I have written the following code to create a list. after that I put the view in a ScrollView.
struct ListView: View {
#State private var selectedState = SortState.commonName
#State private var searchText: String = ""
let alphabet = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
var body: some View {
NavigationView {
VStack(alignment: .leading, spacing: nil, content: {
Picker("Selected Sort State", selection: $selectedState) {
ForEach(SortState.allCases, id: \.rawValue) { sortState in
Text(sortState.rawValue).tag(sortState)
}
}.pickerStyle(SegmentedPickerStyle()).padding(.horizontal)
SearchBarView(searchText: $searchText)
ScrollViewReader { proxy in
itemList.overlay(SectionIndexTitles(proxy: proxy, titles: alphabet))
}
})
.navigationTitle("Items")
}
}
var itemList: some View {
return List{
ForEach(alphabet, id:\.self) { letter in
Section(header: Text(letter).id(letter)) {
ForEach(items.filter(
{
(item) -> Bool in
item.name.prefix(1) == letter
}
), id:\.itemId) { item in
NavigationLink(destination: DetailView()) {
ItemRow(item: item)
}
}
}
}
}
}
}
The code work well when I do not use a ScrollView to wrap the itemList.
However, when I put it inside a ScrollView. The content disappeared.
ScrollViewReader { proxy in
ScrollView(.vertical, showsIndicators: true, content: {
itemList.overlay(SectionIndexTitles(proxy: proxy, titles: alphabet))
})
}
The content gone.
Any idea? I have also tried to enclose that in a VStack inside the ScrollView, also failed.
Use GeometryReader
ScrollViewReader { proxy in
GeometryReader { geometry in
ScrollView(.vertical, showsIndicators: true, content: {
itemList.overlay(SectionIndexTitles(proxy: proxy, titles: alphabet))
.frame(width: geometry.size.width, height: geometry.size.height, alignment: .center)
})
}
}
Related
I am trying to push from login view to detail view but not able to make it.even navigation bar is not showing in login view. How to push on button click in SwiftUI? How to use NavigationLink on button click?
var body: some View {
NavigationView {
VStack(alignment: .leading) {
Text("Let's get you signed in.")
.bold()
.font(.system(size: 40))
.multilineTextAlignment(.leading)
.frame(width: 300, height: 100, alignment: .topLeading)
.padding(Edge.Set.bottom, 50)
Text("Email address:")
.font(.headline)
TextField("Email", text: $email)
.frame(height:44)
.accentColor(Color.white)
.background(Color(UIColor.darkGray))
.cornerRadius(4.0)
Text("Password:")
.font(.headline)
SecureField("Password", text: $password)
.frame(height:44)
.accentColor(Color.white)
.background(Color(UIColor.darkGray))
.cornerRadius(4.0)
Button(action: {
print("login tapped")
}) {
HStack {
Spacer()
Text("Login").foregroundColor(Color.white).bold()
Spacer()
}
}
.accentColor(Color.black)
.padding()
.background(Color(UIColor.darkGray))
.cornerRadius(4.0)
.padding(Edge.Set.vertical, 20)
}
.padding(.horizontal,30)
}
.navigationBarTitle(Text("Login"))
}
To fix your issue you need to bind and manage tag with NavigationLink, So create one state inside you view as follow, just add above body.
#State var selection: Int? = nil
Then update your button code as follow to add NavigationLink
NavigationLink(destination: Text("Test"), tag: 1, selection: $selection) {
Button(action: {
print("login tapped")
self.selection = 1
}) {
HStack {
Spacer()
Text("Login").foregroundColor(Color.white).bold()
Spacer()
}
}
.accentColor(Color.black)
.padding()
.background(Color(UIColor.darkGray))
.cornerRadius(4.0)
.padding(Edge.Set.vertical, 20)
}
Meaning is, when selection and NavigationLink tag value will match then navigation will be occurs.
I hope this will help you.
iOS 16+
Note: Below is a simplified example of how to present a new view. For a more advanced generic example please see this answer.
In iOS 16 we can access the NavigationStack and NavigationPath.
