I have looked at a few similar issues, but none were close enough to my state to work. I have 3 files:
- ContentView.swift
- VariableSetupModel.swift
- ContentNavView.swift
Previously the code in all 3 were in a single file (ContentView). I am now working on splitting it up to make the code cleaner. I am a fairly novice iOS developer. I moved all of my variables to the VariableSetupModel and got that working fine. I reference values in that file, they update, and return to the ContentView to update the views.
Now I am working on splitting my views on the same page into multiple files, starting with the nav. The view shows up, reading values from the VariableSetupModel correctly when the page first opens. But when the value changes from a button in ContentView, it does not update the title on the view in ContentNavView. Below is a simplified version of the code I have.
ContentView.swift
struct ContentView: View {
//Pull in variables from "VariableSetupModel"
@ObservedObject var viewModel = VariableSetupModel()
@State var counter:Int = 0
var body: some View {
//Main Views
VStack (alignment: .leading) {
// MARK: Climbs-Title
ContentNavView()
}
}
Button(action: {
if viewModel.toggleListGraphs == "graph" {
viewModel.toggleListGraphs = "list"
}else{
viewModel.toggleListGraphs = "graph"
}
}) {
Image(systemName: "list.bullet.below.rectangle")
.font(.title)
}
}
VariableSetupModel.swift
final class VariableSetupModel: ObservableObject {
static let shared = VariableSetupModel()
//Visuals
@Published var toggleListGraphs = "graph"
}
ContentNavView.swift
struct ContentNavView: View {
//Pull in variables from "VariableSetupModel"
@ObservedObject var viewModel = VariableSetupModel()
//var viewModel = VariableSetupModel.shared
var body: some View {
HStack{
if viewModel.toggleListGraphs == "graph"{
Text("All Sends")
.font(.title)
.padding(.horizontal)
}else{
Text("All Climbs")
.font(.title)
.padding(.horizontal)
}
Spacer()
Button(action: {
viewModel.showSettingsModal = true
}) {
Image("logoIcon")
.renderingMode(.original)
.resizable()
.aspectRatio(contentMode: .fit)
.frame(width: 35, height: 35)
}.padding().foregroundColor(Color("whiteblack"))
}.sheet(isPresented: $viewModel.showSettingsModal, onDismiss: {
//print(viewModel.showSettingsModal)
}) {
SettingsView()
}
}
}
There are many ways to have the
viewModel
changes reflected in different Views, the following is an example, where the main idea is to have one source of truth that you use in all the different Views:declare
@StateObject var viewModel = VariableSetupModel()
inContentView
and@EnvironmentObject var viewModel: VariableSetupModel
inContentNavView
.Pass
viewModel
fromContentView
toContentNavView
using.environmentObject(viewModel)
, that is, add this toContentView
, eg:VStack (alignment: .leading) {...}.environmentObject(viewModel)
Note, there is no need for
VariableSetupModel
to be a singleton, remove thestatic let shared = VariableSetupModel()
.Note also, to have the
viewModel
available inSettingsView()
use,SettingsView().environmentObject(viewModel)
Another approach is to pass a
ObservedObject
from one view to another. For example:declare
@StateObject var viewModel = VariableSetupModel()
inContentView
and@ObservedObject var viewModel: VariableSetupModel
inContentNavView
.Pass
viewModel
fromContentView
toContentNavView
usingContentNavView(viewModel: viewModel)
.