如何将某些内容附加到列表中？
How to append something to a list?
我现在是 Swift 的新手，我无法添加到待办事项列表。我没有收到错误，所以我不知道出了什么问题。我希望代码不会太多，但我什至不知道问题出在哪里。
有一个 sheet 模式可以正常打开和关闭。唯一的问题是，当我按下保存按钮时，我输入的信息没有添加到列表中。
我添加了 ViewModel、NewTaskView(sheet)、TaskView(自定义列表)，以及列表应该位于的 DetailView 的一些代码。
import Foundation
import SwiftUI
class TaskViewModel : Identifiable , ObservableObject {
@Published var tasks : [Task] = [
Task(taskName: "Lab", taskDate: Date(), taskCompleted: false),
Task(taskName: "Assignment 4.02", taskDate: Date(), taskCompleted: false)
]
@Published var sortType : SortType = .alphabetical
@Published var isPresented = false
@Published var searched = ""
func addTask(task : Task){
tasks.append(task)
}
func removeTask(indexAt : IndexSet){
tasks.remove(atOffsets: indexAt)
}
func sort(){
switch sortType {
case .alphabetical :
tasks.sort(by: { [=10=].taskName < .taskName })
case .date :
tasks.sort(by: { [=10=].taskDate > .taskDate })
}
}
}
struct Task : Identifiable , Equatable {
var id : String = UUID().uuidString
let taskName : String
let taskDate : Date
var taskCompleted: Bool
}
enum SortType : String , Identifiable , CaseIterable {
var id : String { rawValue }
case alphabetical
case date
}
struct NewTaskView: View {
@Environment(\.presentationMode) var presentationMode
@ObservedObject var taskVM : TaskViewModel
@State var taskName = ""
@State var taskCompleted = Bool()
@State var taskDate = Date()
var body: some View {
NavigationView {
VStack(spacing: 14) {
Spacer()
TextField("Assignment Name",text: $taskName)
.padding()
.background(Color("tan"))
.cornerRadius(5)
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 15))
.padding(.bottom, 20)
HStack{
Text("Due Date")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 15))
Image(systemName: "bell.badge")
.foregroundColor(.gray)
.frame(width: 30, height: 30, alignment: .leading)
VStack{
DatePicker("Select Date", selection: $taskDate, displayedComponents: .date)
.labelsHidden()
}
}
HStack{
Text("Mark as Completed")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 15))
Button(action : {
taskCompleted.toggle()
}){
if taskCompleted == true {
Image(systemName: "checkmark.circle.fill")
.foregroundColor(Color("orange"))
.font(.title2)
}
else {
Image(systemName: "circle")
.foregroundColor(Color("lightorange"))
.font(.title2)
}
}
}
Spacer()
Button(action:{taskVM.addTask(task: .init(taskName: taskName, taskDate: taskDate, taskCompleted: taskCompleted))
presentationMode.wrappedValue.dismiss()},
label:{
Text("Save")
})
}.padding()
.navigationBarItems(trailing: Button(action: {
presentationMode.wrappedValue.dismiss()
}) {
HStack{
Image(systemName: "xmark")
.foregroundColor(Color("orange"))
}
})
}
}
}
struct NewTaskView_Previews: PreviewProvider {
static var previews: some View {
NewTaskView(taskVM: TaskViewModel())
}
}
struct TaskView: View {
var task : Task
@Environment(\.managedObjectContext) var moc
@State var currentDate: Date = Date()
@State var taskCompleted = false
func getDateFormatString(date:Date) -> String
{
var dateString = ""
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MMM. dd"
dateString = dateFormatter.string(from: date)
return dateString
}
var body: some View {
HStack {
Button(action : {
self.taskCompleted.toggle()
try? self.moc.save()
}){
if self.taskCompleted {
Image(systemName: "checkmark.circle.fill")
.foregroundColor(Color("orange"))
.font(.title2)
}
else {
Image(systemName: "circle")
.foregroundColor(Color("lightorange"))
.font(.title2)