Usage #1
A new view is activated by a simple NavigationLink:
struct ContentView: View {
var body: some View {
NavigationStack {
NavigationLink(value: "NewView") {
Text("Show NewView")
}
.navigationDestination(for: String.self) { view in
if view == "NewView" {
Text("This is NewView")
}
}
}
}
}
Usage #2
A new view is activated by a standard Button:
struct ContentView: View {
#State private var path = NavigationPath()
var body: some View {
NavigationStack(path: $path) {
Button {
path.append("NewView")
} label: {
Text("Show NewView")
}
.navigationDestination(for: String.self) { view in
if view == "NewView" {
Text("This is NewView")
}
}
}
}
}
Usage #3
A new view is activated programmatically:
struct ContentView: View {
#State private var path = NavigationPath()
var body: some View {
NavigationStack(path: $path) {
Text("Content View")
.navigationDestination(for: String.self) { view in
if view == "NewView" {
Text("This is NewView")
}
}
}
.onAppear {
path.append("NewView")
}
}
}
iOS 13+
The accepted answer uses NavigationLink(destination:tag:selection:) which is correct.
However, for a simple view with just one NavigationLink you can use a simpler variant: NavigationLink(destination:isActive:)
Usage #1
NavigationLink is activated by a standard Button:
struct ContentView: View {
#State var isLinkActive = false
var body: some View {
NavigationView {
VStack(alignment: .leading) {
...
NavigationLink(destination: Text("OtherView"), isActive: $isLinkActive) {
Button(action: {
self.isLinkActive = true
}) {
Text("Login")
}
}
}
.navigationBarTitle(Text("Login"))
}
}
}
Usage #2
NavigationLink is hidden and activated by a standard Button:
struct ContentView: View {
#State var isLinkActive = false
var body: some View {
NavigationView {
VStack(alignment: .leading) {
...
Button(action: {
self.isLinkActive = true
}) {
Text("Login")
}
}
.navigationBarTitle(Text("Login"))
.background(
NavigationLink(destination: Text("OtherView"), isActive: $isLinkActive) {
EmptyView()
}
.hidden()
)
}
}
}
Usage #3
NavigationLink is hidden and activated programmatically:
struct ContentView: View {
#State var isLinkActive = false
var body: some View {
NavigationView {
VStack(alignment: .leading) {
...
}
.navigationBarTitle(Text("Login"))
.background(
NavigationLink(destination: Text("OtherView"), isActive: $isLinkActive) {
EmptyView()
}
.hidden()
)
}
.onAppear {
self.isLinkActive = true
}
}
}
Here is a GitHub repository with different SwiftUI extensions that makes navigation easier.
Another approach:
SceneDelegate
if let windowScene = scene as? UIWindowScene {
let window = UIWindow(windowScene: windowScene)
window.rootViewController = UIHostingController(rootView: BaseView().environmentObject(ViewRouter()))
self.window = window
window.makeKeyAndVisible()
}
BaseView
import SwiftUI
struct BaseView : View {
#EnvironmentObject var viewRouter: ViewRouter
var body: some View {
VStack {
if viewRouter.currentPage == "view1" {
FirstView()
} else if viewRouter.currentPage == "view2" {
SecondView()
.transition(.scale)
}
}
}
}
#if DEBUG
struct MotherView_Previews : PreviewProvider {
static var previews: some View {
BaseView().environmentObject(ViewRouter())
}
}
#endif
ViewRouter
import Foundation
import Combine
import SwiftUI
class ViewRouter: ObservableObject {
let objectWillChange = PassthroughSubject<ViewRouter,Never>()
var currentPage: String = "view1" {
didSet {
withAnimation() {
objectWillChange.send(self)
}
}
}
}
FirstView
import SwiftUI
struct FirstView : View {
#EnvironmentObject var viewRouter: ViewRouter
var body: some View {
VStack {
Button(action: {self.viewRouter.currentPage = "view2"}) {
NextButtonContent()
}
}
}
}
#if DEBUG
struct FirstView_Previews : PreviewProvider {
static var previews: some View {
FirstView().environmentObject(ViewRouter())
}
}
#endif
struct NextButtonContent : View {
var body: some View {
return Text("Next")
.foregroundColor(.white)
.frame(width: 200, height: 50)
.background(Color.blue)
.cornerRadius(15)
.padding(.top, 50)
}
}
SecondView
import SwiftUI
struct SecondView : View {
#EnvironmentObject var viewRouter: ViewRouter
var body: some View {
VStack {
Spacer(minLength: 50.0)
Button(action: {self.viewRouter.currentPage = "view1"}) {
BackButtonContent()
}
}
}
}
#if DEBUG
struct SecondView_Previews : PreviewProvider {
static var previews: some View {
SecondView().environmentObject(ViewRouter())
}
}
#endif
struct BackButtonContent : View {
var body: some View {
return Text("Back")
.foregroundColor(.white)
.frame(width: 200, height: 50)
.background(Color.blue)
.cornerRadius(15)
.padding(.top, 50)
}
}
Hope this helps!
