Im new to Swift and I have a question regarding the list view.
The code below creates a List of an image as a button followed by a text.
The problem is that the List elements are initially slightly left, but they move to the right into place when they're first updated.
import SwiftUI
struct TodoItem {
var name: String
var completed: Bool
init(_ name: String) {
self.name = name
self.completed = false
}
}
struct ContentView: View {
#State var todos: [TodoItem] = [
TodoItem("This"),
TodoItem("Is"),
TodoItem("Some"),
TodoItem("Todo"),
TodoItem("Task")
]
var body: some View {
NavigationView {
List(todos.indices) { index in
HStack {
Image(systemName: self.todos[index].completed ? "checkmark.circle" : "circle")
.imageScale(.large)
.onTapGesture {
self.todos[index].completed.toggle()
}
Text(self.todos[index].name)
Spacer()
}
}
.navigationBarTitle("Todos")
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Here is fixed body (tested & works with Xcode 11.3.1)
var body: some View {
NavigationView {
List {
ForEach (todos.indices) { index in
HStack {
Image(systemName: self.todos[index].completed ? "checkmark.circle" : "circle")
.imageScale(.large)
.onTapGesture {
self.todos[index].completed.toggle()
}
Text(self.todos[index].name)
Spacer()
}
}.listRowInsets(EdgeInsets(top: 0, leading: 20, bottom: 0, trailing: 20))
}
.navigationBarTitle("Todos")
}
}
Related
In SwiftUI, for this code to toggle the display of view:
#State var show = true
Button { withAnimation { show.toggle() }}
label: { Image(systemName: show ? "chevron.down" : "chevron.right") }
if show { ... }
The animation will be shown if the show is the #State variable.
However, I found that if show is changed to #AppStorage (so to keep the show state), the animation will not be shown.
Is there a way to keep the show state and also preserve the animation?
You can also replace the withAnimation {} with the .animation(<#T##animation: Animation?##Animation?#>, value: <#T##Equatable#>) modifier and then it seems to work directly with the #AppStorage wrapped variable.
import SwiftUI
struct ContentView: View {
#AppStorage("show") var show: Bool = true
var body: some View {
VStack {
Button {
self.show.toggle()
}
label: {
Rectangle()
.fill(Color.red)
.frame(width: self.show ? 200 : 400, height: 200)
.animation(.easeIn, value: self.show)
}
Rectangle()
.fill(Color.red)
.frame(width: self.show ? 200 : 400, height: 200)
.animation(.easeIn, value: self.show)
}
.padding()
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
EDIT: Following the comments, another solution
import SwiftUI
struct ContentView: View {
#State private var show: Bool
init() {
self.show = UserDefaults.standard.bool(forKey: "show")
// Or self._show = State(initialValue: UserDefaults.standard.bool(forKey: "show"))
}
var body: some View {
VStack {
Button {
withAnimation {
self.show.toggle()
}
}
label: {
Text("Toggle")
}
if show {
Rectangle()
.fill(Color.red)
.frame(width: 200 , height: 200)
}
}
.padding()
.onChange(of: self.show) { newValue in
UserDefaults.standard.set(newValue, forKey: "show")
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
I'm trying to create a Binding in two views so I can change something on one side and have it reflected on the other.
I basically have:
a circle on both views
a button to change the other view's circle color
and one to go to the other view
It all works fine if I only have a Binding in the "ColorChange2"
view, but when I add a Binding in "ColorChange1" I get into trouble.
It tells me: Missing argument for parameter 'isOn2'.
But when I add isOn2 into ColorChange1() it wants a binding, but if I do ColorChange1(isOn2: $isOn2) it says it can't find '$isOn2' in scope.
I found one solution suggesting to add .constant(true)) into the preview but since it's a constant, it wont change the view like I wanted since it's a constant.
What can I do to make it work?
