擷取文字欄位的值

在本食譜中，學習如何透過以下步驟來擷取使用者在文字欄位中輸入的文字：

1. 建立一個 TextEditingController。
2. 將 TextEditingController 提供給 TextField。
3. 顯示文字欄位的目前值。

若要擷取使用者在文字欄位中輸入的文字，請建立一個 TextEditingController 並將其提供給 TextField 或 TextFormField。

// Define a custom Form widget.
class MyCustomForm extends StatefulWidget {
  const MyCustomForm({super.key});

  @override
  State<MyCustomForm> createState() => _MyCustomFormState();
}

// Define a corresponding State class.
// This class holds the 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 dispose() {
    // Clean up the controller when the widget is disposed.
    myController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    // Fill this out in the next step.
  }
}

現在您已經有了 TextEditingController，使用 controller 屬性將它連接到文字欄位

return TextField(
  controller: myController,
);

將 TextEditingController 提供給文字欄位後，開始讀取值。使用 TextEditingController 提供的 text() 方法來擷取使用者在文字欄位中輸入的字串。

當使用者點擊浮動操作按鈕時，以下程式碼會顯示一個快顯對話方塊，其中包含文字欄位的目前值。

FloatingActionButton(
  // When the user presses the button, show an alert dialog containing
  // the text that the user has entered into the text field.
  onPressed: () {
    showDialog(
      context: context,
      builder: (context) {
        return AlertDialog(
          // Retrieve the text that the user has entered by using the
          // TextEditingController.
          content: Text(myController.text),
        );
      },
    );
  },
  tooltip: 'Show me the value!',
  child: const Icon(Icons.text_fields),
),

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

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

// Define a custom Form widget.
class MyCustomForm extends StatefulWidget {
  const MyCustomForm({super.key});

  @override
  State<MyCustomForm> createState() => _MyCustomFormState();
}

// Define a corresponding State class.
// This class holds the 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 dispose() {
    // Clean up the controller when the widget is disposed.
    myController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Retrieve Text Input'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16),
        child: TextField(
          controller: myController,
        ),
      ),
      floatingActionButton: FloatingActionButton(
        // When the user presses the button, show an alert dialog containing
        // the text that the user has entered into the text field.
        onPressed: () {
          showDialog(
            context: context,
            builder: (context) {
              return AlertDialog(
                // Retrieve the text the that user has entered by using the
                // TextEditingController.
                content: Text(myController.text),
              );
            },
          );
        },
        tooltip: 'Show me the value!',
        child: const Icon(Icons.text_fields),
      ),
    );
  }
}

除非另有說明，否則本網站上的文件反映的是 Flutter 的最新穩定版本。頁面最後更新於 2024-06-26。 檢視原始碼 或 回報問題。