So I want to use this thing to make my view scroll up when editing a TextField (it's a TabbedView App btw).
However the animation didn't work unless I embedded it into a scroll view. This somehow broke my App.
So I get a Thread 1: EXC_BAD_ACCESS (code=1, address=0x8) in my AppDelegate now each time when I try to switch to another tab from the start of my App. I had a similar issue earlier where it I couldn't add my environmentObject() to my TabbedView directly but had to add it to the ContentView in the SceneDelegate. So this time my App works if I remove all my #State var for some reason.. can you see anything that is wrong with that?
struct Home: View {
//#State var isSheetPresented = false //if this one isn't commented out it breaks my tabbed-view app
#State var comment: String = "" //this one doesn't break everything?!?
#EnvironmentObject var someStore: SomeStore //works fine as well
var body: some View {
NavigationView {
ScrollView{ //This is THE ScrollView without everything else works (besides the animation)
VStack(spacing: 20) {
Text("Hi!")
}
}
}
}
}
//--------------------
struct ContentView : View {
#State private var selection = 0
var body: some View {
TabbedView(selection: $selection){
Home()
.tabItem{
Image(systemName: "house")
Text("Home")
}
.tag(0)
Text("Tab # 2")
.tabItem{
Image(systemName: "gear")
Text("#2")
}
.tag(1)
}
}
}
So yea, if you experienced sth. similar or have any idea what is going on please let me know....
Related
I have the following:
#State private var showNext = false
...
NavigationStack {
VStack {
NavigationLink(destination: NextView(showSelf: $showNext),
isActive: $showNext) { EmptyView() }
Button("Show Next") {
showNext = true
}
}
}
...
struct NextView: View {
#Binding var showSelf: Bool
var body: some View {
Text("Next")
.navigationTitle("Next")
Button("Dismiss") {
showSelf = false
}
.padding(30)
}
}
When tapping Show Next, the NextView is shown as expected.
But when tapping Dismiss, nothing happens.
Turns out that showSelf was already false before it's set to false. So it seems something went wrong with passing the binding into NextView.
What could be wrong?
The issue was caused by NavigationStack. When I replaced it with NavigationView it worked as expected.
The isActive binding of NavigationLink does not appear to work (or to be supported) when embedded in a NavigationStack.
isActive binding is for NavigationView, try:
NavigationView {
...
}
.navigationViewStyle(.stack)`
You are trying to mix code for iOS >= 16 (NavigationStack) and for iOS < 16 (the previous way to handle NavigationLink). Similarly for the dismiss part, which is iOS < 15.
Here is your code for iOS 16:
import SwiftUI
struct ContentView: View {
var body: some View {
NavigationStack {
VStack {
NavigationLink {
NextView()
} label: {
Text("Show next view")
}
}
}
}
}
struct NextView: View {
#Environment(\.dismiss) private var dismiss
var body: some View {
VStack {
Text("You are in the next view")
Button("Dismiss", action: dismiss.callAsFunction)
}
.navigationTitle("Next")
}
}
I have used the simplest construction of NavigationLink. A more complex one would be used in conjunction with .navigationDestination. The best examples I have found are here:
https://swiftwithmajid.com/2022/06/15/mastering-navigationstack-in-swiftui-navigator-pattern/
https://swiftwithmajid.com/2022/06/21/mastering-navigationstack-in-swiftui-deep-linking/
https://www.pointfree.co/blog/posts/78-reverse-engineering-swiftui-s-navigationpath-codability
And if you want to dive more into very strange behaviour of the stack, you can look at my post here: Found a strange behaviour of #State when combined to the new Navigation Stack - Is it a bug or am I doing it wrong?
If you need to produce code for iOS < 16, you should replace NavigationStack with NavigationView and work from there.
I have a weird issue, where I navigate to EditView and edit a state variable from ContentView. After that I dismiss EditView with presentation.wrappedValue.dismiss(). The problem is, as soon as the view is dismissed, it reappears again.
I'm using XCode 12.4 and my iOS deployment target is set to 14.4
Observations:
EditView doesn't reappear if the value isn't edited
removing the changed value Text("Value: \(title)") >> Text("Value") from ContentView tree resolves the issue, but that obviously isn't a solution.
moving the NavigationLink from .toolbar e.g.
