Creating Custom Color Palettes in Jetpack Compose

Jetpack Compose has revolutionized Android development by introducing a modern, declarative approach to UI design. One of its standout features is the ability to seamlessly integrate Material Design principles, including support for dynamic theming. Among these, managing and customizing color palettes is a vital aspect of creating visually appealing and brand-consistent apps.

In this blog post, we’ll explore how to create custom color palettes in Jetpack Compose, diving into advanced concepts, best practices, and practical implementation tips for experienced Android developers.

Understanding the Role of Colors in Jetpack Compose

Colors in Jetpack Compose are an integral part of Material Design. They not only define the visual appeal but also impact user experience, accessibility, and app branding. Jetpack Compose leverages the Color class and MaterialTheme to manage colors efficiently. Here’s how colors are structured:

  1. Primary Colors: Used prominently in the app’s interface, such as the app bar and buttons.

  2. Secondary Colors: Highlight additional components like switches, sliders, or floating action buttons.

  3. Background and Surface Colors: Applied to app backgrounds and containers, ensuring contrast and readability.

  4. On Colors: Define the colors used on top of primary, secondary, background, or surface colors (e.g., text and icons).

Jetpack Compose allows developers to create custom themes with tailored color palettes that align with the app’s design language.

Setting Up a Custom Color Palette

To define a custom color palette in Jetpack Compose, follow these steps:

1. Define Your Colors

Start by creating a Color.kt file to centralize your color definitions. Use the Color class to define colors using ARGB hex codes.

import androidx.compose.ui.graphics.Color

val PrimaryColor = Color(0xFF6200EE)
val PrimaryVariant = Color(0xFF3700B3)
val SecondaryColor = Color(0xFF03DAC6)
val BackgroundColor = Color(0xFFFFFFFF)
val SurfaceColor = Color(0xFFFFFFFF)
val ErrorColor = Color(0xFFB00020)

val OnPrimaryColor = Color(0xFFFFFFFF)
val OnSecondaryColor = Color(0xFF000000)
val OnBackgroundColor = Color(0xFF000000)
val OnSurfaceColor = Color(0xFF000000)

2. Create a Custom Color Scheme

Jetpack Compose uses lightColorScheme and darkColorScheme to define palettes for light and dark themes.

import androidx.compose.material3.ColorScheme
import androidx.compose.material3.darkColorScheme
import androidx.compose.material3.lightColorScheme

val LightColorScheme = lightColorScheme(
    primary = PrimaryColor,
    onPrimary = OnPrimaryColor,
    primaryContainer = PrimaryVariant,
    secondary = SecondaryColor,
    onSecondary = OnSecondaryColor,
    background = BackgroundColor,
    onBackground = OnBackgroundColor,
    surface = SurfaceColor,
    onSurface = OnSurfaceColor,
    error = ErrorColor
)

val DarkColorScheme = darkColorScheme(
    primary = PrimaryColor,
    onPrimary = OnPrimaryColor,
    primaryContainer = PrimaryVariant,
    secondary = SecondaryColor,
    onSecondary = OnSecondaryColor,
    background = Color(0xFF121212),
    onBackground = OnBackgroundColor,
    surface = Color(0xFF121212),
    onSurface = OnSurfaceColor,
    error = ErrorColor
)

Applying the Custom Theme

Once your color schemes are defined, integrate them into your app’s theme by customizing the MaterialTheme.

1. Create a Theme.kt File

This file manages the app’s dynamic theme switching based on system settings or user preferences.

import androidx.compose.material3.MaterialTheme
import androidx.compose.runtime.Composable
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.platform.LocalConfiguration

@Composable
fun MyAppTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    content: @Composable () -> Unit
) {
    val colorScheme = if (darkTheme) DarkColorScheme else LightColorScheme

    MaterialTheme(
        colorScheme = colorScheme,
        typography = Typography,
        shapes = Shapes,
        content = content
    )
}

2. Apply the Theme Globally

Wrap the MyAppTheme composable around your app’s main content to ensure a consistent look and feel.

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            MyAppTheme {
                // Main content goes here
                MainScreen()
            }
        }
    }
}

Advanced Use Cases

1. Dynamic Color Palettes

With Android 12 and Material You, you can generate dynamic color palettes based on the user’s wallpaper. This feature enhances personalization and is supported by the dynamicColorScheme function.

import androidx.compose.material3.dynamicDarkColorScheme
import androidx.compose.material3.dynamicLightColorScheme
import androidx.compose.ui.platform.LocalContext

@Composable
fun MyAppTheme(
    useDynamicColors: Boolean = true,
    content: @Composable () -> Unit
) {
    val context = LocalContext.current
    val colorScheme = when {
        useDynamicColors && isSystemInDarkTheme() -> dynamicDarkColorScheme(context)
        useDynamicColors -> dynamicLightColorScheme(context)
        isSystemInDarkTheme() -> DarkColorScheme
        else -> LightColorScheme
    }

    MaterialTheme(
        colorScheme = colorScheme,
        typography = Typography,
        shapes = Shapes,
        content = content
    )
}

2. Accessibility Considerations

When designing custom palettes, ensure sufficient contrast ratios for text and UI elements. Tools like Google’s Material Theme Builder can help fine-tune color choices.

3. Runtime Theme Switching

Allow users to toggle between light and dark themes within the app. Combine rememberSaveable and mutableStateOf for a stateful implementation.

import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.rememberSaveable

@Composable
fun ThemeSwitcher(content: @Composable () -> Unit) {
    val isDarkTheme = rememberSaveable { mutableStateOf(false) }

    MyAppTheme(darkTheme = isDarkTheme.value) {
        // Include a toggle button to switch themes
        content()
    }
}

Best Practices for Custom Color Palettes

  1. Consistency: Maintain consistent primary and secondary colors across screens to enhance brand identity.

  2. Contrast: Ensure text and UI elements have sufficient contrast for readability and accessibility.

  3. Testing: Test your color palette on real devices under various lighting conditions to identify potential issues.

  4. Dynamic Theming: Leverage dynamic colors for apps targeting Android 12+ to enhance personalization.

  5. Performance: Avoid overloading composables with unnecessary color calculations to maintain UI performance.

Conclusion

Custom color palettes in Jetpack Compose provide endless possibilities for creating unique and visually stunning Android apps. By leveraging the flexibility of MaterialTheme and adhering to best practices, you can build an app that stands out while delivering a consistent and accessible user experience.

Start experimenting with custom themes today, and watch your app’s design elevate to the next level!