Code example for DataSetObservable

Methods: unregisterObserver

    void registerDataSetObserver(DataSetObserver observer) {
    void unregisterDataSetObserver(DataSetObserver observer) {
     * This method may be called by the ViewPager to obtain a title string 
     * to describe the specified page. This method may return null 
     * indicating no title for this page. The default implementation returns 
     * null. 
     * @param position The position of the title requested 
     * @return A title for the requested page 
    public CharSequence getPageTitle(int position) {
        return null;