Fragment疑问

//当Fragment中再次嵌套Fragment时，就用fm.getChildFragmentManager()来代替getFragmentManager()?class GalleryAdapter extends FragmentPagerAdapter {        int count = 3;// 默认10        public GalleryAdapter(MainPage fm) {            super(fm.getChildFragmentManager());        }        @Override        public Fragment getItem(int position) {            return fragments.get(position);        }        /**         * 数量设置为最大         *         * @return         */        @Override        public int getCount() {            return fragments.size();        }        /**         * 真实数量         *         * @return         */        public int getRealCount() {            return this.count;        }    }