The Flutter code generator for your assets, fonts, colors, … — Get rid of all String-based APIs.
Inspired by SwiftGen.
Using asset path string directly is not safe.
# pubspec.yaml
flutter:
assets:
- assets/images/profile.jpg
❌ Bad
What would happen if you made a typo?
Widget build(BuildContext context) {
return Image.asset('assets/images/profile.jpeg');
}
// The following assertion was thrown resolving an image codec:
// Unable to load asset: assets/images/profile.jpeg
⭕️ Good
We want to use it safely.
Widget build(BuildContext context) {
return Assets.images.profile.image();
}
Works with macOS and Linux.
brew install FlutterGen/tap/fluttergen
Works with macOS and Linux. asdf-fluttergen is compatible with mise.
# add plugin
asdf plugin add fluttergen
# or
asdf plugin add fluttergen https://github.com/FlutterGen/asdf-fluttergen.git
# install fluttergen
asdf install fluttergen latest
See also: FlutterGen/asdf-fluttergen
Works with macOS, Linux and Windows.
dart pub global activate flutter_gen
You might need to set up your path.
- Add build_runner and FlutterGen to your package's pubspec.yaml file:
dev_dependencies:
build_runner:
flutter_gen_runner:
- Install FlutterGen
flutter pub get
- Use FlutterGen
dart run build_runner build
Works with macOS and Linux.
- uses: FlutterGen/setup-fluttergen@v1
with:
version: ${{ fluttergen_version }}
See also: FlutterGen/setup-fluttergen
Run fluttergen
after the configuration pubspec.yaml
.
fluttergen -h
fluttergen -c example/pubspec.yaml
FlutterGen generates dart files based on the key flutter
and flutter_gen
of pubspec.yaml
.
Default configuration can be found here.
# pubspec.yaml
# ...
flutter_gen:
output: lib/gen/ # Optional (default: lib/gen/)
line_length: 80 # Optional (default: 80)
# Optional
integrations:
flutter_svg: true
rive: true
lottie: true
colors:
inputs:
- assets/color/colors.xml
flutter:
uses-material-design: true
assets:
- assets/images/
fonts:
- family: Raleway
fonts:
- asset: assets/fonts/Raleway-Regular.ttf
- asset: assets/fonts/Raleway-Italic.ttf
style: italic
You can also configure generate options in the build.yaml
, it will be read before the pubspec.yaml
if it exists.
# build.yaml
# ...
targets:
$default:
builders:
flutter_gen_runner: # or flutter_gen
options:
output: lib/build_gen/ # Optional (default: lib/gen/)
line_length: 120 # Optional (default: 80)
Following the doc
Adding assets and images#Specifying assets
to specify assets, then FlutterGen will generate related dart files.
No other specific configuration is required.
Ignore duplicated.
# pubspec.yaml
flutter:
assets:
- assets/images/
- assets/images/chip3/chip.jpg
- assets/images/chip4/chip.jpg
- assets/images/icons/paint.svg
- assets/images/icons/dart@test.svg
- assets/json/fruits.json
- assets/flare/Penguin.flr
- assets/rive/vehicles.riv
- pictures/ocean_view.jpg
These configurations will generate assets.gen.dart
under the lib/gen/
directory by default.
Flutter supports
Conditionally bundling assets based on flavor.
Assets are only available with flavors if specified.
flutter_gen
will generate the specified flavors
for assets regardless the current flavor.
The flavors
field accessible though .flavors
, for example:
print(MyAssets.images.chip4.flavors); // -> {'extern'}
You can specify flutter_gen > assets > exclude
using Glob
patterns to exclude particular assets.
flutter_gen:
assets:
exclude:
- folder-your-want-to-exclude/**
- specified-asset.jpg
See more patterns with the package:glob
.
If you want to generate assets for a package,
use package_parameter_enabled
under flutter_gen > assets > outputs
.
flutter_gen:
assets:
outputs:
package_parameter_enabled: true # <- Add this line.
This would add the package constant to the generated class. For example:
class Assets {
Assets._();
static const String package = 'test';
static const $AssetsImagesGen images = $AssetsImagesGen();
static const $AssetsUnknownGen unknown = $AssetsUnknownGen();
}
Then you can use assets with the package implicitly or explicitly:
// Implicit usage for `Image`/`SvgPicture`/`Lottie`.
Widget build(BuildContext context) {
return Assets.images.icons.paint.svg(
width: 120,
height: 120,
);
}
or
// Explicit usage for `Image`/`SvgPicture`/`Lottie`.
Widget build(BuildContext context) {
return SvgPicture.asset(
Assets.images.icons.paint.path,
package: Assets.package,
width: 120,
height: 120,
);
}
If you want to generate the path of directories,
use directory_path_enabled
under flutter_gen > assets > outputs
.
flutter_gen:
assets:
outputs:
directory_path_enabled: true # <- Add this line.
This would add the path
getter to the generated directory class. For example:
class $AssetsImagesGen {
const $AssetsImagesGen();
///******///
/// Directory path: assets/images
String get path => 'assets/images';
}
At build time, additional metadata may be included in the generated class, by using the
parse_metadata
option.
flutter_gen:
parse_metadata: true # <- Add this line (default: false)
For image based assets, a new nullable size
field is added to the
generated class. For example:
AssetGenImage get logo =>
const AssetGenImage('assets/images/logo.png', size: Size(209.0, 49.0));
Which can now be used at runtime without parsing the information from the actual asset.
Widget build(BuildContext context) {
return Assets.images.logo.size!.width;
}
FlutterGen generates Image class if the asset is Flutter supported image format.