Simplest and most effective solution is :
NavigationLink(destination:ScoresTableView()) {
Text("Scores")
}.navigationBarHidden(true)
.frame(width: 90, height: 45, alignment: .center)
.foregroundColor(.white)
.background(LinearGradient(gradient: Gradient(colors: [Color.red, Color.blue]), startPoint: .leading, endPoint: .trailing))
.cornerRadius(10)
.contentShape(Rectangle())
.padding(EdgeInsets(top: 16, leading: UIScreen.main.bounds.size.width - 110 , bottom: 16, trailing: 20))
ScoresTableView is the destination view.
In my opinion a cleaner way for iOS 16+ is using a state bool to present the view.
struct ButtonNavigationView: View {
#State private var isShowingSecondView : Bool = false
var body: some View {
NavigationStack {
VStack{
Button(action:{isShowingSecondView = true} ){
Text("Show second view")
}
}.navigationDestination(isPresented: $isShowingSecondView) {
Text("SecondView")
}
}
}
}
I think above answers are nice, but simpler way should be:
NavigationLink {
TargetView()
} label: {
Text("Click to go")
}
Problem:
I am unable to force my alpha, beta, or gamma buttons to turn ON when an input parameter is passed from Landing.swift.
I do not understand why when onAppear fires in the stack, the output becomes:
gamma is the title
beta is the title
alpha is the title
gamma is the title
beta is the title
alpha is the title
Confused -> Why is this outputting 2x when the ForEach loop has only 3 elements inside?
Background:
I am trying to pass a parameter from one view (Landing.swift) to another (ContentView.swift) and then based on that parameter force the correct button (in ContentView) to trigger an ON state so it's selected. I have logic shown below in ButtonOnOff.swift that keeps track of what's selected and not.
For instance, there are 3 buttons in ContentView (alpha, beta, and gamma) and based on the selected input button choice from Landing, the respective alpha, beta, or gamma button (in ContentView) should turn ON.
I am dynamically generating these 3 buttons in ContentView and want the flexibility to extend to possibly 10 or more in the future. Hence why I'm using the ForEach in ContentView. I need some help please understanding if I'm incorrectly using EnvironmentObject/ObservedObject or something else.
Maintaining the ON/OFF logic works correctly with the code. That is, if you manually press alpha, it'll turn ON but the other two will turn OFF and so forth.
