Swiftui list: trigger an action on tap and mimic basic select then auto-unselect - swiftui

I'm starting to learn swiftui and I've run into a problem that is both very basic and easily solvable in UIKit; but after spending days searching the internet and watching WWDC videos I've found no native solution.
The premise is simple: I have an array of songs I want to display in a list; when a user taps on a song view it should highlight the view on press, unhighlight after release, and then play the song (ie trigger an action). Sounds simple right?
Here's what I tried and spent way too much time on:
Using List(selection) + .onEvent(changed): I end up with a UUID (because i've only gotten selection to work with a UUID) that I then have to check against an array of songs to match AND the cell won't unhighlight/select itself; even when I try to manually set the State variable to nil or another generated UUID.
Using .onTap (either on or in the cell): I have to tap on the text of the cell to trigger onTap so I get a lot of taps that just don't work (because I have lots of white space in the cell). I also don't get a nice UI color change on press/release.
So after spending hours trying many different things I've finally come up with a solution and I basically wanted to create an account and share it to hopefully help other developers in my position. Because this so very annoyed me that something so basic took so much effort and time to do.
In the end the best solution I came up with was this:
Using ZStack and an empty button:
edit: I found I need to include and hide the content otherwise the button doesn't grow to fill the space (seems in lists it does for some reason). Though not sure what the hit on performance is of rendering the content twice when hiding it. Maybe a GeometryReader would work better?
struct SelectionView: ViewModifier {
let onSelect: () -> Void
func body(content: Content) -> some View {
ZStack (alignment: .leading) {
Button {
onSelect()
} label: {
content
.hidden()
}
content
}
}
}
extension View {
func onSelection(_ selection: #escaping () -> Void) -> some View {
self.modifier(SelectionView(onSelect: selection))
}
}
then to use it:
SongCell(song: song)
.onSelection {
// Do whatever action you want
}
No messing around with list selection, no weird tap hit boxes, and get the press/release color change. Basically put an empty button in a ZStack and trigger off it's action. Could possibly cause tap/touch issues with more complicated cells (?) but it does exactly what I need it to do for my basic app. I'm just not sure why it took so much effort and why apple doesn't support such a basic use case by default? If I've overlooked something native please do inform me. Thanks.

I got the basic idea what you are trying to do. I'm Going to show simple example. Maybe using this you will be able to find proper solution.
First let's create a color : -
#State var colorToShow : Color = Color.blue
Now in body we have our ZStack or Your cell that we want to deal with : -
ZStack{
colorToShow
}.frame(width: 50, height: 50).padding()
.onLongPressGesture(minimumDuration: 3) {
print("Process Complete")
colorToShow = .green
} onPressingChanged: { pressing in
if pressing {
print("Pressing")
colorToShow = .red
} else {
print("Pressing Released")
colorToShow = .blue
}
}
Here we are using .onLongPressGesture. You can set minimum duration on which you want to perform action. Now on process completion You set what you want to do. OnPressingChange give you a bool value that changes according to user is pressing that button or not. Show color change(Highlight) or do action while bool value is true. When user release button do action or unhighlight since bool value turns false.
Hope you find it useful.

Related

how to match the font of an existing view

I'm curious, is there a way to make the fonts in a view match those of an existing view in SwiftUI? I don't like the default selections of swiftUI in a certain context, and I'd like some control over the situation.
Here's some code to illustrate:
struct FontMatchView: View {
var body: some View {
Form {
Section {
Text("Some Controls Here")
} header: {
HStack {
Text("Header")
Spacer()
Button("Option") {
}
}
}
}
}
}
This gives this result:
In the Section Header, I'd like the font in the button on the right (with label "OPTION") to match the label to its left ("HEADER"). I'm guessing this will be hard because the font is not known at the time of view definition. But the choices SwiftUI has made here are "clearly wrong" :-), and I need to fix this.
Is there a way we solve this (other than overriding both fonts)? Ideally, I could say "use a font that is 0.8 x the height of whatever font will be used in view X". But I'd settle for "use the same font as will be used in view X".
You can remove "buttonizing" (which includes adjusting the font) by applying .buttonStyle(.plain). This will make it match the other Text in the current context. If you then want to re-accent it, you may:
Button("Option") {}
.buttonStyle(.plain)
.foregroundColor(.accentColor)
That said (and somewhat unrelated), making the button as small as the HEADER text may make it uncomfortably small as a hit area. It may be better to make HEADER larger rather than OPTION smaller.

