Android Data Management
SharedPreferences, DataStore, File I/O, Internal/External Storage, Scoped Storage
1What is SharedPreferences in Android?
What is SharedPreferences in Android?
回答
SharedPreferences is a simple key-value storage system for saving primitive data (int, boolean, float, long, String, Set<String>). Data persists between app sessions and reboots. It's ideal for user preferences, settings, small data. Simple API: getSharedPreferences(), edit(), putString(), apply()/commit().
2How to save a value in SharedPreferences?
How to save a value in SharedPreferences?
回答
Get instance: val prefs = context.getSharedPreferences('name', Context.MODE_PRIVATE). Edit: val editor = prefs.edit(); editor.putString('key', 'value'); editor.apply() (async) or editor.commit() (sync). Can also chain: prefs.edit().putString('key', 'value').apply().
3What's the difference between apply() and commit()?
What's the difference between apply() and commit()?
回答
apply() is asynchronous (writes in background, doesn't block UI thread), returns nothing, recommended in most cases. commit() is synchronous (blocks until written), returns boolean (true if success), useful if you need to verify success immediately. apply() is more performant for UI.
How to read a value from SharedPreferences?
What is Jetpack DataStore?
+26 面接問題