大多数小部件的启用和禁用功能是相同的。

前，按钮，开关，复选框等。

只需设置onPressed属性，如下所示

onPressed: null返回禁用小部件

onPressed:(){}或onPressed: _functionName返回启用的小部件

对于特定且数量有限的小部件，将它们包装在小部件IgnorePointer中正是这样做的:当它的忽略属性被设置为true时，子小部件(实际上是整个子树)是不可点击的。

IgnorePointer(
    ignoring: true, // or false
    child: RaisedButton(
        onPressed: _logInWithFacebook,
        child: Text("Facebook sign-in"),
        ),
),

否则，如果您打算禁用整个子树，请查看AbsorbPointer()。

简单的答案是onPressed: null给出一个禁用按钮。

如果你正在寻找一种快速的方法，而不关心让用户在一个按钮上点击多次。你也可以这样做:

// Constant whether button is clicked
bool isClicked = false;

然后在onPressed()函数中检查用户是否已经单击了按钮。

onPressed: () async {
    if (!isClicked) {
       isClicked = true;
       // await Your normal function
    } else {
       Toast.show(
          "You click already on this button", context,
          duration: Toast.LENGTH_LONG, gravity: Toast.BOTTOM);
    }
}

有两种方法:

1- https://stackoverflow.com/a/49354576/5499531

2-你可以使用MaterialStatesController:

final _statesController = MaterialStatesController();

然后将状态更改为:

_statesController.update(
   MaterialState.disabled,
   true, // or false depending on your logic
);

在你的按钮上

ElevatedButton(
    onPressed: _onPressed,
    statesController: _statesController,
    child: Text("Awesome"),
),

此外，你可以改变按钮的风格，当禁用: 在主题设置中:

....
elevatedButtonTheme: ElevatedButtonThemeData(
              style: ElevatedButton.styleFrom(
                backgroundColor: colors.primary500, // set your own color
                textStyle: button, // set your own style
                onPrimary: colors.onPrimary100, // set your own color
                enableFeedback: true,
                disabledBackgroundColor: colors.primary300, // set your own color
                disabledForegroundColor: colors.primary300, // set your own color
                disabledMouseCursor: SystemMouseCursors.forbidden, // when is disable the change the cursor type
              ),
            ),
...

这个答案是基于更新的按钮TextButton/ElevatedButton/OutlinedButton颤振2.x

不过，按钮是基于onPressed属性启用或禁用的。如果该属性为空，则按钮将被禁用。如果你将函数分配给onPressed，那么按钮将被启用。 在下面的代码片段中，我展示了如何启用/禁用按钮，并相应地更新它的样式。

这篇文章也说明了如何将不同的风格应用到新的 颤振2。x按钮。

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  bool textBtnswitchState = true;
  bool elevatedBtnSwitchState = true;
  bool outlinedBtnState = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: <Widget>[
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                TextButton(
                  child: Text('Text Button'),
                  onPressed: textBtnswitchState ? () {} : null,
                  style: ButtonStyle(
                    foregroundColor: MaterialStateProperty.resolveWith(
                      (states) {
                        if (states.contains(MaterialState.disabled)) {
                          return Colors.grey;
                        } else {
                          return Colors.red;
                        }
                      },
                    ),
                  ),
                ),
                Column(
                  children: [
                    Text('Change State'),
                    Switch(
                      value: textBtnswitchState,
                      onChanged: (newState) {
                        setState(() {
                          textBtnswitchState = !textBtnswitchState;
                        });
                      },
                    ),
                  ],
                )
              ],
            ),
            Divider(),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                ElevatedButton(
                  child: Text('Text Button'),
                  onPressed: elevatedBtnSwitchState ? () {} : null,
                  style: ButtonStyle(
                    foregroundColor: MaterialStateProperty.resolveWith(
                      (states) {
                        if (states.contains(MaterialState.disabled)) {
                          return Colors.grey;
                        } else {
                          return Colors.white;
                        }
                      },
                    ),
                  ),
                ),
                Column(
                  children: [
                    Text('Change State'),
                    Switch(
                      value: elevatedBtnSwitchState,
                      onChanged: (newState) {
                        setState(() {
                          elevatedBtnSwitchState = !elevatedBtnSwitchState;
                        });
                      },
                    ),
                  ],
                )
              ],
            ),
            Divider(),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                OutlinedButton(
                  child: Text('Outlined Button'),
                  onPressed: outlinedBtnState ? () {} : null,
                  style: ButtonStyle(
                      foregroundColor: MaterialStateProperty.resolveWith(
                    (states) {
                      if (states.contains(MaterialState.disabled)) {
                        return Colors.grey;
                      } else {
                        return Colors.red;
                      }
                    },
                  ), side: MaterialStateProperty.resolveWith((states) {
                    if (states.contains(MaterialState.disabled)) {
                      return BorderSide(color: Colors.grey);
                    } else {
                      return BorderSide(color: Colors.red);
                    }
                  })),
                ),
                Column(
                  children: [
                    Text('Change State'),
                    Switch(
                      value: outlinedBtnState,
                      onChanged: (newState) {
                        setState(() {
                          outlinedBtnState = !outlinedBtnState;
                        });
                      },
                    ),
                  ],
                )
              ],
            ),
          ],
        ),
      ),
    );
  }
}