How to observe a TextField value with SwiftUI and Combine?

ios swiftui combine
Sorin Lica picture Sorin Lica · Jun 24, 2019 · Viewed 7.3k times · Source

I'm trying to execute an action every time a textField's value is changed.

@Published var value: String = ""

var body: some View {            
     $value.sink { (val) in
        print(val)
     }
     return TextField($value)       
}

But I get below error.

Cannot convert value of type 'Published' to expected argument type 'Binding'

Answer

valexa picture valexa · Sep 26, 2019

This should be a non-fragile way of doing it: 

class MyData: ObservableObject {
    var value: String = "" {
        willSet(newValue) {
            print(newValue)
        }
    }
}

struct ContentView: View {
    @ObservedObject var data = MyData()
    var body: some View {
        TextField("Input:", text: $data.value)
    }
}

Related questions

iOS Swift Combine: cancel a Set<AnyCancellable>

If I have stored a cancellable set into a ViewController: private var bag = Set<AnyCancellable>() Which contains multiple subscription. 1 - Should I cancel subscription in deinit? or it does the job automatically? 2 - If so, how can I …

Read More
What is PassthroughSubject & CurrentValueSubject

I happen to look into Apple's new Combine framework, where I see two things PassthroughSubject<String, Failure> CurrentValueSubject<String, Failure> Can someone explain to me what is meaning & use of them?

Read More
An equivalent to computed properties using @Published in Swift Combine?

In imperative Swift, it is common to use computed properties to provide convenient access to data without duplicating state. Let's say I have this class made for imperative MVC use: class ImperativeUserManager { private(set) var currentUser: User? { didSet { if oldValue != …

Read More