primarySwatch not working in flutter in android

Solution:

The issue is that primarySwatch expects a MaterialColor, but Colors.yellow is just a Color. To fix this, you need to create a custom MaterialColor. Here’s how you can do it:

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: HomePage(),
      theme: ThemeData(
        primarySwatch: createMaterialColor(Color(0xFFFFEB3B)), // Custom yellow color
      ),
    );
  }
}

MaterialColor createMaterialColor(Color color) {
  List strengths = <double>[.05];
  final swatch = <int, Color>{};
  final int r = color.red, g = color.green, b = color.blue;

  for (int i = 1; i < 10; i++) {
    strengths.add(0.1 * i);
  }
  for (var strength in strengths) {
    final double ds = 0.5 - strength;
    swatch[(strength * 1000).round()] = Color.fromRGBO(
      r + ((ds < 0 ? r : (255 - r)) * ds).round(),
      g + ((ds < 0 ? g : (255 - g)) * ds).round(),
      b + ((ds < 0 ? b : (255 - b)) * ds).round(),
      1,
    );
  }
  return MaterialColor(color.value, swatch);
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('To-Do List'),
      ),
      body: Center(
        child: Text('Hello World'),
      ),
    );
  }
}

Alternatively, if you don’t need a custom color and can use a predefined material swatch, you can do this:

theme: ThemeData(
  primarySwatch: Colors.amber, // Predefined swatch
),

This should resolve the issue and apply the correct color to your app.

Tags: [flutter] [dart] [flutter-layout] [flutter-theme]