|---|
V1.0 | 2020.07.04 星期日 |
前言
前面寫了那麼多篇主要着眼於局部問題的解決,包括特定功能的實現、通用工具類的封裝、視頻和語音多媒體的底層和實現以及動畫酷炫的實現方式等等。接下來這幾篇我們就一起看一下關於iOS系統架構以及獨立做一個APP的架構設計的相關問題。感興趣的可以看上面幾篇。
1. 架構之路 (一) —— iOS原生系統架構(一)
2. 架構之路 (二) —— APP架構分析(一)
3. 架構之路 (三) —— APP架構之網絡層分析(一)
4. 架構之路 (四) —— APP架構之工程實踐中網絡層的搭建(二)
5. 架構之路 (五) —— VIPER架構模式(一)
6. 架構之路 (六) —— VIPER架構模式(二)
7. 架構之路 (七) —— iOS App的SOLID原則(一)
源碼
1. Swift
修改之前
首先看下工程組織結構
下面就是源碼了
1. Date.swift
import Foundation
extension Date {
var startOfDay: Date {
return Calendar.current.startOfDay(for: self)
}
var startOfMonth: Date {
let calendar = Calendar(identifier: .gregorian)
let components = calendar.dateComponents([.year, .month], from: self)
return calendar.date(from: components) ?? Date()
}
var startOfWeek: Date {
let calendar = Calendar(identifier: .gregorian)
let components = calendar.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)
return calendar.date(from: components) ?? Date()
}
var endOfDay: Date {
var components = DateComponents()
components.day = 1
components.second = -1
return Calendar.current.date(byAdding: components, to: startOfDay) ?? Date()
}
var endOfMonth: Date {
var components = DateComponents()
components.month = 1
components.second = -1
return Calendar(identifier: .gregorian).date(byAdding: components, to: startOfMonth) ?? Date()
}
var endOfWeek: Date {
var components = DateComponents()
components.weekOfYear = 1
components.second = -1
return Calendar(identifier: .gregorian).date(byAdding: components, to: startOfWeek) ?? Date()
}
}
2. ExpenseModel+CoreDataClass.swift
import Foundation
import CoreData
@objc(ExpenseModel)
public class ExpenseModel: NSManagedObject {
}
3. ExpenseModel+CoreDataProperties.swift
import Foundation
import CoreData
extension ExpenseModel {
@nonobjc
public class func fetchRequest() -> NSFetchRequest<ExpenseModel> {
return NSFetchRequest<ExpenseModel>(entityName: "ExpenseModel")
}
@NSManaged public var title: String?
@NSManaged public var price: Double
@NSManaged public var comment: String?
@NSManaged public var date: Date?
@NSManaged public var id: UUID?
}
extension ExpenseModel: Identifiable {
}
4. DailyReportsDataSource.swift
import CoreData
import Combine
class DailyReportsDataSource: ObservableObject {
var viewContext: NSManagedObjectContext
@Published private(set) var currentEntries: [ExpenseModel] = []
init(viewContext: NSManagedObjectContext = AppMain.container.viewContext) {
self.viewContext = viewContext
prepare()
}
func prepare() {
currentEntries = getEntries()
}
private func getEntries() -> [ExpenseModel] {
let fetchRequest: NSFetchRequest<ExpenseModel> = ExpenseModel.fetchRequest()
fetchRequest.sortDescriptors = [NSSortDescriptor(keyPath: \ExpenseModel.date, ascending: false)]
fetchRequest.predicate = NSPredicate(
format: "%@ <= date AND date <= %@",
Date().startOfDay as CVarArg,
Date().endOfDay as CVarArg)
do {
let results = try viewContext.fetch(fetchRequest)
return results
} catch let error {
print(error)
return []
}
}
func saveEntry(title: String, price: Double, date: Date, comment: String) {
let newItem = ExpenseModel(context: viewContext)
newItem.title = title
newItem.date = date
newItem.comment = comment
newItem.price = price
newItem.id = UUID()
if let index = currentEntries.firstIndex(where: { $0.date ?? Date() < date }) {
currentEntries.insert(newItem, at: index)
} else {
currentEntries.append(newItem)
}
try? viewContext.save()
}
func delete(entry: ExpenseModel) {
viewContext.delete(entry)
try? viewContext.save()
}
}
5. MonthlyReportsDataSource.swift
import CoreData
import Combine
class MonthlyReportsDataSource: ObservableObject {
