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Added in API level 1

SharedPreferences

public interface SharedPreferences

android.content.SharedPreferences


Interface for accessing and modifying preference data returned by 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 SharedPreferences.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.

Note: currently this class does not support use across multiple processes. This will be added later.

Developer Guides

For more information about using SharedPreferences, read the Data Storage developer guide.

See also:

Summary

Nested classes

interface SharedPreferences.Editor

Interface used for modifying values in a SharedPreferences object. 

interface SharedPreferences.OnSharedPreferenceChangeListener

Interface definition for a callback to be invoked when a shared preference is changed. 

Public methods

abstract boolean contains(String key)

Checks whether the preferences contains a preference.

abstract SharedPreferences.Editor edit()

Create a new Editor for these preferences, through which you can make modifications to the data in the preferences and atomically commit those changes back to the SharedPreferences object.

abstract Map<String, ?> getAll()

Retrieve all values from the preferences.

abstract boolean getBoolean(String key, boolean defValue)

Retrieve a boolean value from the preferences.

abstract float getFloat(String key, float defValue)

Retrieve a float value from the preferences.

abstract int getInt(String key, int defValue)

Retrieve an int value from the preferences.

abstract long getLong(String key, long defValue)

Retrieve a long value from the preferences.

abstract String getString(String key, String defValue)

Retrieve a String value from the preferences.

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

Retrieve a set of String values from the preferences.

abstract void registerOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener listener)

Registers a callback to be invoked when a change happens to a preference.

abstract void unregisterOnSharedPreferenceChangeListener(SharedPreferences.OnSharedPreferenceChangeListener listener)

Unregisters a previous callback.

Public methods

contains

Added in API level 1
boolean contains (String key)

Checks whether the preferences contains a preference.

Parameters
key String: The name of the preference to check.
Returns
boolean Returns true if the preference exists in the preferences, otherwise false.

edit

Added in API level 1
SharedPreferences.Editor edit ()

Create a new Editor for these preferences, through which you can make modifications to the data in the preferences and atomically commit those changes back to the SharedPreferences object.

Note that you must call commit() to have any changes you perform in the Editor actually show up in the SharedPreferences.

Returns
SharedPreferences.Editor Returns a new instance of the SharedPreferences.Editor interface, allowing you to modify the values in this SharedPreferences object.

getAll

Added in API level 1
Map<String, ?> getAll ()

Retrieve all values from the preferences.

Note that you must not modify the collection returned by this method, or alter any of its contents. The consistency of your stored data is not guaranteed if you do.

Returns
Map<String, ?> Returns a map containing a list of pairs key/value representing the preferences.
Throws
NullPointerException

getBoolean

Added in API level 1
boolean getBoolean (String key, 
                boolean defValue)

Retrieve a boolean value from the preferences.

Parameters
key String: The name of the preference to retrieve.
defValue boolean: Value to return if this preference does not exist.
Returns
boolean Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not a boolean.
Throws
ClassCastException

getFloat

Added in API level 1
float getFloat (String key, 
                float defValue)

Retrieve a float value from the preferences.

Parameters
key String: The name of the preference to retrieve.
defValue float: Value to return if this preference does not exist.
Returns
float Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not a float.
Throws
ClassCastException

getInt

Added in API level 1
int getInt (String key, 
                int defValue)

Retrieve an int value from the preferences.

Parameters
key String: The name of the preference to retrieve.
defValue int: Value to return if this preference does not exist.
Returns
int Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not an int.
Throws
ClassCastException

getLong

Added in API level 1
long getLong (String key, 
                long defValue)

Retrieve a long value from the preferences.

Parameters
key String: The name of the preference to retrieve.
defValue long: Value to return if this preference does not exist.
Returns
long Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not a long.
Throws
ClassCastException

getString

Added in API level 1
String getString (String key, 
                String defValue)

Retrieve a String value from the preferences.

Parameters
key String: The name of the preference to retrieve.
defValue String: Value to return if this preference does not exist.
Returns
String Returns the preference value if it exists, or defValue. Throws ClassCastException if there is a preference with this name that is not a String.
Throws
ClassCastException

getStringSet

Added in API level 11
Set<String> getStringSet (String key, 
                Set<String> defValues)

Retrieve a set of String values from the preferences.

Note that you must not modify the set instance returned by this call. The consistency of the stored data is not guaranteed if you do, nor is your ability to modify the instance at all.

Parameters
key String: The name of the preference to retrieve.
defValues Set: Values to return if this preference does not exist.
Returns
Set<String> Returns the preference values if they exist, or defValues. Throws ClassCastException if there is a preference with this name that is not a Set.
Throws
ClassCastException

registerOnSharedPreferenceChangeListener

Added in API level 1
void registerOnSharedPreferenceChangeListener (SharedPreferences.OnSharedPreferenceChangeListener listener)

Registers a callback to be invoked when a change happens to a preference.

Caution: The preference manager does not currently store a strong reference to the listener. You must store a strong reference to the listener, or it will be susceptible to garbage collection. We recommend you keep a reference to the listener in the instance data of an object that will exist as long as you need the listener.

Parameters
listener SharedPreferences.OnSharedPreferenceChangeListener: The callback that will run.

See also:

unregisterOnSharedPreferenceChangeListener

Added in API level 1
void unregisterOnSharedPreferenceChangeListener (SharedPreferences.OnSharedPreferenceChangeListener listener)

Unregisters a previous callback.

Parameters
listener SharedPreferences.OnSharedPreferenceChangeListener: The callback that should be unregistered.

See also:

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