How to use EnvironmentObject to initialize State Property in SwiftUI?

Question

I am having a small Issue with initializing a State with Data from an EnvironmentObject.

@EnvironmentObject var settings: Settings
    
@State var localAllowReminders: Bool
    
init() {
    self._localAllowReminders = State(initialValue: settings.allowReminders)
}

Obviously, I get the following Error Message: 'self' used before all stored properties are initialized.

Question: How can I initialize a State with Data out of a EnvironmentObject?

Thanks for your help.

You're best off not using @EnvironmentObject but rather injecting Settings properly and storing it as @ObservedObject. — David Pasztor
– David Pasztor, Commented Jan 15, 2021 at 16:22

Asperi · Accepted Answer · 2021-01-15 16:04:02Z

11

EnvironmentObject is injected after view constructor call, so you have to initialize state to some default and reset it to desired value in top body view onAppear modifier, like

@EnvironmentObject var settings: Settings
@State var localAllowReminders: Bool = false   // << just any default
    
var body: some View {
    VStack {       // << any top view
        // ...
    }
    .onAppear {
       self.localAllowReminders = settings.allowReminders   // << here !!
    }
}

answered Jan 15, 2021 at 16:04

Asperi

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2 Comments

onthemoon Over a year ago

May I know how do you know that EnvironmentObject is injected after view constructor call?

Ildar Zaripov Over a year ago

@onthemoon, I am getting error No ObservableObject of type "" found when I am trying to get access to environment object from .onAppear method

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