Coming from SwiftUI

In SwiftUI the body is computed and the view invalidates itself when @State changes. In CrossFly you build once and mutate. Read the philosophy first.

Translation table

Target difference

SwiftUI runs on Apple only. CrossFly is one Java codebase that runs on iOS and Android, Desktop and Web — the same screen code on all of them (see platforms).

Before / after — form

// SwiftUI
struct LoginView: View {
   @State private var email = ""
   var body: some View {
      VStack {
         TextField("E-mail", text: $email)
         Button("Entrar") { entrar(email) }
      }
   }
}

// CrossFly
public class LoginScreen extends Window {
   @Override public void onShow() throws Exception {
      super.onShow();
      setLayout(new VerticalLayout());
      TextField email = new TextField().caption("E-mail");
      add(LAY_AUTO, email);
      Button entrar = new Button("Entrar");
      entrar.onAction(c -> entrar(email.getText()));   // reads the value on submit (no $binding)
      add(LAY_AUTO, entrar);
   }
}

No $binding: you read getText() when you need it (e.g., in onAction); there is no automatic field↔variable binding (see Text fields).

See also

• Forms and input · Navigation