• 无状态组件不允许写事件
    • 有状态组件由两个类组成, 一个是StatefulWidget ,一个是state类
    • state类持有Widget的生命周期
    • setState() 更改数据 ```javascript class HomeContent extends StatefulWidget { @override State createState() { // TODO: implement createState return _HomeContnetState(); } }

    class _HomeContnetState extends State { int _conuter = 1; @override Widget build(BuildContext context) { return Container( child: RaisedButton( child: Text(“$_conuter”), onPressed: addCount, )); } void addCount() { setState(() { _conuter++; }); } } ```