Thanks for your help in advance! :)
Testing.swift
import SwiftUI
#main
struct Testing: App {
#StateObject var buttonsEnvironmentObject = ButtonOnOff()
var body: some Scene {
WindowGroup {
Landing().environmentObject(buttonsEnvironmentObject)
}
}
}
Landing.swift
import SwiftUI
struct Landing: View {
#State private var tag:String? = nil
var body: some View {
NavigationView {
ZStack{
HStack{
NavigationLink(destination: ContentView(landingChoice:tag ?? ""), tag: tag ?? "", selection: $tag) {
EmptyView()
}
Button(action: {
self.tag = "alpha"
}) {
HStack {
Text("alpha")
}
}
Button(action: {
self.tag = "beta"
}) {
HStack {
Text("beta")
}
}
Button(action: {
self.tag = "gamma"
}) {
HStack {
Text("gamma")
}
}
}
.navigationBarHidden(true)
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
}
ContentView.swift
import SwiftUI
struct ContentView: View {
var btnName:String
#EnvironmentObject var buttonEnvObj:ButtonOnOff
init(landingChoice:String){
self.btnName = landingChoice
print("\(self.btnName) is the input string")
}
var body: some View {
VStack{
Form{
Section{
ScrollView(.horizontal, showsIndicators: false) {
HStack(spacing:10) {
ForEach(0..<buttonEnvObj.buttonNames.count) { index in
BubbleButton(label: "\(buttonEnvObj.buttonNames[index])")
.padding(EdgeInsets(top: 5, leading: 5, bottom: 5, trailing: 0))
.onAppear {
print("\(buttonEnvObj.buttonNames[index]) is the title")
}
}
}
}.frame(height: 50)
}
}
}
}
}
struct BubbleButton: View{
#EnvironmentObject var buttonBrandButtons:ButtonOnOff
var label: String
var body: some View{
HStack{
Button(action: {
print("Button action")
buttonBrandButtons.changeState(buttonName: self.label)
}) {
ZStack {
VStack{
HStack {
Spacer()
Text(label)
.font(.system(size: 12,weight:.regular, design: .default))
.foregroundColor(buttonBrandButtons.buttonBrand[self.label]! ? Color.white : Color.gray)
Spacer()
}
}
.frame(height:30)
.fixedSize()
}
}
.background(buttonBrandButtons.buttonBrand[self.label]! ? Color.blue : .clear)
.cornerRadius(15)
.overlay(buttonBrandButtons.buttonBrand[self.label]! ?
RoundedRectangle(cornerRadius: 15).stroke(Color.blue,lineWidth:1) : RoundedRectangle(cornerRadius: 15).stroke(Color.gray,lineWidth:1))
.animation(.linear, value: 0.15)
}
}
}
ButtonOnOff.swift
import Foundation
class ButtonOnOff:ObservableObject{
var buttonNames = ["alpha","beta","gamma"]
#Published var buttonBrand:[String:Bool] = [
"alpha":false,
"beta":false,
"gamma":false
]
func changeState(buttonName:String) -> Void {
for (key,_) in buttonBrand{
if key == buttonName && buttonBrand[buttonName] == true{
buttonBrand[buttonName] = false
} else{
buttonBrand[key] = (key == buttonName) ? true : false
}
}
print(buttonBrand)
}
}
For a short answer just add
.onAppear(){
buttonEnvObj.changeState(buttonName: self.btnName)
}
to ContentView that will highlight the button that was selected.
As for a solution that can be expanded at will. I would suggest a single source of truth for everything and a little simplifying.
struct Landing: View {
#EnvironmentObject var buttonEnvObj:ButtonOnOff
#State private var tag:String? = nil
var body: some View {
NavigationView {
ZStack{
HStack{
NavigationLink(destination: ContentView(), tag: tag ?? "", selection: $tag) {
EmptyView()
}
//Put your buttons here
HStack{
//Use the keys of the dictionary to create the buttons
ForEach(buttonEnvObj.buttonBrand.keys.sorted(by: <), id: \.self){ key in
//Have the button set the value when pressed
Button(action: {
self.tag = key
buttonEnvObj.changeState(buttonName: key)
}) {
Text(key)
}
}
}
}
.navigationBarHidden(true)
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
}
struct ContentView: View {
#EnvironmentObject var buttonEnvObj:ButtonOnOff
var body: some View {
VStack{
Form{
Section{
ScrollView(.horizontal, showsIndicators: false) {
HStack(spacing:10) {
//Change this to use the dictionary
ForEach(buttonEnvObj.buttonBrand.sorted(by: {$0.key < $1.key }), id:\.key) { key, value in
BubbleButton(key: key, value: value)
.padding(EdgeInsets(top: 5, leading: 5, bottom: 5, trailing: 0))
.onAppear {
print("\(value) is the title")
}
}
}
}.frame(height: 50)
}
}
}
}
}
struct BubbleButton: View{
#EnvironmentObject var buttonBrandButtons:ButtonOnOff
var key: String
var value: Bool
var body: some View{
HStack{
Button(action: {
print("Button action")
buttonBrandButtons.changeState(buttonName: key)
}) {
ZStack {
VStack{
HStack {
Spacer()
Text(key)
.font(.system(size: 12,weight:.regular, design: .default))
.foregroundColor(value ? Color.white : Color.gray)
Spacer()
}
}
.frame(height:30)
.fixedSize()
}
}
.background(value ? Color.blue : .clear)
.cornerRadius(15)
.overlay(value ?
