A Powerful and Efficient Way to Display Images in Flutter

Cached network image

A flutter library to show images from the internet and keep them in the cache directory.

Sponsors

How to use

The CachedNetworkImage can be used directly or through the ImageProvider. Both the CachedNetworkImage as CachedNetworkImageProvider have minimal support for web. It currently doesn't include caching.

With a placeholder:

CachedNetworkImage(
        imageUrl: "http://via.placeholder.com/350x150",
        placeholder: (context, url) => CircularProgressIndicator(),
        errorWidget: (context, url, error) => Icon(Icons.error),
     ),

Or with a progress indicator:

CachedNetworkImage(
       imageUrl: "http://via.placeholder.com/350x150",
       progressIndicatorBuilder: (context, url, downloadProgress) => 
               CircularProgressIndicator(value: downloadProgress.progress),
       errorWidget: (context, url, error) => Icon(Icons.error),
    ),

Image(image: CachedNetworkImageProvider(url))

When you want to have both the placeholder functionality and want to get the imageprovider to use in another widget you can provide an imageBuilder:

CachedNetworkImage(
  imageUrl: "http://via.placeholder.com/200x150",
  imageBuilder: (context, imageProvider) => Container(
    decoration: BoxDecoration(
      image: DecorationImage(
          image: imageProvider,
          fit: BoxFit.cover,
          colorFilter:
              ColorFilter.mode(Colors.red, BlendMode.colorBurn)),
    ),
  ),
  placeholder: (context, url) => CircularProgressIndicator(),
  errorWidget: (context, url, error) => Icon(Icons.error),
),

How it works

The cached network images stores and retrieves files using the flutter_cache_manager.

FAQ

My app crashes when the image loading failed. (I know, this is not really a question.)

Does it really crash though? The debugger might pause, as the Dart VM doesn't recognize it as a caught exception; the console might print errors; even your crash reporting tool might report it (I know, that really sucks). However, does it really crash? Probably everything is just running fine. If you really get an app crashes you are fine to report an issue, but do that with a small example so we can reproduce that crash.

See for example this or this answer on previous posted issues.

.editorconfig

# EditorConfig is awesome:http://EditorConfig.org

# top-most EditorConfig file
root = true

# Don't use tabs for indentation.
[*]
indent_style = space
# (Please don't specify an indent_size here; that has too many unintended consequences.)

# Code files
[*.{cs,csx,vb,vbx}]
indent_size = 4
insert_final_newline = true
charset = utf-8-bom

# Xml project files
[*.{csproj,vbproj,vcxproj,vcxproj.filters,proj,projitems,shproj}]
indent_size = 2

# Xml config files
[*.{props,targets,ruleset,config,nuspec,resx,vsixmanifest,vsct}]
indent_size = 2

# JSON files
[*.json]
indent_size = 2

# Dotnet code style settings:
[*.{cs,vb}]
# Sort using and Import directives with System.* appearing first
dotnet_sort_system_directives_first = true
# Avoid "this." and "Me." if not necessary
dotnet_style_qualification_for_field = false:suggestion
dotnet_style_qualification_for_property = false:suggestion
dotnet_style_qualification_for_method = false:suggestion
dotnet_style_qualification_for_event = false:suggestion

# Use language keywords instead of framework type names for type references
dotnet_style_predefined_type_for_locals_parameters_members = true:suggestion
dotnet_style_predefined_type_for_member_access = true:suggestion

# Suggest more modern language features when available
dotnet_style_object_initializer = true:suggestion
dotnet_style_collection_initializer = true:suggestion
dotnet_style_coalesce_expression = true:suggestion
dotnet_style_null_propagation = true:suggestion
dotnet_style_explicit_tuple_names = true:suggestion

# CSharp code style settings:
[*.cs]
# Prefer "var" everywhere
csharp_style_var_for_built_in_types = true:suggestion
csharp_style_var_when_type_is_apparent = true:suggestion
csharp_style_var_elsewhere = true:suggestion

# Prefer method-like constructs to have a block body
csharp_style_expression_bodied_methods = false:none
csharp_style_expression_bodied_constructors = false:none
csharp_style_expression_bodied_operators = false:none

# Prefer property-like constructs to have an expression-body
csharp_style_expression_bodied_properties = true:none
csharp_style_expression_bodied_indexers = true:none
csharp_style_expression_bodied_accessors = true:none

