Update LazyVGrid list - swiftui

Question

I have a LazyVGrid list which need to be updated whenever a data is updated. The data is in a singleton class.
class BluetoothManager: NSObject {
static let shared = BluetoothManager()
#objc dynamic private(set) var stations: [BHStation] = []
}
And the list is
var body: some View {
let columns: [GridItem] = Array(repeating: .init(.flexible()), count: UIDevice.current.userInterfaceIdiom == .pad ? 2 : 1)
ScrollView {
LazyVGrid(columns: columns, alignment: .center, spacing: 10, pinnedViews: [], content: {
ForEach(BluetoothManager.shared.stations, id: \.peripheral.identifier) { item in
NavigationLink(destination: DetailView()) {
MainCell()
}
}
})
}
}
I tried to use ObservableObject with #Published, or to use #State/#Binding but none of them worked.
How can I make the list get updated whenever stations is get updated? #objc dynamic is necessary to be used in the other UIKit classes.

Answer 1

In order for your SwiftUI View to know to update, you should use an ObservableObject with a #Published property and store it as a #ObservedObject or #StateObject:
class BluetoothManager: NSObject, ObservableObject {
static let shared = BluetoothManager()
private override init() { }
#Published var stations: [BHStation] = []
}
struct ContentView : View {
#ObservedObject private var manager = BluetoothManager.shared
var body: some View {
let columns: [GridItem] = Array(repeating: .init(.flexible()), count: UIDevice.current.userInterfaceIdiom == .pad ? 2 : 1)
ScrollView {
LazyVGrid(columns: columns, alignment: .center, spacing: 10, pinnedViews: [], content: {
ForEach(manager.stations, id: \.peripheral.identifier) { item in //<-- Here
NavigationLink(destination: DetailView()) {
MainCell()
}
}
})
}
}
}
The #Published may interfere with your #objc requirement, but since you haven't given any information on how you use it in UIKit or why it's necessary, it's not possible to say directly what the fix is. You may need a different setter to use when interacting with it in UIKit.
Also, be aware that #Published won't update as expected unless the model type it is storing (BHStation) is a struct. If it's a class, you may need to call objectWillChange directly to get the #Published publisher to trigger correctly.