RoundedRectangle(cornerRadius: 15).stroke(Color.blue,lineWidth:1) : RoundedRectangle(cornerRadius: 15).stroke(Color.gray,lineWidth:1))
.animation(.linear, value: 0.15)
}
}
}
class ButtonOnOff:ObservableObject{
//Get rid of this so you can keep the single source
//var buttonNames = ["alpha","beta","gamma"]
//When you want to add buttons just add them here it will all adjust
#Published var buttonBrand:[String:Bool] = [
"alpha":false,
"beta":false,
"gamma":false
]
func changeState(buttonName:String) -> Void {
for (key,_) in buttonBrand{
if key == buttonName && buttonBrand[buttonName] == true{
buttonBrand[buttonName] = false
} else{
buttonBrand[key] = (key == buttonName) ? true : false
}
}
print(buttonBrand)
}
}
This is my second post and I need your help as much as possible. I am creating a favorite button on my parent view and detail view. I need both buttons to work correspondent to each other. When I marked favorite on the ForEach loop of my parent view, I want to show the item is favorited in my detail view. Also, I can unfavorite or favorite from my detail view vice vasa. It is really hard for me to figure out how to bind those two ForEach loops. Below I provide an example of my codes. If you want to test with my full code, you can access it here: Making favorite button from several layers and binding two list using EnvironmentObject
struct Data: Identifiable {
let id = UUID()
let number: Int
var name1: String
let name2: String
}
public struct DataList {
static var dot = [
Data(number: 1,
name1: "Pasian Phatna",
name2: "Praise God, from whom All Blessings Flow"),
Data(number: 2,
name1: "Itna Kumpi, Ka Tuu-Cing Pa",
name2: "The King of Love My Shephaerd Is (Dominus Regit Me)"),
Data(number: 3,
name1: "Kumpipa Bia Un",
name2: "O Worship the King"),
Data(number: 4,
name1: "Pa Tung Min Than'na Om Hen",
name2: "Gloria Patri (1st Tune)"),
Data(number: 5,
name1: "Pa Tung Min Than'na Om Hen",
name2: "Gloria Patri (2nd Tune)")
]
}
struct ParentView: View {
#State var datas: [Data] = DataList.dot
var body: some View {
NavigationView {
ScrollView (.vertical, showsIndicators: false) {
LazyVStack(spacing: 5) {
ForEach (datas, id: \.id) { data in
MainData(data: data)
Divider()
.padding(.all)
}
}
}
.navigationBarHidden(true)
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
struct MainData: View {
#State var data: Data
#State var selectedFavoriteSong: Bool = false
var body: some View {
HStack {
Button(action: {
self.selectedFavoriteSong.toggle()
}, label: {
if selectedFavoriteSong {
Image(systemName: "suit.heart.fill")
.foregroundColor(.red)
.padding(.horizontal)
} else {
Image(systemName: "suit.heart")
.padding(.horizontal)
}
})
Spacer()
Text("\(data.number)")
Spacer()
}
.padding(.top)
VStack {
Text(data.name1)
.font(.title2.smallCaps())
.fontWeight(.bold)
.foregroundColor(.primary)
Text(data.name2)
.font(.title3)
.fontWeight(.medium)
.foregroundColor(.secondary)
.italic()
}
.padding(.horizontal)
.multilineTextAlignment(.center)
}
}
Please consider, the Search() below will pop up when I tapped the search icon (which is not presented here). My point is the Search() is not directly connect to the ParentView() but the DetailView() is embedded in the Search().
