dependencies:
  clipboard_watcher: ^0.2.0

class HomePage extends StatefulWidget {
  const HomePage({Key? key}) : super(key: key);

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

class _HomePageState extends State<HomePage> with ClipboardListener {
  @override
  void initState() {
    clipboardWatcher.addListener(this);
    // start watch
    clipboardWatcher.start();
    super.initState();
  }

  @override
  void dispose() {
    clipboardWatcher.removeListener(this);
    // stop watch
    clipboardWatcher.stop();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    // ...
  }

  @override
  void onClipboardChanged() async {
    ClipboardData? newClipboardData = await Clipboard.getData(Clipboard.kTextPlain);
    print(newClipboardData?.text ?? "");
  }
}