@Override
        public Object instantiateItem(View collection, int position) {
            LinearLayout layout = null;
            switch(position) {
            case MAIN_ACTIVITY :
//              layout = (LinearLayout) LinearLayout.inflate(getApplicationContext(), R.id.ma_main, (ViewPager) collection);
                layout = (LinearLayout)findViewById(R.id.ma_main);
                initMainLayout();
                break;
            case SETTINGS_ACTIVITY :
//              layout = (LinearLayout) LinearLayout.inflate(getApplicationContext(), R.id.ma_settings, (ViewPager) collection);
                layout = (LinearLayout)findViewById(R.id.ma_settings);
                initSettingsLayout();
                break;
            case FRIEND_LIST_ACTIVITY :
//              layout = (LinearLayout) LinearLayout.inflate(getApplicationContext(), R.id.ma_friend_list, (ViewPager) collection);
                layout = (LinearLayout)findViewById(R.id.ma_friend_list);
                initFriendListLayout();
                break;
            }
            ((ViewPager)collection).addView(layout, position);
            return layout;
        }