Flutter2.2中提示 The parameter 'key' can't have a value of 'null' because of its type

Flutter2.2中提示 The parameter ‘key’ can’t have a value of ‘null’ because of its type, but the implicit default value is ‘null’. Try adding either an explicit non-‘null’ default value or the ‘required’ 解决方案

解决办法：

实例化的时候把Key配置成可选参数

class PayPage extends StatefulWidget {
  PayPage({Key? key}) : super(key: key);

  _PayPageState createState() => _PayPageState();
}