SharedPreferences for key-value in Flutter - Build, Publish & Deploy

Build & Publish - SharedPreferences for key-value

Performance Impact

Using SharedPreferences for key-value storage is lightweight and fast for small data. It runs on the main thread but is optimized for quick reads and writes, so it usually does not affect frame rate. However, frequent writes can cause minor delays and battery use if done excessively.

Optimization Tips

To keep your app smooth at 60fps, avoid writing to SharedPreferences too often. Batch updates or write only when necessary. Read values once and cache them in memory if used frequently. Use async calls properly to prevent blocking the UI thread.

App Size and Startup Time

SharedPreferences adds minimal size to your app bundle since it is part of Flutter plugins. It does not significantly affect startup time because it loads data asynchronously. Keep stored data small to avoid slow reads during app launch.

iOS vs Android Differences

On Android, SharedPreferences uses XML files stored in app storage. On iOS, it uses NSUserDefaults. Both platforms handle small key-value pairs efficiently. iOS may cache values more aggressively, so changes might not appear instantly if not synced properly.

Store Review Guidelines

Ensure your app respects user privacy when storing data. Do not store sensitive information like passwords in SharedPreferences without encryption. Follow Apple's and Google's guidelines on data storage and user consent for personal data.

Self-Check

Your app takes 5 seconds to load this screen. What's likely wrong?

• Excessive synchronous reads or writes to SharedPreferences blocking the UI thread.
• Storing large amounts of data in SharedPreferences causing slow access.
• Not caching values in memory, causing repeated slow reads.

Key Result

SharedPreferences is efficient for small key-value storage with minimal impact on app size and performance. Optimize by minimizing writes and caching reads to maintain smooth UI and fast startup.