var viewContext: NSManagedObjectContext
@Published private(set) var currentEntries: [ExpenseModel] = []
init(viewContext: NSManagedObjectContext = AppMain.container.viewContext) {
self.viewContext = viewContext
prepare()
}
func prepare() {
currentEntries = getEntries()
}
private func getEntries() -> [ExpenseModel] {
let fetchRequest: NSFetchRequest<ExpenseModel> = ExpenseModel.fetchRequest()
fetchRequest.sortDescriptors = [NSSortDescriptor(keyPath: \ExpenseModel.date, ascending: false)]
fetchRequest.predicate = NSPredicate(
format: "%@ <= date AND date <= %@",
Date().startOfMonth as CVarArg,
Date().endOfMonth as CVarArg)
do {
let results = try viewContext.fetch(fetchRequest)
return results
} catch let error {
print(error)
return []
}
}
func saveEntry(title: String, price: Double, date: Date, comment: String) {
let newItem = ExpenseModel(context: viewContext)
newItem.title = title
newItem.date = date
newItem.comment = comment
newItem.price = price
newItem.id = UUID()
if let index = currentEntries.firstIndex(where: { $0.date ?? Date() < date }) {
currentEntries.insert(newItem, at: index)
} else {
currentEntries.append(newItem)
}
try? viewContext.save()
}
func delete(entry: ExpenseModel) {
viewContext.delete(entry)
try? viewContext.save()
}
}
6. ContentView.swift
import SwiftUI
struct ContentView: View {
var body: some View {
NavigationView {
List {
NavigationLink(
"Today",
destination: dailyReport
.navigationTitle("Today"))
NavigationLink(
"This Month",
destination: monthlyReport
.navigationTitle("This Month"))
}
.navigationTitle("Reports")
}
}
var dailyReport: DailyExpensesView {
let dailyDataSource = DailyReportsDataSource()
return DailyExpensesView(dataSource: dailyDataSource)
}
var monthlyReport: MonthlyExpensesView {
let monthlyDataSource = MonthlyReportsDataSource()
return MonthlyExpensesView(dataSource: monthlyDataSource)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
7. DailyExpensesView.swift
import SwiftUI
import Combine
struct DailyExpensesView: View {
@State private var isAddPresented = false
@ObservedObject var dataSource: DailyReportsDataSource
var body: some View {
VStack {
List {
ForEach(dataSource.currentEntries, id: \.id) { item in
ExpenseItemView(expenseItem: item)
}
}
TotalView(totalExpense: dataSource.currentEntries.reduce(0) { $0 + $1.price })
}
.toolbar {
Button(action: {
isAddPresented.toggle()
}, label: {
Image(systemName: "plus")
})
}
.fullScreenCover(
isPresented: $isAddPresented) {
AddExpenseView { title, price, time, comment in
dataSource.saveEntry(title: title, price: price, date: time, comment: comment)
}
}
.onAppear {
dataSource.prepare()
}
}
}
struct DailyExpensesView_Previews: PreviewProvider {
static var previews: some View {
let reportsDataSource = DailyReportsDataSource(viewContext: AppMain.previewContainer.viewContext)
DailyExpensesView(dataSource: reportsDataSource)
}
}
8. MonthlyExpensesView.swift
import SwiftUI
import Combine
struct MonthlyExpensesView: View {
@State private var isAddPresented = false
@ObservedObject var dataSource: MonthlyReportsDataSource
var body: some View {
VStack {
List {
ForEach(dataSource.currentEntries, id: \.id) { item in
ExpenseItemView(expenseItem: item)
}
}
TotalView(totalExpense: dataSource.currentEntries.reduce(0) { $0 + $1.price })
}
.toolbar {
Button(action: {
isAddPresented.toggle()
}, label: {
Image(systemName: "plus")
})
}
.fullScreenCover(
isPresented: $isAddPresented) {
AddExpenseView { title, price, time, comment in
dataSource.saveEntry(title: title, price: price, date: time, comment: comment)
}
}
