android-lint-and-quality

Android Code Quality & Linting 🧹🛡️

Professional strategies for enforcing team standards and preventing technical debt through automated static analysis.

⚡ When to Use

• Code Review Readiness: Automatically checking Pull Requests for common errors.
• Enforcing Style: Ensuring all developers follow the same Kotlin formatting.
• Complex Bug Prevention: Using custom Lint rules to catch project-specific issues.
• CI/CD Automation: Failing builds on logic or style violations.
• Gradual Refactoring: Deprecating legacy methods and encouraging migration.

🏗️ The 3 Layers of Analysis

1. Android Lint (Built-in)

• Rules: Catch memory leaks, missing accessibility labels, and incorrect resource usages.
• Customization: Use lint-rules module to write your own rules specific to your app architecture.

2. Detekt (Core Logic Static Analysis)

• Benefit: Checks for code smells (Long methods, deep nested loops, cognitive complexity).
• Gradle Task: ./gradlew detekt

3. KtLint (Formatting)

• Benefit: Focuses purely on coding style (Indentation, line length, spacing).
• Rule: Follow the Official Android Kotlin Style Guide.
• Gradle Task: ./gradlew ktlintCheck / ./gradlew ktlintFormat

🚀 Quality Enforcement Checklist

• [ ] Fail Fast: Set abortOnError = true in Gradle to ensure bad code never stays in the repo.
• [ ] Custom Rules: For example: "No Log.d allowed in production" or "All ViewModels must inherit from BaseViewModel".
• [ ] Baseline Files: Use baseline.xml to ignore existing issues in older code and only enforce rules on new changes.

🛠️ Configuration Example

// build.gradle.kts
lint {
    isWarningsAsErrors = true
    isAbortOnError = true
    xmlReport = true
    htmlReport = true
}

detekt {
    buildUponDefaultConfig = true
    allRules = false
    config = files("$projectDir/config/detekt.yml")
}

📐 Team Policy Best Practices

• Pre-commit Hooks: Use Git Hooks to run KtLint locally before pushing.
• CI Report Annotation: Configure CI (e.g., GitHub Actions) to comment directly on PR lines with Lint/Detekt findings.
• Quality Gates: Maintain a score using tools like SonarQube or Codecov.

🧪 Testing Your Quality Setup

• Lint Tests: Use LintDetectorTest to verify that your custom rules actually catch what they should.
• Baseline Evolution: Regularly review and clean up baseline files to pay down technical debt.

🔗 Related Resources

• Android Lint Official Guide
• Detekt Documentation
• KtLint Documentation