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SwiftData fetch array only when i needed
I used Query(filter:sortBy:) and show them in the ListView. When I change the property of the model, because I fetched filtered and sorted array, the model immediately reflect the change and find its position. What I want is at initializing it fetches filtered and sorted array. And when I change the property nothing happens. But when I tap on refresh button, then the array should change. For example in ToDoList app, the array consists of not done works. when I tap done, it should stay until I refresh. Is it possible?
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342
Apr ’24
SwiftData app storage
I created an app using SwiftData to store titles, dates, and images. When creating and deleting data models repeatedly, the app's storage space should remains the same, but for me it steadily accumulate so now its 5GB in the app's settings despite having no data. Why is this happening?
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445
Mar ’24
SwiftData delete doesn't work
I'm using SwiftData to save title and images. When I delete the model, the fetched model count reduces. But in the settings - storage - myApp, the document and data does not change. I deleted all the models but its like 9GB left. I followed the SwiftData example app provided by Apple as much as possible. I tried isAutosaveEnabled = false and put save() to every delete functions. deleteRule = .cascade
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401
Mar ’24
SwiftData deleteRule .cascade
I made simple school & student model with RelationShip import SwiftUI import SwiftData @Model final class School { var name: String @Relationship(deleteRule: .cascade, inverse: \Student.school) var studentList: [Student] = [Student]() init(name: String) { self.name = name } } @Model final class Student { var name: String var school: School? init(name: String) { self.name = name } } ~ struct SchoolView: View { @Environment(\.modelContext) private var modelContext @Query(sort: \School.name) var schools: [School] @Query(sort: \Student.name) var students: [Student] var body: some View { NavigationStack { List { ForEach(schools) { school in NavigationLink { StudentView(school: school) } label: { HStack { Text(school.name) Spacer() Text("\(school.studentList.count)") } } .swipeActions { Button(role: .destructive) { deleteSchool(school) } label: { Label("Delete", systemImage: "trash") } } } .onDelete(perform: deleteSchools(at:)) } .navigationTitle("Home") .listStyle(.plain) .toolbar { ToolbarItem(placement: .topBarTrailing) { Button { addSchool() } label: { Image(systemName: "plus") } } ToolbarItem(placement: .topBarLeading) { VStack(alignment: .leading) { Text("School: \(schools.count)") Text("Student: \(students.count)") } } } } } private func randomString() -> String { let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" return String((0..<5).map { _ in letters.randomElement()! }) } private func addSchool() { let newSchool = School(name: randomString()) modelContext.insert(newSchool) } private func deleteSchools(at offsets: IndexSet) { offsets.map { schools[$0] }.forEach(deleteSchool) } private func deleteSchool(_ school: School) { modelContext.delete(school) try? modelContext.save() } } struct StudentView: View { @Environment(\.modelContext) private var modelContext var school: School var body: some View { List { ForEach(school.studentList) { student in Text(student.name) } .onDelete(perform: deleteStudents(at:)) } .navigationTitle("Home") .navigationBarTitleDisplayMode(.inline) .listStyle(.plain) .toolbar { ToolbarItem(placement: .topBarTrailing) { Button { addStudent() } label: { Image(systemName: "plus") } } } } private func addStudent() { let newSchool = Student(name: randomString()) modelContext.insert(newSchool) newSchool.school = school school.studentList.append(newSchool) } private func randomString() -> String { let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" return String((0..<5).map { _ in letters.randomElement()! }) } private func deleteStudents(at offsets: IndexSet) { withAnimation { offsets.forEach { let student = school.studentList[$0] modelContext.delete(student) try? modelContext.save() } } } } I try my best to follow the SampleTrips app from Apple developer. When I delete one of the schools, then all the students in the school should be deleted. But the student count never changes. Deleting the student itself works well - the student count decreases. Thank you!
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552
Nov ’23
SwiftUI MapKit search
In the Maps app, when we search for the location let request = MKLocalSearch.Request() request.region = // ??? The app automatically searches again when we scroll the map to the other region. How to do it? Setting the region to the current view of the map Tracking map scrolling start and finish
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481
Oct ’23
Nested NavigationStack destination
struct View1: View { var category: String var body: some View { NavigationStack { List { ... NavigationLink(value: category) { Text("Link to View2") } } .navigationDestination(for: String.self) { str in View2(item: str) } } } } struct View2: View { var item: String var body: some View { NavigationStack { List { ... NavigationLink(value: category) { Text("Link to View3") } } .navigationDestination(for: String.self) { str in View3(number: str) } } } } struct View3: View { var number: String var body: some View { List { ... } } } In this code View1 when press one of the List item it says " there is no matching navigationDestination declaration visible from the location of the link. " But when I delete the NavigationStack bracket in the View2, then it works. Why is that? And I want to put the path to the NavigationStack for going to the root. So I think I should leave the NavigationStack in the View2. Is it right? or is there another way?
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2k
Sep ’23
PhotosPicker delay
struct ImageTest: View { @State private var selectedPhotos: [PhotosPickerItem] = [] @State private var photosData: [Data] = [] @State private var text: String = "" var body: some View { NavigationStack{ Form { Section { HStack { PhotosPicker(selection: $selectedPhotos, maxSelectionCount: 10, matching: .images, photoLibrary: .shared()) { AddPhotoIcon(numOfImages: photosData.count) } .task(id: selectedPhotos) { for selectedPhoto in selectedPhotos { if let data = try? await selectedPhoto.loadTransferable(type: Data.self) { self.photosData.append(data) } } self.selectedPhotos = [] } if !photosData.isEmpty { ScrollView(.horizontal) { HStack { ForEach(photosData, id: \.self) { data in if let image = UIImage(data: data) { Image(uiImage: image) .resizable() .scaledToFill() .frame(width: 50, height: 50) } } } } } Spacer() } } Section { TextField("Any", text: $text) } } } } } Here with SwiftData I'm making the model that contains images and title. There is a delay when entering just ten-character text after selecting photos for like 2~3 seconds. In the debug the memory usage it soars to 700MB. How can I improve it?
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844
Sep ’23