我正在努力解决以下问题:我正在try 构建一个非常简单的应用程序,它允许您在一个可以折叠的专用视图中添加项目.我设法编写了一个简单的函数,使我可以添加多个这样的定制可折叠视图.这是我的第一个应用程序,所以我想遵循MVVM协议.我想我一路上都搞混了,因为现在我添加的每个项目都会自动添加到我创建的所有自定义可折叠视图中.有什么办法可以解决这个问题吗?我以为使用UUID可以解决这个问题..我猜我必须定制"saveButtonPressed"函数,但我不知道如何告诉它只将项目添加到我按下"加号"按钮的视图中.
以下是各个项目和可折叠视图的模型:
struct ItemModel: Identifiable, Equatable {
let id: String
let title: String
init(id: String = UUID().uuidString, title: String) {
self.id = id
self.title = title
}
func updateCompletion() -> ItemModel {
return ItemModel(id: id, title: title)
}
}
-
import Foundation
struct CollapsableItem: Equatable, Identifiable, Hashable {
let id: String
var title: String
init(id: String = UUID().uuidString, title: String) {
self.id = id
self.title = title
}
func updateCompletion() -> CollapsableItem {
return CollapsableItem(id: id, title: title)
}
}
以下是我的两个视图模型:
class ListViewModel: ObservableObject {
@Published var items: [ItemModel] = []
init() {
getItems()
}
func getItems() {
let newItems = [
ItemModel(title: "List Item1"),
ItemModel(title: "List Item2"),
ItemModel(title: "List Item3"),
]
items.append(contentsOf: newItems)
}
func addItem(title: String) {
let newItem = ItemModel(title: title)
items.append(newItem)
}
func updateItem(item: ItemModel) {
if let index = items.firstIndex(where: { $0.id == item.id}) {
items[index] = item.updateCompletion()
}
}
}
-
class CollapsedViewModel: ObservableObject {
@Published var collapsableItems: [CollapsableItem] = []
@Published var id = UUID().uuidString
init() {
getCollapsableItems()
}
func getCollapsableItems() {
let newCollapsableItems = [
CollapsableItem(title: "Wake up")
]
collapsableItems.append(contentsOf: newCollapsableItems)
}
func addCollapsableItem(title: String) {
let newCollapsableItem = CollapsableItem(title: title)
collapsableItems.append(newCollapsableItem)
}
func updateCollapsableItem(collapsableItem: CollapsableItem) {
if let index = collapsableItems.firstIndex(where: { $0.id ==
collapsableItem.id}) {
collapsableItems[index] =
collapsableItem.updateCompletion()
}
}
}
项目视图:
struct ListRowView: View {
@EnvironmentObject var listViewModel: ListViewModel
let item: ItemModel
var body: some View {
HStack() {
Text(item.title)
.font(.body)
.fontWeight(.bold)
.foregroundColor(.white)
.multilineTextAlignment(.center)
.lineLimit(1)
.frame(width: 232, height: 16)
}
.padding( )
.frame(width: 396, height: 56)
.background(.gray)
.cornerRadius(12.0)
}
}
可折叠的视图:
struct CollapsedView2<Content: View>: View {
@State var collapsableItem: CollapsableItem
@EnvironmentObject var collapsedViewModel: CollapsedViewModel
@State private var collapsed: Bool = true
@EnvironmentObject var listViewModel: ListViewModel
@State var label: () -> Text
@State var content: () -> Content
@State private var show = true
var body: some View {
ZStack{
VStack {
HStack{
Button(
action: { self.collapsed.toggle() },
label: {
HStack() {
Text("Hello")
.font(.title2.bold())
Spacer()
Image(systemName: self.collapsed ? "chevron.down" :
"chevron.up")
}
.padding(.bottom, 1)
.background(Color.white.opacity(0.01))
}
)
.buttonStyle(PlainButtonStyle())
Button(action: saveButtonPressed, label: {
Image(systemName: "plus")
.font(.title2)
.foregroundColor(.white)
})
}
VStack {
self.content()
}
ForEach(listViewModel.items) { item in ListRowView (item: item)
}
.lineLimit(1)
.fixedSize(horizontal: true, vertical: true)
.frame(minWidth: 396, maxWidth: 396, minHeight: 0, maxHeight: collapsed ?
0 : .none)
.animation(.easeInOut(duration: 1.0), value: show)
.clipped()
.transition(.slide)
}
}
}
func saveButtonPressed() {
listViewModel.addItem(title: "Hello")
}
}
最后是主要观点:
struct ListView: View {
@EnvironmentObject var listViewModel: ListViewModel
@EnvironmentObject var collapsedViewModel: CollapsedViewModel
var body: some View {
ZStack{
ScrollView{
VStack{
HStack{
Text("MyFirstApp")
.font(.largeTitle.bold())
Button(action: newCollapsablePressed, label: {
Image(systemName: "plus")
.font(.title2)
.foregroundColor(.white)
})
}
.padding()
.padding(.leading)
ForEach(collapsedViewModel.collapsableItems) { collapsableItem in
CollapsedView2 (collapsableItem: collapsableItem,
label: { Text("") .font(.title2.bold()) },
content: {
HStack {
Text("")
Spacer() }
.frame(maxWidth: .infinity)
})
}
.padding()
}
}
.frame(maxWidth: .infinity, maxHeight: .infinity)
.statusBar(hidden: false)
.navigationBarHidden(true)
}
}
func newCollapsablePressed() {
collapsedViewModel.addCollapsableItem(title: "hello2")
}
}
我很想知道我怎么才能解决这个问题!