如何为文本字段提供初始值？

Question

我想为文本字段提供一个初始值，并用空值重新绘制它以清除文本。使用Flutter的API执行此操作的最佳方法是什么？

Answer 1

您不必在小部件作用域中定义单独的变量，只需以内联方式执行此操作：

TextField(
  controller: TextEditingController()..text = 'Your initial value',
  onChanged: (text) => {},
)

Answer 2

(来自邮件列表。这个答案不是我想出来的。)

class _FooState extends State<Foo> {
  TextEditingController _controller;

  @override
  void initState() {
    super.initState();
    _controller = new TextEditingController(text: 'Initial value');
  }

  @override
  Widget build(BuildContext context) {
    return new Column(
      children: <Widget>[
        new TextField(
          // The TextField is first built, the controller has some initial text,
          // which the TextField shows. As the user edits, the text property of
          // the controller is updated.
          controller: _controller,
        ),
        new RaisedButton(
          onPressed: () {
            // You can also use the controller to manipuate what is shown in the
            // text field. For example, the clear() method removes all the text
            // from the text field.
            _controller.clear();
          },
          child: new Text('CLEAR'),
        ),
      ],
    );
  }
}

Answer 3

您可以使用＜code＞TextFormField，并使用＜code>initialValue

TextFormField(initialValue: "I am smart")