How to respond to view lifecycle events in SwiftUI?
onAppear()
onDisappear()
XCode Version: 12.0
Like this way :
VStack {
Text("Hello World")
}.onAppear {
print("ContentView appeared!")
}.onDisappear {
print("ContentView disappeared!")
}
Related
This is probably a custom view but in the Reddit app there's a toolbar and the top left button(3 lines) opens this kind of view from the side that moves the current view to the right so you can only see about 25% of it and a new view that takes up about 75% of the screen slides in. Is there anything like this built into SwiftUI and if there isn't how would I go about implementing something like this?
This is my custom side bar behave similarly to what you just mentioned, you can try it. (Images and Code are below)
Before click:
After clicked:
struct ContentView: View {
#State var isClicked = false
var body: some View {
HStack {
Rectangle()
.fill(.orange)
.frame(width: isClicked ? UIScreen.main.bounds.width * 0.75 : 0)
VStack {
HStack {
Button {
withAnimation {
isClicked.toggle()
}
} label: {
Image(systemName: "menucard.fill")
.padding(.leading)
}
Spacer()
}
Spacer()
}
}
}
}
I'm following this page for how to implement a keyboard accessory in SwiftUI. The done button is showing up and functioning as expected for the TextField I am modifying. However, every other keyboard in the same view also ends up decorated.
import SwiftUI
struct ContentView: View {
var body: some View {
VStack {
TextField("", text: .constant(""))
.textFieldStyle(.roundedBorder)
.toolbar {
ToolbarItemGroup(placement: .keyboard) {
Button("Click me!") {
print("Clicked")
}
}
}
TextField("", text: .constant(""))
.textFieldStyle(.roundedBorder)
}
}
}
Why is the 2nd TextField here also receiving the Toolbar when it is not being modified? Is this a bug, or am I misunderstanding something?
I am trying to figure out how to hide the primaryAction ToolbarItem under the navigation bar in a watchOS app written in SwiftUI. Apple's documentation states
In watchOS the system places the primary action beneath the navigation bar; the user reveals the action by scrolling.
ToolbaritemPlacement - primaryAction
Here is the view that I am using:
var body: some View {
NavigationView {
ScrollView {
VStack(alignment: .leading) {
ForEach(0..<100) {
Text("Row \($0)")
}
}
.toolbar {
ToolbarItem(placement: .primaryAction) {
Button("Settings") {}
}
}
}
}
.navigationTitle("Navigation")
}
The primary action button always displays and is never hidden. I have seen an example where one used a ScrollViewReader to programmatically change the position but I feel like that isn't what Apple has stated is possible and I'm trying to understand what I'm doing wrong. Apple's documentation also states that the toolbar needs to be inside the scrollview:
Place a toolbar button only in a scrolling view. People frequently scroll to the top of a scrolling view, so discovering a toolbar button is almost automatic. Placing a toolbar button in a nonscrolling view makes it permanently visible, eliminating the advantage of hiding it when it’s not needed.
Toolbar Buttons watchOS
Try this:
struct ContentView: View {
var body: some View {
ScrollView {
VStack(alignment: .leading) {
ForEach(0..<100) {
Text("Row \($0)")
}
}
.toolbar {
ToolbarItem(placement: .primaryAction) {
Button("Settings") {}
}
}
.navigationTitle {
Text("Navigation")
}
}
}
}
I am new in swift ui. I want to put image button on the side of the NavigationBar title.
I want to be able to click the user image and navigate to another view. How?
You need to use navigationBarItems for putting image to navigation bar and you should add NavigationLink to that image. For center the title you need to set navigation bar title's displayMode to .inline or you can use new Toolbar api
struct ContentView: View {
var body: some View {
NavigationView {
Text("Welcome to Stack Overflow")
.navigationBarTitle("Header", displayMode: .inline)
.navigationBarItems(leading: NavigationLink(destination: Text("Destination")) {
Image(systemName: "person.crop.circle.fill")
.font(.title)
})
}
}
}
Screenshot
Another way using toolbar item.
I am adding TapGesture on image icon, and keeping it out of navigation link, as the image is not getting circular inside the NavigationLink in ToolbarItemGroup.
By leveraging isActive property of NavigationLink which monitors onTap state we can determine either we want to push our view or not.
import SwiftUI
struct WeatherView: View {
#State var onTap = false
var borderColor: Color = Color("Black")
var addProjectToolbarItem: some ToolbarContent {
ToolbarItemGroup(placement: .navigationBarLeading) {
NavigationLink(destination:Text("Welcome"), isActive: self.$onTap) {
EmptyView()
}
Image("yourImage")
.resizable()
.frame(width: 32, height: 32)
.clipShape(Circle())
.onTapGesture {
onTap.toggle()
}
}
}
var body: some View {
NavigationView {
VStack {
Text("First view")
}
.toolbar{
addProjectToolbarItem
}
.navigationTitle("Header")
.navigationBarTitleDisplayMode(.inline)
}
}
}
Goal is to make a translucent sidebar on Mac Catalyst.
The code bellow gives a not translucent sidebar (image 1).
On Mac (not catalyst) the sidebar looks fine (image 2).
is it possible to have a translucent sidebar on Mac Catalyst?
import SwiftUI
struct ContentView: View {
var body: some View {
NavigationView {
//sidebar
List {
Label("Books", systemImage: "book.closed")
Label("Tutorials", systemImage: "list.bullet.rectangle")
}
.background(Color.clear)
.listStyle(SidebarListStyle())
//content
Text("Sidebar")
.navigationTitle("Sidebar")
}
}
}
You should select "Optimize Interface for Mac" in your target's General settings tab. Then the sidebar will be translucent.
Start with the AppDelegate main and follow Apple's tutorial re: UISplitViewController "Apply a Translucent Background to Your Primary View Controller".
https://developer.apple.com/documentation/uikit/mac_catalyst/optimizing_your_ipad_app_for_mac
In wrapping UISplitViewController in a UIViewControllerRepresentable, I wasn't able to get translucency, but did get full-height sidebar.
I figured out that using .background(Color.clear) on sidebar View makes possible translucent background even if ListStyle is not specified as SidebarListStyle(). Works in Xcode 13.1 for me
struct ContentView: View {
var body: some View {
NavigationView { // without wrapping to NavigationView it won't work
List { // can be VStack or HStack
Text("Hello, world!")
.padding()
}
.listStyle(SidebarListStyle()) // works with other styles
Text("")
}
}
}
struct YourApp: App {
var body: some Scene {
WindowGroup {
ContentView()
.toolbar {
Button {
} label: {
Image(systemName: "gear")
}
}
.background(Color.clear) // 3 <-- MUST HAVE!
}
}
}