颤振 - 'initialValue == null ||控制器==空'：不是真的。表单小部件中的错误

时间：2021-07-02 19:36:31

标签： flutter flutter-dependencies flutter-web

颤振 - 'initialValue == null ||控制器==空'：不是真的。错误。我正在尝试编辑我想要在添加产品中使用的表单中的产品详细信息的产品。但问题出在 imageUrl 上，因为它有一个 textEditing 控制器。我试过这种方式，但对我不起作用

@override
      void didChangeDependencies() {
        if (_isinit) {
          final productId = ModalRoute.of(context)!.settings.arguments as String;
          if (productId != null) {
            _editedproduct =
                Provider.of<Products>(context, listen: false).FindByID(productId);
            _imageUrlController.text = _editedproduct.imageUrl;           //error
            _initValues = {
              'title': _editedproduct.title,
              'description': _editedproduct.description,
              'Price': _editedproduct.price.toString(),
              
              'imageUrl': '',                              //error
            };
          }
        }
        _isinit = false;
        super.didChangeDependencies();
      }

enter image description here

import 'dart:html';

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:shoppingapp/Providers/Product.dart';
import 'package:shoppingapp/Providers/Products.dart';

class EditProductScreen extends StatefulWidget {
  static const routeName = '/edit-products';
  @override
  _EditProductScreenState createState() => _EditProductScreenState();
}

class _EditProductScreenState extends State<EditProductScreen> {
  final _priceFocusNode = FocusNode();
  final _descriptionFocusNode = FocusNode();
  final _imageUrlController = TextEditingController();
  final _imageUrlFocusNode = FocusNode();
  final _form = GlobalKey<FormState>();
  var _editedproduct =
      Product(id: '', title: '', description: '', price: 0, imageUrl: '');
  var _isinit = true;

  var _initValues = {
    'title': '',
    'description': '',
    'price': '',
    'imageUrl': '',
  };
  @override
  void initState() {
    _imageUrlFocusNode.addListener(_updateImageUrl);
    super.initState();
  }

  @override
  void didChangeDependencies() {
    if (_isinit) {
      final productId = ModalRoute.of(context)!.settings.arguments as String;
      if (productId != null) {
        _editedproduct =
            Provider.of<Products>(context, listen: false).FindByID(productId);
        _imageUrlController.text = _editedproduct.imageUrl;           //error
        _initValues = {
          'title': _editedproduct.title,
          'description': _editedproduct.description,
          'Price': _editedproduct.price.toString(),
          
          'imageUrl': '',                              //error
        };
      }
    }
    _isinit = false;
    super.didChangeDependencies();
  }

  @override
  void dispose() {
    _imageUrlFocusNode.removeListener(_updateImageUrl);
    _priceFocusNode.dispose();
    _descriptionFocusNode.dispose();
    _imageUrlFocusNode.dispose();

    super.dispose();
  }

  void _updateImageUrl() {
    if (!_imageUrlFocusNode.hasFocus) {
      setState(() {});
    }
  }

  void _saveForm() {
    final isValid = _form.currentState!.validate();
    if (isValid) {
      return;
    }
    _form.currentState!.save();
    if (_editedproduct.id != null) {
      Provider.of<Products>(context, listen: false)
          .updateProducts(_editedproduct.id, _editedproduct);
    } else {
      Provider.of<Products>(context, listen: false).addProducts(_editedproduct);
    }