SwiftUI: Custom view is un-hittable in XCTest

During Xcode UI test, I found my custom view's (MenuViewButton) is un-hittable in a test, I could found it but cannot touch it. In debug , when I po isHittable in console, it returns false. However I'm not sure if this is the correct behavior.
Per this thread XCUIElement exists, but is not hittable said, isHittable is default false for custom view element, and default true for UIKit standard view. But I don't know if it is the same behavior in SwiftUI.
Since the way someView.isAccessibilityElement = true is not possible in SwiftUI. My question is how could I let my custom view became hittable? Then it could be tapped in a test.
private var aView: some View {
MenuViewButton(
image: Image("an image name"),
text: Text("a string")
)
.accessibility(identifier: "xxx name")
}
I also use force tap with coordinate in case tap() is not working, but to give a offset of normalizedOffset didn't fix the problem in all places, it means some un-hittable element could be tapped, that is great but some others still not.
So may I know where normalizedOffset is start, from the middle of frame to give the offset or the top left?
func forceTapElement(timeout: TimeInterval) {
if !self.waitForExistence(timeout: timeout) {
return
}
if self.isHittable {
self.tap()
} else {
let coordinate: XCUICoordinate = self.coordinate(withNormalizedOffset: CGVector(dx: 0.1, dy: 0.0))
coordinate.tap()
}
}
Add https://github.com/devexperts/screenobject as a dependency
Use .tapUnhittable() instead of .tap() for this particular view. It gets the coordinates and taps using them
I have the same situation and am looking for answers. What has worked for me was to use:
let coordinate = element.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.5))
Still this seems like workaround for a real problem. One other strange thing is that i do not have this problem on iOS15.0 simulator, only for later versions. Currently trying with iOS15.2
One more thing I've tried is to add
.accessibilityElement(children: .combine)
and specificly telling it's a button with
.accessibility(addTraits: .isButton)
But this doesn't solve the problem.
Seems that isAccessibilityElement would be an answer here, but SwiftUI doesn't seem to have such.

Swiftui: multiple lines in a menu item or picker

I've started using SwiftUI and trying to convert an application that I've created with Jetpack Compose to iOS, but I've run into a problem with menus (or picker if that's easier).
What I want to do is to be able to create items that has multi-lines and different font size for the two lines. But I can't make it work, only the first line is visible
I've tried something like:
Picker("Select menu item", selection: $selectedItem) {
ForEach(0..<items.count) {
VStack {
Text("Menu item 1").fontWeight(.bold) // Only this text is shown
Text("Description")
}
}
}
I've also tried with
Menu("Options") {
VStack {
Text("Menu item 1").fontWeight(.bold) // Only this text is shown
Text("Description")
}
}
What I want it to look like is something like:
I've spent many hours trying to find an example of something like this. Is this possible to do in SwiftUI? If not, what control should you suggest to use instead?

SwiftUI - ScrollView move content to be visible with KeyboardAwareSwiftUI

I found this answer great for views but for a scrollview it works with this half text view height effect:
Is this something I can do with this KeyboardAwareSwiftUI classes? I tried to play with magical numbers to increase this values here:
func body(content: Content) -> some View {
content
.padding(.bottom, self.keyboard.height + 100)
.edgesIgnoringSafeArea(self.keyboard.height > 0 ? .bottom : [])
.animation(.easeOut)
}
but this just increased some area above the keyboard but text view is still hidden a bit:
I would recommend using this library instead, and you never have to worry about view positioning when keyboard is shown: https://github.com/hackiftekhar/IQKeyboardManager
It's a non swiftui library, however, this issue here shows how to add it to your swiftui app seamlessly and only a few line of code:
https://github.com/hackiftekhar/IQKeyboardManager/issues/1606
hope this helps

SwiftUI TextField freezes when deleting first character

When specifying a minimumScaleFactor for a TextField in SwiftUI the TextField behaves normally while you enter text and reduces the font as specified when the content does not fit the TextView. However, if you start deleting characters everything works as usual until you delete the first character. Everything freezes.
At the beginning I though it was something in the way I was handling the variable that stores the text that in my application I have it as an ObservedObject. However, after debugging the frozen app I noticed that the code was circling around the drawing of the TextField over and over, function after function everything pointed to an error in the drawing of the object on the screen.
The following code illustrates the issue. The TextField works perfectly when you enter characters and delete them until you get to the first one. The it freezes.
import SwiftUI
struct ContentView: View {
#State var sensorNumber: String = ""
var body: some View {
TextField("WC0.000.000.000", text: $sensorNumber)
.padding(.all, 5.0)
.font(Font.custom("Helvetica", size:40.0))
.minimumScaleFactor(0.90)
}
}
The problem seems to be related to the interaction of the Custom Font. Obviously, my application is using custom fonts but here I just wanted to simplify the code.
This code does not fail if you don't use a custom font or if you don't specify a minimumScaleFactor. I have found a workaround that is not very elegant but it works until Apple fixes this bug:
import SwiftUI
struct ContentView: View {
#State var sensorNumber: String = ""
var body: some View {
TextField("WC0.000.000.000", text: $sensorNumber)
.padding(.all, 5.0)
.font(Font.custom("Helvetica", size:40.0))
.minimumScaleFactor(sensorNumber.count < 2 ? 1.0 : 0.90)
}
}
I am submitting a radar to Apple but looking for a better solution for the problem here.