How to Implement Custom Fonts using Downloadable Google Fonts?

A step-by-step guide to implementing custom font by downloading (instead of manually copying) Google fonts and using them in your Jetpack Compose app.

Roboto is the default font used by Material 3. However, we often want to change it for our app. Instead of manually copying the font asset, you can now download the Google font asynchronously and use them in your Jetpack Compose app.

This is a quick guide to changing the default Roboto font to Arvo font.

1. Add the dependency

build.gradle.kts example

dependencies {
    /*...*/
    implementation("androidx.compose.ui:ui-text-google-fonts:1.3.2")
}

2. Copy font_cert.xml

Copy the font-cert.xml to your res\values folder.

3. Create Font Provider

In Type.kt, create the GoogleFont.Provider:

@OptIn(ExperimentalTextApi::class)
private val fontProvider = GoogleFont.Provider(
    providerAuthority = "com.google.android.gms.fonts",
    providerPackage = "com.google.android.gms",
    certificates = R.array.com_google_android_gms_fonts_certs
)

4. Create Google Font

Search the Google Font that you would like to use here. In this example, we're going to use Arvo font.

Not all fonts are supported, so you need to try them by yourself. If the font is not supported, it reverts to Roboto font.

In Type.kt, create the GoogleFont:

@OptIn(ExperimentalTextApi::class)
private val googleFont = GoogleFont("Arvo")

5. Create Font Family

In Type.kt, create the FontFamily:

@OptIn(ExperimentalTextApi::class)
private val fontFamily = FontFamily(
    Font(googleFont = googleFont, fontProvider = fontProvider)
)

6. Override the Typography

In Type.kt, overrides fontFamily in the Typography:

private val typography = Typography()
val Typography = Typography(
    displayLarge = typography.displayLarge.copy(fontFamily = fontFamily),
    displayMedium = typography.displayMedium.copy(fontFamily = fontFamily),
    displaySmall = typography.displaySmall.copy(fontFamily = fontFamily),

    headlineLarge = typography.headlineLarge.copy(fontFamily = fontFamily),
    headlineMedium = typography.headlineMedium.copy(fontFamily = fontFamily),
    headlineSmall = typography.headlineSmall.copy(fontFamily = fontFamily),

    titleLarge = typography.titleLarge.copy(fontFamily = fontFamily),
    titleMedium = typography.titleMedium.copy(fontFamily = fontFamily),
    titleSmall = typography.titleSmall.copy(fontFamily = fontFamily),

    bodyLarge = typography.bodyLarge.copy(fontFamily = fontFamily),
    bodyMedium = typography.bodyMedium.copy(fontFamily = fontFamily),
    bodySmall = typography.bodySmall.copy(fontFamily = fontFamily),

    labelLarge = typography.labelLarge.copy(fontFamily = fontFamily),
    labelMedium = typography.labelMedium.copy(fontFamily = fontFamily),
    labelSmall = typography.labelSmall.copy(fontFamily = fontFamily),
)

7. Use the New Typography

Make sure in your Theme.kt, the newly created Typography above is passed to the MaterialTheme(). Example:

@Composable
fun YourAppTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    useSystemUIController: Boolean = true,
    content: @Composable () -> Unit
) {
    /*...*/
    MaterialTheme(
        colorScheme = colorScheme,
        shapes = Shapes,
        typography = Typography,
        content = content,
    )
}

Reference

Downloadable fonts (from the official doc)

Example

GitHub Repository: YouTubeWorkouts

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Originally published at https://vtsen.hashnode.dev.