I want to mark the items in the list with checkmarks. But some kind of error occurs because the checkmark is installed, but not removed.
Why is this happening?
This is a Model:
import UIKit
struct Food: Codable {
var name: String
var isSelected: Bool = false
}
This is a TableViewController:
import UIKit
class SelectFoods: UITableViewController {
var foods = [Food]()
override func viewDidLoad() {
super.viewDidLoad()
foods = loadRealOrDemoData() // Load data
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return foods.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "selectFood", for: indexPath)
let food = foods[indexPath.row]
cell.textLabel?.text = food.name
// Assign checkmark from the selected item to the cell
if food.isSelected {
cell.accessoryType = .checkmark
} else {
cell.accessoryType = .none
}
cell.selectionStyle = .none
return cell
}
// MARK: - Select Food
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
// Create variable and check it.
guard let cell = tableView.cellForRow(at: indexPath) else { return }
//Clean cell format before select
cell.accessoryType = .none
// Get an item
var item = foods[indexPath.row]
// Set checkmark
if item.isSelected == false {
cell.accessoryType = .checkmark
item.isSelected.toggle()
// Remove checkmark
} else {
cell.accessoryType = .none
item.isSelected.toggle()
}
}
}
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Hi everyone,
I'm trying to follow the Landmarks project tutorial and got stuck in the second part, in the second section (Create the Row View), step 6 where it says "Modify the text view to use the landmark property’s name." This must be done in the LandmarkRow.swift file.
https://developer.apple.com/tutorials/swiftui/building-lists-and-navigation
The tutorial shows that after doing this, the preview will display the name of the landmark (Turtle Rock) instead of the usual "Hello world" greeting. But my replacement is not happening. Moreover, from this point on, the preview stops working. There are no error messages in the code, except for the message that the preview could not be performed.
I checked and rewrote the code several times, replaced the data source files, but nothing helped.
At the same time, the preview works well in other view files.
I can't figure out what's wrong with my code? Any ideas as to what the reason will be is appreciated.
Below is the code of two files, the LandmarkRow.swift, where view does not work, the second is ModelData.swift and it is related to the previous one.
LandmarkRow.swift
import SwiftUI
struct LandmarkRow: View {
var landmark: Landmark
var body: some View {
HStack {
landmark.image
.resizable()
.frame(width: 50, height: 50)
Text(landmark.name)
Spacer()
}
}
}
struct LandmarkRow_Previews: PreviewProvider {
static var previews: some View {
LandmarkRow(landmark: landmarks[0])
}
}
ModelData.swift
import Foundation
var landmarks: [Landmark] = load("landmarkData.json")
func loadT: Decodable(_ filename: String) - T {
let data: Data
guard let file = Bundle.main.url(forResource: filename, withExtension: nil)
else {
fatalError("Couldn't find \(filename) in main bundle")
}
do {
data = try Data(contentsOf: file)
} catch {
fatalError("Couldn't load \(filename) from main bundle:\n\(error)")
}
do {
let decoder = JSONDecoder()
return try decoder.decode(T.self, from: data)
} catch {
fatalError("Couldn't parse \(filename) as \(T.self):\n\(error)")
}
}
I want to use a Date Picker inside a TableViewCell but it shows some empty field - look the attached image.
What is it and how to remove that empty field?
Hi everyone,
I want to perform the tutorial from video WWDC19 - 204. Here is an example of building the "Rooms" application. At 42 minutes, the author of the video, Jacob Xiao, shows how to add a new room. But when I try to repeat it, nothing happens. The new room is not added.
My code and code of Jacob Xiao are the same.
import SwiftUI
struct ContentView: View {
@ObservedObject var store = RoomStore()
// Instead of //var rooms: [Room] = []
// @ObservedObject is instead of @ObjectBinding
var body: some View {
NavigationView {
List {
Button(action: addRoom) {
Text("Add Room")
}
ForEach(store.rooms) { room in
RoomCell(room: room)
}
}
.navigationBarTitle(Text("Rooms"))
}
}
func addRoom() {
store.rooms.append(Room(name: "Hall 2", capacity: 2000))
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView(store: RoomStore(rooms: testData))
}
}
struct RoomCell: View {
var room: Room
var body: some View {
NavigationLink(destination: RoomDetail(room: room)) {
Image(room.thumbnailName)
.cornerRadius(8)
VStack(alignment: .leading) {
Text(room.name)
Text("\(room.capacity) people")
.font(.subheadline)
.foregroundColor(.secondary)
}
}
}
}
My project has also an image named "Hall 2".