Code:
struct ColorChange1: View {
#State private var isOn = false
#Binding var isOn2 : Bool
var body: some View {
NavigationView {
VStack {
Circle()
.fill(isOn ? .green : .red)
.frame(width: 100)
Button(action: {
isOn2.toggle()
}, label: {
Text("Change button view 2")
.padding()
})
NavigationLink(destination: {
ColorChange2(isOn: $isOn)
}, label: {
Text("Go to view 2")
})
}
}
}
}
struct ColorChange2: View {
#Binding var isOn : Bool
#State private var isOn2 = false
#Environment(\.dismiss) var dismiss
var body: some View {
VStack {
Circle()
.fill(isOn2 ? .green : .red)
.frame(width: 100)
Button(action: {
isOn.toggle()
}, label: {
Text("Change button view 1")
.padding()
})
Button(action: {
dismiss.callAsFunction()
}, label: {
Text("Go to view 1")
})
}
.navigationBarBackButtonHidden(true)
}
}
struct ColorChange_Previews: PreviewProvider {
static var previews: some View {
// ColorChange(isOn2: .constant(true))
ColorChange1()
}
} ```
You don't need both #Binding value in both screen to connect between screen like that.
#Binding means that get the value in #State of the first view and make a connection in the second view. In this scenero, when you go back from second view, it was dismissed.
For your problem, make an ObservableObject to store value. 1 for present in first view and 1 for second view. Then add it to second view when ever you need to display.
Code will be like this
class ColorModel : ObservableObject {
#Published var isOnFirstView = false
#Published var isOnSecondView = false
func didTapChangeColor(atFirstView: Bool) {
if atFirstView {
isOnSecondView = !isOnSecondView
} else {
isOnFirstView = !isOnFirstView
}
}
}
struct ColorChange2: View {
// binding model
#ObservedObject var colorModel : ColorModel
#Environment(\.dismiss) var dismiss
var body: some View {
VStack {
Circle()
.fill(colorModel.isOnSecondView ? .green : .red)
.frame(width: 100)
Button(action: {
colorModel.didTapChangeColor(atFirstView: false)
}, label: {
Text("Change button view 1")
.padding()
})
Button(action: {
dismiss.callAsFunction()
}, label: {
Text("Go to view 1")
})
}
.navigationBarBackButtonHidden(true)
}
}
struct ColorChange1: View {
#StateObject private var colorModel = ColorModel()
var body: some View {
NavigationView {
VStack {
Circle()
.fill(colorModel.isOnFirstView ? .green : .red)
.frame(width: 100)
Button(action: {
colorModel.didTapChangeColor(atFirstView: true)
}, label: {
Text("Change button view 2")
.padding()
})
NavigationLink(destination: {
ColorChange2(colorModel: colorModel)
}, label: {
Text("Go to view 2")
})
}
}
}
}
struct ColorChange_Previews: PreviewProvider {
static var previews: some View {
ColorChange1()
}
}
currently having an issue with a tutorial I followed which creates an underlined tab bar with SwiftUI. At the current stage, the tab bar scrolls with a scrollview when a view is changed, however, instead of this happening I want the buttons to remain idle in their place as a normal (still functioning) underlined tab bar. This is currently what it looks like when a view is swiped across:
Notice how when a tab changes, instead of remaining still within the tab bar, the labels scroll over. I have tried removing the scroll view of the tab bar but just can't seem to work out how to get it to remain fixed within the screen.
