for two days I try to solve the well known issue with
Context in environment is not connected to a persistent store coordinator: <NSManagedObjectContext: ...>
in my app.
I tried nearly ever posted solution found on good old google - even I tried to understand Japanese sites. I've put the line
.environment(\.managedObjectContext, persistenceController.container.viewContext)
to nearly every line of code: either error or no result.
My problem: I like to open a new window and display a list of something (here: addresses). There must be a simple solution for that without rewriting and expanding parts of the framework. In my opinion this is not a very special thing so therefor apple might have an easy solution for that, I can't see.
My code so far:
XXXXApp.swift
import SwiftUI
#main <<-- here: Context in environment is not connected to a persis....
struct XXXXApp: App {
let persistenceController = PersistenceController.shared
var body: some Scene {
WindowGroup {
ContentView()
.environment(\.managedObjectContext, persistenceController.container.viewContext)
.navigationTitle("Buchliste")
}
WindowGroup("AddressBook") {
AddressBookView()
.environment(\.managedObjectContext, persistenceController.container.viewContext)
.navigationTitle("Adressbuch")
}.windowToolbarStyle(UnifiedCompactWindowToolbarStyle()).windowStyle(HiddenTitleBarWindowStyle())
Settings {
PreferencePane()
}
}
}
class WindowController<RootView: View>: NSWindowController {
let persistenceController = PersistenceController.shared
convenience init(rootView: RootView, width: Int, height: Int) {
let hostingController = NSHostingController(rootView: rootView.frame(width: CGFloat(width), height: CGFloat(height)))
let window = NSWindow(contentViewController: hostingController) <<-- here: Context in environment is not connected to a persis....
window.setContentSize(NSSize(width: width, height: height))
self.init(window: window)
}
}
snippet in ContextView.swift:
ToolbarItem(placement: .automatic) {
Button {
let windowController = WindowController(rootView: AddressBookView(), width: 800, height: 600 )
windowController.window?.title = "Adressbuch" <<-- here: Context in environment is not connected to a persis....
windowController.showWindow(nil)
} label: {
Label("Adressbuch", systemImage: "book")
}
}
So, where is my mistake? Where do I have to put which code to make the app run properly?
HEUREKA!!
class WindowController<RootView: View>: NSWindowController {
convenience init(rootView: RootView, width: Int, height: Int) {
let persistenceController = PersistenceController.shared
let hostingController = NSHostingController(rootView: rootView.frame(width: CGFloat(width), height: CGFloat(height)).environment(\.managedObjectContext, persistenceController.container.viewContext))
let window = NSWindow(contentViewController: hostingController)
window.setContentSize(NSSize(width: width, height: height))
self.init(window: window)
}
}
That's the right code for the WindowController. The environment-bla has to be added after frame as parameter. The persistenceController into the init and here we go!
Related
I'm trying to use a view written in SwiftUI as an accessory view of my NSSavePanel but I struggled to get it working properly.
Here's the implementation for my SwiftUI view:
struct ExportAccessoryView: View {
enum ExportFileType: String, Identifiable {
// ... enum declaration
}
#State var selectedExportFileType: ExportFileType = .png
#State var resolution = 256.0
#Binding var selectedFileTypeBinding: ExportFileType
#Binding var resolutionBinding: Double
var body: some View {
VStack(alignment: .leading, spacing: 12) {
Picker(selection: $selectedExportFileType, label: Text("Format:")) {
Text("PDF").tag(ExportFileType.pdf)
// ... other items
}
.frame(width: 170)
.padding(.leading, 21)
if [ExportFileType.png, ExportFileType.jpeg, ExportFileType.tiff].contains(selectedExportFileType) {
HStack {
Slider(value: $resolution, in: 128...1024,
label: { Text("Resolution:") })
.frame(width: 200)
Text("\(Int(resolution))")
.frame(width: 40, alignment: .leading)
.padding(.leading, 5)
}
}
}
.padding(10)
.onChange(of: selectedExportFileType) { newValue in
self.selectedFileTypeBinding = newValue
}
.onChange(of: resolution) { newValue in
self.resolutionBinding = newValue
}
}
}
Here's how I implemented my save panel:
class DocumentWindow: NSWindowController {
var exportFileType: ExportAccessoryView.ExportFileType = .pdf
var resolution = 256.0
lazy var exportPanel: NSSavePanel = {
let savePanel = NSSavePanel()
savePanel.message = "Specify where and how you wish to export..."
savePanel.nameFieldLabel = "Export As:"
savePanel.canCreateDirectories = true
savePanel.isExtensionHidden = false
savePanel.showsTagField = true
let fileTypeBinding = Binding {
return self.exportFileType
} set: { newValue in
self.exportFileType = newValue
// update file extension
self.exportPanel.allowedContentTypes = [UTType(newValue.rawValue)!]
