复制、粘贴和剪切对话框不适用于flutter中的iOS

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return CupertinoContextMenu(
      child: Container(
        child: Text('Long press to show menu'),
      ),
      actions: <Widget>[
        CupertinoContextMenuAction(
          child: Text('Copy'),
          onPressed: () {
            // 复制操作
          },
        ),
        CupertinoContextMenuAction(
          child: Text('Paste'),
          onPressed: () {
            // 粘贴操作
          },
        ),
        CupertinoContextMenuAction(
          child: Text('Cut'),
          onPressed: () {
            // 剪切操作
          },
        ),
      ],
    );
  }
}