The code from the tutorial looks like this:
import SwiftUI
struct ContentView: View {
#State var currentTab: Int = 0
var body: some View {
ZStack(alignment: .top) {
TabView(selection: self.$currentTab) {
View1().tag(0)
View2().tag(1)
}
.tabViewStyle(.page(indexDisplayMode: .never))
.edgesIgnoringSafeArea(.all)
TabBarView(currentTab: self.$currentTab)
}
}
}
struct TabBarView: View {
#Binding var currentTab: Int
#Namespace var namespace
var tabBarOptions: [String] = ["View 1", "View 2"]
var body: some View {
ScrollView(.horizontal, showsIndicators: false) {
HStack(spacing: 20) {
ForEach(Array(zip(self.tabBarOptions.indices,
self.tabBarOptions)),
id: \.0,
content: {
index, name in
TabBarItem(currentTab: self.$currentTab,
namespace: namespace.self,
tabBarItemName: name,
tab: index)
})
}
.padding(.horizontal)
}
.background(Color.white)
.frame(height: 80)
.edgesIgnoringSafeArea(.all)
}
}
struct TabBarItem: View {
#Binding var currentTab: Int
let namespace: Namespace.ID
var tabBarItemName: String
var tab: Int
var body: some View {
Button {
self.currentTab = tab
} label: {
VStack {
Spacer()
Text(tabBarItemName)
if currentTab == tab {
Color.black
.frame(height: 2)
.matchedGeometryEffect(id: "underline",
in: namespace,
properties: .frame)
} else {
Color.clear.frame(height: 2)
}
}
.animation(.spring(), value: self.currentTab)
}
.buttonStyle(.plain)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Help resolving this would be greatly appreciated! Thanks!!
Try this code. This should sole your problem. The main issue was that you used a ZStack instead of a VStack. After that, just fiddle around with the spacing and positioning of the elements you build in your VStack.
Let me know if it creates the result you want.
import SwiftUI
struct ContentView: View {
#State var currentTab: Int = 0
var body: some View {
VStack(alignment: .center, spacing: 0) {
TabBarView(currentTab: self.$currentTab)
TabView(selection: self.$currentTab) {
Text("This is view 1").tag(0)
Text("This is view 2").tag(1)
}
.tabViewStyle(.page(indexDisplayMode: .never))
.background(Color.secondary) // <<<< Remove
}
.edgesIgnoringSafeArea(.all)
}
}
struct TabBarView: View {
#Binding var currentTab: Int
#Namespace var namespace
var tabBarOptions: [String] = ["View 1", "View 2"]
var body: some View {
HStack(spacing: 20) {
ForEach(Array(zip(self.tabBarOptions.indices,
self.tabBarOptions)),
id: \.0,
content: {
index, name in
TabBarItem(currentTab: self.$currentTab,
namespace: namespace.self,
tabBarItemName: name,
tab: index)
})
}
.padding(.horizontal)
.background(Color.orange) // <<<< Remove
.frame(height: 80)
}
}
struct TabBarItem: View {
#Binding var currentTab: Int
let namespace: Namespace.ID
var tabBarItemName: String
var tab: Int
var body: some View {
Button {
self.currentTab = tab
} label: {
VStack {
Spacer()
Text(tabBarItemName)
if currentTab == tab {
Color.black
.frame(height: 2)
.matchedGeometryEffect(id: "underline",
in: namespace,
properties: .frame)
} else {
Color.clear.frame(height: 2)
}
}
.animation(.spring(), value: self.currentTab)
}
.buttonStyle(.plain)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
I want when I finish selecting the language and click the Save button it will return the ContentView page and display the language I have selected. And when I click again, it has to checkmark the language I selected before.
I have successfully displayed the data, but I don't know how to save it when I click the Save button
Here is all my code currently
ContentView
struct ContentView: View {
var body: some View {
NavigationView {
HStack {
NavigationLink(destination:LanguageView() ) {
Text("Language")
Spacer()
Text("I want to show the language here ")
}
}
}
}
}
LanguageView
struct LanguageView: View {
var body: some View {
VStack {
CustomLanguageView()
Button(action: {
})
{
Text("Save")
.foregroundColor(.black)
}
.padding()
Spacer()
}
}
}
struct CustomLanguageView: View {
var language = ["US", "English", "Mexico", "Canada"]
#State var selectedLanguage: String? = nil
var body: some View {
LazyVStack {
ForEach(language, id: \.self) { item in
SelectionCell(language: item, selectedLanguage: self.$selectedLanguage)
.padding(.trailing,40)
Rectangle().fill(Color.gray)
.frame( height: 1,alignment: .bottom)
}
.frame(height:15)
}
}
}
struct SelectionCell: View {
let language: String
#Binding var selectedLanguage: String?
var body: some View {
HStack {
Text(language)
Spacer()
if language == selectedLanguage {
Image(systemName: "checkmark")
.resizable()
.frame(width:20, height: 15)
}
}
.onTapGesture {
self.selectedLanguage = self.language
}
}
}
There are multiple ways to "Save" something but if you are just trying to get it back to the other view you could do something like this that I quickly setup.
struct ContentView: View {
#State var language: String? = ""
var body: some View {
NavigationView {
HStack {
NavigationLink(destination:LanguageView(language: $language)) {
Text("Language")
.padding()
Spacer()
Text(language!)
