I'm trying to create a TextEditor view where the user can customize the font size, but whenever I adjust the font size using a Slider and go back to typing in the TextEditor, the TextEditor starts glitching: the scroll position jumps up and down, the cursor ends up in the wrong position, and the text flickers.
Here's a reduced test case:
struct ContentView: View {
#State var text: String
#State var textSize: CGFloat
var body: some View {
VStack {
Slider(value: $textSize, in: 20.0...80.0)
TextEditor(text: $text)
.font(.system(size: textSize, weight: .semibold))
}
.padding()
}
}
Just type some text, adjust the font size, type more text. You might need to repeat that a few times, but it eventually starts glitching.
My hypothesis is that part of the UI isn't being updated on the main thread, but maybe that's just me coming from UIKit and not fully understanding SwiftUI yet.
Using Xcode 14.2 and iOS 16.2.
Related
I'm dipping my toe into SwiftUI and WatchOS for the first time. I'm making good progress, but I can't figure out how to get rid of the black "gutters" on either side of my Image controls. I've tried setting all the backgrounds to white, but the gutter persists.
What property on which view do I need to set to change the color of the gutters to match the background?
SwiftUI
struct ContentView: View {
var body: some View {
List {
Image("cat-1").resizable().scaledToFill().background(Color.white)
Image("cat-2").resizable().scaledToFit().padding(5).background(Color.white)
Image("cat-3").resizable().scaledToFit().padding(.top, 5).background(Color.white)
}.background(Color.white).listStyle(CarouselListStyle())
.background(Color.white)
}
}
Try adding a
.listRowPlatterColor(.clear)
put it inside the list like this...
struct ContentView: View {
var body: some View {
List {
Image("cat-1")
.resizable()
.scaledToFit()
.listRowPlatterColor(.clear)
Image("cat-2").resizable().scaledToFit().padding(5).background(Color.white)
Image("cat-1")
.resizable()
.scaledToFit()
.padding(.top, 5)
.background(Color.white)
}
.listStyle(CarouselListStyle())
}
}
I put it in the first item and left it off of the second and third so that you could see the difference. This other question can provide some more details:
How to style rows in SwiftUI List on WatchOS? .
You should then be able to style it however you like.
I am looking at the Apple Reminders app and want to build the same pop over like view on iPhone. This the screen I am referring to:
So, I can present a popover like UI on an iPad using the popover modifier.
struct ContentView: View {
// 1.
#State var isPopoverPresented = false
var body: some View {
// 2.
Button(action: {
self.isPopoverPresented = true
}) {
Text("Some content")
}
// 3.
.popover(isPresented: $isPopoverPresented) {
Text("Popover is Presented")
.font(.largeTitle)
.frame(width: 200, height: 300)
}
}
}
However when that code runs on an iPhone, the popover turns in a fullscreen modal coming up from the bottom.
I want to know if there is a native way to build a screen like the one shown in the Reminders app or, is that screen a custom View with custom layout logic on an iPhone?
You're looking for a Menu (UIMenu in UIKit). Note that it's iOS 14+ only.
I have a vanilla TabView, an #ObservedObject, and a background task running which periodically updates the #Published field of the #ObservedObject.
I've noticed that when the background task runs more frequently, and generates more changes to the #ObservedObject, the navigation tabs on the TabView become less responsive - they 'miss' taps. If I tap two or three times, I can normally change the view. The more frequent the background updates, the more often taps are 'missed'.
So I'm wondering if the TabView somehow fails to notice taps while it is redrawing, or something like that?
Any insights?
import Foundation
import SwiftUI
struct ContentView2: View {
enum Tabs {
case main
case audio
case preferences
}
#State var tab = Tabs.preferences
#ObservedObject var appState = Globals.appState
var body: some View {
TabView(selection: $tab) {
MainView()
.tabItem {
Image(systemName: "video.fill")
Text("Main")
}.tag(Tabs.main)
AudioControlView()
.tabItem {
Image(systemName: "speaker.fill")
Text("Audio")
}.tag(Tabs.audio)
PreferenceView()
.tabItem {
Image(systemName: "gear")
Text("Prefs")
}.tag(Tabs.preferences)
}
}
}
Found the problem...
