Another Exception was thrown: Nosuchmethoderror: The getter 'zipcode' was called on null

Question

I’m making a shipping calculator screen, the code ta all " working" however at the time of running the app and get on the calular screen presents me this Error

Follows some Codes.

import 'package:Flutter2/src/address.dart';
import 'package:Flutter2/src/cart_manager.dart';
import 'package:Flutter2/src/custom_icon_button.dart';
import 'package:brasil_fields/formatter/cep_input_formatter.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:provider/provider.dart';

class CepInputField extends StatefulWidget {
  const CepInputField(this.address);

  final Address address;

  @override
  _CepInputFieldState createState() => _CepInputFieldState();
}

class _CepInputFieldState extends State<CepInputField> {
  final TextEditingController cepController = TextEditingController();

  @override
  Widget build(BuildContext context) {
    final cartManager = context.watch<CartManager>();
    final primaryColor = Theme.of(context).primaryColor;

    if (widget.address.zipCode == null)
      return Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: <Widget>[
          TextFormField(
            enabled: !cartManager.loading,
            controller: cepController,
            decoration: const InputDecoration(
                isDense: true, labelText: 'CEP', hintText: '12.345-678'),
            inputFormatters: [
              WhitelistingTextInputFormatter.digitsOnly,
              CepInputFormatter(),
            ],
            keyboardType: TextInputType.number,
            validator: (cep) {
              if (cep.isEmpty)
                return 'Campo obrigatório';
              else if (cep.length != 10) return 'CEP Inválido';
              return null;
            },
          ),
          if (cartManager.loading)
            LinearProgressIndicator(
              valueColor: AlwaysStoppedAnimation(primaryColor),
              backgroundColor: Colors.transparent,
            ),
          RaisedButton(
            onPressed: !cartManager.loading
                ? () async {
                    if (Form.of(context).validate()) {
                      try {
                        await context
                            .read<CartManager>()
                            .getAddress(cepController.text);
                      } catch (e) {
                        Scaffold.of(context).showSnackBar(SnackBar(
                          content: Text('$e'),
                          backgroundColor: Colors.red,
                        ));
                      }
                    }
                  }
                : null,
            textColor: Colors.white,
            color: primaryColor,
            disabledColor: primaryColor.withAlpha(100),
            child: const Text('Buscar CEP'),
          ),
        ],
      );
    else
      return Padding(
        padding: const EdgeInsets.symmetric(vertical: 4),
        child: Row(
          children: <Widget>[
            Expanded(
              child: Text(
                'CEP: ${widget.address.zipCode}',
                style:
                    TextStyle(color: primaryColor, fontWeight: FontWeight.w600),
              ),
            ),
            CustomIconButton(
              iconData: Icons.edit,
              color: primaryColor,
              size: 20,
              onTap: () {
                context.read<CartManager>().removeAddress();
              },
            ),
          ],
        ),
      );
  }
}

    class Address {
  Address(
      {this.street,
      this.number,
      this.complement,
      this.district,
      this.zipCode,
      this.city,
      this.state,
      this.lat,
      this.long});

  String street;
  String number;
  String complement;
  String district;
  String zipCode;
  String city;
  String state;

  double lat;
  double long;

  Address.fromMap(Map<String, dynamic> map) {
    street = map['street'] as String;
    number = map['number'] as String;
    complement = map['complement'] as String;
    district = map['district'] as String;
    zipCode = map['zipCode'] as String;
    city = map['city'] as String;
    state = map['state'] as String;
    lat = map['lat'] as double;
    long = map['long'] as double;
  }

  Map<String, dynamic> toMap() {
    return {
      'street': street,
      'number': number,
      'complement': complement,
      'district': district,
      'zipCode': zipCode,
      'city': city,
      'state': state,
      'lat': lat,
      'long': long,
    };
  }
}

I thank you all

Answer 1

The problem is that you are not passing a value to your property address by instantiating the class CepInputField, so the constructor returns NULL to it and when accessing it as widget.address.zipCode the error occurs as you are calling the property zipcode at a null value.

class CepInputField extends StatefulWidget {
  const CepInputField(this.address);

  final Address address;

  @override
  _CepInputFieldState createState() => _CepInputFieldState();
}

Heed

As the property is optional, you need to treat in your code when the property is not informed.

Or change the constructor of the class, as follows:

class CepInputField extends StatefulWidget {
  const CepInputField(@Required this.address);

  final Address address;

  @override
  _CepInputFieldState createState() => _CepInputFieldState();
}