Interface definition for a callback to be invoked when the value of this
Preference has been changed by the user and is
about to be set and/or persisted. This gives the client a chance
to prevent setting and/or persisting the value.
Called when a Preference has been changed by the user.
Called when a Preference has been changed by the user. This is called before the state of the Preference is about to be updated and before the state is persisted.
|The changed Preference.
|The new value of the Preference.