flutter - AppBar如何根据不同的url显示不同的leading？

Question

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Answer 1

@override
Widget build(BuildContext context) {
  Widget widget;

  switch (url) {
    case "url_1":
      widget = Widget1();
      break;

    case "url_2":
      widget = Widget2();
      break;

    case "url_3":
      widget = Widget3();
      break;

    default:
      widget = DefaultWidget();
  }

  return Scaffold(
    appBar: AppBar(leading: widget),
  );
}