# Suggest more modern language features when available
csharp_style_pattern_matching_over_is_with_cast_check = true:suggestion
csharp_style_pattern_matching_over_as_with_null_check = true:suggestion
csharp_style_inlined_variable_declaration = true:suggestion
csharp_style_throw_expression = true:suggestion
csharp_style_conditional_delegate_call = true:suggestion

# Newline settings
csharp_new_line_before_open_brace = all
csharp_new_line_before_else = true
csharp_new_line_before_catch = true
csharp_new_line_before_finally = true
csharp_new_line_before_members_in_object_initializers = true
csharp_new_line_before_members_in_anonymous_types = true

.gitattributes

# This file is understood by git 1.7.2+.

# Windows specific files should always be crlf on checkout
*.bat text eol=crlf
*.cmd text eol=crlf
*.ps1 text eol=crlf

# Check out the following as ln always for osx/linux/cygwin
*.sh text eol=lf

# Opt in the following types to always normalize line endings
# on checkin and always use native endings on checkout.
*.config  text
*.cs      text diff=csharp
*.csproj  text
*.md      text
*.msbuild text
*.nuspec  text
*.pp      text
*.ps1     text
*.sln     text
*.tt      text
*.txt     text
*.xaml    text
*.xml     text

# Binary files
*.bmp     binary
*.jpeg    binary
*.jpg     binary
*.nupkg   binary
*.png     binary
*.sdf     binary

*.java linguist-language=Dart
*.kt linguist-language=Dart
*.swift linguist-language=Dart
*.m linguist-language=Dart
*.h linguist-language=Dart

.gitignore

# Miscellaneous
*.class
*.lock
*.log
*.pyc
*.swp
.DS_Store
.atom/
.buildlog/
.history
.project
.svn/
bin/

# IntelliJ related
*.iml
*.ipr
*.iws
.idea/

# Android Studio related
android/.classpath
android/.settings/

# Visual Studio Code related
.vscode/

# Flutter repo-specific
/bin/cache/
/bin/mingit/
/dev/benchmarks/mega_gallery/
/dev/bots/.recipe_deps
/dev/bots/android_tools/
/dev/docs/doc/
/dev/docs/lib/
/dev/docs/pubspec.yaml
/packages/flutter/coverage/
version

# Flutter/Dart/Pub related
**/doc/api/
.dart_tool/
.flutter-plugins
.packages
.pub-cache/
.pub/
build/
flutter_*.png
linked_*.ds
unlinked.ds
unlinked_spec.ds
flutter_export_environment.sh

# Android related
**/android/**/gradle-wrapper.jar
**/android/.gradle
**/android/captures/
**/android/gradlew
**/android/gradlew.bat
**/android/local.properties
**/android/**/GeneratedPluginRegistrant.java

# iOS/XCode related
**/ios/**/*.mode1v3
**/ios/**/*.mode2v3
**/ios/**/*.moved-aside
**/ios/**/*.pbxuser
**/ios/**/*.perspectivev3
**/ios/**/*sync/
**/ios/**/.sconsign.dblite
**/ios/**/.tags*
**/ios/**/.vagrant/
**/ios/**/DerivedData/
**/ios/**/Icon?
**/ios/**/Pods/
**/ios/**/.symlinks/
**/ios/**/profile
**/ios/**/xcuserdata
**/ios/.generated/
**/ios/Flutter/App.framework
**/ios/Flutter/Flutter.framework
**/ios/Flutter/Generated.xcconfig
**/ios/Flutter/app.flx
**/ios/Flutter/app.zip
**/ios/Flutter/flutter_assets/
**/ios/ServiceDefinitions.json
**/ios/Runner/GeneratedPluginRegistrant.*

# Exceptions to above rules.
!**/ios/**/default.mode1v3
!**/ios/**/default.mode2v3
!**/ios/**/default.pbxuser
!**/ios/**/default.perspectivev3
!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
example/.flutter-plugins-dependencies
cached_network_image/example/.flutter-plugins-dependencies
cached_network_image/example/lib/generated_plugin_registrant.dart
cached_network_image/.flutter-plugins-dependencies

Download details:

Author: Baseflow
Source: https://github.com/Baseflow/flutter_cached_network_image

#flutter #dart