android - 将网络图像添加到颤振中的问题

Question

我正在创建一个颤振壁纸应用程序，我在制作包含某些类别的列表时遇到了问题。图像未加载并且显示此错误 [: package:flutter/src/_newtwork_image_io.dart': failed assertion: line 25 pos 14: 'url != null': is not true。另请参阅 https://flutter.dev/docs/testing/errors ]

可以帮助我吗这是我的应用程序代码这是我的 main.dart :===

// this is my main.dart :
import 'package:flutter/material.dart';
import 'package:wallpaperdex/views/home.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'WallpaperDex',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primaryColor: Colors.white,
      ),
      home: Home(),
    );
  }
}

这是我的 home.dart 我正在创建我的列表

import 'package:flutter/material.dart';
import 'package:wallpaperdex/data/data.dart';
import 'package:wallpaperdex/model/categorie_model.dart';
import 'package:wallpaperdex/widgets/widget.dart';

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {
  //
  List<CategorieModel> categories = new List();

  @override
  void initState() {
    categories = getCategories();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      appBar: AppBar(
        title: BrandName(),
        elevation: 0.0,
      ),
      body: Container(
        child: Column(
          children: <Widget>[
            Container(
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(36),
                color: Color(0xfff5f8fd),
              ),
              margin: EdgeInsets.symmetric(horizontal: 24),
              padding: EdgeInsets.symmetric(horizontal: 20),
              child: Row(
                children: <Widget>[
                  Expanded(
                    child: TextField(
                      decoration: InputDecoration(
                          hintText: "Search", border: InputBorder.none),
                    ),
                  ),
                  Icon(Icons.search),
                ],
              ),
            ),
            SizedBox(
              height: 16,
            ),
            Container(
              height: 80,
              child: ListView.builder(
                // padding: ,
                itemCount: categories.length,
                shrinkWrap: true,
                scrollDirection: Axis.horizontal,
                itemBuilder: (context, index) {
                  return CategoriesTile(categories[index].categorieName,
                      categories[index].imgUrl);
                },
              ),
            )
          ],
        ),
      ),
    );
  }
}

class CategoriesTile extends StatelessWidget {
  final String imgUrl, title;
  CategoriesTile(this.title, this.imgUrl);

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Stack(
        children: <Widget>[
          Container(
            child: Image.network(imgUrl),
          ),
          Container(
            child: Text(title),
          ),
        ],
      ),
    );
  }
}

这是我的 data.dart：

import 'package:wallpaperdex/model/categorie_model.dart';

List<CategorieModel> getCategories() {
  List<CategorieModel> categories = new List();
  CategorieModel categorieModel = new CategorieModel();

  categorieModel.imgUrl =
      "https://images.pexels.com/photos/545008/pexels-photo-545008.jpeg?auto=compress&cs=tinysrgb&dpr=2&w=500";
  categorieModel.categorieName = "Street Art";
  categories.add(categorieModel);
  categorieModel = new CategorieModel();

  //
  categorieModel.imgUrl =
      "https://images.pexels.com/photos/704320/pexels-photo-704320.jpeg?auto=compress&cs=tinysrgb&dpr=2&w=500";
  categorieModel.categorieName = "Wild Life";
  categories.add(categorieModel);
  categorieModel = new CategorieModel();

  //
  categorieModel.imgUrl =
      "https://images.pexels.com/photos/34950/pexels-photo.jpg?auto=compress&cs=tinysrgb&dpr=2&w=500";
  categorieModel.categorieName = "Nature";
  categories.add(categorieModel);
  categorieModel = new CategorieModel();

  //
  categorieModel.imgUrl =
      "https://images.pexels.com/photos/466685/pexels-photo-466685.jpeg?auto=compress&cs=tinysrgb&dpr=2&w=500";
  categorieModel.categorieName = "City";
  categories.add(categorieModel);
  categorieModel = new CategorieModel();

  //
  categorieModel.imgUrl =
      "https://images.pexels.com/photos/1434819/pexels-photo-1434819.jpeg?auto=compress&cs=tinysrgb&h=750&w=1260";
  categorieModel.categorieName = "Motivation";

  categories.add(categorieModel);
  categorieModel = new CategorieModel();

  //
  categorieModel.imgUrl =
      "https://images.pexels.com/photos/2116475/pexels-photo-2116475.jpeg?auto=compress&cs=tinysrgb&dpr=2&w=500";
  categorieModel.categorieName = "Bikes";
  categories.add(categorieModel);
  categorieModel = new CategorieModel();

  //
  categorieModel.imgUrl =
      "https://images.pexels.com/photos/1149137/pexels-photo-1149137.jpeg?auto=compress&cs=tinysrgb&dpr=2&w=500";
  categorieModel.categorieName = "Cars";
  categories.add(categorieModel);
  categorieModel = new CategorieModel();

  return categories;
}

这是我的 widget.dart ：

import 'package:flutter/material.dart';

// ignore: non_constant_identifier_names
Widget BrandName() {
  return Row(
    mainAxisAlignment: MainAxisAlignment.center,
    children: <Widget>[
      Text(
        "Wallpaper",
        style: TextStyle(color: Colors.black87),
      ),
      Text(
        "Dex",
        style: TextStyle(color: Colors.blue),
      )
    ],
  );
}

这是我的 category_model.dart

class CategorieModel {
  String categorieName;
  String imgUrl;
}

就是这样，这是错误的屏幕截图，请在此处 输入图像描述

标签： androidiosflutterdartmobile