}
let resolutionBinding = Binding {
return self.resolution
} set: { newValue in
self.resolution = newValue
}
let accessoryView = ExportAccessoryView(selectedFileTypeBinding: fileTypeBinding,
resolutionBinding: resolutionBinding)
let exportAccessoryView = NSHostingController(rootView: accessoryView)
savePanel.accessoryView = exportAccessoryView.view
savePanel.allowedContentTypes = [UTType(self.exportFileType.rawValue)!]
return savePanel
}()
}
The save panel is presented by invoking beginSheetModal(for:completionHandler:).
It has no problem displaying but the accessory view is exhibiting some bizarre behavior: it seems to be doing its own thing at random (I sought for patterns but I failed to do so).
Sometimes it works properly, sometimes it becomes unclickable (but the function is still accessible via switch control using TAB). The alignment is always different from the last time I expanded/collapsed or opened/closed the panel: sometimes it's left aligned, sometimes it's centered (even if I have explicitly opted for .leading for alignment).
I have absolutely no idea what's going on. I don't know if this is an issue with SwiftUI+AppKit or is it that I'm doing it all wrong, which is highly likely since I'm a total newbie in SwiftUI. What should I do to get it working properly?
I remembered from back in the days when I was using XIB for implementing an accessory view: I used to embed the controls within an NSView and then set up constraints to make it work. So I applied the same idea here of embedding the NSHostingView's view within a custom NSView and after tweaking it for a bit, I made it work:
lazy var exportPanel: NSSavePanel = {
// ... setting up save panel
// instantiate SwiftUI view and its hosting controller
let accessoryView = ExportAccessoryView(selectedFileTypeBinding: fileTypeBinding,
resolutionBinding: resolutionBinding)
let exportAccessoryView = NSHostingController(rootView: accessoryView)
// embed the SwiftUI in a custom view
let customView = NSView(frame: NSRect(x: 0, y: 0, width: 300, height: 60))
customView.addSubview(exportAccessoryView.view)
// use my own constraints
exportAccessoryView.view.translatesAutoresizingMaskIntoConstraints = false
// top and bottom clipped to custom view
exportAccessoryView.view.topAnchor.constraint(equalTo: customView.topAnchor).isActive = true
exportAccessoryView.view.bottomAnchor.constraint(equalTo: customView.bottomAnchor).isActive = true
// leading and trailing spaces can stretch as far as they need to be, hence ≥0
exportAccessoryView.view.leadingAnchor.constraint(greaterThanOrEqualTo: customView.leadingAnchor).isActive = true
exportAccessoryView.view.trailingAnchor.constraint(greaterThanOrEqualTo: customView.trailingAnchor).isActive = true
// center the SwiftUI view horizontal within custom view
exportAccessoryView.view.centerXAnchor.constraint(equalTo: customView.centerXAnchor).isActive = true
// usually fixed width and height
// can be flexible when SwiftUI view is dynamic
exportAccessoryView.view.widthAnchor.constraint(equalToConstant: customView.frame.width).isActive = true
exportAccessoryView.view.heightAnchor.constraint(greaterThanOrEqualToConstant: customView.frame.height).isActive = true
savePanel.accessoryView = customView
// ... additional setup
return savePanel
}()
Now it works perfectly as expected. Don't know if this is the "proper way" to implement such integration.
How to set window coordinates in SwiftUI on MacOS Desktop? For example, should the window appear always in the center or always in the upper right corner?