    Navigator.of(context).pop();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Edit Product'),
        actions: [
          IconButton(
            icon: Icon(Icons.save),
            onPressed: _saveForm,
          ),
        ],
      ),
      body: Padding(
        padding: const EdgeInsets.all(15.0),
        child: Form(
          key: _form,
          child: ListView(
            children: [
              TextFormField(
                decoration: InputDecoration(
                  labelText: 'Title',
                ),
                initialValue: _initValues['title'],
                textInputAction: TextInputAction.next,
                validator: (value) {
                  if (value!.isEmpty) {
                    return 'Please provide a value.';
                  }
                  return null;
                },
                onFieldSubmitted: (_) {
                  FocusScope.of(context).requestFocus(_priceFocusNode);
                },
                onSaved: (value) {
                  _editedproduct = Product(
                      title: value as String,
                      price: _editedproduct.price,
                      description: _editedproduct.description,
                      imageUrl: _editedproduct.imageUrl,
                      id: _editedproduct.id,
                      isFavourite: _editedproduct.isFavourite);
                },
              ),
              TextFormField(
                initialValue: _initValues['price'],
                decoration: InputDecoration(
                  labelText: 'Price',
                ),
                textInputAction: TextInputAction.next,
                keyboardType: TextInputType.number,
                focusNode: _priceFocusNode,
                validator: (value) {
                  if (value!.isEmpty) {
                    return 'Please enter a  price ';
                  }
                  if (double.tryParse(value) == null) {
                    return 'Please Enter a Valid Number';
                  }
                  if (double.parse(value) <= 0) {
                    return 'Please Enter the number greather no than zero';
                  }
                },
                onSaved: (value) {
                  _editedproduct = Product(
                      title: _editedproduct.title,
                      price: double.parse(value!),
                      description: _editedproduct.description,
                      imageUrl: _editedproduct.imageUrl,
                      id: _editedproduct.id,
                      isFavourite: _editedproduct.isFavourite);
                },
              ),
              TextFormField(
                decoration: InputDecoration(
                  labelText: 'Description',
                ),
                initialValue: _initValues['description'],
                maxLines: 3,
                textInputAction: TextInputAction.next,
                keyboardType: TextInputType.multiline,
                focusNode: _descriptionFocusNode,
                validator: (value) {
                  if (value!.isEmpty) {
                    return 'Please enter a  description ';
                  }
                  if (value.length < 10) {
                    return 'Should be at least 10 characters long.';
                  }
                  return null;
                },
                onSaved: (value) {
                  _editedproduct = Product(
                      title: _editedproduct.title,
                      price: _editedproduct.price,
                      description: value as String,
                      imageUrl: _editedproduct.imageUrl,
                      id: _editedproduct.id,
                      isFavourite: _editedproduct.isFavourite);
                },
              ),
              Row(
                crossAxisAlignment: CrossAxisAlignment.end,
                children: [
                  Container(
                    width: 100,
                    height: 100,
                    margin: EdgeInsets.only(top: 8, right: 10),
                    decoration: BoxDecoration(
                        border: Border.all(width: 1, color: Colors.grey)),
                    child: _imageUrlController.text.isEmpty
                        ? Text('Enter a URL')
                        : FittedBox(
                            child: Image.network(
                              _imageUrlController.text,
                              fit: BoxFit.cover,
                            ),
                          ),
                  ),
                  Expanded(
                    child: TextFormField(
                      decoration: InputDecoration(labelText: 'Image URl'),
                      keyboardType: TextInputType.url,
                      initialValue: _initValues['imageUrl'],    //error
                      textInputAction: TextInputAction.done,
                      controller: _imageUrlController,        //error
                      focusNode: _imageUrlFocusNode,
                      validator: (value) {
                        if (value!.isEmpty) {
                          return 'Please enter a  URL ';
                        }
                        if (!value.startsWith('http') &&
                            !value.startsWith('https')) {
                          return 'Please Enter a valid URL';
                        }
                        if (!value.endsWith('.png') &&
                            !value.endsWith('.jpg') &&
                            !value.endsWith('.jpeg')) {
                          return 'Please enter a valid image URL';
                        }
                        return null;
                      },
                      onFieldSubmitted: (_) {
                        _saveForm();
                      },
                      onSaved: (value) {
                        _editedproduct = Product(
                            title: _editedproduct.title,
                            price: _editedproduct.price,
                            description: _editedproduct.description,
                            imageUrl: value as String,
                            id: _editedproduct.id,
                            isFavourite: _editedproduct.isFavourite);
                      },
                    ),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}

1 个答案:

答案 0 :(得分：0)

我认为错误的原因是因为您设置了控制器和初始值。您只需设置这些属性之一。初始值或控制器。在所有情况下都这样做

例如改变这个

 TextFormField(
                  decoration: InputDecoration(labelText: 'Image URl'),
                  keyboardType: TextInputType.url,
                  initialValue: _initValues['imageUrl'],    //error
                  textInputAction: TextInputAction.done,
                  controller: _imageUrlController,        //error
                  focusNode: _imageUrlFocusNode,
                  validator: (value) {
                    if (value!.isEmpty) {
                      return 'Please enter a  URL ';
                    }
                    if (!value.startsWith('http') &&
                        !value.startsWith('https')) {
                      return 'Please Enter a valid URL';
                    }
                    if (!value.endsWith('.png') &&
                        !value.endsWith('.jpg') &&
                        !value.endsWith('.jpeg')) {
                      return 'Please enter a valid image URL';
                    }
                    return null;
                  },
                  onFieldSubmitted: (_) {
                    _saveForm();
                  },
                  onSaved: (value) {
                    _editedproduct = Product(
                        title: _editedproduct.title,
                        price: _editedproduct.price,
                        description: _editedproduct.description,
                        imageUrl: value as String,
                        id: _editedproduct.id,
                        isFavourite: _editedproduct.isFavourite);
                  },
                ),

以下省略初始值

 TextFormField(
                  decoration: InputDecoration(labelText: 'Image URl'),
                  keyboardType: TextInputType.url,
                  textInputAction: TextInputAction.done,
                  controller: _imageUrlController,        //error
                  focusNode: _imageUrlFocusNode,
                  validator: (value) {
                    if (value!.isEmpty) {
                      return 'Please enter a  URL ';
                    }
                    if (!value.startsWith('http') &&
                        !value.startsWith('https')) {
                      return 'Please Enter a valid URL';
                    }
                    if (!value.endsWith('.png') &&
                        !value.endsWith('.jpg') &&
                        !value.endsWith('.jpeg')) {
                      return 'Please enter a valid image URL';
                    }
                    return null;
                  },
                  onFieldSubmitted: (_) {
                    _saveForm();
                  },
                  onSaved: (value) {
                    _editedproduct = Product(
                        title: _editedproduct.title,
                        price: _editedproduct.price,
                        description: _editedproduct.description,
                        imageUrl: value as String,
                        id: _editedproduct.id,
                        isFavourite: _editedproduct.isFavourite);
                  },
                ),

我相信这种方法应该有效

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