When starting a new Flutter project, one of the most crucial steps is defining the theme. A well-thought-out theme lays the foundation for a consistent, scalable, and visually appealing user interface. For my app, MealTime, I began by setting up the theme system, which includes spacing, color palettes, and typography.

When starting a new Flutter project, one of the most crucial steps is defining the theme. A well-thought-out theme lays the foundation for a consistent, scalable, and visually appealing user interface. For my app, MealTime, I began by setting up the theme system, which includes spacing, color palettes, and typography.

This article dives into the technical setup and the reasoning behind the decisions, showcasing how these foundational elements set the stage for the rest of the app.

Why Theming Matters

Theming is more than just choosing colors and fonts — it’s about creating a unified design language that:

• Enhances scalability: Makes it easier to maintain and update styles.
• Improves developer efficiency: Allows for quick and consistent styling across components.
• Boosts user experience: Delivers a polished and professional look.

1️⃣ AppSpacing: Consistent Layouts

Spacing defines the structure of your app’s layout. To centralize spacing values for padding, margins, and radii, I created the AppSpacingclass.

class AppSpacing {
  AppSpacing._(); // Prevent instantiation

  // Spacing
  static const double s8 = 8.0; 
  static const double s16 = 16.0;
  static const double s24 = 24.0;

  // Radius
  static const double r8 = 8.0; 
  static const double r16 = 16.0;
}

Why it’s Useful?

By defining these constants, I can maintain a consistent layout style across the app. If a spacing value needs adjustment, I update it in one place, and it reflects throughout the app.

2️⃣ AppPalette: Branding with Colors

The color palette is a key part of branding. For MealTime, I created a centralized AppPalette class to manage all colors, including swatches for primary, secondary, and neutral tones.

Here’s how the primary swatch looks:

class AppPalette {
  AppPalette._();
  
  static const MaterialColor primarySwatch = MaterialColor(
  0xFFF58700, // Base color
  <int, Color>{
    100: Color(0xFFFFE4C2),
    500: Color(0xFFF58700), // Primary shade
    900: Color(0xFF291600),
    // ...
  },
 );
  
// ..
}

Highlight Features

• Primary Swatch: A vibrant orange to represent MealTime’s identity.
• Secondary Swatch: A calming green for secondary actions.
• Grey Swatch: Neutral tones for text and backgrounds.

This setup allows for a consistent and cohesive color scheme, simplifying styling throughout the app.

3️⃣ AppTypography: Unified Text Styles

Typography plays a significant role in the user experience. For MealTime, I centralized text styles in the AppTypographyclass using the DM Sans font.

class AppTypography {
  AppTypography._();

  static const String familyDMSans = 'DM Sans';

  // Font Size
  static const double h1Bold = 64.0; // Main heading
  static const double b2Regular = 16.0; // Regular body text

  // Font Weight
  static const FontWeight w500 = FontWeight.w500; // Medium
}

Why This Matters?

Defining fonts in one place ensures that headings, body text, and labels maintain a consistent appearance throughout the app.

Benefits of This Setup

1. Scalability: Add or update styles easily without hunting through multiple files.
2. Consistency: Uniform design language across screens and components.
3. Maintainability: Adjustments are simple, even in large projects.

Next Steps

With the theme setup complete, the next step is integrating it into components and implementing the first screens of MealTime. This is where the app will start to come to life!

Join the Journey!

If you’re interested in the code, check out the repository:
👉 GitHub: MealTime

👉 Figma Design: MealTime

Follow my journey as I document the development process, share insights, and explore best practices in Flutter app development.

Thank you for reading! If you have tips or suggestions for improving theming in Flutter, drop them in the comments below — I’d love to learn from you!