Here is my version, however, I shift the code and close it, when I open it, it appears first in the old place, and then jumps to a new place.
import SwiftUI
let WIDTH: CGFloat = 400
let HEIGTH: CGFloat = 200
#main
struct ForVSCode_MacOSApp: App {
#State var window : NSWindow?
var body: some Scene {
WindowGroup {
ContentView(win: $window)
}
}
}
struct WindowAccessor: NSViewRepresentable{
#Binding var window: NSWindow?
func makeNSView(context: Context) -> some NSView {
let view = NSView()
let width = (NSScreen.main?.frame.width)!
let heigth = (NSScreen.main?.frame.height)!
let resWidth: CGFloat = (width / 2) - (WIDTH / 2)
let resHeigt: CGFloat = (heigth / 2) - (HEIGTH / 2)
DispatchQueue.main.async {
self.window = view.window
self.window?.setFrameOrigin(NSPoint(x: resWidth, y: resHeigt))
self.window?.setFrameAutosaveName("mainWindow")
self.window?.isReleasedWhenClosed = false
self.window?.makeKeyAndOrderFront(nil)
}
return view
}
func updateNSView(_ nsView: NSViewType, context: Context) {
}
}
and ContentView
import SwiftUI
struct ContentView: View {
#Binding var win: NSWindow?
var body: some View {
VStack {
Text("it finally works!")
}
.font(.largeTitle)
.frame(width: WIDTH, height: HEIGTH, alignment: .center)
.background(WindowAccessor(window: $win))
}
}
struct ContentView_Previews: PreviewProvider {
#Binding var win: NSWindow?
static var previews: some View {
ContentView(win: .constant(NSWindow()))
.frame(width: 250, height: 150, alignment: .center)
}
}
I do have the same issue in one of my projects and thought I will investigate a bit deeper and I found two approaches to control the window position.
So my first approach to influence the window position is by pre-defining the windows last position on screen.
Indirect control: Frame autosave name
When the first window of an app is opened, macOS will try to restore the last window position when it was last closed. To distinguish the different windows, each window has its own frameAutosaveName.
The windows frame is persisted automatically in a text format in the apps preferences (UserDefaults.standard) with the key derived from the frameAutosaveName: "NSWindow Frame <frameAutosaveName>" (see docs for saveFrame).
If you do not specify an ID in your WindowGroup, SwiftUI will derive the autosave name from your main views class name. The first three windows will have the following autosave names:
<ModuleName>.ContentView-1-AppWindow-1
<ModuleName>.ContentView-1-AppWindow-2
<ModuleName>.ContentView-1-AppWindow-3
By setting an ID for example WindowGroup(id: "main"), the following autosave names are used (again for the first three windows):
main-AppWindow-1
main-AppWindow-2
main-AppWindow-3
When you check in your apps preferences directory (where UserDefaults.standard is stored), you will see in the plist one entry:
NSWindow Frame main-AppWindow-1 1304 545 400 228 0 0 3008 1228
There are a lot of numbers to digest. The first 4 integers describe the windows frame (origin and size), the next 4 integers describe the screens frame.
There are a few things to keep in mind when manually setting those value:
macOS coordinate system has it origin (0,0) in the bottom left corner.
the windows height includes the window title bar (28px on macOS Monterey but may be different on other versions)
the screens height excludes the title bar
I don't have documentation on this format and used trial and error to gain knowledge about it...
So to fake the initial position in the center of the screen I used the following function which I run in the apps (or the ContentView) initializer. But keep in mind: with this method only the first window will be centered. All the following windows are going to be put down and right of the previous window.
func fakeWindowPositionPreferences() {
let main = NSScreen.main!
let screenWidth = main.frame.width
let screenHeightWithoutMenuBar = main.frame.height - 25 // menu bar
let visibleFrame = main.visibleFrame
let contentWidth = WIDTH
let contentHeight = HEIGHT + 28 // window title bar
let windowX = visibleFrame.midX - contentWidth/2
let windowY = visibleFrame.midY - contentHeight/2
let newFramePreference = "\(Int(windowX)) \(Int(windowY)) \(Int(contentWidth)) \(Int(contentHeight)) 0 0 \(Int(screenWidth)) \(Int(screenHeightWithoutMenuBar))"
UserDefaults.standard.set(newFramePreference, forKey: "NSWindow Frame main-AppWindow-1")
}
My second approach is by directly manipulating the underlying NSWindow similar to your WindowAccessor.
Direct control: Manipulating NSWindow
Your implementation of WindowAccessor has a specific flaw: Your block which is reading view.window to extract the NSWindow instance is run asynchronously: some time in the future (due to DispatchQueue.main.async).
This is why the window appears on screen on the SwiftUI configured position, then disappears again to finally move to your desired location. You need more control, which involves first monitoring the NSView to get informed as soon as possible when the window property is set and then monitoring the NSWindow instance to get to know when the view is becoming visible.
