flutter - Flutter通过回调传递字符串

Question

这是简单的代码，用于显示具有叠加支持的小部件，并且在onReplay中，我想获取字符串作为消息来显示，例如使用toast

showOverlayNotification((context) {
  return MessageNotification(
    message: messages[3],
    onReplay: (message) {
      OverlaySupportEntry.of(context).dismiss();
      toast(message);
    },
  );
}, duration: Duration(milliseconds: 4000));

我实现的将消息作为字符串传递的代码不正确，我得到了

error: The final variable 'onReply' must be initialized.

我该如何解决这个问题？

typedef StringToVoidFunc = void Function(String);
const messages = [
  ...
];

class MessageNotification extends StatelessWidget {
  //final VoidCallback onReplay;
  final StringToVoidFunc onReply;
  final String message;

  const MessageNotification({
    Key key,
    this.onReplay,
    @required this.message,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: InkWell(
        onTap: (){
          if (onReplay != null) onReplay("sample pass message");
        },
        child: Center(
          child: Text(
            'ssss',
            style: TextStyle(
              fontSize: 26.0,
            ),
          ),
        ),
      ),
    );
  }
}

Answer 1

您在类型错误中做错了

改变这个

final StringToVoidFunc onReply;

至

final StringToVoidFunc onReplay;

错误已解决。