Project Standarts With Ktlint

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Introduction

Hi 👋, there can be small details that we overlook in code snippets that need to be delivered urgently in our projects. We might not have the opportunity to fix these small details later, or we may find ourselves at the end of the project surrounded by such disorder while thinking “I’ll look at it later”. In situations like this, I’m here to remind you of the details that make our code more organized and beautiful, such as warnings from our IDE that indicate areas for improvement even though they are not errors, and the whitespace that should be left behind.

Let’s take a look at what ktlint is❓ And how it is used❓

What is ktlint❓

Ktlint is a code inspection tool for the Kotlin programming language. It can be used in integrated development environments (IDEs) like Android Studio to check the compliance of your codebase with style and quality guidelines.

Ktlint verifies whether your Kotlin code adheres to a specific style guide (typically the Kotlin Style Guide or a customized style file). These style guides are based on best practices and standards for the Kotlin language. It checks elements such as code formatting, indentation, whitespace, parentheses usage, and other coding styles.

Ktlint automatically detects code that deviates from the style guide and provides developers with suggestions for appropriate fixes. It is a valuable tool for ensuring code consistency within a team and making the codebase more readable and maintainable.

To use ktlint in Android Studio, you may need to add the ktlint plugin to your project and configure the configuration file. Ktlint can also be used as a command-line tool and can be integrated with certain continuous integration (CI) tools.

In summary, ktlint is a code inspection tool that checks the compliance of your Kotlin code with style guidelines and provides suggestions for appropriate fixes. It helps improve the readability and maintainability of your code.

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How to Use ktlint❓

Step 1: Let’s start by handling the configurations in our build.gradle file as the first step. I will share all the necessary steps with you using a single gist.

build.gradle

Step 2: Let’s create an .editorconfig file.

The .editorconfig file is a configuration file used for formatting project files. Tools like ktlint read the settings in the .editorconfig file to apply specific code formatting and style rules.

In Kotlin projects, the .editorconfig file ensures consistent code formatting and style throughout the project. This file contains a set of style settings that are automatically applied to project files.

For example, the .editorconfig file can be configured as follows:

.editor config file

In the above code example, the indent_style setting is set to "space", indicating that indentation should be done using space characters. The indent_size is set to 4, meaning that 4 spaces will be used for each level of indentation. Other settings specify a specific character encoding, trimming trailing whitespace, and adding a newline at the end of the file.

The .editorconfig file ensures the consistency of code style among the project team and helps make the project more readable and manageable overall.

Yes, I believe we’ve handled all the configurations. Now, let’s move on to the terminal🙃.

Checking the code style: You can scan your project files and detect errors that do not conform to a specific code style by using the ktlintCheck command. For example:

Terminal usage

This command scans the specified file or directory for Kotlin files and checks the code style. Errors that do not conform to the code style are reported.

Fixing style violations: The ktlintFormat command can automatically fix style violations and update project files. For example:

Terminal usage

This command scans the specified file or directory for Kotlin files and automatically fixes style violations. It updates the files accordingly.

Project integration: ktlint can be integrated into your projects for build processes or CI/CD pipelines. This ensures that the code style is checked and style violations are reported during each build or CI/CD process.

In addition, we can also ensure that ktlint is automatically executed with every build process, even if we forget to run it manually.

Using Git Hooks: Git hooks are custom scripts that are automatically run at certain stages of Git operations (commit, push, etc.). For example, using a pre-commit hook, you can automatically run ktlint before each commit. Here’s a simple example:

• Create the .git/hooks/pre-commit file (if it doesn’t exist) and add the following script:

pre-commit file

terminal usage

Now, ktlint will automatically run before each commit, and if any style violations are detected, the commit process will be prevented.

Integration into the build process: You can include ktlint in the project’s build process. This way, the commands used to compile or build the project can automatically run ktlint. For example, for a Gradle project, you can add the following configuration to the build.gradle file:

build.gradle file

The above configuration will automatically run ktlint after the Kotlin compilation process. It will scan the Kotlin files in the src/main/kotlin directory and report any style violations. If style violations are detected during the compilation process, the build will fail.

With these methods, you can automatically run ktlint before committing or during the compilation process and ensure that your code adheres to specific style rules. It’s up to you to decide which method is more suitable for your project and how to integrate it.

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Conclusion

Projects are collaborative environments where multiple individuals work together. If each individual applies their own standards, the resulting product can become inconsistent and messy. That’s why certain rules and standards have been established. These rules may not always be a priority for developers, which can lead to code inconsistency. Ktlint helps ensure that multiple developers working on the same project write code in a consistent manner. As projects continue to evolve, maintaining a consistent codebase becomes crucial for the smooth onboarding of new developers.

Until the next article, stay healthy and code well! 👨‍💻🙋‍♂️

References

GitHub — JLLeitschuh/ktlint-gradle: A ktlint gradle plugin

Static code analysis tools for Android (Kotlin)