Flutter : Why is the exception not caught?-CodePudding

I want to show a snackbar when an error occurs. The Exception is working but is not caught in the main.dart. Can you see what is the problem? I am new to Flutter so I may not be good. Thank you.

main.dart

Future<void> _signInWithPhoneNumber() async {
    try {
      postPhoneInfo(
          tokenValue,
          _packageInfo.appName,
          _packageInfo.version,
          Theme.of(context).platform.toString().substring(15),
          "phone number");
      print("debug : try");
    } catch (e) {
      print("debug : catch");
      // print(e);
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text("${e.toString()}")));
    }
  }

this is postPhoneInfo()

Future<phoneInfo> postPhoneInfo(String token, String appName, String appVersion,
    String platform, String phone) async {
  var queryParameters = {
    'param1': token,
    'param2': appName,
    'param3': appVersion,
    'param4': platform,
    'param5': phone
  };
  var uri =
      Uri.http('~~', '~~', queryParameters);
  final response = await http.post(uri, headers: <String, String>{
    'Content-Type': 'application/json; charset=UTF-8',
  });

  if (response.statusCode == 200) {
    final parsedJson = jsonDecode(response.body);

    if (parsedJson["Res"] == "1") {
      print("user is registered");
      return phoneInfo.fromJson(jsonDecode(response.body));
    } else {
      print("user is not registered");
      throw Exception("user is not registered");
    }
  } else {
    print(response.statusCode);
    throw Exception('not connected');
  }
}

CodePudding user response：

ScaffoldMessenger.of(context) must be called in a Scaffold widget. Check the context where it comes from.

CodePudding user response：

You need to await the postPhoneInfo function call in main. Otherwise, the exception is thrown in an async context.

You would have to use runZoned to catch those. Documentation: https://api.flutter.dev/flutter/dart-async/runZoned.html