I'm using the following implementation of WindowAccessor. It takes a onChange callback closure which is called whenever window is changing. First it starts monitoring the NSViews window property to get informed when the view is added to a window. When this happened, it starts listening for NSWindow.willCloseNotification notifications to detect when the window is closing. At this point it will stop any monitoring to avoid leaking memory.
import SwiftUI
import Combine
struct WindowAccessor: NSViewRepresentable {
let onChange: (NSWindow?) -> Void
func makeNSView(context: Context) -> NSView {
let view = NSView()
context.coordinator.monitorView(view)
return view
}
func updateNSView(_ view: NSView, context: Context) {
}
func makeCoordinator() -> WindowMonitor {
WindowMonitor(onChange)
}
class WindowMonitor: NSObject {
private var cancellables = Set<AnyCancellable>()
private var onChange: (NSWindow?) -> Void
init(_ onChange: #escaping (NSWindow?) -> Void) {
self.onChange = onChange
}
/// This function uses KVO to observe the `window` property of `view` and calls `onChange()`
func monitorView(_ view: NSView) {
view.publisher(for: \.window)
.removeDuplicates()
.dropFirst()
.sink { [weak self] newWindow in
guard let self = self else { return }
self.onChange(newWindow)
if let newWindow = newWindow {
self.monitorClosing(of: newWindow)
}
}
.store(in: &cancellables)
}
/// This function uses notifications to track closing of `window`
private func monitorClosing(of window: NSWindow) {
NotificationCenter.default
.publisher(for: NSWindow.willCloseNotification, object: window)
.sink { [weak self] notification in
guard let self = self else { return }
self.onChange(nil)
self.cancellables.removeAll()
}
.store(in: &cancellables)
}
}
}
This implementation can then be used to get a handle to NSWindow as soon as possible. The issue we still face: we don't have full control of the window. We are just monitoring what happens and can interact with the NSWindow instance. This means: we can set the position, but we don't know exactly at which instant this should happen. E.g. setting the windows frame directly after the view has been added to the window, will have no impact as SwiftUI is first doing layout calculations to decide afterwards where it will place the window.
After some fiddling around, I started tracking the NSWindow.isVisible property. This allows me to set the position whenever the window becomes visible. Using above WindowAccessor my ContentView implementation looks as follows:
import SwiftUI
import Combine
let WIDTH: CGFloat = 400
let HEIGHT: CGFloat = 200
struct ContentView: View {
#State var window : NSWindow?
#State private var cancellables = Set<AnyCancellable>()
var body: some View {
VStack {
Text("it finally works!")
.font(.largeTitle)
Text(window?.frameAutosaveName ?? "-")
}
.frame(width: WIDTH, height: HEIGHT, alignment: .center)
.background(WindowAccessor { newWindow in
if let newWindow = newWindow {
monitorVisibility(window: newWindow)
} else {
// window closed: release all references
self.window = nil
self.cancellables.removeAll()
}
})
}
private func monitorVisibility(window: NSWindow) {
window.publisher(for: \.isVisible)
.dropFirst() // we know: the first value is not interesting
.sink(receiveValue: { isVisible in
if isVisible {
self.window = window
placeWindow(window)
}
})
.store(in: &cancellables)
}
private func placeWindow(_ window: NSWindow) {
let main = NSScreen.main!
let visibleFrame = main.visibleFrame
let windowSize = window.frame.size
let windowX = visibleFrame.midX - windowSize.width/2
let windowY = visibleFrame.midY - windowSize.height/2
let desiredOrigin = CGPoint(x: windowX, y: windowY)
window.setFrameOrigin(desiredOrigin)
}
}
I hope this solution helps others who want to get more control to the window in SwiftUI.
