Flutter ThemeData Primary color not changing from theme when trying to add a primary color

Question

Im following the BMI Calculator app from the London App Brewery on LinkedIn Learning. when attempting to set the primaryColor to red, my emulator still shows the Light Blue default AppBar even though i am overriding the Primary Color. here's the code

    import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primaryColor: Colors.red,
      ),
      home: const InputPage(),
    );
  }
}

class InputPage extends StatefulWidget {
  const InputPage({Key? key}) : super(key: key);

  @override
  _InputPageState createState() => _InputPageState();
}

class _InputPageState extends State<InputPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('BMI CALCULATOR'),
      ),
      body: const Center(
        child: Text('Body Text'),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {},
        child: const Icon(Icons.add),
      ),
    );
  }
}

Solution 1

Use primarySwatch

theme: ThemeData(
    primarySwatch: Colors.red,
  ),

Solution 2

I am also attending same training from LondonAppBrewery. This code fixed the problem.

Widget build(BuildContext context) {
return MaterialApp(
  title: "BMI Calculator",
  debugShowCheckedModeBanner: false,
  theme: ThemeData.dark().copyWith(
    appBarTheme:AppBarTheme(
      backgroundColor: Color(0xff0a0e21),
    ),
    scaffoldBackgroundColor: Color(0xff0a0e21),
  ),
  home: InputPage(),
);

Solution 3

This issue has been pointed at flutter github page. They say

We will eventually be moving all components away from ThemeData.primaryColor

So you can use

 theme: ThemeData(
     colorScheme: ColorScheme.light().copyWith(primary: Colors.red),
 );

Solution 4

Using the following approach you can have full control over the individual properties in Themedata

class BMICalculator extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primarySwatch: Colors.pink,
        appBarTheme: AppBarTheme(
          backgroundColor: Colors.orangeAccent,
        ),
      ),
      home: InputPage(),
    );
  }
}

Solution 5

I'm undergoing the same training program. As Mohtashim mentioned above, I tried to tweak the background app theme code and it worked as expected.

theme: ThemeData(
  primarySwatch: Colors.pink,
  appBarTheme: AppBarTheme(
    backgroundColor: Color(0xFF101427), //use your hex code here
  ),
)

View more solutions

Comments

[F Perroch]

Your code is still good ! You may pay attention on reinstalling your app or check if hot reload is working

[skr]

How would you use a hex color?

[programmer]

check out this article on dev dev.to/rohanjsh/…

[Jeremy Caney]

Welcome to Stack Overflow, and thank you for contributing an answer. Would you kindly edit your answer to to include an explanation of your code? That will help future readers better understand what is going on, and especially those members of the community who are new to the language and struggling to understand the concepts. That's especially important when there's already four other answers that have been submitted. Under what conditions might your approach be preferred? Are you taking advantage of different capabilities? E.g., why do you prefer colorScheme over primarySwatch?

[ali masarra]

thanks bro, same here following her course