Flutter 如何在 PopupMenuButton 小部件中获取上下文？

Question

I have a PopupMenuButton. But if I want to call a method that will jump to another page

Navigator.push(context,MaterialPageRoute(builder: (context) => SingleOrder()),);

I have an error. Undefined name context . How can I get the context in Navigator.push ?

Widget _childPopup() => PopupMenuButton<int>(

 onSelected: (result) {
  if (result == 0) {
  Navigator.push(
    context,
    MaterialPageRoute(builder: (context) => SingleOrder()),
   );
 }
},

itemBuilder: (context) => [
  PopupMenuItem(
   value: 0,
    child: Text(
    "MENU 1",
    style: TextStyle(
        color: Colors.black54),
  ),
),
PopupMenuItem(
  value: 1,
  child: Text(
    "MENU 2",
    style: TextStyle(
        color:  Colors.black54),
    ),
  ),
],
);

Answer 1

You need to pass BuildContext to your _childPopup function. You likely defined this function in a place where BuildContext is not directly available. Ex.

Widget _childPopup(BuildContext context) => PopupMenuButton<int>(

 onSelected: (result) {
  if (result == 0) {
  Navigator.push(
    context,
    MaterialPageRoute(builder: (context) => SingleOrder()),
   );
 }
},

itemBuilder: (context) => [
  PopupMenuItem(
   value: 0,
    child: Text(
    "MENU 1",
    style: TextStyle(
        color: Colors.black54),
  ),
),
PopupMenuItem(
  value: 1,
  child: Text(
    "MENU 2",
    style: TextStyle(
        color:  Colors.black54),
    ),
  ),
],
);

Doing this ensures that BuildContext will be available to the function and allows you to better control which context it will use.