question: private void notifyChange ( int previous , int current ) { mSoundPlayer . play ( mSoundId , 1 , 1 , 0 , 0 , 1 ) ; if ( mOnValueChangeListener != null ) { mOnValueChangeListener . onValueChange ( this , previous , mValue ) ; } }
target:  Notifies the listener, if registered, of a change of the value of this NumberPicker.