[Flutter][Simple app] hosts management GUI

ip_detail.dart

import 'package:flutter/material.dart';

class IpDetail extends StatelessWidget {
  final String ipAddr;
  final List<String> ipDomains;

  IpDetail(this.ipAddr, this.ipDomains);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('IP Detail: ${this.ipAddr}'),
      ),
      body: Container(
        child: ListView.builder(
          itemCount: this.ipDomains.length ?? 0,
          itemBuilder: (BuildContext context, idx) {
            return Card(
              child: ListTile(
                title: Text(this.ipDomains[idx]),
              ),
            );
          },
        ),
      )
    );
  }
}

main.dart

import 'dart:io';

import 'package:example_flutter/ip_detail.dart';
import 'package:flutter/foundation.dart' show debugDefaultTargetPlatformOverride;
import 'package:flutter/material.dart';

void main() async {
  debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;

  runApp(HostsGUI());
}

class HostsGUI extends StatefulWidget {
  @override
  HostsGUIState createState() => HostsGUIState();
}

class HostsGUIState extends State<HostsGUI> {
  List<String> hostsLines = [];
  List<String> hostsIPs = [];
  Map<String, List<String>> ipDomainMap = {};

  getHostsContent() async {
    try {
      File file = File('/etc/hosts');
      String fileContent = await file.readAsString();

      fileContent.split('\n').forEach((line) {
        line = line.trim();
        RegExp commentLineRegExp = RegExp(r'^\#.+$');

        if (!commentLineRegExp.hasMatch(line) && line != r'\n' && line != null && line != '') {
          hostsLines.add(line.replaceAll(r'\s+', ' ').trim());
        }
      });

      hostsLines.forEach((hostsLine) {
        List<String> hostInfo = hostsLine.split(' ');
        String ipAddr = hostInfo?.first;
        var domainObj = ipDomainMap[ipAddr] ?? [];

        hostInfo?.skip(1)?.forEach((domain) {
          domainObj.add(domain);
        });

        ipDomainMap[ipAddr] = domainObj;
        hostsIPs.add(hostInfo?.first);
      });

      setState(() {
        hostsIPs = hostsIPs.toSet().toList();
        ipDomainMap = ipDomainMap;
      });
    } on Exception catch (e) {
      print(e);
    }
  }

  @override
  void initState() {
    super.initState();
    getHostsContent();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'hosts Management GUI',
      home: Scaffold(
        appBar: AppBar(
          title: Text('IP Addresses'),
          actions: <Widget>[
            FlatButton(
              child: Icon(Icons.save),
            ),
            FlatButton(
              child: Icon(Icons.exit_to_app),
            )
          ],
        ),
        body: Container(
          child: ListView.builder(
            itemCount: hostsIPs.length,
            itemBuilder: (BuildContext context, int index) {
              String ipAddr = hostsIPs[index];
              List<String> ipDomains = ipDomainMap[ipAddr];

              return Card(
                child: ListTile(
                  title: Text(ipAddr),
                  trailing: Icon(Icons.chevron_right),
                  onTap: () {
                    Navigator.push(
                      context,
                      MaterialPageRoute(builder: (context) => IpDetail(ipAddr, ipDomains))
                    );
                  },
                ),
              );
            },
          ),
        ),
      ),
    );
  }
}