如何在Flutter的TextFromField上使用按键事件？

Question

有什么方法可以在文本字段中捕获按键？在我的情况下，当用户在文本字段内按Enter键时，将存储值。为此，我需要像Kotlin + Android一样使用Keypress-event。由于它有趣且跨平台，所以我本周才开始尝试颤动。

Answer 1

有两种方法可以执行1）。使用像这样的TextField小部件随附的onChanged方法，

TextField(
  onChanged: (text) {
    print("First text field: $text");
  },
);

2）。使用TextEditingController

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Retrieve Text Input',
      home: MyCustomForm(),
    );
  }
}

// Define a custom Form widget.
class MyCustomForm extends StatefulWidget {
  @override
  _MyCustomFormState createState() => _MyCustomFormState();
}

// Define a corresponding State class.
// This class holds data related to the Form.
class _MyCustomFormState extends State<MyCustomForm> {
  // Create a text controller and use it to retrieve the current value
  // of the TextField.
  final myController = TextEditingController();

  @override
  void initState() {
    super.initState();

    myController.addListener(_printLatestValue);
  }

  @override
  void dispose() {
    // Clean up the controller when the widget is removed from the widget tree.
    // This also removes the _printLatestValue listener.
    myController.dispose();
    super.dispose();
  }

  _printLatestValue() {
    print("Second text field: ${myController.text}");
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Retrieve Text Input'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: <Widget>[
            TextField(
              onChanged: (text) {
                print("First text field: $text");
              },
            ),
            TextField(
              controller: myController,
            ),
          ],
        ),
      ),
    );
  }
}

示例取自https://flutter.dev/docs/cookbook/forms/text-field-changes