What could be the reason that a new room is not being added? Any ideas, please.
Hi everyone,I try to pass data from View Controller through Tab Bar Controller and Navigation Controller to Table View Controller. Screenshot of storyboard is bellow.https://drive.google.com/open?id=1GW6gaDxfK1zaEOk2aPE8izkS5B67ldZLMy code is next:1. Send data from View Controller@IBAction func addToCarButton(_ sender: UIButton) {
tabBarController?.selectedIndex = 1
let navVC = tabBarController?.viewControllers![1] as! UINavigationController//
let cartTableViewController = navVC.topViewController as! CartTableViewController
cartTableViewController.titleItem = titleLabel.text
cartTableViewController.image = SomeImage(photo: imageView.image!)
}2. Get data in Table View Controllerimport UIKit
class CartTableViewController: UITableViewController {
// MARK: - Store data
// Create variables for receiving data (title and data from image) from VC
var titleItem: String?
var image: SomeImage?
// Create shopping cart - array of selected items
var cartItems = [Cart]()
var cartItem: Cart?
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
//Load data from archive file
cartItems = Cart.loadFromFile()
// Create a new item
if titleItem != nil, image != nil {
print("titleItem in Cart View Appear - \(String(describing: titleItem))")
cartItem = Cart(title: titleItem!, image: image!)
}
// Add new item to shopping cart
if cartItem != nil {
cartItems.append(cartItem!)
}
tableView.reloadData()
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return cartItems.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "SecondCell", for: indexPath)
// Pass title to cell
cell.textLabel?.text = cartItems[indexPath.row].title
// Retrieve image from array of archive file and convert from Data to UIImage format
let image = UIImage(data: cartItems[indexPath.row].image.photo)
// Pass image to cell:
cell.imageView?.image = image
return cell
}
// MARK: - Save data to archieve file
override func viewWillDisappear(_ animated: Bool) {
Cart.saveToFile(cartItems: cartItems)
tableView.reloadData()
}
// Clear cart
@IBAction func clearCartButton(_ sender: UIBarButtonItem) {
cartItems.removeAll()
tableView.reloadData()
}But data are appear only after second click. I.e., I add item 1 and cart is empty. When I add item 2, cart has item 1. If then I add item 3, card has item 1 and item 2, and go on.I have done link bellow on gif that shows how it works.https://drive.google.com/open?id=1_ilwKHXTRBT250zB4At7UsbWJ09fQARlI tried to use different options, but I can not understand what is happening here.Could you give me advice how to fix it?
I want to create a button, but for some reason it does not work. The text message is not printed in the console.
import SwiftUI
struct Test: View {
var body: some View {
NavigationView {
Text("My Test")
.navigationTitle("Welcome")
.toolbar {
Button("Help") {
print("Help tapped!")
}
}
}
}
}
struct Test_Previews: PreviewProvider {
static var previews: some View {
Test()
}
}
Hello, forum admins.
Thank you for your work in maintaining the forum in an active working condition.
I have a question for you. Is it possible here, on the forum, not only to ask questions and get answers, but also to conduct technical discussions on current programming issues?
For example, I would like to publish an article on design programming patterns and hear the opinions of other programmers working in this direction.
I know that there are resources where we can publish articles. But here is the most big and active community of programmers using Apple technologies and it would be great to have the opportunity to publish articles here and organize thematic discussions.