I have ContentView.swift
struct ContentView: View {
#State var seconds: String = "60"
init(_ appDelegate: AppDelegate) {
launchTimer()
}
func launchTimer() {
let timer = DispatchTimeInterval.seconds(5)
let currentDispatchWorkItem = DispatchWorkItem {
print("in timer", "seconds", seconds) // Always `"60"`
print("in timer", "$seconds.wrappedValue", $seconds.wrappedValue) // Always `"60"`
launchTimer()
}
DispatchQueue.main.asyncAfter(deadline: .now() + timer, execute: currentDispatchWorkItem)
}
var body: some View {
TextField("60", text: $seconds)
}
func getSeconds() -> String {
return $seconds.wrappedValue;
}
}
And AppDelegate.swift
class AppDelegate: NSObject, NSApplicationDelegate {
var contentView = ContentView()
func applicationDidFinishLaunching(_ aNotification: Notification) {
launchTimer()
}
func launchTimer() {
print(contentView.getSeconds()) // Always `"60"`
let timer = DispatchTimeInterval.seconds(Int(contentView.getSeconds()) ?? 0)
DispatchQueue.main.asyncAfter(deadline: .now() + timer) {
self.launchTimer()
}
}
#objc func showPreferenceWindow(_ sender: Any?) {
if(window != nil) {
window.close()
}
window = NSWindow(
contentRect: NSRect(x: 0, y: 0, width: 480, height: 300),
styleMask: [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView],
backing: .buffered, defer: false)
window.isReleasedWhenClosed = false
window.contentView = NSHostingView(rootView: contentView)
window.center()
window.makeKeyAndOrderFront(nil)
NSApplication.shared.activate(ignoringOtherApps: true)
}
}
contentView.getSeconds() always returns 60, even if I modify the value of the TexField in my content view (by manually typing in the text field).
How does one get the wrapped value/real value of a state variable from the app delegate?
#State/#StateObject is tricky business, what happens is that SwiftUI connects the state values to a certain view instance from the UI hierarchy.
In your case, the #State var seconds: String = "60" is connected to the view below (simplified scheme):
NSWindow
-> NSHostingView
-> ContentView <----- this is where the #State usage is valid
And as others said, ContentView being a struct, it's a value type, meaning that its contents are copied in all usage sites, so instead of having a unique instance, like a class has, you end up with multiple instances.
And only one of those instances, the copy SwiftUI makes when it adds the view to the UI tree, is the one that is connected to the text field, and gets updated.
To make things even funnier, the State property wrapper is also a struct, meaning that it "suffers" from the same symptoms as the view.
That's one of the perks of using SwiftUI, in contrast with UIKit, you don't care at all about the view instances.
Now, if you want to use the value of seconds from AppDelegate, or any other place, you will have to circulate the data storage instead of the view.
For starters, change the view to receive a #Binding instead
struct ContentView: View {
#Binding var seconds: String = "60"
// the rest of the view code remains the same
Then create an ObservableObject that stores the data, and inject its $seconds binding when creating the view:
class AppData: ObservableObject {
#Published var seconds: String = "60"
}
class AppDelegate {
let appData = AppData()
// ... other code left out for clarity
#objc func showPreferenceWindow(_ sender: Any?) {
// ...
let contentView = ContentView(seconds: appData.$seconds
window.contentView = NSHostingView(rootView: contentView)
// ...
}
}
SwiftUI is more about the data than the view itself, so if you want to access the same data in multiple places, make sure you circulate the storage instead of the view the data is attached to. And also make sure that the source of truth of that data is a class, as object references are guaranteed to point to the same memory location (assuming of course the reference doesn't change).
Your ContentView (as well as any other SwiftUI view) is a struct, ie. value type, so in every place where you use it - you use a new copy of initially created value, ie.:
class AppDelegate: NSObject, NSApplicationDelegate {
var contentView = ContentView() // << 1st copy
...
func launchTimer() {
print(contentView.getSeconds()) // << 2nd copy
let timer = DispatchTimeInterval.seconds(Int(contentView.getSeconds()) ?? 0) // << 3d copy
...
}
...
#objc func showPreferenceWindow(_ sender: Any?) {
...
window.contentView = NSHostingView(rootView: contentView) // << 4th copy
}
}
You should not use any #State externally, because it is valid only inside view's body.
If you need something to share/access in different places then use class confirming to ObservableObject as view model type, and as instances of such class is a reference type then passing it here and there you can use/access same object from different places.
Update:
why the value stays to "60" even inside the ContentView
You call launchTimer in init, but in that place State is not constructed yet, so binding to it is not valid. As was already written above state is valid in body, so you have to set your timer also in body when binding will be ready, say in .onAppear, like below
var body: some View {
TextField("60", text: $seconds)
.onAppear {
launchTimer()
}
}
Prepared & tested with Xcode 13 / iOS 15
add a variable to appDelegate
var seconds : Int?
then do this in your contentView :
.onChange(of: seconds) { seconds in
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {return}
appDelegate.seconds = seconds
}
Ended up instantiating the ContentView with the AppDelegate as a param. I added a seconds attribute to the AppDelegate to be modified by the ContentView.