}
}.padding()
VStack (alignment: .leading, spacing: 2){
Text("\(task.taskName)")
.font(Font.custom(FontNameManager.Montserrat.bold, size: 18))
.foregroundColor(Color("dark"))
.padding([.leading, .trailing], 1)
if self.taskCompleted {
Text("Completed")
.font(Font.custom(FontNameManager.Montserrat.bold, size: 12))
.foregroundColor(Color("burntorange"))
.frame(width: 95, height: 20)
.background(Color("lightorange"))
.cornerRadius(4)
}
else if currentDate > task.taskDate {
Text("Late")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 12))
.foregroundColor(.white)
.frame(width: 95, height: 18)
.background(Color("lightbrown"))
.cornerRadius(4)
}
else {
let diffs = Calendar.current.dateComponents([.day], from: currentDate, to: task.taskDate )
Text("\(diffs.day!) days left")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 12))
.foregroundColor(Color("burntorange"))
.frame(width: 95, height: 20)
.background(Color("lightorange"))
.cornerRadius(4)
}
}
Spacer()
Text(getDateFormatString(date: task.taskDate ))
.font(Font.custom(FontNameManager.Montserrat.medium, size: 12))
.padding()
}
.padding(10)
.cornerRadius(10)
.background(
RoundedRectangle(cornerRadius: 10 , style: .continuous)
.foregroundColor(.white))
}
}
struct TaskView_Previews: PreviewProvider {
static var previews: some View {
TaskView(task: Task(id: "", taskName: "Task Name", taskDate: Date(), taskCompleted: false))
}
}
struct DetailsView: View {
@Environment(\.managedObjectContext) var moc
@ObservedObject var developers : Developer
@ObservedObject var taskVM : TaskViewModel
@Environment(\.presentationMode) var presen
@Environment(\.editMode) var editButton
@State var taskCompleted = false
@State var show = false
@State var showSearch = false
@State var txt = ""
@State var currentDate: Date = Date()
@State var image : Data = .init(count: 0)
@State var indices : [Int] = []
func getDateFormatString(date:Date) -> String
{
var dateString = ""
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MMM. dd"
dateString = dateFormatter.string(from: date)
return dateString
}
var body: some View {
NavigationView {
ZStack {
ZStack{
VStack{
Color("lightorange")
.clipShape(CustomCorners(corners: [.bottomLeft, .bottomRight], size: 70))
.ignoresSafeArea(.all, edges: .top)
.frame(width: 420, height: 175)
Spacer()
}
VStack{
HStack {
if !self.showSearch{
Button(action: {
withAnimation(.spring()){
self.presen.wrappedValue.dismiss()
}
}) {
Image(systemName: "chevron.left")
.font(.title2)
.foregroundColor(Color("dark"))
.padding(10)
}
}
Spacer(minLength: 0)
HStack {
if self.showSearch{
Image(systemName: "magnifyingglass")
.font(.title2)
.foregroundColor(Color("dark"))
.padding(.horizontal, 8)
TextField("Search", text: $taskVM.searched , onEditingChanged: { (isBegin) in
if isBegin {
showSearch = true
} else {
showSearch = false
}
})
Button(action: {
withAnimation{
self.showSearch.toggle()
}
}) {
Image(systemName: "xmark").foregroundColor(.black).padding(.horizontal, 8)
}
}
else {
Button(action: {
withAnimation {
self.showSearch.toggle()
}
}) {
Image(systemName: "magnifyingglass")
.font(.title2)
.foregroundColor(Color("dark"))
.padding(10)
}
}
}.padding(self.showSearch ? 10 : 0)
.background(Color("lightorange"))
.cornerRadius(20)
}
ZStack{
RoundedRectangle(cornerRadius: 25)
.foregroundColor(Color("tan"))
.frame(width: 335, height: 130)
HStack {
VStack (alignment: .leading){
// Image(uiImage: UIImage(data: developers.imageD ?? self.image)!)