Best regards,
John
Topic:
Developer Tools & Services
SubTopic:
Developer Forums
I want to programmatically set the constraints for the view. I'm using the code from Apple's Swift library:
Creating layout anchors
// Get the superview's layout
let margins = view.layoutMarginsGuide
// Pin the leading edge of myView to the margin's leading edge
myView.leadingAnchor.constraint(equalTo: margins.leadingAnchor).isActive = true
Link
But my code doesn't work.
import UIKit
class ViewController: UIViewController {
var myView = UIView()
override func viewDidLoad() {
super.viewDidLoad()
myView.frame.size.width = 100
myView.frame.size.height = 100
myView.backgroundColor = .green
view.addSubview(myView)
let margins = view.layoutMarginsGuide
myView.trailingAnchor.constraint(equalTo: margins.trailingAnchor).isActive = true
}
}
I am not getting any error messages. But my view always stays in the same place, in the upper left corner. Even if I change the constraint to center or bottom, the view doesn't move.
Could you tell me what is wrong in my code?
Please, help me to understand one line of code.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "toDetailScreenSegue" {
let detail = segue.destination as! DetailScreenViewController
detail.name = item.name
}
}
What is happening in this line of code below?
let detail = segue.destination as! DetailScreenViewController
Is a copy of the DetailScreenViewController class being made?
And since this is a class, not a structure, then not a separate copy is created, but a reference to the DetailScreenViewController class?
Is this right?
Does SwiftUI now have a NavigationButton? And if not, what is it replaced by?
Hi everyone,
I want to perform the tutorial from video WWDC19 - 204. Here is an example of building the "Rooms" application. At 11 minutes, the author of the video, Jacob Xiao, shows how he performs the extract subview operation. But when I try to repeat this operation an error occurs - Cannot find 'room' in scope.
My code and code of Jacob Xiao are the same.
import SwiftUI
struct ContentView: View {
var rooms: [Room] = []
var body: some View {
NavigationView {
List(rooms) { room in
ExtractedView()
}
.navigationBarTitle(Text("Rooms"))
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView(rooms: testData)
}
}
struct ExtractedView: View {
var body: some View {
NavigationLink(
destination: Text(room.name)) { // Cannot find 'room' in scope
Image(room.thumbnailName)
.cornerRadius(8)
VStack(alignment: .leading) {
Text(room.name)
Text("\(room.capacity) people")
.font(.subheadline)
.foregroundColor(.secondary)
}
}
}
}
I think the reason is that SwiftUI on my computer is a newer version, so some of the previous functions may not work.
Could you tell me how to perform this subview extract operation today?
I am using a date picker and want to assign the value from it to an object property. But for some reason this does not happen and the object property contains nil.
I put code next to it where a date value is assigned to a simple property. It works.
Please tell me what's the matter here? How do I store a date into a property of an object?
import UIKit
struct NewDate {
var date: Date?
}
class MyViewController: UIViewController {
var newDate: NewDate?
@IBOutlet weak var pickerOutlet: UIDatePicker!
override func viewDidLoad() {
super.viewDidLoad()
let date = pickerOutlet.date
print(date) // Prints: 2021-09-03 03:56:17 +0000
newDate?.date = pickerOutlet.date
print(newDate?.date) // Prints: nil
}
}
Sometimes I see weird posts here on the forum with an offer to call women?
What the hell? Admin wake up!
Hi everyone,
I am studying SwiftUI on the Apple tutorial - https://developer.apple.com/tutorials/swiftui/creating-a-macos-app.
In the Creating a MacOS App chapter in section 3 Update a Row View, there is a following instruction: Step 6 Choose the WatchLandmarks target to see a watchOS preview of the list.
How to do this?
It should be easy and simple, but somehow I haven't found it.
Hello everyone, recently I started to learn the SwiftUI. Now I have this code but I don't understand how can I call a view in canvas? At the first case I have error which says that argument is missing.
import SwiftUI
struct EmployeeDetails: View {
var employee: Employee
var body: some View {
VStack(alignment: .leading) {
Text(employee.name)
.font(.largeTitle)
.foregroundColor(.primary)
Text(employee.jobTitle)
.foregroundColor(.secondary)
EmailAddress(address: employee.emailAddress)
}
}
}
struct EmployeeDetails_Previews: PreviewProvider {
static var previews: some View {
EmployeeDetails()
}
}
And when I use "employee" like argument in brackets, I have another error - can't find employee in scope.
struct EmployeeDetails_Previews: PreviewProvider {
static var previews: some View {
EmployeeDetails(employee)
}
}
Please, help me to understand how can I call that view?