I need some direction to resolve a problem. I have multiple videos inside a scroll view and I want only one of them to play at a time. I know about geo.frame to know the position of the view in screen but how can I constantly check if the screen moved to a point? I want to use this code in the video player view but I can only put this to .onAppear and it won't work because it is only called once. Is there a method that I can check when the screen is moved (scroll view is dragged) so that I can play the video in the middle and stop the other ones?
if (geo.frame(in: .global).midY > 200 && geo.frame(in: .global).midY < 800) {
avPlayer.play()
print("Global center: \(geo.frame(in: .global).midX) x \(geo.frame(in: .global).midY)")
print("Video to play: \(postID)")
}
You can put this code inside your view body using the Geometry reader. The value of geo is updated as the items are being scrolled and moved around.
Put this in a view of a row in your table of videos:
struct Example: View {
private func checkLocation(geo: GeometryProxy) -> Bool {
let loc = geo.frame(in: .global).midY
print ("Loc is: \(loc)")
if loc > 200 {
return true
}
return false
}
var body: some View {
GeometryReader { geo in
if checkLocation(geo: geo) {
Text ("This is working")
}
}
}
}
Related
This example is pretty contrived, but it illustrates the behavior. I know you can use .accessibilityIdentifier to uniquely identify a control, but I'm just trying to better understand the interplay between XCUIElement and XCUIElementQuery.
Let's say you have an app like this:
import SwiftUI
struct ContentView: View {
#State var showRedButton = true
var body: some View {
VStack {
if showRedButton {
Button("Click me") {
showRedButton = false
}
.background(.red)
}
else {
HStack {
Button("Click me") {
showRedButton = true
}
.background(.blue)
Spacer()
}
}
}
}
}
And you are UI testing like this:
import XCTest
final class MyAppUITests: XCTestCase {
func testExample() throws {
let app = XCUIApplication()
app.launch()
print(app.debugDescription)
// At this point, the Element subtree shows a single Button:
// Button, 0x14e40d290, {{162.3, 418.3}, {65.3, 20.3}}, label: 'Click me'
let btn = app.buttons["Click me"]
btn.tap() // <-- This tap makes the red button disappear and shows the blue button
print(app.debugDescription)
// Now, the Element subtree shows a single Button that has a different ID
// and different x-y coordinates:
// Button, 0x15dc12e50, {{0.0, 418.3}, {65.3, 20.3}}, label: 'Click me'
btn.tap() // <-- This tap now works on the blue button?? Without requerying?
print(app.debugDescription)
// The red button reappears, but with a different ID (which makes sense).
}
}
Why does the second tap work, even though it's a different control? This must mean that SwiftUI is automatically re-running the XCUIElementQuery to find the button that matches "Click me". Apparently the variable btn isn't linked to the control with the ID 0x14e40d290. Does this mean XCUIElement actually represents an XCUIElementQuery? I expected it to require me to explicitly re-run the query like this,
btn = app.buttons["Click me"]
prior to running the 2nd tap, or the tap would've said that btn was no longer available.
The final print of the Element subtree shows that the red button has a different ID now. This makes sense, because when SwiftUI redraws the red button, it's not the same instance as the last time. This is explained well in the WWDC videos. Nevertheless, at the moment I connected the variable "btn" to the control, I thought there was a tighter affiliation. Maybe UI testing has to behave this way because SwiftUI redraws controls so frequently?
I have an app, that shows posts on a vertical SwiftUIPager. Each page fills the whole screen.
So, when the app launches, I fetch the 10 most recent posts and display them.
As soon as those posts are fetched, I start listening for new posts. (see code below) Whenever that callback gets triggered, a new post is created. I take it and place it on the top of my list.
The thing is when I scroll to find the new post, its views get mixed up with the views of the next post.
