com.unity.uiwidgets/Samples/UIWidgetSample/txt/TextFieldSample.cs

using Unity.UIWidgets.material;
using Unity.UIWidgets.painting;
using Unity.UIWidgets.ui;
using Unity.UIWidgets.widgets;
using UnityEngine;
using DialogUtils = Unity.UIWidgets.material.DialogUtils;

namespace UIWidgetsSample {
    public class TextFieldSample : UIWidgetsSamplePanel {
        protected override void Awake() {
            base.Awake();
            FontManager.instance.addFont(Resources.Load<Font>(path: "MaterialIcons-Regular"), "Material Icons");
        }

        protected override Widget createWidget() {
            return new MaterialApp(
                title: "Text Fields",
                home: new MyCustomForm()
            );
        }
    }

    class MyCustomForm : StatefulWidget {
        public override State createState() {
            return new _MyCustomFormState();
        }
    }

    class _MyCustomFormState : State<MyCustomForm> {
        readonly TextEditingController myController = new TextEditingController();

        public override void dispose() {
            this.myController.dispose();
            base.dispose();
        }

        public override Widget build(BuildContext context) {
            return new Scaffold(
                appBar: new AppBar(
                    title: new Text("Retrieve Text Input")
                ),
                body: new Padding(
                    padding: EdgeInsets.all(16.0f),
                    child: new TextField(controller: this.myController)
                ),
                floatingActionButton: new FloatingActionButton(
                    // When the user presses the button, show an alert dialog with the
                    // text the user has typed into our text field.
                    onPressed: () => {
                        DialogUtils.showDialog(
                            context: context,
                            builder: (_context) => {
                                return new AlertDialog(
                                    // Retrieve the text the user has typed in using our
                                    // TextEditingController
                                    content: new Text(this.myController.text)
                                );
                            });
                    },
                    tooltip: "Show me the value",
                    child: new Icon(Icons.search)
                )
            );
        }
    }
}