struct Search: View {
#State var datas: [Data] = DataList.dot
var body: some View {
NavigationView {
ScrollView (.vertical, showsIndicators: false) {
LazyVStack(alignment: .leading, spacing: 10) {
ForEach (datas, id: \.id) { data in
NavigationLink(
destination: DetailView(data: data),
label: {
Text("Search")
})
}
}.padding(.horizontal)
}
}
}
}
struct DetailView: View {
#State var data: Data
#State var selectedFavoriteSong: Bool = false
var body: some View {
HStack {
Button(action: {
self.selectedFavoriteSong.toggle()
}, label: {
if selectedFavoriteSong {
Image(systemName: "suit.heart.fill")
.foregroundColor(.red)
.padding(.horizontal)
} else {
Image(systemName: "suit.heart")
.padding(.horizontal)
}
})
Spacer()
Text("\(data.name1)")
Spacer()
}
.padding(.top)
VStack {
Text(data.name2)
.font(.title2.smallCaps())
.fontWeight(.bold)
.foregroundColor(.primary)
}
.padding(.horizontal)
.multilineTextAlignment(.center)
Spacer()
}
}
So, I want to connect the parent view and the detail view with some kind of binding property. But there is impossible to connect these two. I can store
#State var selectedFavoriteSong: Bool = false
inside the EnvironmentObject. But when I click favorite, all the items inside the ForEach loop are selected. Please help me on this issue. If you need a full code, the above link will direct to my first post. Thank you.
I'd suggest storing all of your data in an ObservableObject that is owned by the parent view and then can get passed into subviews (either explicitly or via an EnvironmentObject):
class DataSource : ObservableObject {
#Published var data : [Data] = DataList.dot
#Published var favoritedItems: Set<UUID> = []
func favoriteBinding(forID id: UUID) -> Binding<Bool> {
.init {
self.favoritedItems.contains(id)
} set: { newValue in
if newValue {
self.favoritedItems.insert(id)
} else {
self.favoritedItems.remove(id)
}
}
}
}
For example:
struct ParentView : View {
#StateObject var dataSource = DataSource()
var body: some View {
VStack {
Search(dataSource: dataSource)
}
}
}
Note that the data source stores a list of IDs that have been favorited. It uses a custom binding that can pass the boolean value down to a detail view:
struct Search: View {
#ObservedObject var dataSource : DataSource
var body: some View {
NavigationView {
ScrollView (.vertical, showsIndicators: false) {
LazyVStack(alignment: .leading, spacing: 10) {
ForEach (dataSource.data, id: \.id) { data in
NavigationLink(
destination: DetailView(data: data,
selectedFavoriteSong: dataSource.favoriteBinding(forID: data.id)),
label: {
Text(data.name1)
})
}
}.padding(.horizontal)
}
}
}
}
struct DetailView: View {
var data : Data
#Binding var selectedFavoriteSong : Bool
var body: some View {
HStack {
Button(action: {
self.selectedFavoriteSong.toggle()
}, label: {
if self.selectedFavoriteSong {
Image(systemName: "suit.heart.fill")
.foregroundColor(.red)
.padding(.horizontal)
} else {
Image(systemName: "suit.heart")
.padding(.horizontal)
}
})
Spacer()
Text("\(data.name1)")
Spacer()
}
.padding(.top)
VStack {
Text(data.name2 ?? "")
.font(.title2.smallCaps())
.fontWeight(.bold)
.foregroundColor(.primary)
}
.padding(.horizontal)
.multilineTextAlignment(.center)
Spacer()
}
}
I have the following view and I'm attempting to have it scroll to the bottom on button click as elements are added to the list. I've searched and found that ScrollViewReader is the option to use however my implementation doesn't appear to be working.
