我需要在flutter中用勾号突出显示按钮，在FLUTTER中淡出其他两个按钮。

import 'package:flutter/material.dart';

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  double opacity1 = 1.0;
  double opacity2 = 1.0;
  double opacity3 = 1.0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Button Animation'),
      ),
      body: Center(
        child: Stack(
          children: [
            AnimatedOpacity(
              opacity: opacity1,
              duration: Duration(milliseconds: 500),
              child: MaterialButton(
                onPressed: () {
                  setState(() {
                    opacity1 = 1.0;
                    opacity2 = 0.5;
                    opacity3 = 0.5;
                  });
                },
                child: Icon(Icons.check),
              ),
            ),
            AnimatedOpacity(
              opacity: opacity2,
              duration: Duration(milliseconds: 500),
              child: MaterialButton(
                onPressed: () {
                  setState(() {
                    opacity1 = 0.5;
                    opacity2 = 1.0;
                    opacity3 = 0.5;
                  });
                },
                child: Text('Button 2'),
              ),
            ),
            AnimatedOpacity(
              opacity: opacity3,
              duration: Duration(milliseconds: 500),
              child: MaterialButton(
                onPressed: () {
                  setState(() {
                    opacity1 = 0.5;
                    opacity2 = 0.5;
                    opacity3 = 1.0;
                  });
                },
                child: Text('Button 3'),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

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