SharedPreferences

public interface SharedPreferences

Interface for accessing and modifying preference data returned by Context.getSharedPreferences(String, int). For any particular set of preferences, there is a single instance of this class that all clients share. Modifications to the preferences must go through an Editor object to ensure the preference values remain in a consistent state and control when they are committed to storage. Objects that are returned from the various get methods must be treated as immutable by the application.

SharedPreferences is best suited to storing data about how the user prefers to experience the app, for example, whether the user prefers a particular UI theme or whether they prefer viewing particular content in a list vs. a grid. To this end, SharedPreferences reflects changes committed or applied by Editors immediately, potentially before those changes are durably persisted. Under some circumstances such as app crashes or termination these changes may be lost, even if an OnSharedPreferenceChangeListener reported the change was successful. SharedPreferences is not recommended for storing data that is sensitive to this kind of rollback to a prior state such as user security or privacy settings. For other high-level data persistence options, see Room or DataStore.

Note: Common implementations guarantee that outstanding edits to preference files are persisted to disk when host Activities become stopped. In some situations (e.g. performing many Editor#commit() or Editor#apply() operations just prior to navigating away from the host Activity) this can lead to blocking the main thread during lifecycle transition events and associated ANR errors. For more details see the documentation for Editor#commit() and Editor#apply().

Note: This class does not support use across multiple processes.

Summary

Public methods

public abstract boolean contains (String key)

public abstract SharedPreferences.Editor edit ()

public abstract Map<String, ?> getAll ()

public abstract boolean getBoolean (String key, 
                boolean defValue)

public abstract float getFloat (String key, 
                float defValue)

public abstract int getInt (String key, 
                int defValue)

public abstract long getLong (String key, 
                long defValue)

public abstract String getString (String key, 
                String defValue)

public abstract Set<String> getStringSet (String key, 
                Set<String> defValues)

public abstract void registerOnSharedPreferenceChangeListener (SharedPreferences.OnSharedPreferenceChangeListener listener)

public abstract void unregisterOnSharedPreferenceChangeListener (SharedPreferences.OnSharedPreferenceChangeListener listener)