Subscribing to changes to @Published

问题

I am trying to bind the value of query to a search box sitting in a SwiftUI view.

class DataSet: ObservedObject {

... 

@Published var query: String = ""

init() {
    let sub = AnySubscriber<String, Never>(
        receiveSubscription: nil,
        receiveValue: { query in
            print(query)
            return .unlimited
        })
    self.$query.subscribe(sub)
}

...
}

When the user changes the value of the query I'd like to filter some other property in my ObservedObject. Yet I cannot find anywhere in the documentation how do I subscribe to changes to query property.

回答1:

I would use the following approach

class DataSet: ObservableObject {

    @Published var query: String = ""

    private var subscribers = Set<AnyCancellable>()
    init() {
        self.$query
            .sink { newQuery in
                    // do something here with newQuery
            }
            .store(in: &subscribers)
    }
}

来源：https://stackoverflow.com/questions/59573754/subscribing-to-changes-to-published