Android apps rarely let users pick their own fonts. It's difficult to implement, and most developers skip it. Fontize, a new open-source library, aims to change that.
The project emerged after JekyllEx—a mobile blogging tool—received feedback from a user dealing with headaches triggered by fonts that didn't suit their eyes. The developer discovered that Android's official accessibility guidelines don't address font customization at all, leaving a gap that affects readers with various needs.
The accessibility gap
Android's accessibility guidelines emphasize supporting users with different abilities, yet font customization remains unaddressed. Users who need specific typefaces for readability often have no recourse beyond avoiding certain apps entirely.
Most existing workarounds iterate through view hierarchies, applying fonts to each text element individually. This breaks down fast for apps using list components, where a single row might contain multiple text fields. Updating hundreds of views manually creates performance problems and code that's hard to maintain.
How Fontize works
The library stores the selected font's resource identifier in SharedPreferences. When a screen loads, Fontize retrieves this value and applies it to supported text views automatically.
SharedPreferences suits this use case well. Values are cached in memory, so repeated reads don't hit the disk, and the approach works across Android versions without requiring runtime theme modifications. Theme-level changes demand higher API levels and would cut off users on older devices.
Setting a default font requires a single call in your launcher activity. The library then handles propagation to all screens that use its custom text view component. When users change fonts later, Fontize updates the stored identifier and applies the new choice to subsequent screens.
Who should care
Fontize matters most for apps where users spend significant time reading. E-readers, note-taking tools, news readers, and blog managers like JekyllEx fall into this category. For quick utility apps—calorie counters, timers, flashlights—the implementation overhead likely outweighs the benefit.
Teams building for accessibility compliance should also pay attention. Font customization addresses a real need that official guidelines sidestep, making this a practical way to improve usability for users with dyslexia, visual impairments, or simply strong typographic preferences.
Our analysis
Fontize trades theme-level elegance for compatibility. A theming approach would handle font changes more holistically, but it demands higher API levels and more complex setup. SharedPreferences-based storage keeps things simple and broad.
The library won't resolve every accessibility concern—font choice is one piece of a larger picture. But it tackles a specific, concrete problem that affects real users. The developer tested this by building it into JekyllEx first, proving the approach works under actual conditions rather than in theory.
Watch for API expansion. If the library gains traction, expect richer features like per-screen font profiles or system-level integration.
Bottom line
Fontize won't grab headlines, but it solves a narrow problem cleanly. For teams wanting to add font customization without building infrastructure from scratch, the library provides a tested path.
Check the repository for maintenance activity before committing. As with any open-source tool, ensure the project has recent commits and responsive issues if you plan to depend on it long-term.
Key takeaways
- Fontize enables per-user font selection without API level restrictions
- SharedPreferences storage keeps performance reasonable through caching
- The library handles propagating font changes across screens automatically
- Best suited for reading-heavy apps where users spend significant time with text
Frequently asked questions
Does Fontize work with custom fonts or only system fonts?
It works with custom fonts bundled in your app's resources. Reference them by resource ID when initializing the library.
Will Fontize slow down my app?
SharedPreferences operations are cached in memory, so the performance impact is minimal for typical use cases.
Can users change fonts without restarting the app?
Yes. Font changes apply to newly inflated screens. A brief transition or scroll may refresh visible content.
Is Fontize actively maintained?
Check the GitHub repository for recent commits and issue response times to assess current activity before adopting it in a production app.