// .resizable()
// .frame(width: 70, height: 70)
// .clipShape(RoundedRectangle(cornerRadius: 20))
Text("\(developers.username ?? "")")
.font(Font.custom(FontNameManager.Montserrat.bold, size: 24))
.foregroundColor(Color("dark"))
Text("\(developers.descriptions ?? "")")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 18))
.foregroundColor(.gray)
}
.padding([.leading, .trailing], 70)
.padding(.bottom, 80)
Spacer()
}
}
HStack{
Text("Assignments")
.font(Font.custom(FontNameManager.Montserrat.bold, size: 20))
Spacer(minLength: 0)
EditButton()
}
.padding([.leading, .trailing], 20)
Spacer()
List {
ForEach (taskVM.tasks.filter {
self.taskVM.searched.isEmpty ? true : [=13=].taskName.localizedCapitalized.contains(self.taskVM.searched)} ){ task in
TaskView(task: task)
.listRowSeparator(.hidden)
}
.onDelete(perform: {
taskVM.removeTask(indexAt: [=13=])
})
}
.listStyle(InsetListStyle())
}
}
VStack {
Spacer()
HStack {
Spacer()
ExpandableFAB(taskVM: TaskViewModel(), show: $show)
}
}
}.navigationBarHidden(true)
.navigationBarBackButtonHidden(true)
}
}
}
struct DetailsView_Previews: PreviewProvider {
static let persistenceController = PersistenceController.shared
static var developers: Developer = {
let context = persistenceController.container.viewContext
let developers = Developer(context: context)
developers.username = "Math"
developers.descriptions = "Calculus"
return developers
}()
static var previews: some View {
DetailsView(developers: developers, taskVM: TaskViewModel()).environment(\.managedObjectContext, persistenceController.container.viewContext)
}
}
struct ExpandableFAB: View {
@Environment(\.managedObjectContext) var moc
@ObservedObject var taskVM : TaskViewModel
@Binding var show: Bool
var body: some View{
VStack(spacing: 20){
if self.show{
Button(action: {
taskVM.isPresented.toggle()
}) {
Image(systemName: "list.bullet.rectangle.portrait").resizable().frame(width: 25, height: 25).padding()
}
.foregroundColor(.white)
.background(Color("orange"))
.clipShape(Circle())
Button(action: {
self.show.toggle()
}) {
Image(systemName: "doc.badge.plus").resizable().frame(width: 25, height: 25).padding()
}.foregroundColor(.white)
.background(Color("orange"))
.clipShape(Circle())
}
Button(action: {
self.show.toggle()
}) {
Image(systemName: "plus").resizable().frame(width: 25, height: 25).padding()
}.foregroundColor(.white)
.background(Color("orange"))
.clipShape(RoundedRectangle(cornerRadius: 20))
.padding()
.rotationEffect(.init(degrees: self.show ? 180 : 0))
}.fullScreenCover(isPresented: $taskVM.isPresented, content: {
NewTaskView(taskVM: taskVM)
})
}
}
@burnsi I don't think I have that anywhere. Where should there be one?
当然你有一个，你需要一个：
ExpandableFAB(taskVM: TaskViewModel(), show: $show)
这一行导致了问题。
您以某种方式在 DetailsView 中注入了一个 TaskViewModel（您没有显示位置），但没有使用它。尝试：
ExpandableFAB(taskVM: taskVM, show: $show)
您创建 ViewModel ('TaskViewModel()') 的地方应该有一个 @StateObject 包装器。
解释：
当您向 ViewModel 添加内容时，会重建取决于 ViewModel 的视图。所以你的 TaskViewModel 最终被重新创建，你的数组中仍然有你的 2 个初始值。
我现在是 Swift 的新手，我无法添加到待办事项列表。我没有收到错误，所以我不知道出了什么问题。我希望代码不会太多，但我什至不知道问题出在哪里。
有一个 sheet 模式可以正常打开和关闭。唯一的问题是，当我按下保存按钮时，我输入的信息没有添加到列表中。
我添加了 ViewModel、NewTaskView(sheet)、TaskView(自定义列表)，以及列表应该位于的 DetailView 的一些代码。
import Foundation
import SwiftUI
class TaskViewModel : Identifiable , ObservableObject {
@Published var tasks : [Task] = [
Task(taskName: "Lab", taskDate: Date(), taskCompleted: false),
Task(taskName: "Assignment 4.02", taskDate: Date(), taskCompleted: false)
]
@Published var sortType : SortType = .alphabetical
@Published var isPresented = false
@Published var searched = ""
func addTask(task : Task){
tasks.append(task)
}
func removeTask(indexAt : IndexSet){
tasks.remove(atOffsets: indexAt)
}
func sort(){
switch sortType {
case .alphabetical :
tasks.sort(by: { [=10=].taskName < .taskName })
case .date :
tasks.sort(by: { [=10=].taskDate > .taskDate })
}
}
}
struct Task : Identifiable , Equatable {
var id : String = UUID().uuidString
let taskName : String
let taskDate : Date
var taskCompleted: Bool
}
enum SortType : String , Identifiable , CaseIterable {
var id : String { rawValue }
case alphabetical
case date
}
struct NewTaskView: View {
@Environment(\.presentationMode) var presentationMode
@ObservedObject var taskVM : TaskViewModel
@State var taskName = ""
@State var taskCompleted = Bool()
@State var taskDate = Date()
var body: some View {
NavigationView {
VStack(spacing: 14) {
Spacer()
TextField("Assignment Name",text: $taskName)
.padding()
.background(Color("tan"))
.cornerRadius(5)
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 15))
.padding(.bottom, 20)
HStack{
Text("Due Date")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 15))
Image(systemName: "bell.badge")
.foregroundColor(.gray)
.frame(width: 30, height: 30, alignment: .leading)
VStack{
DatePicker("Select Date", selection: $taskDate, displayedComponents: .date)
.labelsHidden()
}
}
HStack{