AppDelegate.swift
import SwiftUI
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
var contentView: ContentView?
var seconds = 60
func applicationDidFinishLaunching(_ aNotification: Notification) {
self.contentView = ContentView(self)
launchTimer()
}
func launchTimer() {
let timer = DispatchTimeInterval.seconds(seconds)
print(timer)
DispatchQueue.main.asyncAfter(deadline: .now() + timer) {
self.launchTimer()
}
}
}
ContentView.swift
import SwiftUI
struct ContentView: View {
#State var seconds: String = "60"
var appDelegate: AppDelegate
init(_ appDelegate: AppDelegate) {
self.appDelegate = appDelegate
}
var body: some View {
TextField("60", text: $seconds, onCommit: {
self.appDelegate.seconds = Int($seconds.wrappedValue) ?? 0
})
}
}
This code hurts my brain and surely there is a better way of doing this 😅. But I'm only so far in my Swift journey, so that will do for now lol. Please post if you have a better solution.
I have a View, in which the user is able to enter some text into a TextField. I want to be able to get the text, which was entered in the TextField and use this value inside of a struct. The concept of the app, is that it shows the elevation degree of the sun. To be able to do this, it is scraping the values from a WebPage. However to make this app dynamic, the user has to be able to edit the url (you can change location, date etc in the url). I thought this would be fairly easy, since I only have to get some text, and edit a url before the url is being loaded. I have been able to pass the value into a view, however I need it in a struct. Maybe the whole "layout of my code is wrong, maybe I should get the data and draw the function in a view? I don't know. This is my first time coding with swift.
I want to change the latitude var.
This is my code:
View 1 (Input):
class ViewModel: ObservableObject {
#Published var latitude:String = ""
#Published var page = 0
}
struct ContentView: View {
#EnvironmentObject var value1: ViewModel
var body: some View {
if value1.page == 0{
VStack{
TextField("", text: $value1.latitude)
Button(action:{ value1.page = 1}){
Text("To next view")
}.frame(width: 300, height: 100, alignment: .center)
}
} else {
elevationGraph()
}
}
}
View 2 (Graph)
struct getHtml {
var url = URL(string: "https://midcdmz.nrel.gov/apps/spa.pl?syear=2020&smonth=1&sday=1&eyear=2020&emonth=1&eday=1&otype=0&step=60&stepunit=1&hr=12&min=0&sec=0&latitude=\(latitude)&longitude=10.757933&timezone=1.0&elev=53&press=835&temp=10&dut1=0.0&deltat=64.797&azmrot=180&slope=0&refract=0.5667&field=0")
func loadData(from url: URL?) -> String {
guard let url = url else {
return "nil"
}
let html = try! String(contentsOf: url, encoding: String.Encoding.utf8)
return html
}
}
struct elevationFunction: Shape {
var url: URL? //This only works in views, is there a way to do it in shape structs?
let html = getHtml.init().loadData(from: getHtml.init().url)
private func dbl1() -> Double {
let leftSideOfTheValue = "0:00:00,"
let rightSideOfTheValue = "\(month)/\(day)/\(year),1:00:00,"
guard let leftRange = html.range(of: leftSideOfTheValue) else {
print("cant find left range")
return 0
}
guard let rightRange = html.range(of: rightSideOfTheValue) else {
print("cant find right range")
return 0
}
let rangeOfTheValue = leftRange.upperBound..<rightRange.lowerBound
return Double(html[rangeOfTheValue].dropLast()) ?? 90
}
func path(in rect: CGRect) -> Path {
var path = Path()
path.move(to: CGPoint(x: 10, y: (125 - (90-dbl1()))))
path.addLine(to: CGPoint(x: 120, y: (125 - (90-45))))
path.addLine(to: CGPoint(x: 250, y: (125 - (90-dbl1()))))
var scale = (rect.height / 350) * (9/10)
var xOffset = (rect.width / 6)
var yOffset = (rect.height / 2)
return path.applying(CGAffineTransform(scaleX: scale, y: scale)).applying(CGAffineTransform(translationX: xOffset, y: yOffset))
}
}
struct elevationGraph: View {
var body: some View {
GeometryReader { geometry in
ZStack {
elevationFunction().stroke(LinearGradient(gradient: Gradient(colors: [Color.yellow, Color.red]), startPoint: .top , endPoint: .bottom), style: StrokeStyle(lineWidth: 6.0)).aspectRatio(contentMode: .fill)
}
.frame(width: 600, height: 800, alignment: .center)
}
}
}
As mentioned in my comment, you can pass a parameter to a Shape just like you can a regular View:
elevationFunction(url: yourURL)
Best practice would be to capitalize this and name it ...Shape as well:
elevationFunction becomes ElevationShape
Regarding your second question in the comment, first, you may want to fix the naming of getHtml for the same reason as above -- uncapitalized, it looks like a variable name. Maybe something like DataLoader.