My attempts at fixing have included explicitly setting the id of the cell on both the inner views as well as the outer HStack{} I even attempted to set the id to a reference of itself, kind of knowing that's a bad idea, but for brevity. I also removed any extra views inside of the list such as HStack{}, Spacer(), etc.. and just left my ColorsChosenView().id(i) thinking that extra views might cause it, but I digress the issue still persists.
var body: some View {
VStack {
ScrollViewReader { reader in
List {
ForEach(0..<vm.guesses.count, id: \.self) { i in
HStack{
Spacer()
ColorsChosenView(locationCorrect: 1,
locationIncorrect: 3,
color1: vm.guesses[i][0],
color2: vm.guesses[i][1],
color3: vm.guesses[i][2],
color4: vm.guesses[i][3])
Spacer()
}.id(i)
}
}.listStyle(InsetListStyle())
Divider()
.frame(maxWidth: 250)
ColorChoicePicker(vm: vm)
Divider()
.frame(maxWidth: 250)
HStack {
Spacer()
FABButton(text: "SUBMIT")
.onTapGesture {
vm.submit()
reader.scrollTo(vm.guesses.count - 1)
}
}.padding()
}
}
.navigationBarHidden(true)
.navigationBarHidden(true)
.onAppear(perform: {
vm.resetGame()
})
}
To simplify things, I found that this works just fine. Yet my implementation doesn't feel much different.
var body: some View {
ScrollViewReader { proxy in
VStack {
Button("Jump to #50") {
proxy.scrollTo(50)
}
List(0..<100, id: \.self) { i in
Text("Example \(i)")
.id(i)
}
}
}
}
Since you're modifying the array, this should work:
1: call the function in the main thread (DispatchQueue.main.async)
-> this will "kinda" work, it will scroll but not to the current but the previous last item
2: (Workaround) handle scrolling in a change-handler (you could also remove the shouldScroll variable if all changes should make it scroll to the bottom)
class NumbersContainer: ObservableObject {
#Published var numbers: [Int] = Array(0..<25)
func submit() {
self.numbers.append(self.numbers.count)
}
}
struct ContentView: View {
#StateObject var nc = NumbersContainer()
#State var shouldScroll: Bool = false
var body: some View {
VStack {
ScrollViewReader { reader in
Button("Submit", action: {
DispatchQueue.main.async {
nc.submit()
}
self.shouldScroll = true
})
List {
ForEach(0..<nc.numbers.count, id: \.self) { i in
HStack {
Spacer()
Text("Row \(i)")
Spacer()
}.id(i)
}
}
.onChange(of: nc.numbers) { newValue in
if shouldScroll {
reader.scrollTo(newValue.count - 1)
shouldScroll = false
}
}
}
}
}
}
Another Possibility would be to use the ScrollReaderProxy as a parameter of the submit function:
class NumbersContainer: ObservableObject {
#Published var numbers: [Int] = Array(0..<25)
func submit(reader: ScrollViewProxy) {
let dispatchGroup = DispatchGroup()
dispatchGroup.enter() // All leaves must have an enter
DispatchQueue.main.async {
self.numbers.append(self.numbers.count)
dispatchGroup.leave() // Notifies the DispatchGroup
}
dispatchGroup.notify(queue: .main) {
reader.scrollTo(self.numbers.count - 1)
}
}
}
struct ContentView: View {
#StateObject var nc = NumbersContainer()
var body: some View {
VStack {
ScrollViewReader { reader in
Button("Submit", action: {
nc.submit(reader: reader)
})
List {
ForEach(0..<nc.numbers.count, id: \.self) { i in
HStack {
Spacer()
Text("Row \(i)")
Spacer()
}.id(i)
}
}
}
}
}
}
Since, the onDelete and onMove are features of List/form I cannot use them when I have custom interfaces without them. I have used a VStack inside a ForEach. I am quite new to swiftUI and unsure on how I can implement custom code for onDelete and onMove.
