The document explains lint, a tool used for analyzing source code to identify errors and improve quality, particularly in Android development. It covers how to run lint checks, configure preferences, and integrate it into existing projects, while also mentioning the creation of custom lint rules and addressing common issues encountered. Specific lint checks and their potential impact on the build process are highlighted, along with sources for further information.

1. Fixing common
problems with Lint
Sinan Kozak
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2. What is Lint?
• lint, or a linter, is a tool that analyzes source code to flag
programming errors, bugs, stylistic errors, and suspicious
constructs. The term originates from a Unix utility that
examined C language source code.
Source: https://en.wikipedia.org/wiki/Lint_%28software%29
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3. Android lint
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4. Default lint checks for Android
• MissingPermission
• MissingSuperCall
• ScrollViewCount
• DuplicateIds
• AppCompatMethod
• ApplySharedPref
• VectorDrawableCompat
And many more…
Sources:
http://tools.android.com/tips/lint-checks
https://android.googlesource.com/platform/tools/base/+/studio-master-dev/lint/libs/lint-
checks/src/main/java/com/android/tools/lint/checks @snnkzk

5. How to run
Android lint
• ./gradlew lint
• ./gradlew lintDebug
With gradle task
• lint [flags] <project directory>
With CLI tool – “android_sdk/tools”
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6. Lint result
• It can fail the build
• abortOnError true
• Print command line
• Create xml and html reports
• Configure warnings as error
to fail build
• warningsAsErrors true
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7. How to configure
You can specify your lint checking
preferences in the ”lint.xml” file
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8. Further setup
with gradle
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9. Integrating to
existing
codebase
After first lint run for a old project, there will
be thousands of issues. Android lint supports
baseline file for ignoring existing issues
You can focus on new code
Lint can be integrated anytime
We run Lint with every pull request

10. Gradle setup for
baseline
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11. Different
ways to setup
Run for modules individually
Run for app module while
checing dependent module
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12. Unused resources
Lint can find unused resources
• Resources need to be used in same module
If you run lint on every module individually
• Use ”checkDependencies true”
• It is slower but checks lint from root persfective
• More suggestion at
• https://groups.google.com/forum/#!msg/lint-dev/RGTvK_uHQGQ/FjJA12aGBAAJ
If you have modules with just resources
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13. Beyond default rules
• You can;
• write custom rule
• integrate libraries with custom rules
• publish library with custom lint rules

14. Writing a
custom rule
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There are lots of blogs about
first lint rule
Android default lints are open
source
You can develop using TDD

15. Using TDD for
lint
development
Android lint has nice testing framework
You can create virtual files (java, kotlin, xml…)
It is way faster than running lint on project
You can create edge cases
You can even test codes with error
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16. Publishing library
with lint
• Libraries can pack their own lints rules
• By default, they are added to customer project
• Enforce best practices
• Check wrong usage of library
• Guided migration
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17. Some
custom
lint rule
libraries
• https://github.com/vanniktech/lint-rules
• AlertDialogUsage
• RawColor
• ResourcesGetColorStateListCall
• UnsupportedLayoutAttribute
• RxJava2MissingCompositeDisposableCl
ear
• https://github.com/kozaxinan/android-lints
• ImmutableDataClassRule
• NetworkLayerClassSerializedNameRule
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18. There are problems
• Android Studio does not care about custom lint setup
• https://issuetracker.google.com/issues/153521705
• Android Studio does not care about baseline file
• https://issuetracker.google.com/issues/153521704
• Lint task is not cacheable or incremental
• https://issuetracker.google.com/issues/64323422
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19. Q/A
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THANK YOU FOR LISTENING SINAN KOZAK
SENIOR ANDROID DEVELOPER
IMMOSCOUT24