How to make copyable Text Widget in Flutter?

When long tab on Text widget, a tooltip show up with 'copy'. When click on the 'copy' the text content should copy to system clipboard.

The following will copy the text on long tap, but does not show up 'copy', so user will not know, the content is copied to the clipboard.

class CopyableText extends StatelessWidget {
  final String data;
  final TextStyle style;
  final TextAlign textAlign;
  final TextDirection textDirection;
  final bool softWrap;
  final TextOverflow overflow;
  final double textScaleFactor;
  final int maxLines;
  CopyableText(
    this.data, {
    this.style,
    this.textAlign,
    this.textDirection,
    this.softWrap,
    this.overflow,
    this.textScaleFactor,
    this.maxLines,
  });
  @override
  Widget build(BuildContext context) {
    return new GestureDetector(
      child: new Text(data,
          style: style,
          textAlign: textAlign,
          textDirection: textDirection,
          softWrap: softWrap,
          overflow: overflow,
          textScaleFactor: textScaleFactor,
          maxLines: maxLines),
      onLongPress: () {
        Clipboard.setData(new ClipboardData(text: data));
      },
    );
  }
}

Since Flutter 1.9 you can use

SelectableText("Lorem ipsum...")

When text is selected the "Copy" context button will appear.

You can use a SnackBar to notify the user about the copy.

Here is a relevant code:

String _copy = "Copy Me";

  @override
  Widget build(BuildContext context) {
    final key = new GlobalKey<ScaffoldState>();
    return new Scaffold(
      key: key,
      appBar: new AppBar(
        title: new Text("Copy"),
        centerTitle: true,
      ),
      body:
      new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            new GestureDetector(
              child: new Text(_copy),
              onLongPress: () {
                Clipboard.setData(new ClipboardData(text: _copy));
                key.currentState.showSnackBar(
                    new SnackBar(content: new Text("Copied to Clipboard"),));
              },
            ),
            new TextField(
                decoration: new InputDecoration(hintText: "Paste Here")),
          ]),


    );
  }

EDIT

I was working on something and I did the followin, so I thought of revisiting this answer:

import "package:flutter/material.dart";
import 'package:flutter/services.dart';

void main() {
  runApp(new MaterialApp(home: new MyApp(),
  ));
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => new _MyAppState();
}

class _MyAppState extends State<MyApp> with TickerProviderStateMixin {
  String _copy = "Copy Me";

  @override
  Widget build(BuildContext context) {
    final key = new GlobalKey<ScaffoldState>();
    return new Scaffold(
      key: key,
      appBar: new AppBar(
        title: new Text("Copy"),
        centerTitle: true,
      ),
      body:
      new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            new GestureDetector(
              child: new CustomToolTip(text: "My Copyable Text"),
              onTap: () {

              },
            ),
            new TextField(
                decoration: new InputDecoration(hintText: "Paste Here")),
          ]),


    );
  }
}

class CustomToolTip extends StatelessWidget {

  String text;

  CustomToolTip({this.text});

  @override
  Widget build(BuildContext context) {
    return new GestureDetector(
      child: new Tooltip(preferBelow: false,
          message: "Copy", child: new Text(text)),
      onTap: () {
        Clipboard.setData(new ClipboardData(text: text));
      },
    );
  }
}

There is also list of properties it in SelectableText to enable option copy, paste, selectAll, cut

        child: Center(
            child: SelectableText('Hello Flutter Developer',
                cursorColor: Colors.red,
                showCursor: true,
                toolbarOptions: ToolbarOptions(
                copy: true,
                selectAll: true,
                cut: false,
                paste: false
                ),
                style: Theme.of(context).textTheme.body2)
            ),

SelectableText widget

        const SelectableText(
            this.data, {
            Key key,
            this.focusNode,
            this.style,
            this.strutStyle,
            this.textAlign,
            this.textDirection,
            this.showCursor = false,
            this.autofocus = false,
            ToolbarOptions toolbarOptions,
            this.maxLines,
            this.cursorWidth = 2.0,
            this.cursorRadius,
            this.cursorColor,
            this.dragStartBehavior = DragStartBehavior.start,
            this.enableInteractiveSelection = true,
            this.onTap,
            this.scrollPhysics,
            this.textWidthBasis,
        })

SelectableText(
  "Copy me",
  onTap: () {
    // you can show toast to the user, like "Copied"
  },
)

If you want to have different styling for text, use

SelectableText.rich(
  TextSpan(
    children: [
      TextSpan(text: "Copy me", style: TextStyle(color: Colors.red)),
      TextSpan(text: " and leave me"),
    ],
  ),
)

I use Clipboard.setData inside function.

...
child: RaisedButton(
    onPressed: (){
        Clipboard.setData(ClipboardData(text: "$textcopy"));
},
    disabledColor: Colors.blue[400],
    child: Text("Copy", style: TextStyle(color: Colors.white),),
),