VStack {
Text("Value: \(title)")
NavigationLink(destination: EditView(title: $title)){
Text("Edit")
}
}
also resolves the issue, but that seems like a hack. Besides, I'd like to keep using .toolbar because I like the .navigationTitle animation and I can't have a button in the upper-right corner of the screen if I have a navigation title without the toolbar.
Here's the full code:
import SwiftUI
struct ContentView: View {
#State var title: String = "Title"
#State var isActive: Bool = false
var body: some View {
NavigationView {
Text("Value: \(title)")
.toolbar {
ToolbarItem(placement: .navigationBarTrailing) {
NavigationLink(destination: EditView(title: $title, isActive: $isActive), isActive: $isActive){
Text("Edit")
}
}
}
}
}
}
struct EditView: View {
#Environment(\.presentationMode) var presentation
#Binding var title: String
#Binding var isActive: Bool
var body: some View {
Button(action: {
title = "\(Date().timeIntervalSince1970)"
// presentation.wrappedValue.dismiss()
isActive = false
}){
Text("Done")
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
As far as I can tell this is a .toolbar bug, and if it turns out that way I'll report it to Apple, but in the meantime, does anyone have a better solution and/or explanation for this?
Cheers!
EDIT:
I updated the code with isActive value for the NavigationLink. It doesn't work when written like that, but uncommenting the commented out line makes it work. But that's quite hacky.
You are mixing up 2 things NavigationLink will push the view on stack, just like NavigationController in swift. That’s why you can see back button after navigating to second view. When you hit back button, it will pop top most view out of stack. presentationMode is not needed , dismissing presented view will not pop it of the stack.
To present a view and dismiss it you can check below code.
import SwiftUI
struct ContentViewsss: View {
#State var title: String = "Title"
#State var isPresented = false
var body: some View {
NavigationView {
Text("Value: \(title)")
.toolbar {
ToolbarItem(placement: .navigationBarTrailing) {
Button(action: {
isPresented.toggle()
}){
Text("Edit")
}
}
}
}.sheet(isPresented: $isPresented, content: {
EditView(title: $title, state: $isPresented)
})
}
}
struct EditView: View {
#Binding var title: String
#Binding var state: Bool
var body: some View {
Button(action: {
title = "\(Date().timeIntervalSince1970)"
state.toggle()
}){
Text("Done")
}
}
}
If you want NavigationLink functionality, you can just remove presentationMode code from second view, and keep ContentView as it is -:
struct EditView: View {
//#Environment(\.presentationMode) var presentation
#Binding var title: String
var body: some View {
Button(action: {
title = "\(Date().timeIntervalSince1970)"
// presentation.wrappedValue.dismiss()
}){
Text("Done")
}
}
}
The .navigationTitle on some views seem to be having some problems. On some views (and only some of the time), the .navigationTitle will not change from .large to .inline as would be expected. Instead, the title stays in place when scrolling up, and the navigation bar is completely invisible (as outlined in the video below). This is all reproducible every time.
Video of reproducible .navigationTitle bugs
I haven't found any people on stack overflow or the Apple Developer forums who have run into this exact issue. There have some people who have produced similar results as this, but those were all fixed by removing some stylizing code to the .navigationbar, of which I am not making any modifications to it anywhere in my code.
Below are some snippets of my code:
import SwiftUI
struct WelcomeUI: View {
var body: some View {
NavigationView {
VStack {
//NavigationLink(destination: SignupUI(), label: {
//Text("Sign Up")
//}
NavigationLink(destination: LoginUI(), label: {
Text("Log In")
})
}
}
}
}
struct LoginUI: View {
var body: some View {
VStack {
NavigationLink(destination: MainUI(), label: { Text("Log In") })
//Button(action: { ... }
}
.navigationBarHidden(false)
}
}
struct MainUI: View {
#State var selectedTab: Views = .add
var body: some View {
TabView(selection: $selectedTab) {
SpendingView()
.tabItem {
Image(systemName: "bag.circle")
Text("Spending")
}.tag(Views.spending)
Text("Adding View")
.tabItem {
Image(systemName: "plus")
Text("Add")
}.tag(Views.add)
Text("Edit View")
.tabItem {
Image(systemName: "pencil")
Text("Edit")
}.tag(Views.edit)
SettingsView()
.tabItem {
Image(systemName: "gear")
Text("Settings")
}.tag(Views.settings)
}
.navigationBarTitle(Text(selectedTab.rawValue))
.navigationBarBackButtonHidden(true)
}
}
enum Views: String {
case spending = "Spending"
case add = "Add"
case edit = "Edit"
case settings = "Settings"
}
struct SettingsView: View {
var body: some View {
VStack{
ZStack {
Form {
Section(header: Text("Section Header")) {
NavigationLink(destination: WelcomeUI()) {
Text("Setting Option")
}
}
Section {
//Button("Log Out") {
//self.logout()
//}
Text("Log Out")
}
}
Button("say-high", action: {print("Hi")})
}
}
}
}
struct SpendingView: View {
var body: some View {
ScrollView{
Text("SpendingView")
NavigationLink("subSpending", destination: SubSpendingView())
}.padding()
}
}
struct SubSpendingView: View {
var body: some View {
ScrollView{
Text("SubSpendingView")
}.navigationBarTitle("SubSpending")
}
}
It almost seems like a bug in SwiftUI itself just because the fact that bringing down the control centre makes it kind of work, but with no animation (as seen in the video). Also, changing which view is selected first in #State var selectedTab: Views seems to let the view selected to work as expected, but lets the rest of the tabs mess up.
