Fragment初始化

1.继承Fragment,重写onCreateView和onActivityCreate方法
2.在MainActivity中初始化Fragment

FragmentManager fm = getSupportFragmentManager();//继承FragmentActivity
FragmentTransaction transaction = fm.beginTransaction();    
transaction.replace(R.id.fl_left_menu, new LeftMenuFragment(), TAG_LEFT_MENU);
transaction.replace(R.id.fl_content, new ContentFragment(), TAG_CONTENT);
transaction.commit();