flutter No Material widget found的解决办法

flutter一直报IconButton的错误：

​​

​Another exception was thrown: No Material widget found.​

​

• AppBar
• BottomAppBar
• FloatingActionButton
• Drawer
• SnackBar
• BottomSheet
• BottomNavigationBar
• IconButton

• ListTile

  等,需要时，要用Scaffold包裹起来，如：

Scaffold(
      body: IconButton(
              // 全屏/横屏按钮
              padding: EdgeInsets.zero,
              iconSize: 26,
              icon: Icon(
                // 根据当前屏幕方向切换图标
                _isFullScreen ? Icons.fullscreen_exit : Icons.fullscreen,
                color: Colors.white,
              ),
      }