.padding()
}
}
}
}
}
struct LanguageView: View {
#Binding var language: String?
#State var selectedLanguage: String? = ""
var body: some View {
VStack {
CustomLanguageView(selectedLanguage: $selectedLanguage)
Button(action: {
language = selectedLanguage
})
{
Text("Save")
.foregroundColor(.black)
}
.padding()
Spacer()
}
}
}
struct CustomLanguageView: View {
var language = ["US", "English", "Mexico", "Canada"]
#Binding var selectedLanguage: String?
var body: some View {
LazyVStack {
ForEach(language, id: \.self) { item in
SelectionCell(language: item, selectedLanguage: self.$selectedLanguage)
.padding(.trailing,40)
Rectangle().fill(Color.gray)
.frame( height: 1,alignment: .bottom)
}
.frame(height:15)
}
}
}
struct SelectionCell: View {
let language: String
#Binding var selectedLanguage: String?
var body: some View {
HStack {
Text(language)
Spacer()
if language == selectedLanguage {
Image(systemName: "checkmark")
.resizable()
.frame(width:20, height: 15)
}
}
.onTapGesture {
self.selectedLanguage = self.language
}
}
}
Or if you are actually trying to save it to the device for later use you could use
UserDefaults.standard.setValue(selectedLanguage, forKey: "language")
Then to Retrieve it later do
UserDefaults.standard.value(forKey: "language") as! String
I am attempting to build a multifaceted openweathermap app. My app is designed to prompt the user to input a city name on a WelcomeView, in order to get weather data for that city. After clicking search, the user is redirected to a sheet with destination: DetailView, which displays weather details about that requested city. My goal is to disable dismissal of the sheet in WelcomeView and instead add a navigationlink to the sheet that redirects to the ContentView. The ContentView in turn is set up to display a list of the user's recent searches (also in the form of navigation links).
My issues are the following:
The navigationLink in the WelcomeView sheet does not work. It appears to be disabled. How can I configure the navigationLink to segue to destination: ContentView() ?
After clicking the navigationLink and redirecting to ContentView, I want to ensure that the city name entered in the WelcomeView textfield is rendered as a list item in the ContentView. For that to work, would it be necessary to set up an action in NavigationLink to call viewModel.fetchWeather(for: cityName)?
