CODEWITHSUNDEEP
eventstriggersswiftui
Michael Boiman
Michael Boiman

Reputation: 41

SwiftUI how to get an event if @Published var changes

I use the library RKmanager to show a calendar with a dateRangePicker. But i can't get an event if the parameter rkManager.endDate is set from nil to a date.

I want activate and deactivate an addButton for the dateRange if a range is set.

The Object from i want to get the trigger if changes:

class RKManager : ObservableObject {
    @Published var startDate: Date! = nil
    @Published var endDate: Date! = nil

Now my View:

import SwiftUI

struct DateRangeView: View {

    @State var rkManager = RKManager(calendar: Calendar.current, minimumDate: Date(), maximumDate: Date().addingTimeInterval(60*60*24*365), mode: 1)

    @State private var addNewDateRangeIsDisabled: Bool = true


    var body: some View {
        VStack(alignment: .leading) {
            RKViewController(isPresented: .constant(false), rkManager: self.rkManager )


            Button(action: {
                if self.rkManager.endDate != nil
                    &&  self.rkManager.startDate != nil
                {
                    self.addNewDateRange()
                }
            }) {
                HStack {
                    Image(systemName: "plus.circle.fill")
                        .resizable()
                        .frame(width: 20, height: 20)
                    Text("Add new DateRange")
                }
            }
            .padding()

            .disabled(self.rkManager.endDate == nil) // --> here i want to change if the value changed
        }.navigationBarTitle("TestRoomName", displayMode: .inline)

    }

Upvotes: 0

Views: 1051

Answers (1)

Asperi
Asperi

Reputation: 257779

A ObservableObject should be represented in view by ObservedObject dynamic property wrapper so view would be updated on published property change.

Here is fix

struct DateRangeView: View {

    @ObservedObject var rkManager = RKManager(calendar: Calendar.current, minimumDate: Date(), maximumDate: Date().addingTimeInterval(60*60*24*365), mode: 1)

   // ... other code

Upvotes: 1

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