Here's what I mean:
Before the new post, I have the one below
https://imgur.com/a/ZmMzfvb
And then, a new post is added to the top
https://imgur.com/a/PJ0trSF
As you'll notice the image seems to be the same, but it shouldn’t! If I scroll for a while and then go back up, the new post will be fixed and display the proper image. (I'm using SDWebImageSwiftUI for async images, but I don't think it matters... I also used Apple's AsyncImage, with the same results)
Here's my feed view model:
#Published var feedPage: Page = .first()
#Published var feedItems = Array(0..<2)
var posts = [Post]()
...
private func subscribeToNewPosts() {
postsService.subscribeToNewPosts() { [weak self] post in
self?.posts.insert(post, at: 0)
DispatchQueue.main.async {
self?.feedItems = Array(0..<(self?.posts.count ?? 1))
}
}
}
And here's my feed view:
private struct FeedPageView: View {
#EnvironmentObject private var viewModel: FeedView.ViewModel
var body: some View {
ZStack {
VStack {
Pager(page: viewModel.feedPage,
data: viewModel.feedItems,
id: \.self,
content: { index in
if index == 0 {
HomeCameraView()
.background(.black)
} else {
PostView(post: viewModel.posts[index - 1])
}
})
.vertical()
.sensitivity(.custom(0.1))
.onPageWillChange { index in
viewModel.willChangeVerticalPage(index: index)
}
}
}
}
}
Any idea what I'm doing wrong?
I am trying to change the swipeAction from "Paid" to "UnPaid" based on payment status and somehow seems to be failing. Error: "The compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions"
Appreciate any help
struct ContentView: View {
var data: [Data] = [data1, data2, data3, data4]
#State var swipeLabel = true
var body: some View {
let grouped = groupByDate(data)
List {
ForEach(Array(grouped.keys).sorted(by: >), id: \.self) { date in
let studentsDateWise = grouped[date]!
Section(header:Text(date, style: .date)) {
ForEach(studentsDateWise, id:\.self) { item in
HStack {
Text(item.name)
padding()
Text(item.date, style: .time)
if(item.paymentStatus == false) {
Image(systemName: "person.fill.questionmark")
.foregroundColor(Color.red)
} else {
Image(systemName: "banknote")
.foregroundColor(Color.green)
}
} // HStack ends here
.swipeActions() {
if(item.paymentStatus) {
Button("Paid"){}
} else {
Button("UnPaid"){}
}
}
} // ForEach ends here...
} // section ends here
} // ForEach ends here
} // List ends here
} // var ends here
}
The body func shouldn't do any grouping or sorting. You need to prepare your data first into properties and read from those in body, e.g. in an onAppear block. Also if your Data is a struct you can't use id: \.self you need to either specify a unique identifier property on the data id:\.myUniqueID or implement the Indentifiable protocol by either having an id property or an id getter that computes a unique identifier from other properties.
I would suggest separating all this code into small Views with a small body that only uses one or a two properties. Work from bottom up. Then eventually with one View works on an array of dates and another on an array of items that contains the small Views made earlier.
You should probably also learn that if and foreach in body are not like normal code, those are converted into special Views. Worth watching Apple's video Demystify SwiftUI to learn about structural identity.
I have a navigation title that is too large on some smaller devices.
I've read many ways to set the titleTextAttributes and largeTitleTextAttributes of the UINavigationBar.appearance() however when setting the paragraph style to word wrap, it seems to remove the standard ... clipping and have the text continue off the edge of the screen without wrapping:
init() {
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineBreakMode = .byWordWrapping
UINavigationBar.appearance().largeTitleTextAttributes = [
.paragraphStyle: paragraphStyle
]
}
I want to maintain the SwiftUI behaviour where the title is shown as large text until the view is scrolled up and it moves to the navigation bar, so getting the .toolbar directly won't help.
I also don't want to just specify a smaller font as I only want it to shrink or wrap if necessary.
Has anyone managed to achieve this?
You can add this line on the initializer of the view where yo have the issue
UILabel.appearance(whenContainedInInstancesOf: [UINavigationBar.self]).adjustsFontSizeToFitWidth = true
Example:
struct YourView: View {
init() {
UILabel.appearance(whenContainedInInstancesOf: [UINavigationBar.self]).adjustsFontSizeToFitWidth = true
}
var body: some View {
NavigationView {
Text("Your content")
.navigationBarTitle("Very very large title to fit in screen")
}
}
}
Here's a simplified example of an approach I want to take, but I can't get the simple example to work.
I have a Combine publisher who's subject is a view model State:
struct State {
let a: Bool
let b: Bool
let transition: Transition?
}
The State includes a transition property. This describes the Transition that the State made in order to become the current state.
enum Transition {
case onAChange, onBChange
}
I want to use transition property to drive animations in a View subscribed to the publisher so that different transitions animate in specific ways.
View code
Here's the code for the view. You can see how it tries to use the transition to choose an animation to update with.
struct TestView: View {
let model: TestViewModel
#State private var state: TestViewModel.State
private var cancel: AnyCancellable?
init(model: TestViewModel) {
self.model = model
self._state = State(initialValue: model.state.value)
self.cancel = model.state.sink(receiveValue: updateState(state:))
}
var body: some View {
VStack(spacing: 20) {
Text("AAAAAAA").scaleEffect(state.a ? 2 : 1)
Text("BBBBBBB").scaleEffect(state.b ? 2 : 1)
}
.onTapGesture {
model.invert()
}
}
private func updateState(state: TestViewModel.State) {
withAnimation(animation(for: state.transition)) {
self.state = state
}
}
private func animation(for transition: TestViewModel.Transition?) -> Animation? {
guard let transition = transition else { return nil }
switch transition {
case .onAChange: return .easeInOut(duration: 1)
case .onBChange: return .easeInOut(duration: 2)
}
}
}
struct TestView_Previews: PreviewProvider {
static var previews: some View {
TestView(model: TestViewModel())
}
}
Model code
final class TestViewModel: ObservableObject {
var state = CurrentValueSubject<State, Never>(State(a: false, b: false, transition: nil))
struct State {
let a: Bool
let b: Bool
let transition: Transition?
}
enum Transition {
case onAChange, onBChange
}
func invert() {
let oldState = state.value
setState(newState: .init(a: !oldState.a, b: oldState.b, transition: .onAChange))
setState(newState: .init(a: !oldState.a, b: !oldState.b, transition: .onBChange))
}
private func setState(newState: State) {
state.value = newState
}
}
You can see in the model code that when invert() is called, two state changes occur. The model first toggles a using the .onAChange transition, and then toggles b using the .onBChange transition.
What should happen
What should happen when this is run is that each time the view is clicked, the text "AAAAAAA" and "BBBBBBB" should toggle size. However, the "AAAAAAA" text should change quickly (1 second) and the "BBBBBBB" text should change slowly (2 seconds).
What actually happens
However, when I run this and click on the view, the view doesn't update at all.
I can see from the debugger that onTapGesture { … } is called and invert() is being called on the model. Also updateState(state:) is also being called. However, TestView is not changing on screen, and body is not invoked again.
Other things I tried
Using a callback
Instead of using a publisher to send the event to the view, I've tried a callback function in the model set to the view's updateState(state:) function. I assigned to this in the init of the view with model.handleUpdate = self.update(state:). Again, this did not work. The function invert() and update(state:) were called, as expected, but the view didn't actually change.
Using #ObservedObject
I change the model to be ObservableObject with its state being #Published. I set up the view to have an #ObservedOject for the model. With this, the view does update, but it updates both pieces of text using the same animation, which I don't want. It seems that the two state updates are squashed and it only sees the last one, and uses the transition from that.
Something that did work – sort of
Finally, I tried to directly copy the model's invert() function in to the view's onTapGesture handler, so that the view updates its own state directly. This did work! Which is something, but I don't want to put all by model update logic in my view.
Question
How can I have a SwiftUI view subscribe to all states that a model sends through its publisher so that it can use a transition property in the state to control the animation used for that state change?
The way you subscribe a view to the publisher is by using .onRecieve(_:perform:), so instead of saving a cancellable inside init, do this:
var body: some View {
VStack(spacing: 20) {
Text("AAAAAAA").scaleEffect(state.a ? 2 : 1)
Text("BBBBBBB").scaleEffect(state.b ? 2 : 1)
}
.onTapGesture {
model.invert()
}
.onReceive(model.state, perform: updateState(state:)) // <- here
}