SwiftUI Representable TextField changes Font on disappear - swift

Question

I am using a Representable ViewController for a custom NSTextField in SwiftUI for MacOS. I am applying a customized, increased font size for that TextField. That works fine, I had a question regarding that topic in my last question here.
I am setting the Font of the TextField in my viewDidAppear() method now, which works fine. I can see a bigger font. The problem is now, when my view is not being in focus, the text size is shrinking back to normal. When I go back and activate the window again, I see the small font size. When I type again, it gets refreshed and I see the correct font size.
That is my code I am using:
class AddTextFieldController: NSViewController {
#Binding var text: String
let textField = NSTextField()
var isFirstResponder : Bool = true
init(text: Binding<String>, isFirstResponder : Bool = true) {
self._text = text
textField.font = NSFont.userFont(ofSize: 16.5)
super.init(nibName: nil, bundle: nil)
NSLog("init")
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func loadView() {
textField.delegate = self
//textField.font = NSFont.userFont(ofSize: 16.5)
self.view = textField
}
override func viewDidAppear() {
self.view.window?.makeFirstResponder(self.view)
textField.font = NSFont.userFont(ofSize: 16.5)
}
}
extension AddTextFieldController: NSTextFieldDelegate {
func controlTextDidChange(_ obj: Notification) {
if let textField = obj.object as? NSTextField {
self.text = textField.stringValue
}
textField.font = NSFont.userFont(ofSize: 16.5)
}
}
And this is the representable:
struct AddTextFieldRepresentable: NSViewControllerRepresentable {
#Binding var text: String
func makeNSViewController(
context: NSViewControllerRepresentableContext<AddTextFieldRepresentable>
) -> AddTextFieldController {
return AddTextFieldController(text: $text)
}
func updateNSViewController(
_ nsViewController: AddTextFieldController,
context: NSViewControllerRepresentableContext<AddTextFieldRepresentable>
) {
}
}
Here is a demo:
I thought about using Notification when the view is coming back, however not sure
NotificationCenter.default.addObserver(self, selector: #selector(willEnterForeground), name: NSApplication.willBecomeActiveNotification, object: nil)

Answer 1

Here is a solution. Tested with Xcode 11.4 / macOS 10.15.4
class AddTextFieldController: NSViewController {
#Binding var text: String
let textField = MyTextField() // << overridden field
and required custom classes (both!!) for cell & control (in all other places just remove user font usage as not needed any more):
class MyTextFieldCell: NSTextFieldCell {
override var font: NSFont? {
get {
return super.font
}
set {
// system tries to reset font to default several
// times (here!), so don't allow that
super.font = NSFont.userFont(ofSize: 16.5)
}
}
}
class MyTextField: NSTextField {
override class var cellClass: AnyClass? {
get { MyTextFieldCell.self }
set {}
}
override var font: NSFont? {
get {
return super.font
}
set {
// system tries to reset font to default several
// times (and here!!), so don't allow that
super.font = NSFont.userFont(ofSize: 16.5)
}
}
}