Text("Mark as Completed")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 15))
Button(action : {
taskCompleted.toggle()
}){
if taskCompleted == true {
Image(systemName: "checkmark.circle.fill")
.foregroundColor(Color("orange"))
.font(.title2)
}
else {
Image(systemName: "circle")
.foregroundColor(Color("lightorange"))
.font(.title2)
}
}
}
Spacer()
Button(action:{taskVM.addTask(task: .init(taskName: taskName, taskDate: taskDate, taskCompleted: taskCompleted))
presentationMode.wrappedValue.dismiss()},
label:{
Text("Save")
})
}.padding()
.navigationBarItems(trailing: Button(action: {
presentationMode.wrappedValue.dismiss()
}) {
HStack{
Image(systemName: "xmark")
.foregroundColor(Color("orange"))
}
})
}
}
}
struct NewTaskView_Previews: PreviewProvider {
static var previews: some View {
NewTaskView(taskVM: TaskViewModel())
}
}
struct TaskView: View {
var task : Task
@Environment(\.managedObjectContext) var moc
@State var currentDate: Date = Date()
@State var taskCompleted = false
func getDateFormatString(date:Date) -> String
{
var dateString = ""
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MMM. dd"
dateString = dateFormatter.string(from: date)
return dateString
}
var body: some View {
HStack {
Button(action : {
self.taskCompleted.toggle()
try? self.moc.save()
}){
if self.taskCompleted {
Image(systemName: "checkmark.circle.fill")
.foregroundColor(Color("orange"))
.font(.title2)
}
else {
Image(systemName: "circle")
.foregroundColor(Color("lightorange"))
.font(.title2)
}
}.padding()
VStack (alignment: .leading, spacing: 2){
Text("\(task.taskName)")
.font(Font.custom(FontNameManager.Montserrat.bold, size: 18))
.foregroundColor(Color("dark"))
.padding([.leading, .trailing], 1)
if self.taskCompleted {
Text("Completed")
.font(Font.custom(FontNameManager.Montserrat.bold, size: 12))
.foregroundColor(Color("burntorange"))
.frame(width: 95, height: 20)
.background(Color("lightorange"))
.cornerRadius(4)
}
else if currentDate > task.taskDate {
Text("Late")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 12))
.foregroundColor(.white)
.frame(width: 95, height: 18)
.background(Color("lightbrown"))
.cornerRadius(4)
}
else {
let diffs = Calendar.current.dateComponents([.day], from: currentDate, to: task.taskDate )
Text("\(diffs.day!) days left")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 12))
.foregroundColor(Color("burntorange"))
.frame(width: 95, height: 20)
.background(Color("lightorange"))
.cornerRadius(4)
}
}
Spacer()
Text(getDateFormatString(date: task.taskDate ))
.font(Font.custom(FontNameManager.Montserrat.medium, size: 12))
.padding()
}
.padding(10)
.cornerRadius(10)
.background(
RoundedRectangle(cornerRadius: 10 , style: .continuous)
.foregroundColor(.white))
}
}
struct TaskView_Previews: PreviewProvider {
static var previews: some View {
TaskView(task: Task(id: "", taskName: "Task Name", taskDate: Date(), taskCompleted: false))
}
}
struct DetailsView: View {
@Environment(\.managedObjectContext) var moc
@ObservedObject var developers : Developer
@ObservedObject var taskVM : TaskViewModel
@Environment(\.presentationMode) var presen
@Environment(\.editMode) var editButton
@State var taskCompleted = false
@State var show = false
@State var showSearch = false
@State var txt = ""
@State var currentDate: Date = Date()
@State var image : Data = .init(count: 0)
@State var indices : [Int] = []
func getDateFormatString(date:Date) -> String
{
var dateString = ""
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MMM. dd"
dateString = dateFormatter.string(from: date)
return dateString
}
var body: some View {
NavigationView {
ZStack {
ZStack{
VStack{
Color("lightorange")
.clipShape(CustomCorners(corners: [.bottomLeft, .bottomRight], size: 70))
.ignoresSafeArea(.all, edges: .top)
.frame(width: 420, height: 175)
Spacer()
}
VStack{
HStack {
if !self.showSearch{
Button(action: {
withAnimation(.spring()){
self.presen.wrappedValue.dismiss()
}
}) {
Image(systemName: "chevron.left")
.font(.title2)
.foregroundColor(Color("dark"))
.padding(10)
}
}
Spacer(minLength: 0)
HStack {
if self.showSearch{
Image(systemName: "magnifyingglass")
.font(.title2)
.foregroundColor(Color("dark"))
.padding(.horizontal, 8)
TextField("Search", text: $taskVM.searched , onEditingChanged: { (isBegin) in
if isBegin {
showSearch = true
} else {
showSearch = false
}
})
Button(action: {
withAnimation{
self.showSearch.toggle()
}
}) {
Image(systemName: "xmark").foregroundColor(.black).padding(.horizontal, 8)
}
}
else {
Button(action: {
withAnimation {
self.showSearch.toggle()
}
}) {
Image(systemName: "magnifyingglass")
.font(.title2)
.foregroundColor(Color("dark"))
.padding(10)
}
}
}.padding(self.showSearch ? 10 : 0)
.background(Color("lightorange"))
.cornerRadius(20)
}
ZStack{
RoundedRectangle(cornerRadius: 25)
.foregroundColor(Color("tan"))
.frame(width: 335, height: 130)
HStack {
VStack (alignment: .leading){
// Image(uiImage: UIImage(data: developers.imageD ?? self.image)!)