Here's my code:
struct Trying: View {
#State private var numbers = [0,1,2,3,4,5,6,7,8,9]
var body: some View {
NavigationView {
VStack (spacing: 10) {
ForEach(numbers, id: \.self) { number in
VStack {
Text("\(number)")
}
.frame(width: 50, height: 50)
.background(Color.red)
}.onDelete(perform: removeRows)
}
.navigationTitle("Trying")
.navigationBarItems(trailing: EditButton())
}
}
func removeRows(at offsets: IndexSet) {
numbers.remove(atOffsets: offsets)
}
}
The way it works right now:
Here is a simple demo of possible approach to implement custom delete (of course with move it would be more complicated due to drag/drop, but idea is the same). Tested with Xcode 12 / iOS 14.
struct DemoCustomDelete: View {
#State private var numbers = [0,1,2,3,4,5,6,7,8,9]
var body: some View {
NavigationView {
VStack (spacing: 10) {
ForEach(numbers, id: \.self) { number in
VStack {
Text("\(number)")
}
.frame(width: 50, height: 50)
.background(Color.red)
.overlay(
DeleteButton(number: number, numbers: $numbers, onDelete: removeRows)
, alignment: .topTrailing)
}.onDelete(perform: removeRows)
}
.navigationTitle("Trying")
.navigationBarItems(trailing: EditButton())
}
}
func removeRows(at offsets: IndexSet) {
withAnimation {
numbers.remove(atOffsets: offsets)
}
}
}
struct DeleteButton: View {
#Environment(\.editMode) var editMode
let number: Int
#Binding var numbers: [Int]
let onDelete: (IndexSet) -> ()
var body: some View {
VStack {
if self.editMode?.wrappedValue == .active {
Button(action: {
if let index = numbers.firstIndex(of: number) {
self.onDelete(IndexSet(integer: index))
}
}) {
Image(systemName: "minus.circle")
}
.offset(x: 10, y: -10)
}
}
}
}
Based on #Asperi's answer, I just generalized it to accept any Equatable sequence.
struct DeleteButton<T>: View where T: Equatable {
#Environment(\.editMode) var editMode
let number: T
#Binding var numbers: [T]
let onDelete: (IndexSet) -> ()
var body: some View {
VStack {
if self.editMode?.wrappedValue == .active {
Button(action: {
if let index = numbers.firstIndex(of: number) {
self.onDelete(IndexSet(integer: index))
}
}) {
Image(systemName: "minus.circle")
}
.offset(x: 10, y: -10)
}
}
}
}
I recently had the need to delete a row and I couldn't use a LIST. Instead I had a scroll view... But I was able to implement the edit to simulate the same onDelete behavior as if it was a list. Initially I couldn't get my code to work. It wasn't until I closely examined my implementation and experimented that I stumbled on why mine worked. I'm coding for an iPad so my NavigationView uses,
.navigationViewStyle(StackNavigationViewStyle())
Once I added this to the struct's NavigationView, when you click on the EditButton it activates editMode?.wrappedValue to .active / .inactive
Below is my implementation for the code sample above...
struct Trying: View {
#State var num: Int = 0
#Environment(\.editMode) var editMode
#State private var numbers = [0,1,2,3,4,5,6,7,8,9]
var body: some View {
NavigationView {
VStack {
ForEach(numbers, id: \.self) { number in
HStack {
if editMode?.wrappedValue == .active {
Button(action: { num = number
removeRows(numbr: num)
}, label: {
Image(systemName: "minus.circle.fill")
.foregroundColor(.red)
})
} // END IF editMode?wrappedValue == .active
Text("\(number)")
.frame(width: 50, height: 50)
.background(Color.red)
}
}
// .onDelete(perform: removeRows)
}
.navigationTitle("Trying")
.navigationBarItems(trailing: EditButton())
}
// FOR SOME REASON THIS ALLOWS THE EditButton() to activate editMode without a LIST being present.
.navigationViewStyle(StackNavigationViewStyle())
}
func removeRows(numbr: Int) {
print("removing \(numbr)")
}
}
It looks like: