Hey guys I have been getting better with making reusable views, and this is the point that I have reached.
So I would like create a reusable button. The code for it being something like this:
let actionCode: () -> ()
let buttonImage: View
I also tried some View, also () —> View and similar attempts.
All to be passed to this
Button(action: {actionCode})
{buttonImage}
Is this possible? Or am I barking up the wrong tree. Also, I did search SO for this
If I understood the description correctly here is a demo of possible approach:
struct ReusableView<ButtonImageType: View>: View {
let actionCode: () -> ()
let buttonImage: ButtonImageType // << !!
var body: some View {
Button(action: actionCode)
{buttonImage}
}
}
Related
I want to create a SwiftUI List, but not show scroll indicators. ScrollView offers showsIndicators to do this. How can it be done?
Any Indicators (List, scrollView, etc.)
you can get rid of showing indicators for all Lists, but with an API of the UITableView. because SwiftUI List is using UITableView for iOS behind the scene:
struct ContentView: View {
init() {
UITableView.appearance().showsVerticalScrollIndicator = false
}
var body: some View {
List(0...100, id: \.self) { item in
Text("hey")
}
}
}
Note that this will eliminate all TableViews and Lists indicators. You should make it visible again if you need to.
⚠️ Not Yet Important Note
Seems like Apple is removing appearance hacks (but not for this one yet). So you can use LazyVStack inside and ScrollView instead of List and use the available argument for hiding the indicators.
struct ContentView: View {
var body: some View {
ScrollView(.vertical, showsIndicators: false) { // <- This argument
LazyVStack {
ForEach(1...100, id: \.self) {
Text("\($0)").frame(height: 40)
}
}
}
}
}
It is actually easy to accomplish this without any appearance work arounds in the answer accepted. You just have to use the ScrollView initializer and set the parameter showsIndicators to false.
ScrollView(.vertical, showsIndicators: false) {
// ... your content for scrollView
}
Inside your ScrollView you could use LazyVStack, if you have a lot of subviews to scroll through. SwiftUI will then render very efficiently your subviews: "lazy" -> only if needed).
Until there is a native SwiftUI way to achieve this, the Introspect library provides a decent solution.
After applying all modifiers to your list just add as a last modifier the following:
List {
...
}
.introspectTableView { tableView in
tableView.showsVerticalScrollIndicator = false // here you can access any other UITableView property
}
I hope there is a native way to do that at some point.
Hide scrolling indicator now became very simple
List {}.scrollIndicators(ScrollIndicatorVisibility.hidden)
List basically creates a tableview (UpdateCoalescingTableView) behind the scenes, and tableview's are scrollable. Unfortunately, however, you can't get to the scrollview attributes in SwiftUI.
You "might" be able to create a UIViewRepresentable that could walk up the view hierarchy until it finds a scrollview, but I wouldn't recommend it.
You could also create your own scrollview, put a vstack inside it, and "fake" a list view, which would probably be the safer approach.
The choosen answer won't work in iOS 16. They released a new viewModifier called .scrollIndicators(.hidden). I created a viewModifier wrapper which you can call like this on your List: .modifier(HideListIndicatorsViewModifier())
struct HideListIndicatorsViewModifier: ViewModifier {
#ViewBuilder
func body(content: Content) -> some View {
if #available(iOS 16.0, *) {
content
.scrollIndicators(.hidden)
} else {
content
}
}
}
swift scrollview hide scrollbar
scrollView.showsHorizontalScrollIndicator = false
scrollView.showsVerticalScrollIndicator = false
hide scroll view indicators bar swiftui
ScrollView(.vertical, showsIndicators: false) {
// ... your content for scrollView
}
I am using Core data and Swiftui and everything have been working fine but in this one view I have a List, ForEach that is not working.
So for testing purpose my code currently look like this:
#ObservedObject var viewModel = NewLearningWhyViewModel()
VStack {
ForEach(viewModel.whys, id: \.self) { why in
Text(why.why)
}
List {
ForEach(viewModel.whys, id: \.self) { why in
Text(why.why)
}
}
Button(action: {
viewModel.createWhy(why: "Test", count: viewModel.whys.count, learning: learn)
viewModel.fetchWhy(predicate: NSPredicate(format: "parentLearning == %#", learn))
}){
Text("Add")
.font(.title)
.foregroundColor(.white)
}
}
The problem is my List { ForEach, first time I press add button it shows the new why, second time i press the button the whole list goes away, the third time I press the button the list shows again with all 3 items.
To test the problem I added that first ForEach part and that shows the correct item at all times, so there is not a problem with the viewmodel or adding the items, the items are added and it is published from the viewmodel since that part is updated.
Does anyone have any clue why my List { ForEach only show every other time?
I have gotten this problem. I figure it out by adding objectWillChange in ViewModel, and send() it manually when your why is changed. Actually I don't know your NewLearningWhyViewModel clearly, so this is just an example, you should try it out.
class NewLearningWhyViewModel: ObservableObject {
let objectWillChange: ObservableObjectPublisher = ObservableObjectPublisher()
#Published var whys: Why = Why() {
didSet {
objectWillChange.send()
}
}
}
Ok the post from Becky Hansmeyer solved it, adding .id(UUID()) to the list solved it and it started working correctly...
because of "viewModel.whys" is set of classes.
SwiftUI does not work with classes directly.
There is 2 solutions:
make it struct instead of class + add #Published modifier inside of view
leave it as is + do it observable object and in init of your view assign into observed object.
More details here:
https://stackoverflow.com/a/62919526/4423545
Let us consider the situation when you have ContentView and DestinationView. Both of them depend on some shared data, that typically lies inside the #ObservedObject var viewModel, that you pass from parent to child either via #EnvironmentObject or directly inside init().
The DestinationView in this case wants to enrich the viewModel by fetching some additional content inside .onAppear.
In this case, when using NavigationLink you might encounter the situation when the DestinationView gets into an update loop when you fetching content, as it also updates the parent view and the whole structure is redrawn.
When using the List you explicitly set the row's ids and thus view is not changed, but if the NavigationLink is not in the list, it would update the whole view, resetting its state, and hiding the DestinationView.
The question is: how to make NavigationLink update/redraw only when needed?
In SwiftUI the update mechanism compares View structs to find out whether they need to be updated, or not. I've tried many options, like making ViewModel Hashable, Equatable, and Identifiable, forcing it to only update when needed, but neither worked.
The only working solution, in this case, is making a NavigationLink wrapper, providing it with id for equality checks and using it instead.
struct NavigationLinkWrapper<DestinationView: View, LabelView: View>: View, Identifiable, Equatable {
static func == (lhs: NavigationLinkWrapper, rhs: NavigationLinkWrapper) -> Bool {
lhs.id == rhs.id
}
let id: Int
let label: LabelView
let destination: DestinationView // or LazyView<DestinationView>
var body: some View {
NavigationLink(destination: destination) {
label
}
}
}
Then in ContentView use it with .equatable()
NavigationLinkWrapper(id: self.viewModel.hashValue,
label: myOrdersLabel,
destination: DestinationView(viewModel: self.viewModel)
).equatable()
Helpful tip:
If your ContentView also does some updates that would impact the DestinationView it's suitable to use LazyView to prevent Destination from re-initializing before it's even on the screen.
struct LazyView<Content: View>: View {
let build: () -> Content
init(_ build: #autoclosure #escaping () -> Content) {
self.build = build
}
var body: Content {
build()
}
}
P.S: Apple seems to have fixed this issue in iOS14, so this is only iOS13 related issue.
I have a SwiftUI view that has a Form that contains a DatePicker:
struct GettingUpTimeSettingView: View {
#State private var viewModel = GettingUpTimeSettingViewModel()
var body: some View {
VStack {
Form {
Spacer()
Text(viewModel.questionString)
.accessibility(identifier: "Question")
Spacer()
DatePicker("Alarm Time",
selection: $viewModel.gettingUpTime,
displayedComponents: .hourAndMinute)
.accessibility(identifier: "Time")
.animation(.easeInOut)
Spacer()
Text(viewModel.explanationString)
.accessibility(identifier: "Explanation")
}
}
}
}
And an XCTestCase class for UI Testing:
class SleepyGPIntroUITests: XCTestCase {
private var app: XCUIApplication!
override func setUp() {
continueAfterFailure = false
app = XCUIApplication()
app.launch()
greeting = app.staticTexts["Greeting"]
}
override func tearDown() {
app = nil
}
func test_InitialScreen_ChangesTo_GettingUpScreen_Automatically() {
//Given
let questionText = "What time do you want to get up?"
let explanationText = "This should be the same time every day, including at weekends and on days off. Our best chance of great sleep comes when we have a regular routine."
let timeText = "7:00am"
let question = app.staticTexts["Question"]
let explanation = app.staticTexts["Explanation"]
let time = app.staticTexts["Time"]
//When
_ = time.waitForExistence(timeout: 2)
//Then
XCTAssertFalse(greeting.exists)
XCTAssertEqual(question.label, questionText, "Should show question at top of view")
XCTAssertEqual(explanation.label, explanationText, "Should show explanation in view")
XCTAssertEqual(time.label, timeText, "Should show the correct default time")
}
When I run the test, it fails and gives me this message:
Failed to get matching snapshot: No matches found for Elements matching predicate '"Time" IN identifiers' from input {(
StaticText, identifier: 'Question', label: 'What time do you want to get up?',
StaticText, identifier: 'Explanation', label: 'This should be the same time every day, including at weekends and on days off. Our best chance of great sleep comes when we have a regular routine.'
)}
I'm not sure whether this is down to the DatePicker() being contained in a Form, or whether it's because I'm not using the correct XCUIElementQuery to find it?
When I move the DatePicker outside the Form, I can find it, but only by using its label, and not its accessibility identifier.
The accessibility identifiers are working fine for the Text objects.
I can also find it using
app.datePickers.firstMatch
when it's outside the form, but not when it's contained within it.
I've found this answer that describes some odd behaviour when SwiftUI objects are contained in forms, but still haven't managed to solve my problem.
Many thanks.
tl:dr Can't get XCUIElementQuery to return DatePicker element when UITesting if the DatePicker is contained in a SwiftUI Form.
I've found the answer, for anyone that's interested.
First of all, a piece of basic advice, if you're struggling to find out how to access an element when UI testing in XCode, just use the record function and access the element manually.
That's what I did, and it showed me that before a DatePicker() is tapped on in SwiftUI, it actually shows as a button, so to access it in the example above I used this code:
let alarmTimeButton = app.tables.buttons["Time"]
I want to create a SwiftUI List, but not show scroll indicators. ScrollView offers showsIndicators to do this. How can it be done?
Any Indicators (List, scrollView, etc.)
you can get rid of showing indicators for all Lists, but with an API of the UITableView. because SwiftUI List is using UITableView for iOS behind the scene:
struct ContentView: View {
init() {
UITableView.appearance().showsVerticalScrollIndicator = false
}
var body: some View {
List(0...100, id: \.self) { item in
Text("hey")
}
}
}
Note that this will eliminate all TableViews and Lists indicators. You should make it visible again if you need to.
⚠️ Not Yet Important Note
Seems like Apple is removing appearance hacks (but not for this one yet). So you can use LazyVStack inside and ScrollView instead of List and use the available argument for hiding the indicators.
struct ContentView: View {
var body: some View {
ScrollView(.vertical, showsIndicators: false) { // <- This argument
LazyVStack {
ForEach(1...100, id: \.self) {
Text("\($0)").frame(height: 40)
}
}
}
}
}
It is actually easy to accomplish this without any appearance work arounds in the answer accepted. You just have to use the ScrollView initializer and set the parameter showsIndicators to false.
ScrollView(.vertical, showsIndicators: false) {
// ... your content for scrollView
}
Inside your ScrollView you could use LazyVStack, if you have a lot of subviews to scroll through. SwiftUI will then render very efficiently your subviews: "lazy" -> only if needed).
Until there is a native SwiftUI way to achieve this, the Introspect library provides a decent solution.
After applying all modifiers to your list just add as a last modifier the following:
List {
...
}
.introspectTableView { tableView in
tableView.showsVerticalScrollIndicator = false // here you can access any other UITableView property
}
I hope there is a native way to do that at some point.
Hide scrolling indicator now became very simple
List {}.scrollIndicators(ScrollIndicatorVisibility.hidden)
List basically creates a tableview (UpdateCoalescingTableView) behind the scenes, and tableview's are scrollable. Unfortunately, however, you can't get to the scrollview attributes in SwiftUI.
You "might" be able to create a UIViewRepresentable that could walk up the view hierarchy until it finds a scrollview, but I wouldn't recommend it.
You could also create your own scrollview, put a vstack inside it, and "fake" a list view, which would probably be the safer approach.
The choosen answer won't work in iOS 16. They released a new viewModifier called .scrollIndicators(.hidden). I created a viewModifier wrapper which you can call like this on your List: .modifier(HideListIndicatorsViewModifier())
struct HideListIndicatorsViewModifier: ViewModifier {
#ViewBuilder
func body(content: Content) -> some View {
if #available(iOS 16.0, *) {
content
.scrollIndicators(.hidden)
} else {
content
}
}
}
swift scrollview hide scrollbar
scrollView.showsHorizontalScrollIndicator = false
scrollView.showsVerticalScrollIndicator = false
hide scroll view indicators bar swiftui
ScrollView(.vertical, showsIndicators: false) {
// ... your content for scrollView
}