.onAppear {
dataSource.prepare()
}
}
}
struct MonthlyExpensesView_Previews: PreviewProvider {
static var previews: some View {
let reportsDataSource = MonthlyReportsDataSource(viewContext: AppMain.previewContainer.viewContext)
MonthlyExpensesView(dataSource: reportsDataSource)
}
}
9. AddExpenseView.swift
import SwiftUI
struct AddExpenseView: View {
@Environment(\.presentationMode) var presentation
var saveClosure: (String, Double, Date, String) -> Void
@State var title: String = ""
@State var time = Date()
@State var comment: String = ""
@State var price: String = ""
@State var saveDisabled = true
var body: some View {
NavigationView {
VStack(alignment: .leading) {
Text("Title:")
TextField("Entry Title", text: $title)
.onChange(of: title) { _ in
validateNonEmptyFields()
}
.padding(.bottom)
Text("Amount:")
TextField("Expense Amount", text: $price)
.keyboardType(.numberPad)
.onChange(of: price) { _ in
validateNonEmptyFields()
}
.padding(.bottom)
DatePicker(
"Time:",
selection: $time,
displayedComponents: [.hourAndMinute])
.padding(.bottom)
Text("Comment:")
TextEditor(text: $comment)
}
.padding(.all)
.navigationBarTitle("Add Expense", displayMode: .inline)
.navigationBarItems(
leading: Button(action: cancelEntry) {
Text("Cancel")
},
trailing: Button(action: saveEntry) {
Text("Save")
}.disabled(saveDisabled))
}
}
func saveEntry() {
guard let numericPrice = Double(price), numericPrice > 0 else {
return
}
saveClosure(title, numericPrice, time, comment)
cancelEntry()
}
func cancelEntry() {
presentation.wrappedValue.dismiss()
}
func validateNonEmptyFields() {
guard Double(price) != nil else {
saveDisabled = true
return
}
saveDisabled = title.isEmpty
}
}
struct AddExpenseView_Previews: PreviewProvider {
static var previews: some View {
AddExpenseView { _, _, _, _ in
}
}
}
10. ExpenseItemView.swift
import SwiftUI
struct ExpenseItemView: View {
let expenseItem: ExpenseModel
static let dateFormatter: DateFormatter = {
var dateFormatter = DateFormatter()
dateFormatter.dateStyle = .medium
dateFormatter.timeStyle = .none
return dateFormatter
}()
static let timeFormatter: DateFormatter = {
var dateFormatter = DateFormatter()
dateFormatter.dateStyle = .none
dateFormatter.timeStyle = .medium
return dateFormatter
}()
var body: some View {
VStack(alignment: .leading) {
HStack {
Text(expenseItem.title ?? "")
Spacer()
Text(String(format: "%.2f", expenseItem.price))
}
Text(expenseItem.comment ?? "")
.font(.caption)
HStack {
Text("\(expenseItem.date ?? Date(), formatter: Self.dateFormatter)")
Spacer()
Text("\(expenseItem.date ?? Date(), formatter: Self.timeFormatter)")
}
}
}
}
struct ExpenseItemView_Previews: PreviewProvider {
static var previews: some View {
ExpenseItemView(expenseItem: AppMain.previewItem)
}
}
11. TotalView.swift
import SwiftUI
struct TotalView: View {
var totalExpense: Double = 0
var body: some View {
HStack {
Text("Total")
Spacer()
Text(String(format: "%.2f", totalExpense))
.font(.title)
}
.padding(.horizontal)
}
}
struct TotalView_Previews: PreviewProvider {
static var previews: some View {
TotalView(totalExpense: 123.45)
}
}
12. AppMain.swift
import SwiftUI
import CoreData
@main
struct AppMain: App {
static var container: NSPersistentContainer = {
let container = NSPersistentContainer(name: "ExpensesModel")
container.loadPersistentStores { _, error in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
return container
}()
static var previewContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "ExpensesModel")
container.persistentStoreDescriptions.first?.url = URL(fileURLWithPath: "/dev/null")
