UITextField text change event

Question

How can I detect any text changes in a textField? The delegate method shouldChangeCharactersInRange works for something, but it did not fulfill my need exactly.

Answer 1

SwiftUI

If you are using the native SwiftUI TextField or just using the UIKit UITextField (here is how), you can observe for text changes like:

SwiftUI 2.0

From iOS 14, macOS 11, or any other OS contains SwiftUI 2.0, there is a new modifier called .onChange that detects any change of the given state:

struct ContentView: View {
    @State var text: String = ""

    var body: some View {
        TextField("Enter text here", text: $text)
            .onChange(of: text) {
                print($0) // You can do anything due to the change here.
                // self.autocomplete($0) // like this
            }
    }
}

SwiftUI 1.0

For older iOS and other SwiftUI 1.0 platforms, you can use onReceive with the help of the combine framework:

import Combine

.onReceive(Just(text)) { 
    print($0)
}

_{Note that you can use text.publisher instead of Just(text) but it returns the change instead of the entire value.}