【发布时间】：2021-07-07 20:27:09
【问题描述】：
我是 Swift UI 的新手。你能帮我更新核心数据吗？ 这是一个问题的重点：
我正在构建一个 WatchOS 应用。那里有 3 个视图：
- FirstView - 带有添加新目标和已添加目标列表的按钮的视图。
- AddGoalView - 按添加新目标后出现。
- RingView - 带有目标环的视图（类似于活动环机制）和显示的所有数据。
问题的重点是下一个：
- 添加新目标后一切正常。数据从 AddGoalView 正确传递到 FirstView。我只需要从 AddGoalView 中传递 2 个项目（一个 String 和一个 Double）。
- 然后，在按下最近创建的目标后，我会出现在环视图中。我成功地传递了 2 个项目（我提到的 String 和 Double）。
- 在 RingView 上，我想更新第 3 项（双项）并将其发回。所以它可以在 FirstView 上更新。
结果： 它似乎只是在前一个目标下方的第一个视图上创建了一个全新的目标，而不是更新这个 3-d 项目。 Photo
我的代码（FirstView）：
struct FirstView: View {
@FetchRequest (
entity:NewGoal.entity(),
sortDescriptors:[NSSortDescriptor(keyPath: \NewGoal.dateAdded, ascending: false)],
animation: .easeInOut )
var results:FetchedResults<NewGoal>
@State var showMe = false
var body: some View {
ScrollView{
VStack{
VStack(alignment: .leading){
Text("My Goals:")
NavigationLink(
destination: AddGoalView(),
isActive: $showMe,
label: {
Image(systemName: "plus")
Text("Set Money Goal")
})
Text("Recents:")
ForEach(results){ item in
VStack(alignment: .leading){
NavigationLink(
destination: RingView(GTitle: item.goalTitle ?? "", Sum: item.neededSum),
label: {
HStack{
Image(systemName: "gear")
VStack(alignment: .leading){
Text(item.goalTitle ?? "")
HStack{
Text("$\(item.yourSum, specifier: "%.f")") ///This item doesn't update
Text("/ $\(item.neededSum, specifier: "%.f")")
}
}
}
})
}
}
}
}
}
}
}
我的代码（AddGoalView）：
struct AddGoalView: View {
@State private var goalTitle = ""
@State private var showMe:Bool = true
@State private var neededSum:Double = 0.0
@State private var isFocusedNum = false
@Environment(\.managedObjectContext) var context
@Environment(\.presentationMode) var presentationMode
var body: some View {
ScrollView{
VStack (alignment: .leading, spacing: 6){
TextField("Goal Name...", text: $goalTitle)
HStack{
Text("$\(neededSum, specifier: "%.f")")
.overlay(
RoundedRectangle(cornerRadius: 9)
.stroke(isFocusedNum ? Color.red : Color.white, lineWidth: 1)
.opacity(1.0))
.focusable(true) { newState in isFocusedNum = newState}
.animation(.easeInOut(duration: 0.1), value: isFocusedNum)
.digitalCrownRotation(
$neededSum,
from: 0,
through: 100000,
by: 25,
sensitivity: .high)
}
Button(action: addGoal) {
Text("Add Goal")
}
.disabled(neededSum == 0.0)
.disabled(goalTitle == "")
.navigationTitle("Edit")
}
}
}
private func addGoal(){
let goal = NewGoal(context: context)
goal.goalTitle = goalTitle
goal.dateAdded = Date()
goal.neededSum = neededSum
do{
try context.save()
presentationMode.wrappedValue.dismiss()
}catch let err{
print(err.localizedDescription)
}
}
我的代码（环视图代码）：
struct RingView: View {
@State private var isFocusedSum = false
@State private var yournewSum:Double = 0.0
var goalItem: NewGoal?
var Sum:Double
var GTitle:String
@Environment(\.managedObjectContext) var context
@Environment(\.presentationMode) var presentationMode
@FetchRequest var results: FetchedResults<NewGoal>
init(GTitle: String, Sum: Double){
self.GTitle = GTitle
self.Sum = Sum
let predicate = NSPredicate(format:"goalTitle == %@", GTitle)
self._results=FetchRequest(
entity: NewGoal.entity(),
sortDescriptors: [NSSortDescriptor(keyPath: \NewGoal.dateAdded, ascending: false)],
predicate: predicate,
animation: .easeInOut
)
}
var body: some View {
ZStack{
ForEach(results) { item in
RingShape(percent:(yournewSum/item.neededSum*100), startAngle: -90, drawnClockwise: false) /// Ring
.stroke(style: StrokeStyle(lineWidth: 10, lineCap: .round))
.fill(AngularGradient(gradient: Gradient(colors: [.red, .pink, .red]), center: .center))
.frame(width: 155, height: 155)
HStack(alignment: .top){
Spacer()
Button(action: addSum) { ///BUTTON TO Update
Image(systemName: "gear")
}
.clipShape(Circle())
}
VStack(alignment: .trailing, spacing: 0.0){
Spacer()
Text("$\(yournewSum, specifier: "%.f")") /// Here is the data I want to change via Digital Crown and update
.font(.title3)
.overlay(
RoundedRectangle(cornerRadius: 7)
.stroke(Color.white, lineWidth: 2)
.opacity(isFocusedSum ? 1.0:0.0)
)
.focusable(true) { newState in isFocusedSum = newState}
.animation(.easeInOut(duration: 0.3), value: isFocusedSum)
.digitalCrownRotation(
$yournewSum,
from: 0,
through: Double((item.neededSum)),
by: 10,
sensitivity: .high)
Text("/ $\(item.neededSum, specifier: "%.f")") ///Here is the Double data I entered in AddGoalView
.font(.caption)
}
.frame(width: 200, height: 230)
.padding(.top, 7)
VStack(alignment: .center, spacing: 1.0){
Text(item.goalTitle ?? "Your Goal Name") ///Here is the String data I entered in AddGoalView
.foregroundColor(.gray)
}
.padding(.top, 200.0)
}
}
.padding([.top, .leading, .trailing], 5.0)
}
private func addSum(){
let goal = goalItem == nil ? NewGoal(context: context): goalItem
goal?.yourSum = yournewSum //// I am trying to update the Data here, but after running the func it creates a duplicate.
do{
try context.save()
presentationMode.wrappedValue.dismiss()
} catch let err{
print(err.localizedDescription)
}
}
【问题讨论】：
标签： core-data swiftui apple-watch watchos