container.loadPersistentStores { _, error in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
for index in 0..<5 {
let newItem = ExpenseModel(context: container.viewContext)
newItem.title = "Test Title \(index)"
newItem.date = Date(timeIntervalSinceNow: Double(index * 60))
newItem.comment = "Test Comment \(index)"
newItem.price = Double(index + 1) * 12.3
newItem.id = UUID()
}
do {
try container.viewContext.save()
} catch {
let nsError = error as NSError
fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
}
return container
}()
static let previewItem: ExpenseModel = {
let newItem = ExpenseModel(context: AppMain.previewContainer.viewContext)
newItem.title = "Preview Item Title"
newItem.date = Date(timeIntervalSinceNow: 60)
newItem.comment = "Preview Item Comment"
newItem.price = 12.34
newItem.id = UUID()
return newItem
}()
var body: some Scene {
WindowGroup {
ContentView()
}
}
}
修改之後
首先看下工程組織結構
下面就是源碼了
1. ReportReader.swift
import Foundation
class ReportReader: ObservableObject {
@Published var currentEntries: [ExpenseModelProtocol] = []
func prepare() {
assertionFailure("Missing override: Please override this method in the subclass")
}
}
2. ExpenseModelProtocol.swift
import Foundation
protocol ExpenseModelProtocol {
var title: String? { get }
var price: Double { get }
var comment: String? { get }
var date: Date? { get }
var id: UUID? { get }
}
3. SaveEntryProtocol.swift
import Foundation
protocol SaveEntryProtocol {
func saveEntry(
title: String,
price: Double,
date: Date,
comment: String
) -> Bool
}
4. ReportRange.swift
import Foundation
enum ReportRange: String, CaseIterable {
case daily = "Today"
case monthly = "This Month"
case weekly = "This Week"
func timeRange() -> (Date, Date) {
let now = Date()
switch self {
case .daily:
return (now.startOfDay, now.endOfDay)
case .monthly:
return (now.startOfMonth, now.endOfMonth)
case .weekly:
return (now.startOfWeek, now.endOfWeek)
}
}
}
5. Date.swift
import Foundation
extension Date {
var startOfDay: Date {
return Calendar.current.startOfDay(for: self)
}
var startOfMonth: Date {
let calendar = Calendar(identifier: .gregorian)
let components = calendar.dateComponents([.year, .month], from: self)
return calendar.date(from: components) ?? Date()
}
var startOfWeek: Date {
let calendar = Calendar(identifier: .gregorian)
let components = calendar.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)
return calendar.date(from: components) ?? Date()
}
var endOfDay: Date {
var components = DateComponents()
components.day = 1
components.second = -1
return Calendar.current.date(byAdding: components, to: startOfDay) ?? Date()
}
var endOfMonth: Date {
var components = DateComponents()
components.month = 1
components.second = -1
return Calendar(identifier: .gregorian).date(byAdding: components, to: startOfMonth) ?? Date()
}
var endOfWeek: Date {
var components = DateComponents()
components.weekOfYear = 1
components.second = -1
return Calendar(identifier: .gregorian).date(byAdding: components, to: startOfWeek) ?? Date()
}
}
6. ExpenseModel+CoreDataClass.swift
import Foundation
import CoreData
@objc(ExpenseModel)
public class ExpenseModel: NSManagedObject {
}
7. ExpenseModel+CoreDataProperties.swift
import Foundation
import CoreData
extension ExpenseModel {
@nonobjc
public class func fetchRequest() -> NSFetchRequest<ExpenseModel> {
return NSFetchRequest<ExpenseModel>(entityName: "ExpenseModel")
}
@NSManaged public var title: String?
@NSManaged public var price: Double
@NSManaged public var comment: String?
@NSManaged public var date: Date?
@NSManaged public var id: UUID?
