UIViewRepresentable view not updating value - ios

Question

I am trying to create a custom SwiftUI View but I am getting problem in updating value through ObservedObject.
import SwiftUI
import Combine
struct ContentView: View {
#ObservedObject var model:InfoViewModel = InfoViewModel()
var body: some View {
VStack(alignment: .leading){
CustomView(value: self.model.title)
.frame(width: 200, height: 200, alignment: .center)
}
.background(Color.green)
.frame(minWidth: 0,
maxWidth: .infinity,
minHeight: 0,
maxHeight: .infinity,
alignment: .topLeading)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
struct CustomView: UIViewRepresentable {
typealias UIViewType = UIView
var value:String
var lblTitle:UILabel = UILabel()
func makeUIView(context: Context) -> UIView {
let view:UIView = UIView()
view.addSubview(lblTitle)
lblTitle.text = value
lblTitle.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
lblTitle.backgroundColor = UIColor.red
lblTitle.textColor = UIColor.black
return view
}
func updateUIView(_ uiView: UIView, context: Context) {
self.lblTitle.text = value
print("LBLTitle:\(self.lblTitle.text!)\nTitleValue:\(self.value)")
}
}
class InfoViewModel: ObservableObject, Identifiable {
#Published var title = "Title"
private var count = 0
init() {
_ = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(fireTimer), userInfo: nil, repeats: true)
}
#objc func fireTimer() {
count += 1
self.title = "\(self.count)"
print("Timer fired!\n\(self.title)")
}
}
Project can be download from here
Edit:
I changed code after #Asperi answer now it is updating value. but as Dávid Pásztor suggested it is not right to create #ObservedObject inside struct then how I will pass the value to CustomView with creating #ObservedObject and link that David provided is old and code in that thread now seems not working.
Here is the code that is working
struct CustomView: UIViewRepresentable {
typealias UIViewType = UIView
var value:String
func makeUIView(context: Context) -> UIView {
let view:UIView = UIView()
let lblTitle:UILabel = UILabel()
view.addSubview(lblTitle)
lblTitle.text = value
lblTitle.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
lblTitle.backgroundColor = UIColor.red
lblTitle.textColor = UIColor.black
return view
}
func updateUIView(_ uiView: UIView, context: Context) {
for view in uiView.subviews
{
if(view.isKind(of: UILabel.self))
{
(view as! UILabel).text = value
print("LBLTitle:\((view as! UILabel).text!)\nTitleValue:\(self.value)")
}
}
}
}

Answer 1

You don't need to keep it as property because struct can be recreated (so you loose it), instead you have access your view via provided in arguments.
Note: UIViewRepresentable handles reference to corresponding view by itself.
struct CustomView: UIViewRepresentable {
typealias UIViewType = UILabel
var value:String
func makeUIView(context: Context) -> UILabel {
let lblTitle = UILabel()
lblTitle.text = value
lblTitle.backgroundColor = UIColor.red
lblTitle.textColor = UIColor.black
return lblTitle
}
func updateUIView(_ uiLabel: UILabel, context: Context) {
uiLabel.text = value
}
}