GestureDetector小部件可能是您需要的。它具有用于点按和长按的回调：https://api.flutter.dev/flutter/widgets/GestureDetector-class.html

您还可以使用InkWell小部件，它具有同时用于onTap和onLongPress的API。

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.light(),home: Scaffold(
        body: Center(
          child: InkWell(
            onTap: () => _takePicture(),onLongPress: () => _takeVideo(),child: Text('Click me'),),);
  }

  void _takePicture() => print('Taking a picture!');

  void _takeVideo() => print('Taking a video!');
}

这是flutter.dev教程，介绍如何使用相机API。 https://flutter.dev/docs/cookbook/plugins/picture-using-camera

您可以使用OutlineButton类，它具有按下和onLongPress方法。

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: OutlineButton(
            onTap: () => takePicture(),onLongPress: () => takeVideo(),);
  }
}