Regarding the crash, you have some circular logic going on -- you call getHtml.init() and then pass a parameter that is again derived from getHtml.init() again. Why not just call getHtml() and have it loadData from its own internal URL property?
There's a larger problem at work, though, which is that you've declared html as a let property on your Shape, which is going to get recreated every time your Shape is rendered. So, on every render, with your current code, you'll create 2 new getHtmls and attempt to load the data (which very well may not actually have time to load the URL request). This very well could be blocking the first render of the Shape as well and is almost certainly causing your crash somewhere in the circular and repetitive logic going on.
Instead, you might want to consider moving your URL request to onAppear or as part of an ObservableObject where you can have a little more control of when and how often this data gets loaded. Here's a good resource on learning more about loading data using URLSession and SwiftUI: https://www.hackingwithswift.com/books/ios-swiftui/sending-and-receiving-codable-data-with-urlsession-and-swiftui
I am grabbing a screenshot of a sub-view in my SwiftUI View to immediately pass to a share sheet in order to share the image.
The view is of a set of questions from a text array rendered as a stack of cards. I am trying to get a screenshot of the question and make it share-able along with a link to the app (testing with a link to angry birds).
I have been able to capture the screenshot using basically Asperi's answer to the below question:
How do I render a SwiftUI View that is not at the root hierarchy as a UIImage?
My share sheet launches, and I've been able to use the "Copy" feature to copy the image, so I know it's actually getting a screenshot, but whenever I click "Message" to send it to someone, or if I just leave the share sheet open, the app crashes.
The message says it's a memory issue, but doesn't give much description of the problem. Is there a good way to troubleshoot this sort of thing? I assume it must be something with how the screenshot is being saved in this case.
Here are my extensions of View and UIView to render the image:
extension UIView {
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
layer.render(in: rendererContext.cgContext)
}
}
}
extension View {
func asImage() -> UIImage {
let controller = UIHostingController(rootView: self)
// locate far out of screen
controller.view.frame = CGRect(x: 0, y: CGFloat(Int.max), width: 1, height: 1)
UIApplication.shared.windows.first!.rootViewController?.view.addSubview(controller.view)
let size = controller.sizeThatFits(in: UIScreen.main.bounds.size)
controller.view.bounds = CGRect(origin: .zero, size: size)
controller.view.sizeToFit()
controller.view.backgroundColor = .clear
let image = controller.view.asImage()
controller.view.removeFromSuperview()
return image
}
}
Here's an abbreviated version of my view - the button is about halfway down, and should call the private function at the bottom that renders the image from the View/UIView extensions, and sets the "questionScreenShot" variable to the rendered image, which is then presented in the share sheet.
struct TopicPage: View {
var currentTopic: Topic
#State private var currentQuestions: [String]
#State private var showShareSheet = false
#State var questionScreenShot: UIImage? = nil
var body: some View {
GeometryReader { geometry in
Button(action: {
self.questionScreenShot = render()
if self.questionScreenShot != nil {
self.showShareSheet = true
} else {
print("Did not set screenshot")
}
}) {
Text("Share Question").bold()
}
.sheet(isPresented: $showShareSheet) {
ShareSheet(activityItems: [questionScreenShot!])
}
}
}
private func render() -> UIImage {
QuestionBox(currentQuestion: self.currentQuestions[0]).asImage()
}
}
I've found a solution that seems to be working here. I start the variable where the questionScreenShot gets stored as nil to start:
#State var questionScreenShot: UIImage? = nil
Then I just make sure to set it to 'render' when the view appears, which means it loads the UIImage so if the user clicks "Share Question" it will be ready to be loaded (I think there was an issue earlier where the UIImage wasn't getting loaded in time once the sharing was done).
It also sets that variable back to nil on disappear.
.onAppear {
self.currentQuestions = currentTopic.questions.shuffled()
self.featuredQuestion = currentQuestions.last!
self.questionScreenShot = render()
}
.onDisappear {
self.questionScreenShot = nil
self.featuredQuestion = nil
}