When I build and run the app on my iPad, it behaves as expected with no bugs, it's only when run on my iPhone and the iOS simulator on Mac that it does this, any way to fix this?
For this to work flawlessly the ScrollView needs to be the direct child of the NavigationView. I ran into a similar issue with wanting to dismiss the TabView when I navigating but SwiftUI won't let that happen. Each tab needs to be a NavigationView and you need to dismiss the TabView creatively if that is what you want.
TabView {
NavigationView {
ScrollView {
// your view here
}
}.tabItem {
// tab label
}
// etc
}
Essentially the navigation view needs to be a child (in the brackets) of the tab view and the scrollview needs to be the direct child of the navigation view.
Use navigationBarTitle("Title") and navigationBarBackButtonHidden(true) on the TabView's sub-view, not on itself.
struct ContentView: View {
var body: some View {
NavigationView {
VStack {
}
.navigationBarTitle("Title")
.navigationBarBackButtonHidden(true)
}
}
}
Im trying to use a simple navigation view, with a navigation link to a different view. When running the app and the navigation link is pressed it takes me to the new view.
However when I'm on a simulator or device the back button dose not work, whereas on the preview it works fine.
Any ideas what the problem may be?
import SwiftUI
struct HomeView: View {
var body: some View {
NavigationView {
VStack {
NavigationLink(destination: Text("Detail View")) {
Text("Hello World")
}
}
.navigationBarTitle("SwiftUI")
}
}
}
struct HomeView_Previews: PreviewProvider {
static var previews: some View {
HomeView()
}
}
I think the problem may be caused by the fact that the HomeView is part of a tabView. The following code is from AppView.swift which is what is run when the app is run (You can see the code for that at the very bottom).
I think this is the problem because when the code bellow is commented out the app works fine.
HomeView()
.tabItem {
Image(systemName: "house.fill")
Text("Home")
}
.onTapGesture {
self.selectedTab = 2
}
.tag(2)
#main
struct Skate_AppApp: App {
var body: some Scene {
WindowGroup {
HomeView()
}
}
}
From your code I can tell that the problem is in onTapGesture, and I presume from self.selectedTab = 2 that you want to get which tab the user has selected.
Let's refactor your code a little bit with the same concept.
Solution: Delete onTapGesture and add onAppear.
TabView {
HomeView().tabItem {
Image(systemName: "house.fill")
Text("Home")
}.onAppear{
self.selectedTab = 2
}.tag(2)
AnotherView().tabItem {
Image(systemName: "car.fill")
Text("Login View")
}.onAppear{
self.selectedTab = 3
}.tag(3)
}
By this whenever a view appears, it means that the user has selected it, onAppear will be called, and your variable selectedTab will be changed. I hope this answer your question.
I am calling API when tab item is appeared if there is any changes. Why onAppear called after called onDisappear?
Here is the simple example :
struct ContentView: View {
var body: some View {
TabView {
NavigationView {
Text("Home")
.navigationTitle("Home")
.onAppear {
print("Home appeared")
}
.onDisappear {
print("Home disappeared")
}
}
.tabItem {
Image(systemName: "house")
Text("Home")
}.tag(0)
NavigationView {
Text("Account")
.navigationTitle("Account")
.onAppear {
print("Account appeared")
}
.onDisappear {
print("Account disappeared")
}
}
.tabItem {
Image(systemName: "gear")
Text("Account")
}.tag(1)
}
}
}
Just run above code and we will see onAppear after onDisappear.
