15 Flutter: Changing icon color onfocus

main.dart
import 'package:flutter/material.dart';
import 'package:meta/meta.dart';
void main() {
runApp(new MaterialApp(
home: new MyApp()
));
}
class MyApp extends StatelessWidget {
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Custom Bottom Nav',
home: new Scaffold(
appBar: new AppBar(title: new Text('Custom Bottom Nav')),
body: new Container(),
bottomNavigationBar: new BottomNav(
navCallback: (i) => print("Navigating to $i"),
),
),
);
}
}
class BottomNav extends StatefulWidget {
final int initialIndex;
final ValueChanged<int> navCallback;
BottomNav({ this.navCallback, this.initialIndex: 0});
_BottomNavState createState() => new _BottomNavState();
}
class _BottomNavState extends State<BottomNav> {
int _selected;
void initState() {
super.initState();
_selected = widget.initialIndex;
notifyCallback();
}
Widget build(BuildContext context) {
return new Material(
color: Colors.white,
elevation: 8.0,
child: new Container(
height: 56.0,
child: new Row(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
_buildButton(0, Icons.home, "Home"),
_buildButton(1, Icons.book, "Bookmarks"),
_buildButton(2, Icons.video_library, "Videos"),
],
),
),
);
}
Widget _buildButton(int index, IconData data, String tooltip) {
return new Flexible(
flex: 1,
child: new Tooltip(
message: tooltip,
child: new InkWell(
onTap: () => onButtonTap(index),
child: new Center(
child: new Icon(data,
color: _selected == index ? Colors.red : Colors.grey,
),
),
),
),
);
}
onButtonTap(int index) {
setState(() {
_selected = index;
});
notifyCallback();
}
notifyCallback() {
widget.navCallback(_selected);
}
}