Example results of assets/images/chip.jpg
:
Assets.images.chip
is an implementation ofAssetImage class
.Assets.images.chip.image(...)
returnsImage class
.Assets.images.chip.provider(...)
returnsImageProvider class
.Assets.images.chip.path
just returns the path string.Assets.images.chip.values
just returns the values list.
Widget build(BuildContext context) {
return Assets.images.chip.image();
}
Widget build(BuildContext context) {
return Assets.images.chip.image(
width: 120,
height: 120,
fit: BoxFit.scaleDown,
);
Widget build(BuildContext context) {
// Assets.images.chip.path = 'assets/images/chip3/chip3.jpg'
return Image.asset(Assets.images.chip.path);
}
If you are using SVG images with flutter_svg you can use the integration feature.
# pubspec.yaml
flutter_gen:
integrations:
flutter_svg: true
flutter:
assets:
- assets/images/icons/paint.svg
Widget build(BuildContext context) {
return Assets.images.icons.paint.svg(
width: 120,
height: 120
);
}
Available Integrations
Packages | File extension | Setting | Usage |
---|---|---|---|
flutter_svg | .svg | flutter_svg: true |
Assets.images.icons.paint.svg() |
rive | .riv | rive: true |
Assets.rive.vehicles.rive() |
lottie | .json, .zip, .lottie | lottie: true |
Assets.lottie.hamburgerArrow.lottie() |
In other cases, the asset is generated as String class.
// If don't use the Integrations.
final svg = SvgPicture.asset(Assets.images.icons.paint);
final json = await rootBundle.loadString(Assets.json.fruits);
FlutterGen also support generating other style of Assets
class:
# pubspec.yaml
flutter_gen:
assets:
outputs:
# Assets.imagesChip
# style: camel-case
# Assets.images_chip
# style: snake-case
# Assets.images.chip (default style)
# style: dot-delimiter
flutter:
assets:
- assets/images/chip.png
The root directory will be omitted if it is either assets
or asset
.
assets/images/chip3/chip.jpg => Assets.images.chip3.chip
assets/images/chip4/chip.jpg => Assets.images.chip4.chip
assets/images/icons/paint.svg => Assets.images.icons.paint
assets/images/icons/dart@test.svg => Assets.images.icons.dartTest
assets/json/fruits.json => Assets.json.fruits
pictures/ocean_view.jpg => Assets.pictures.oceanView
Example of code generated by FlutterGen
Just follow the doc Use a custom font to specify fonts, then FlutterGen will generate related dart files.
No other specific configuration is required.
Ignore duplicated.
# pubspec.yaml
flutter:
fonts:
- family: Raleway
fonts:
- asset: assets/fonts/Raleway-Regular.ttf
- asset: assets/fonts/Raleway-Italic.ttf
style: italic
- family: RobotoMono
fonts:
- asset: assets/fonts/RobotoMono-Regular.ttf
- asset: assets/fonts/RobotoMono-Bold.ttf
weight: 700
These configurations will generate fonts.gen.dart
under the lib/gen/
directory by default.
If you want to generate fonts for a package,
use package_parameter_enabled
under flutter_gen > fonts > outputs
.
flutter_gen:
fonts:
outputs:
package_parameter_enabled: true # <- Add this line.
This would add the package constant to the generated class. For example:
class Fonts {
Fonts._();
static const String package = 'test';
static const String raleway = 'packages/$package/Raleway';
static const String robotoMono = 'packages/$package/RobotoMono';
}
Text(
'Hi there, I\'m FlutterGen',
style: TextStyle(
fontFamily: FontFamily.robotoMono,
fontFamilyFallback: const [FontFamily.raleway],
),
)
Example of code generated by FlutterGen
FlutterGen supports generating colors from XML format files.
Ignore duplicated.
# pubspec.yaml
flutter_gen:
colors:
inputs:
- assets/color/colors.xml
- assets/color/colors2.xml
FlutterGen can generate a Color class based on the name
attribute and the color hex value.
If the element has the attribute type
, then a specially color will be generated.
Currently supported special color types:
Noticed that there is no official material color generation algorithm. The implementation is based on the mcg project.
<color name="milk_tea">#F5CB84</color>
<color name="cinnamon" type="material">#955E1C</color>
<color name="yellow_ocher" type="material material-accent">#DF9527</color>
These configurations will generate colors.gen.dart
under the lib/gen/
directory by default.
Text(
'Hi there, I\'m FlutterGen',
style: TextStyle(
color: ColorName.denim,
),
Example of code generated by FlutterGen
The material color generation implementation is based on mcg and TinyColor.
Please file FlutterGen specific issues, bugs, or feature requests in our issue tracker.
Plugin issues that are not specific to FlutterGen can be filed in the Flutter issue tracker.
If you get an error message like this:
[SEVERE] flutter_gen_runner:flutter_gen_runner on $package$:
Bad state: No element
[SEVERE] Failed after 16.0s
The you most likely have a customized build.yaml
to configure the build runner. In that case, all you have to do is to add the pubspec.yaml
as build source to your build.yaml
targets:
$default:
sources:
include:
- pubspec.yaml # add this line
- ...
See #268 for the corresponding issue discussion.
Error with internationalization
Please try to remove generate: true
in your pubspec.yaml
and disable synthetic-package
in your l10n.yaml
like:
# pubspec.yaml
flutter:
generate: true <--- ⚠️Remove this line⚠️
# l10n.yaml
arb-dir: lib/l10n
template-arb-file: app_en.arb
output-localization-file: app_localizations.dart
synthetic-package: false <--- ⚠️Add this line⚠️
If you get
We are looking for co-developers.
If you wish to contribute a change to any of the existing plugins in this repo, please review our contribution guide and open a pull request.