Home appeared
---After switch tab to Account---
Home disappeared
Account appeared
Home appeared
Is there any solution to avoid this?
It's very annoying bug, imagine this scenario:
Home view onAppear method contains a timer which is fetching data repeatedly.
Timer is triggered invisibly by switching to the Account view.
Workaround:
Create a standalone view for every embedded NavigationView content
Pass the current selection value on to standalone view as #Binding parameter
E.g.:
struct ContentView: View {
#State var selected: MenuItem = .HOME
var body: some View {
return TabView(selection: $selected) {
HomeView(selectedMenuItem: $selected)
.navigationViewStyle(StackNavigationViewStyle())
.tabItem {
VStack {
Image(systemName: "house")
Text("Home")
}
}
.tag(MenuItem.HOME)
AccountView(selectedMenuItem: $selected)
.navigationViewStyle(StackNavigationViewStyle())
.tabItem {
VStack {
Image(systemName: "gear")
Text("Account")
}
}
.tag(MenuItem.ACCOUNT)
}
}
}
enum MenuItem: Int, Codable {
case HOME
case ACCOUNT
}
HomeView:
struct HomeView: View {
#Binding var selectedMenuItem: MenuItem
var body: some View {
return Text("Home")
.onAppear(perform: {
if MenuItem.HOME == selectedMenuItem {
print("-> HomeView")
}
})
}
}
AccountView:
struct AccountView: View {
#Binding var selectedMenuItem: MenuItem
var body: some View {
return Text("Account")
.onAppear(perform: {
if MenuItem.ACCOUNT == selectedMenuItem {
print("-> AccountView")
}
})
}
}
To whom it may help.
Because this behaviour I only could reproduce on iOS 14+, I end up using https://github.com/NicholasBellucci/StatefulTabView (which properly only get called when showed; but don't know if it's a bug or not, but it works with version 0.1.8) and TabView on iOS 13+.
I'm not sure why you are seeing that behaviour in your App. But I can explain why I was seeing it in my App.
I had a very similar setup to you and was seeing the same behaviour running an iOS13 App on iOS14 beta. In my Home screen I had a custom Tab Bar that would animate in and out when a detail screen was displayed. The code for triggering the hiding of the Tab Bar was done in the .onAppear of the Detail screen. This was triggering the Home screen to be redrawn and the .onAppear to be called. I removed the animation and found a much better set up due to this bug and the Home screen .onAppear stopped being called.
So if you have something in your Account Screen .onAppear that has a visual effect on the Home Screen then try commenting it out and seeing if it fixes the issue.
Good Luck.
I have been trying to understand this behavior for a number of days now. If you are working with a TabView, all of your onAppears() / onDisapear() will fire immediately on app init and never again. Which actually makes since I guess?
This was my solution to fix this:
import SwiftUI
enum TabItems {
case one, two
}
struct ContentView: View {
#State private var selection: TabItems = .one
var body: some View {
TabView(selection: $selection) {
ViewOne(isSelected: $selection)
.tabBarItem(tab: .one, selection: $selection)
ViewTwo(isSelected: $selection)
.tabBarItem(tab: .two, selection: $selection)
}
}
}
struct ViewOne: View {
#Binding var isSelected: TabItems
var body: some View {
Text("View One")
.onChange(of: isSelected) { _ in
if isSelected == .one {
// Do something
}
}
}
}
struct ViewTwo: View {
#Binding var isSelected: TabItems
var body: some View {
Text("View Two")
.onChange(of: isSelected) { _ in
if isSelected == .two {
// Do something
}
}
}
}
View Modifier for custom TabView
struct TabBarItemsPreferenceKey: PreferenceKey {
static var defaultValue: [TabBarItem] = []
static func reduce(value: inout [TabBarItem], nextValue: () -> [TabBarItem]) {
value += nextValue()
}
}
struct TabBarItemViewModifer: ViewModifier {
let tab: TabBarItem
#Binding var selection: TabBarItem
func body(content: Content) -> some View {
content
.opacity(selection == tab ? 1.0 : 0.0)
.preference(key: TabBarItemsPreferenceKey.self, value: [tab])
}
}
extension View {
func tabBarItem(tab: TabBarItem, selection: Binding<TabBarItem>) -> some View {
modifier(TabBarItemViewModifer(tab: tab, selection: selection))
}
}