I am trying to make an app that rolls the dice for me and following a tutorial for the same. It looks like the tutorial is old that's why I am getting the error. the error takes me to the image_provider.dart page which says
<-----------------
@protected
Future<ui.Codec> _loadAsync(AssetBundleImageKey key, DecoderCallback decode) async {
ByteData? data;
// Hot reload/restart could change whether an asset bundle or key in a
// bundle are available, or if it is a network backed bundle.
try {
data = await key.bundle.load(key.name);
} on FlutterError {
PaintingBinding.instance.imageCache.evict(key);
rethrow;
}
if (data == null) {
PaintingBinding.instance.imageCache.evict(key);
throw StateError('Unable to read data');
}
return decode(data.buffer.asUint8List());
}
}
---------->
In the emulator I am unable to see the images.
import 'package:flutter/material.dart';
import 'homepage.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Dice Roller',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.green,
),
home: HomePage(),
);
}
}
this is homepage.dart
import 'dart:math';
import 'package:flutter/material.dart';
class HomePage extends StatefulWidget {
const HomePage({Key? key}) : super(key: key);
@override
State<HomePage> createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
AssetImage one = const AssetImage("images/one.png");
AssetImage two = const AssetImage("images/two.png");
AssetImage three = const AssetImage("images/three.png");
AssetImage four = const AssetImage("images/four.png");
AssetImage five = const AssetImage("images/five.png");
AssetImage six = const AssetImage("images/six.png");
AssetImage? diceImage;
@override
void initState() {
super.initState();
setState(() {
diceImage = one;
});
}
void rollDice() {
int rnd = 1 (Random().nextInt(6));
AssetImage? newImage;
switch (rnd) {
case 1:
newImage = one;
break;
case 2:
newImage = two;
break;
case 3:
newImage = three;
break;
case 4:
newImage = four;
break;
case 5:
newImage = five;
break;
case 6:
newImage = six;
break;
}
setState(() {
diceImage = newImage;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Dice Roller'),
),
body: Container(
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Image(
image: AssetImage('$diceImage'),
width: 200.0,
height: 200.0,
),
Container(
margin: const EdgeInsets.only(top: 100.0),
child: ElevatedButton(
onPressed: rollDice,
child: const Text("Roll The Dice!!"),
),
),
],
),
),
),
);
}
}
this is pubsec.yaml
name: diceroller
description: A new Flutter project.
# The following line prevents the package from being accidentally published to
# pub.dev using `flutter pub publish`. This is preferred for private packages.
publish_to: "none" # Remove this line if you wish to publish to pub.dev
# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a .
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0 1
environment:
sdk: ">=2.17.0 <3.0.0"
# Dependencies specify other packages that your package needs in order to work.
# To automatically upgrade your package dependencies to the latest versions
# consider running `flutter pub upgrade --major-versions`. Alternatively,
# dependencies can be manually updated by changing the version numbers below to
# the latest version available on pub.dev. To see which dependencies have newer
# versions available, run `flutter pub outdated`.
dependencies:
flutter:
sdk: flutter
# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^1.0.2
dev_dependencies:
flutter_test:
sdk: flutter
# The "flutter_lints" package below contains a set of recommended lints to
# encourage good coding practices. The lint set provided by the package is
# activated in the `analysis_options.yaml` file located at the root of your
# package. See that file for information about deactivating specific lint
# rules and activating additional ones.
flutter_lints: ^2.0.0
# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec
# The following section is specific to Flutter packages.
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true
# To add assets to your application, add an assets section, like this:
assets:
- images/
# An image asset can refer to one or more resolution-specific "variants", see
# https://flutter.dev/assets-and-images/#resolution-aware
# For details regarding adding assets from package dependencies, see
# https://flutter.dev/assets-and-images/#from-packages
# To add custom fonts to your application, add a fonts section here,
# in this "flutter" section. Each entry in this list should have a
# "family" key with the font family name, and a "fonts" key with a
# list giving the asset and other descriptors for the font. For
# example:
# fonts:
# - family: Schyler
# fonts:
# - asset: fonts/Schyler-Regular.ttf
# - asset: fonts/Schyler-Italic.ttf
# style: italic
# - family: Trajan Pro
# fonts:
# - asset: fonts/TrajanPro.ttf
# - asset: fonts/TrajanPro_Bold.ttf
# weight: 700
#
# For details regarding fonts from package dependencies,
# see https://flutter.dev/custom-fonts/#from-packages
Debug console says Unable to load asset: AssetImage(bundle: null, name: "images/one.png")
CodePudding user response：
There can be any of the following reasons for getting this error:
1- Spelling mistake in the image name 2- Wrong Image path provided (Image doesn’t exist at specified location) 3- Wrong indentation for assets in pubspec.yaml file
CodePudding user response：
below code only works if one.png is inside the images directory. if any other directory contains images directory, then you need to implement it in pubspec.yaml.
try this and confirm.
Image(
image: AssetImage("images/one.png"),
width: 200.0,
height: 200.0,
),
if this works, you need to check the value of $diceImage
CodePudding user response：
diceImage is already AssetImage.
Image(
image: diceImage,
width: 200.0,
height: 200.0,
),
CodePudding user response：
Here, you are assigning AssetImage directly
AssetImage? diceImage;
@override
void initState() {
super.initState();
setState(() {
diceImage = one;
});
}
So I believe you should use it like,
children: <Widget>[
Image(
image: diceImage,
width: 200.0,
height: 200.0,
),
Container(
margin: const EdgeInsets.only(top: 100.0),
child: ElevatedButton(
onPressed: rollDice,
child: const Text("Roll The Dice!!"),
),
),
],