Flutter button new theme copyWith doesn't change color - flutter

Question

I've got a little piece of code below. It should show "add icon" with blue color. Instead it shows button with black color (as accentColor in MaterialApp).
Am I doing something wrong in "floatingActionButton"?
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
// TODO: implement build
final appName = "Custom Themes";
return new MaterialApp(
title: appName,
theme: new ThemeData(
brightness: Brightness.dark,
primaryColor: Colors.red[300],
accentColor: Colors.black,
),
home: new MyHomePage(
title: appName
),
);
}
}
class MyHomePage extends StatelessWidget {
final String title;
MyHomePage({Key key, #required this.title}) : super(key: key);
#override
Widget build(BuildContext context) {
// TODO: implement build
return new Scaffold(
appBar: AppBar(
title: new Text(title),
),
body: new Center(
child: new Container(
color: Theme.of(context).primaryColor,
child: new Text(
"Text with background color",
style: Theme.of(context).textTheme.title,
),
),
),
floatingActionButton: new Theme(
data: Theme.of(context).copyWith(accentColor: Colors.blue),
child: new FloatingActionButton(
onPressed: null,
child: new Icon(Icons.add),
),
)
);
}
}
I watched a tutorial (it is flutter in iOS) and everything works like a charm there.
Tut is from April 2019. Maybe there is something that changed from that time?

Answer 1

You can use
Theme.of(context).copyWith(
colorScheme:
Theme.of(context).colorScheme.copyWith(secondary: Colors.blue),
)
detail reference https://flutter.dev/docs/cookbook/design/themes#complete-example
full code
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
void main() {
runApp( MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
// TODO: implement build
final appName = "Custom Themes";
return MaterialApp(
title: appName,
theme: ThemeData(
brightness: Brightness.dark,
primaryColor: Colors.red[300],
accentColor: Colors.black,
),
home: MyHomePage(
title: appName
),
);
}
}
class MyHomePage extends StatelessWidget {
final String title;
MyHomePage({Key key, #required this.title}) : super(key: key);
#override
Widget build(BuildContext context) {
// TODO: implement build
return Scaffold(
appBar: AppBar(
title: Text(title),
),
body: Center(
child: Container(
color: Theme.of(context).primaryColor,
child: Text(
"Text with background color",
style: Theme.of(context).textTheme.title,
),
),
),
floatingActionButton: Theme(
data: Theme.of(context).copyWith(
colorScheme:
Theme.of(context).colorScheme.copyWith(secondary: Colors.blue),
),
child: FloatingActionButton(
onPressed: null,
child: Icon(Icons.add),
),
)
);
}
}