flutter_resource_generator 1.0.0

Generator resource class automatically

Overview

Import resource file into pubspec.yaml and generate resource class automatically by build runner

Getting Started

For example, there are some image files under your asset folder named assets which is located in the root folder of your project

project root/
    assets/
        iamge_a.jpg
        image_b.jpg

Firstly, add flutter_resource_generator and build_runner under dev_dependency in your pubspec.yaml

dev_dependencies:
  build_runner: ^1.8.1
  flutter_resource_generator: ^0.0.1

Then add ResourceConfig annotation on your app class

@ResourceConfig(resourcePath: 'assets/')
class MyApp extends StatelessWidget {}

Finally, run build runner command

flutter packages pub run build_runner build --delete-conflicting-outputs

After build runner finished, image file items have been added into pubsepc.yaml

flutter:
  assets:
    - assets/image_a.jpg
    - assets/image_b.jpg

and resource class has been create along with dart file which your app class located in, for example the dart file is main.dart, then the generated resource class dart file will be main.resource.dart.

The content of the resource class will be some thing like

abstract class R_Image {
  static const String IMAGE_A = "assets/image_a.jpg"
  static const String IMAGE_B = "assets/image_b.jpg"
}

Then you can use R_Image.IMAGE_A to access this image at anywhere you want

ResourceConfig

You can use ResourceConfig class to customize how to handle resource file, here is all the parameters you can modify:

• String resourcePath: The relative path of your asset file folder, for example 'assets/', must NOT be empty

• String imageClassName: The name of image resource class, by default, it is R_Image, can be null

• String fontClassName: The name of font resource class, by default, it is R_Font, can be null

• bool handleFontFile: Whether font file will be handled, by default, it is false, can be null

• List<String> ignoreExtensions: The file with extension existed in this list will be ignored, can be null

• List<String> extraImageExtensions: The file with extension existed in [".png", ".jpg", ".jpeg", ".gif", ".webp", ".icon", ".bmp", ".wbmp", ".svg"] or extraImageExtensions will be treat as image, can be null

• Map<String, String> extensionClassNameMapping: By default, the class name of other files will be R_${extension}, for example, the resource class of json files will be R_Json. if you want customize the class name of json file, like JsonRes, you can pass {".json", "JsonRes"}, can be null

Font

Since font conifguration is very complex, family, weight and style can be set for each font file. You need to set these paramters for every single font file to generate font resource information, the workload is the same as directly add this parameters into pubspec file. So by default, we don't handle font file, if you set handleFontFile to true, we will add every font file into pubspec file as separate font family, and the original font section in pubspec file will be OVERWRITE.

For example, you have three font files in your resource folder

project root/
    assets/
        font_a.ttf
        font_b.ttf
        font_c.ttf

the generated font section in pubspec file will be something like

fonts:
    - family: font_a
      fonts:
        - asset: assets/font_a.ttf
    - family: font_b
      fonts:
        - asset: assets/font_b.ttf
    - family: font_c
      fonts:
        - asset: assets/font_c.ttf

No matter whether handleFontFile is true or false, font family resource class will be generated by parsing every family item under fonts section in pubspec file, as the font section showed before, the generated font class will be something like this

abstract class R_Font {
  static const String FONT_A = "assets/font_a.jpg"
  static const String FONT_B = "assets/font_b.jpg"
  static const String FONT_C = "assets/font_c.jpg"
}

Ilegal char

Some char is legal for file name but ilegal for class or varaiable name, such as '-', these ilegal char will be replaced by '_' in class name and variable name in generated resource class. And number 0-9 is ilegal as first char for class and variable name, so if resource file name is start by number, '$' will be added as prefix.

FAQ

Q. I add new resource file into project, then run build runner command, why new file is not added into pubsepc file and resource class? A. You need run 'flutter packages pub run build_runner clean' first

Contact Info

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