Here is my code:
WelcomeView
struct WelcomeView: View {
#StateObject var viewModel = WeatherViewModel()
#State private var cityName = ""
#State private var showingDetail: Bool = false
#State private var linkActive: Bool = true
#State private var acceptedTerms = false
var body: some View {
Section {
HStack {
TextField("Search Weather by City", text: $cityName)
.padding()
.overlay(RoundedRectangle(cornerRadius: 10.0).strokeBorder(Color.gray, style: StrokeStyle(lineWidth: 1.0)))
.padding()
Spacer()
Button(action: {
viewModel.fetchWeather(for: cityName)
cityName = ""
self.showingDetail.toggle()
}) {
HStack {
Image(systemName: "plus")
.font(.title)
}
.padding(15)
.foregroundColor(.white)
.background(Color.green)
.cornerRadius(40)
}
.sheet(isPresented: $showingDetail) {
VStack {
NavigationLink(destination: ContentView()){
Text("Return to Search")
}
ForEach(0..<viewModel.cityNameList.count, id: \.self) { city in
if (city == viewModel.cityNameList.count-1) {
DetailView(detail: viewModel.cityNameList[city])
}
}.interactiveDismissDisabled(!acceptedTerms)
}
}
}.padding()
}
}
}
struct WelcomeView_Previews: PreviewProvider {
static var previews: some View {
WelcomeView()
}
}
ContentView
let coloredToolbarAppearance = UIToolbarAppearance()
struct ContentView: View {
// Whenever something in the viewmodel changes, the content view will know to update the UI related elements
#StateObject var viewModel = WeatherViewModel()
#State private var cityName = ""
#State var showingDetail = false
init() {
// toolbar attributes
coloredToolbarAppearance.configureWithOpaqueBackground()
coloredToolbarAppearance.backgroundColor = .systemGray5
UIToolbar.appearance().standardAppearance = coloredToolbarAppearance
UIToolbar.appearance().scrollEdgeAppearance = coloredToolbarAppearance
}
var body: some View {
NavigationView {
VStack() {
List () {
ForEach(viewModel.cityNameList) { city in
NavigationLink(destination: DetailView(detail: city)) {
HStack {
Text(city.name).font(.system(size: 32))
Spacer()
Text("\(city.main.temp, specifier: "%.0f")°").font(.system(size: 32))
}
}
}.onDelete { index in
self.viewModel.cityNameList.remove(atOffsets: index)
}
}.onAppear() {
viewModel.fetchWeather(for: cityName)
}
}.navigationTitle("Weather")
.toolbar {
ToolbarItem(placement: .bottomBar) {
HStack {
TextField("Enter City Name", text: $cityName)
.frame(minWidth: 100, idealWidth: 150, maxWidth: 240, minHeight: 30, idealHeight: 40, maxHeight: 50, alignment: .leading)
Spacer()
Button(action: {
viewModel.fetchWeather(for: cityName)
cityName = ""
self.showingDetail.toggle()
}) {
HStack {
Image(systemName: "plus")
.font(.title)
}
.padding(15)
.foregroundColor(.white)
.background(Color.green)
.cornerRadius(40)
}.sheet(isPresented: $showingDetail) {
ForEach(0..<viewModel.cityNameList.count, id: \.self) { city in
if (city == viewModel.cityNameList.count-1) {
DetailView(detail: viewModel.cityNameList[city])
}
}
}
}
}
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
DetailView
struct DetailView: View {
var detail: WeatherModel
var body: some View {
VStack(spacing: 20) {
Text(detail.name)
.font(.system(size: 32))
Text("\(detail.main.temp, specifier: "%.0f")°")
.font(.system(size: 44))
Text(detail.firstWeatherInfo())
.font(.system(size: 24))
}
}
}
struct DetailView_Previews: PreviewProvider {
static var previews: some View {
DetailView(detail: WeatherModel.init())
}
}
ViewModel
class WeatherViewModel: ObservableObject {
#Published var cityNameList = [WeatherModel]()
func fetchWeather(for cityName: String) {
guard let url = URL(string: "https://api.openweathermap.org/data/2.5/weather?q=\(cityName)&units=imperial&appid=<MyAPIKey>") else { return }
let task = URLSession.shared.dataTask(with: url) { data, _, error in
guard let data = data, error == nil else { return }
do {
let model = try JSONDecoder().decode(WeatherModel.self, from: data)
DispatchQueue.main.async {
self.cityNameList.append(model)
}
}
catch {
print(error) // <-- you HAVE TO deal with errors here
}
}
task.resume()
}
}
Model
struct WeatherModel: Identifiable, Codable {
let id = UUID()
var name: String = ""
var main: CurrentWeather = CurrentWeather()
var weather: [WeatherInfo] = []
func firstWeatherInfo() -> String {
return weather.count > 0 ? weather[0].description : ""
}
}
struct CurrentWeather: Codable {
var temp: Double = 0.0
}
struct WeatherInfo: Codable {
var description: String = ""
}
DemoApp
#main
struct SwftUIMVVMWeatherDemoApp: App {
var body: some Scene {
WindowGroup {
// ContentView()
WelcomeView()
}
}
}