}
extension ExpenseModel: Identifiable {
}
8. ReportsDataSource.swift
import CoreData
import Combine
class ReportsDataSource: ReportReader, SaveEntryProtocol {
let reportRange: ReportRange
init(
viewContext: NSManagedObjectContext = PersistenceController.shared.container.viewContext,
reportRange: ReportRange
) {
self.viewContext = viewContext
self.reportRange = reportRange
super.init()
currentEntries = getEntries()
}
override func prepare() {
currentEntries = getEntries()
}
var viewContext: NSManagedObjectContext
private func getEntries() -> [ExpenseModelProtocol] {
let fetchRequest: NSFetchRequest<ExpenseModel> =
ExpenseModel.fetchRequest()
fetchRequest.sortDescriptors = [NSSortDescriptor(keyPath: \ExpenseModel.date, ascending: false)]
let (startDate, endDate) = reportRange.timeRange()
fetchRequest.predicate = NSPredicate(
format: "%@ <= date AND date <= %@",
startDate as CVarArg,
endDate as CVarArg)
do {
let results = try viewContext.fetch(fetchRequest)
return results
} catch let error {
print(error)
return []
}
}
func saveEntry(title: String, price: Double, date: Date, comment: String) -> Bool {
let newItem = ExpenseModel(context: viewContext)
newItem.title = title
newItem.date = date
newItem.comment = comment
newItem.price = price
newItem.id = UUID()
if let index = currentEntries.firstIndex(where: { $0.date ?? Date() < date }) {
currentEntries.insert(newItem, at: index)
} else {
currentEntries.append(newItem)
}
try? viewContext.save()
return true
}
func delete(entry: ExpenseModel) {
viewContext.delete(entry)
try? viewContext.save()
}
}
9. Persistence.swift
import Foundation
import CoreData
struct PersistenceController {
static let shared = PersistenceController()
let container: NSPersistentContainer
init(inMemory: Bool = false) {
container = NSPersistentContainer(name: "ExpensesModel")
if inMemory {
container.persistentStoreDescriptions.first?.url = URL(
fileURLWithPath: "/dev/null")
}
container.loadPersistentStores { _, error in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
}
}
10. ExpenseModel+Protocol.swift
import Foundation
extension ExpenseModel: ExpenseModelProtocol { }
11. ContentView.swift
import SwiftUI
struct ContentView: View {
var body: some View {
NavigationView {
List {
ForEach(ReportRange.allCases, id: \.self) { value in
NavigationLink(
value.rawValue,
destination: expenseView(for: value)
.navigationTitle(value.rawValue))
}
}
.navigationTitle("Reports")
}
}
func expenseView(for range: ReportRange) -> ExpensesView {
let dataSource = ReportsDataSource(reportRange: range)
return ExpensesView(dataSource: dataSource)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
12. ExpensesView.swift
import SwiftUI
import Combine
struct ExpensesView: View {
@State private var isAddPresented = false
@ObservedObject var dataSource: ReportReader
var body: some View {
VStack {
List {
ForEach(dataSource.currentEntries, id: \.id) { item in
ExpenseItemView(expenseItem: item)
}
}
TotalView(totalExpense: dataSource.currentEntries.reduce(0) { $0 + $1.price })
}
.toolbar {
Button(action: {
isAddPresented.toggle()
}, label: {
Image(systemName: "plus")
})
}
.fullScreenCover(isPresented: $isAddPresented) { () -> AddExpenseView? in
guard let saveHandler = dataSource as? SaveEntryProtocol else {
return nil
}
return AddExpenseView(saveEntryHandler: saveHandler)
}
.onAppear {
dataSource.prepare()
}
}
}
struct ExpensesView_Previews: PreviewProvider {
struct PreviewExpenseEntry: ExpenseModelProtocol {
var title: String?
var price: Double
var comment: String?
var date: Date?
var id: UUID? = UUID()
}
class PreviewReportsDataSource: ReportReader, SaveEntryProtocol {
override init() {
super.init()
for index in 1..<6 {
_ = saveEntry(
title: "Test Title \(index)",
price: Double(index) * 12.3,
date: Date(timeIntervalSinceNow: Double(index * -60)),
comment: "Test Comment \(index)")
}
}
override func prepare() {
}
func saveEntry(
title: String,
price: Double,
date: Date,
comment: String
) -> Bool {
let newEntry = PreviewExpenseEntry(
title: title,
price: price,
comment: comment,
date: date)
currentEntries.append(newEntry)
return true
}
}
static var previews: some View {
ExpensesView(dataSource: PreviewReportsDataSource())
}
}
13. AddExpenseView.swift
import SwiftUI
struct AddExpenseView: View {
@Environment(\.presentationMode) var presentation
var saveEntryHandler: SaveEntryProtocol
@State var title: String = ""
@State var time = Date()
@State var comment: String = ""
@State var price: String = ""
@State var saveDisabled = true
var body: some View {
NavigationView {
VStack(alignment: .leading) {
Text("Title:")
TextField("Entry Title", text: $title)
.onChange(of: title) { _ in
validateNonEmptyFields()
}
.padding(.bottom)
Text("Amount:")
TextField("Expense Amount", text: $price)
.keyboardType(.numberPad)
.onChange(of: price) { _ in
validateNonEmptyFields()
}
.padding(.bottom)
DatePicker(
"Time:",
selection: $time,
displayedComponents: [.hourAndMinute])
.padding(.bottom)
Text("Comment:")
TextEditor(text: $comment)
}
.padding(.all)
.navigationBarTitle("Add Expense", displayMode: .inline)
.navigationBarItems(
leading: Button(action: cancelEntry) {
Text("Cancel")
},
trailing: Button(action: saveEntry) {
Text("Save")
}
.disabled(saveDisabled))
}
}
func saveEntry() {
guard let numericPrice = Double(price), numericPrice > 0 else {
return
}
guard saveEntryHandler.saveEntry(
title: title,
price: numericPrice,
date: time,
comment: comment)
else {
print("Invalid entry.")
