加入写了新场景SecondScene,结果在cpp文件里类名地方报错说undefined reference to `vtable for SecondScene',加入写了新场景SecondScene,结果在cpp文件里类名地方报错说undefined refer
加入写了新场景SecondScene,结果在cpp文件里类名地方报错说undefined reference to `vtable for SecondScene',加入写了新场景SecondScene,结果在cpp文件里类名地方报错说undefined refer