The TabView doesn't need #ObservedObject var appState = Globals.appState because the TabView itself doesn't depend on the #Published fields.
Instead, the individual tabs (MainView() etc. ) need to observe.
So what was happening was that the TabView was being unnecessarily recomputed and redrawn for every change. Removing this line fixed everything.
I want to use the awesome MultiSegmentPicker written by Yonat Sharon in my SwiftUI View.
https://github.com/yonat/MultiSelectSegmentedControl
However, I don't fully understand the interaction between the UIViewRepresentable View and my SwiftUI View. How do I get the host view controller to shrink its height down to the size of the segmented control?
Here's the debugger view of the demo page - notice the blue area around the top bar:
The demo code doesn't give a lot of insight into the issue, it's just a call to the UIViewRepresentable view. I've simplified it to just one example here:
struct MultiSegmentPickerX: View {
#State private var selectedSegmentIndexes: IndexSet = []
var body: some View {
VStack(alignment: .center) {
Spacer()
MultiSegmentPicker(
selectedSegmentIndexes: $selectedSegmentIndexes,
items: ["First", "Second", "Third", "Done"]
)
}
}
}
Notice I have a VStack with a Spacer() before the control.
The desired behavior for this example would be that the bar with "First", "Second", etc. would be snug against the bottom of the screen. Instead the Host Controller holds onto all that space...
Do I need to use Geometry reader to solve this issue and shrink the height down. Or do I have to adjust something in the UIViewRepresentable View?
Any insights into bridging UIKit and SwiftUI are always appreciated...
Is this an easy fix anyone?
These did not solve my issue:
UIViewRepresentable content not updating
How do I make SwiftUI UIViewRepresentable view hug its content?
How do I size a UITextView to its content?
Cannot test it now, just by thoughts, try with fixed size as below
MultiSegmentPicker(
selectedSegmentIndexes: $selectedSegmentIndexes,
items: ["First", "Second", "Third", "Done"]
).fixedSize() // << here !!
I'm embedding a view controller with variable-height UITextView inside a parent SwiftUI VStack and the view controller sizes it's frame to the whole screen between viewDidLoad and viewDidLayoutSubviews. The UITextView expands only to the size of the text inside itself and centers itself inside the parent view.
I'm trying to add this view controller in a VStack and have it behave externally like other SwiftUI components do - sized exactly to the content it contains - but it wants to be sized to the whole screen minus the other VStack elements.
I can get the correct size of the UITextView in didLayoutSubviews and pass it upwards to SwiftUI where it can be set properly - but where do I do that?
In the example screenshot below, the orange is the embedded UIView background, the green is the UITextView and the VStack looks like this:
VStack {
HighligherVC()
Text("Tap and drag to highlight")
.foregroundColor(.gray)
.font(.caption)
}
Without being able to see more of your code, it's slightly difficult to say what the best solution would be, but based purely on this part of your question...
I can get the correct size of the UITextView in didLayoutSubviews and pass it upwards to SwiftUI where it can be set properly - but where do I do that?
I would suggest that you pass a binding property to your view controller that can be set to the calculated text view height, meaning that the view that contains your VStack would have a #State property like this:
#State private var textViewHeight: CGFloat = 0
You would then declare a #Binding property on your HighlighterVC and add an initializer like this:
#Binding var textViewHeight: CGFloat
init(textViewHeight: Binding<CGFloat>) {
self._textViewHeight = textViewHeight
}
And then you would set textViewHeight to the calculated height in your didLayoutSubviews and add a .frame modifier to your HighlighterVC like this:
VStack {
HighlighterVC(textViewHeight: self.$textViewHeight)
.frame(height: self.textViewHeight)
Text("Tap and drag to highlight")
.foregroundColor(.gray)
.font(.caption)
}
Like I said at the beginning of my answer, this solution (that I believe would work, but since I can't test it, I'm not 100% certain) is based on your thoughts about what it is that you need. Without seeing more code, it's impossible for me to say if this is the best solution.
Add fixedSize may solve this.
.fixedSize(horizontal: false, vertical: true)