Class Preferences

java.lang.Object
com.codename1.io.Preferences
public final class Preferences extends Object

Simple map like class to store application and Codename One preference settings in the com.codename1.io.Storage.

Simple usage of the class for storing a String token:

// save a token to storage
Preferences.set("token", myToken);

// get the token from storage or null if it isn't there
String token = Preferences.get("token", null);

Notice that this class might get somewhat confusing with primitive numbers e.g. if you use Preferences.set("primitiveLongValue", myLongNumber) then invoke Preferences.get("primitiveLongValue", 0) you might get an exception!

This would happen because the value is physically a Long object but you are trying to get an Integer.

The workaround is to remain consistent and use code like this Preferences.get("primitiveLongValue", (long)0).

  • Method Summary

    Modifier and Type
    Method
    Description
    static void
    addPreferenceListener(String pref, PreferenceListener listener)
    Adds a preference listener for the specified property to the list of listeners.
    static void
    clearAll()
    Remove all preferences
    static void
    delete(String pref)
    Deletes a value for the given setting
    static boolean
    get(String pref, boolean def)
    Gets the value as a number
    static double
    get(String pref, double def)
    Gets the value as a number
    static float
    get(String pref, float def)
    Gets the value as a number
    static int
    get(String pref, int def)
    Gets the value as a number
    static long
    get(String pref, long def)
    Gets the value as a number
    static String
    get(String pref, String def)
    Gets the value as a String
    static boolean
    getAndSet(String pref, boolean def)
    Gets the value as a number if the value is null def is returned and saved
    static double
    getAndSet(String pref, double def)
    Gets the value as a number if the value is null def is returned and saved
    static float
    getAndSet(String pref, float def)
    Gets the value as a number if the value is null def is returned and saved
    static int
    getAndSet(String pref, int def)
    Gets the value as a number if the value is null def is returned and saved
    static long
    getAndSet(String pref, long def)
    Gets the value as a number if the value is null def is returned and saved
    static String
    getAndSet(String pref, String def)
    Gets the value as a String if the value is null def is returned and saved
    static String
    getPreferencesLocation()
    Returns the location within the storage of the preferences file to an arbitrary name.
    static boolean
    removePreferenceListener(String pref, PreferenceListener listener)
    Remove the listener for the specified preference.
    static void
    set(String pref, boolean b)
    Sets a preference value
    static void
    set(String pref, double d)
    Sets a preference value
    static void
    set(String pref, float f)
    Sets a preference value
    static void
    set(String pref, int i)
    Sets a preference value
    static void
    set(String pref, long l)
    Sets a preference value
    static void
    set(String pref, String s)
    Sets a preference value
    static void
    set(Map<String,Object> values)
    Sets a set of preference values as a batch, and performs a single save.
    static void
    setPreferencesLocation(String storageFileName)
    Sets the location within the storage of the preferences file to an arbitrary name.

    Methods inherited from class Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • getPreferencesLocation

      public static String getPreferencesLocation()

      Returns the location within the storage of the preferences file to an arbitrary name. This is useful in a case of encryption where we would want preferences to use a different file name.

      Returns

      the storage file name

    • setPreferencesLocation

      public static void setPreferencesLocation(String storageFileName)

      Sets the location within the storage of the preferences file to an arbitrary name. This is useful in a case of encryption where we would want preferences to use a different file name.

      Parameters
      • storageFileName: the name of the preferences file

    • set

      public static void set(Map<String,Object> values)

      Sets a set of preference values as a batch, and performs a single save.

      Parameters
      • values: The key/value pairs to set in preferences.

    • set

      public static void set(String pref, String s)

      Sets a preference value

      Parameters

      • pref: the key any unique none null value that doesn't start with cn1

      • s: a String

    • set

      public static void set(String pref, int i)

      Sets a preference value

      Parameters

      • pref: the key any unique none null value that doesn't start with cn1

      • i: a number

    • set

      public static void set(String pref, long l)

      Sets a preference value

      Parameters

      • pref: the key any unique none null value that doesn't start with cn1

      • l: a number

    • set

      public static void set(String pref, double d)

      Sets a preference value

      Parameters

      • pref: the key any unique none null value that doesn't start with cn1

      • d: a number

    • set

      public static void set(String pref, float f)

      Sets a preference value

      Parameters

      • pref: the key any unique none null value that doesn't start with cn1

      • f: a number

    • delete

      public static void delete(String pref)

      Deletes a value for the given setting

      Parameters
      • pref: the preference value

    • clearAll

      public static void clearAll()
      Remove all preferences

    • set

      public static void set(String pref, boolean b)

      Sets a preference value

      Parameters

      • pref: the key any unique none null value that doesn't start with cn1

      • b: the value

    • get

      public static String get(String pref, String def)

      Gets the value as a String

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • getAndSet

      public static String getAndSet(String pref, String def)

      Gets the value as a String if the value is null def is returned and saved

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • getAndSet

      public static int getAndSet(String pref, int def)

      Gets the value as a number if the value is null def is returned and saved

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • get

      public static int get(String pref, int def)

      Gets the value as a number

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • getAndSet

      public static long getAndSet(String pref, long def)

      Gets the value as a number if the value is null def is returned and saved

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • get

      public static long get(String pref, long def)

      Gets the value as a number

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • getAndSet

      public static double getAndSet(String pref, double def)

      Gets the value as a number if the value is null def is returned and saved

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • get

      public static double get(String pref, double def)

      Gets the value as a number

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • getAndSet

      public static float getAndSet(String pref, float def)

      Gets the value as a number if the value is null def is returned and saved

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • get

      public static float get(String pref, float def)

      Gets the value as a number

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • getAndSet

      public static boolean getAndSet(String pref, boolean def)

      Gets the value as a number if the value is null def is returned and saved

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • get

      public static boolean get(String pref, boolean def)

      Gets the value as a number

      Parameters

      • pref: the preference key

      • def: the default value

      Returns

      the default value or the value

    • addPreferenceListener

      public static void addPreferenceListener(String pref, PreferenceListener listener)

      Adds a preference listener for the specified property to the list of listeners. When calling this method, it is advisable to also read the current value and set it, since the value may have changed since the last time the listener was removed. (Should this return the current value of the preference?)

      Parameters

      • pref: The preference to listen to

      • listener: The listener to add, which cannot be null.

    • removePreferenceListener

      public static boolean removePreferenceListener(String pref, PreferenceListener listener)

      Remove the listener for the specified preference.

      Parameters

      • pref: The preference that the listener listens to

      • listener: The listener to remove

      Returns

      true if the listener was removed, false if it was not found.