Flutter Theme Changing dark to light using onpress event - flutter

Question

I am working with flutter projects
and I want to change the themecolor using an onpressed event
I tried some code but not working.
main.dart file
import 'package:flutter/material.dart';
import 'Screens/HomePage.dart';
void main()=> runApp(MyApp());
ThemeData _lightTheme = ThemeData(
brightness: Brightness.light,
primaryColor: Colors.white,
);
ThemeData _darkTheme = ThemeData(
brightness: Brightness.light,
primaryColor: Colors.white,
);
bool _ktheme = true;
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Wallbay',
theme: _ktheme ? _lightTheme : _darkTheme,
home: MyHomePage('Alpha Papers'),
);
}
}
HomePage.dart file
........
IconButton(
icon: Icon(Icons.brightness_medium_outlined),
onPressed: () {
setState(() {
_ktheme = !ktheme;
});
},
)
......

Answer 1

Your theme objects _lightTheme & _darkTheme are the same objects with different names.
They both have brightness set to Brightness.light & primaryColor as Colors.white.
ThemeData _lightTheme = ThemeData(
brightness: Brightness.light, // <----
primaryColor: Colors.white, // <----
);
ThemeData _darkTheme = ThemeData(
brightness: Brightness.light, // <--- Dark mode having light brightness
primaryColor: Colors.white, // <---- Dark mode having white color
);
Change these to the following:
ThemeData _lightTheme = ThemeData(
brightness: Brightness.light, // light mode
primaryColor: Colors.white,
);
ThemeData _darkTheme = ThemeData(
brightness: Brightness.dark, // dark mode
primaryColor: Colors.black,
);
Also, your onPressed code looks wrong.
setState(() {
_ktheme = !_ktheme; // Notice: I renamed ktheme to _ktheme
});