// .resizable()
// .frame(width: 70, height: 70)
// .clipShape(RoundedRectangle(cornerRadius: 20))
Text("\(developers.username ?? "")")
.font(Font.custom(FontNameManager.Montserrat.bold, size: 24))
.foregroundColor(Color("dark"))
Text("\(developers.descriptions ?? "")")
.font(Font.custom(FontNameManager.Montserrat.semibold, size: 18))
.foregroundColor(.gray)
}
.padding([.leading, .trailing], 70)
.padding(.bottom, 80)
Spacer()
}
}
HStack{
Text("Assignments")
.font(Font.custom(FontNameManager.Montserrat.bold, size: 20))
Spacer(minLength: 0)
EditButton()
}
.padding([.leading, .trailing], 20)
Spacer()
List {
ForEach (taskVM.tasks.filter {
self.taskVM.searched.isEmpty ? true : [=13=].taskName.localizedCapitalized.contains(self.taskVM.searched)} ){ task in
TaskView(task: task)
.listRowSeparator(.hidden)
}
.onDelete(perform: {
taskVM.removeTask(indexAt: [=13=])
})
}
.listStyle(InsetListStyle())
}
}
VStack {
Spacer()
HStack {
Spacer()
ExpandableFAB(taskVM: TaskViewModel(), show: $show)
}
}
}.navigationBarHidden(true)
.navigationBarBackButtonHidden(true)
}
}
}
struct DetailsView_Previews: PreviewProvider {
static let persistenceController = PersistenceController.shared
static var developers: Developer = {
let context = persistenceController.container.viewContext
let developers = Developer(context: context)
developers.username = "Math"
developers.descriptions = "Calculus"
return developers
}()
static var previews: some View {
DetailsView(developers: developers, taskVM: TaskViewModel()).environment(\.managedObjectContext, persistenceController.container.viewContext)
}
}
struct ExpandableFAB: View {
@Environment(\.managedObjectContext) var moc
@ObservedObject var taskVM : TaskViewModel
@Binding var show: Bool
var body: some View{
VStack(spacing: 20){
if self.show{
Button(action: {
taskVM.isPresented.toggle()
}) {
Image(systemName: "list.bullet.rectangle.portrait").resizable().frame(width: 25, height: 25).padding()
}
.foregroundColor(.white)
.background(Color("orange"))
.clipShape(Circle())
Button(action: {
self.show.toggle()
}) {
Image(systemName: "doc.badge.plus").resizable().frame(width: 25, height: 25).padding()
}.foregroundColor(.white)
.background(Color("orange"))
.clipShape(Circle())
}
Button(action: {
self.show.toggle()
}) {
Image(systemName: "plus").resizable().frame(width: 25, height: 25).padding()
}.foregroundColor(.white)
.background(Color("orange"))
.clipShape(RoundedRectangle(cornerRadius: 20))
.padding()
.rotationEffect(.init(degrees: self.show ? 180 : 0))
}.fullScreenCover(isPresented: $taskVM.isPresented, content: {
NewTaskView(taskVM: taskVM)
})
}
}
@burnsi I don't think I have that anywhere. Where should there be one?
当然你有一个，你需要一个：
ExpandableFAB(taskVM: TaskViewModel(), show: $show)
这一行导致了问题。
您以某种方式在 DetailsView 中注入了一个 TaskViewModel（您没有显示位置），但没有使用它。尝试：
ExpandableFAB(taskVM: taskVM, show: $show)
您创建 ViewModel ('TaskViewModel()') 的地方应该有一个 @StateObject 包装器。
解释：
当您向 ViewModel 添加内容时，会重建取决于 ViewModel 的视图。所以你的 TaskViewModel 最终被重新创建，你的数组中仍然有你的 2 个初始值。