return
}
cancelEntry()
}
func cancelEntry() {
presentation.wrappedValue.dismiss()
}
func validateNonEmptyFields() {
guard Double(price) != nil else {
saveDisabled = true
return
}
saveDisabled = title.isEmpty
}
}
struct AddExpenseView_Previews: PreviewProvider {
class PreviewSaveHandler: SaveEntryProtocol {
func saveEntry(title: String, price: Double, date: Date, comment: String) -> Bool {
return true
}
}
static var previews: some View {
AddExpenseView(saveEntryHandler: PreviewSaveHandler())
}
}
14. ExpenseItemView.swift
import SwiftUI
struct ExpenseItemView: View {
let expenseItem: ExpenseModelProtocol
static let dateFormatter: DateFormatter = {
var dateFormatter = DateFormatter()
dateFormatter.dateStyle = .medium
dateFormatter.timeStyle = .none
return dateFormatter
}()
static let timeFormatter: DateFormatter = {
var dateFormatter = DateFormatter()
dateFormatter.dateStyle = .none
dateFormatter.timeStyle = .medium
return dateFormatter
}()
var body: some View {
VStack(alignment: .leading) {
HStack {
Text(expenseItem.title ?? "")
Spacer()
Text(String(format: "%.2f", expenseItem.price))
}
Text(expenseItem.comment ?? "")
.font(.caption)
HStack {
Text("\(expenseItem.date ?? Date(), formatter: Self.dateFormatter)")
Spacer()
Text("\(expenseItem.date ?? Date(), formatter: Self.timeFormatter)")
}
}
}
}
struct ExpenseItemView_Previews: PreviewProvider {
struct PreviewExpenseModel: ExpenseModelProtocol {
var title: String? = "Preview Item"
var price: Double = 123.45
var comment: String? = "This is a preview item"
var date: Date? = Date()
var id: UUID? = UUID()
}
static var previews: some View {
ExpenseItemView(expenseItem: PreviewExpenseModel())
}
}
15. TotalView.swift
import SwiftUI
struct TotalView: View {
var totalExpense: Double = 0
var body: some View {
HStack {
Text("Total")
Spacer()
Text(String(format: "%.2f", totalExpense))
.font(.title)
}
.padding(.horizontal)
}
}
struct TotalView_Previews: PreviewProvider {
static var previews: some View {
TotalView(totalExpense: 123.45)
}
}
16. AppMain.swift
import SwiftUI
import CoreData
@main
struct AppMain: App {
static var container: NSPersistentContainer = {
let container = NSPersistentContainer(name: "ExpensesModel")
container.loadPersistentStores { _, error in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
return container
}()
static var previewContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "ExpensesModel")
container.persistentStoreDescriptions.first?.url = URL(fileURLWithPath: "/dev/null")
container.loadPersistentStores { _, error in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
}
for index in 0..<5 {
let newItem = ExpenseModel(context: container.viewContext)
newItem.title = "Test Title \(index)"
newItem.date = Date(timeIntervalSinceNow: Double(index * 60))
newItem.comment = "Test Comment \(index)"
newItem.price = Double(index + 1) * 12.3
newItem.id = UUID()
}
do {
try container.viewContext.save()
} catch {
let nsError = error as NSError
fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
}
return container
}()
static let previewItem: ExpenseModel = {
let newItem = ExpenseModel(context: AppMain.previewContainer.viewContext)
newItem.title = "Preview Item Title"
newItem.date = Date(timeIntervalSinceNow: 60)
newItem.comment = "Preview Item Comment"
newItem.price = 12.34
newItem.id = UUID()
return newItem
}()
var body: some Scene {
WindowGroup {
ContentView()
}
}
}
後記
本篇主要講述了
iOS App
的SOLID
原則,感興趣的給個贊或者關注~~~