android-ktlint-formatting

name	android-ktlint-formatting
description	Use when formatting Kotlin code, enforcing the Android style guide, or configuring KtLint for Android.
category	quality
risk	low
source	community
date_added	2026-03-31
metadata	{"triggers":["@ktlint","kotlin-format","style-guide","reformatting","ktlint-check"]}

Android KtLint Formatting Excellence 🧹💎

Standardized formatting rules for Android developers based on the official Kotlin and Android Style Guides.

⚡ When to Use

• Code Cleanup: Automatically reformatting messy files.
• Pre-commit Audit: Ensuring the code is perfectly formatted before pushing.
• CI/CD Configuration: Setting up a gatekeeper for code style.
• New Project Setup: Initializing a project with the correct .editorconfig.

🏗️ Core Rules (Android Style)

1. Indentation

• Use 4 spaces for indentation.
• No TAB characters allowed.
• Follow "Continuation Indents" for long method calls (8 spaces).

2. Imports

• Rule: Avoid wildcard imports (import com.example.*).
• Order alphabetically.
• Group by java.*, kotlin.*, then external libraries.

3. Blank Lines

• Single blank line between classes, properties, and methods.
• NO trailing whitespace at the end of lines.
• NO multiple blank lines.

4. Naming

• Classes/Interfaces: PascalCase.
• Properties/Variables: camelCase.
• Functions: camelCase.
• Constants: SCREAMING_SNAKE_CASE.

🛠️ Essential Commands

Check Formatting

./gradlew ktlintCheck

Auto-Fix Formatting

• Rule: ALWAYS run this before committing if formatting changes are extensive.

./gradlew ktlintFormat

📜 Configuration (.editorconfig)

Ensure your project has a .editorconfig that KtLint reads:

[*.{kt,kts}]
indent_size=4
insert_final_newline=true
max_line_length=120
ij_kotlin_allow_trailing_comma=true

🚀 Performance & Tips

• IDE Integration: Install the "KtLint" or "Kotlin" plugin and enable "On Save" actions.
• Trailing Comma: Use trailing commas for all multi-line collections and arguments for better diffs.
• Imports Cleanup: Periodically run Alt+Enter → "Optimize Imports".

🧪 Verification Checklist

• No Wildcards: All imports are explicit.
• No Tabs: Only spaces.
• EndOfLine: File ends with exactly one newline.
• No Redundant Semicolons: Clean up all unnecessary ;.

🔗 Related Resources

• Official Pinterest KtLint
• Android Kotlin Style Guide
• Code Review Expert