Flutter Build Runner is one of the most imperative tools in the Flutter development environment. It provides various build options such as running Flutter tests, generating Dart code files, building APKs & IPA files, and more. Flutter Build Runner is essentially a command-line interface to perform actions on your project.
In this article, we will take a closer look at what Flutter Build Runner is, what it does, and how to use it with code examples.
What is Flutter Build Runner?
Flutter Build Runner is a tool provided by Flutter SDK that serves as an effective tool for building and running your Flutter applications. It is a command-line interface to run a set of tasks that are related to your project development. These tasks can be running tests, generating code, building APKs and IPAs, and more.
Furthermore, Flutter Build Runner provides you with custom templates to run a set of tasks related to your project development. For example, we can define that we need to run tests before building the application. It will force the Flutter Build Runner to run tests before it actually builds the application.
Using Flutter Build Runner
The best way to show how to use Flutter Build Runner is by presenting the most commonly used commands with examples.
Flutter Build
The Flutter build command is one of the most important commands that the Build Runner provides. It is used to build Flutter applications for different platforms such as Android and iOS. You can also provide custom options to the Flutter build command when building the application like providing the target platform and building a specific Flutter module.
Example:
$ flutter build // Builds the current module for the current platform
$ flutter build –target-platform=ios // Builds the current module for iOS platform
$ flutter build –module=my_module // Builds the my_module module
Flutter Gen
Flutter Gen is another useful command that the Build Runner provides. It is used to generate files based on templates that are defined in your project. For example, you can use Flutter Gen to generate a localization class using the localization template.
Example:
$ flutter gen localizations // Generates a localization class using the localization template
Flutter Test
Flutter Test is the command used to run tests in your Flutter project. You can run all the tests at once or a specific test if you prefer. It also provides options to generate code coverage reports and format them based on your preference.
Example:
$ flutter test // Runs all the tests in the project
$ flutter test test/widget_test.dart // Runs the widget_test.dart test file
Flutter Clean
Flutter Clean is a command that is used to clear the build artifacts generated by the Build Runner. It is useful when you want to start building the project from scratch. The command erases all the compiled code for the project and resets the environment.
Example:
$ flutter clean // Clears all the built artifacts in the project
Conclusion
Flutter Build Runner is an essential tool for developers to build and run Flutter applications. The Build Runner provides various commands to automate the most commonly used tasks in Flutter development, such as building and testing.
In this article, we have covered some basic commands used by Flutter Build Runner along with their examples. These commands will help you get started with using Build Runner in your own projects, and make your development process faster and more efficient.
let's dive deeper into some of the topics covered in the previous section.
Flutter Build
Flutter Build is a command that is used to build a Flutter project for different platforms such as Android, iOS, and web. You can also build custom options when building the application, including providing a custom output directory, building a specific module, and providing arguments to the build.
For example, if you want to build an APK for Android, you can use the following command:
flutter build apk
This will build an APK file for your project. You can also provide additional options such as the output directory, as shown below:
flutter build apk --target-platform android-arm --split-per-abi --output-dir build/app/outputs/apk/
This will build an APK with the target platform of android-arm and also split the APK per ABI (Application Binary Interface), which means separate APKs will be generated for different device architectures. The result will be saved to the build/app/outputs/apk/ directory.
Flutter Gen
Flutter Gen is a command that is used to generate code based on templates defined in your project. The templates define how the generated code will look like, and you can customize them to your liking.
For example, if you want to generate a localization class, you can use the following command:
flutter gen localizations --template=arb
This will generate a localization class based on the ARB (Application Resource Bundle) template. The resulting class will be placed in the lib/generated directory of your project.
You can also customize the templates to your liking by creating a gen directory in your project directory and placing your templates inside the directory. You can then reference the templates in your commands using the --template option.
Flutter Test
Flutter Test is a command that is used to run tests in your Flutter project. You can run all the tests at once or a specific test if you prefer. It also provides options to generate code coverage reports and format them based on your preference.
For example, if you want to run all the tests in your project, you can use the following command:
flutter test
This will run all the tests in your project. You can also provide additional options such as -p to run tests in parallel, -j to specify the number of test shards to use for parallel execution, and -r to specify a regular expression that matches the names of the tests that should be run.
Flutter Clean
Flutter Clean is a command that is used to clear the build artifacts generated by the Build Runner. It is useful when you want to start building the project from scratch. The command erases all the compiled code for the project and resets the environment.
For example, if you want to clean your project, you can use the following command:
flutter clean
This will erase all the built artifacts, such as the build directory and any compiled code.
Conclusion
Flutter Build Runner is a powerful tool provided by the Flutter SDK that can automate many of the common tasks in Flutter development, such as building, testing, and code generation. By using the commands provided by the Build Runner, you can make your development process faster and more efficient.
Popular questions
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What is Flutter Build Runner?
Flutter Build Runner is an essential tool provided by Flutter SDK that enables developers to build and run Flutter applications. It provides a command-line interface to run a set of tasks related to your project development, such as building the application, running tests, and generating code. -
What are some common commands used with Flutter Build Runner?
Some common commands used with Flutter Build Runner includeflutter buildto build the application for different platforms,flutter gento generate code based on templates defined in your project,flutter testto run tests in your project, andflutter cleanto clear the build artifacts generated by Build Runner. -
Can you customize the templates used by Flutter Gen?
Yes, you can customize the templates used by Flutter Gen by creating agendirectory in your project directory and placing your templates inside the directory. You can then reference the templates in your commands using the--templateoption. -
What is the purpose of Flutter Clean?
Flutter Clean is a command that is used to erase all the built artifacts, such as the build directory and any compiled code. It is useful when you want to start building the project from scratch or need to reset the environment. -
How can you build an APK for Android using Flutter Build?
To build an APK for Android using Flutter Build, you can use the commandflutter build apk. You can also provide additional options, such as the target platform, the output directory, and the split-per-ABI option to generate separate APKs for different device architectures.
Tag
FlutterBuildRunnerExamples
