Remove Unused Resources Plugin for Android
A gradle plugin to remove unused android resources by Android Lint results xml file.
This is useful for CI because that is provided by gradle task.
Concepts
- This plugin uses Android Lint results xml file for detect unused resources.
- It supports multi module Android project, because of using Android Lint.
- It supports generated sources like DataBinding, Epoxy...
- Android Lint supports them by isCheckGeneratedSources option.
- This plugin provides gradle task.
- It is suitable to run in CI action.
- It is equivalent to Android Studio's
Refactor > Remove Unused Resources...action.
- Support all Android's resource type and alternative resources detection.
- Support all resources (animator, anim, color...) in https://developer.android.com/guide/topics/resources/providing-resources#ResourceTypes
- Support alternative resources (
-: ex, values-night, drawable-hdpi, values-v26...) - Support 9-patch drawable files detection.
- Preserve original characters in XML
- This plugin can delete unused XML element without modifying other characters and XML structures.
- example: don't extract
&#{unicode};, don't replace>with>, don't replace XML empty tag...
- example: don't extract
- This plugin can delete unused XML element without modifying other characters and XML structures.
- Fast
- It is fast task because this plugin executes only deleting resource tags or files.
- Android Lint task may takes long time than this plugin takes
😇
- Android Lint task may takes long time than this plugin takes
- It is fast task because this plugin executes only deleting resource tags or files.
Requires
- Gradle 5.6 ~
- use new Plugin version management system (settings.gradle.kts + pluginManagement)
- Android Gradle Plugin 4.0.0 ~
Usage
Add pluginManagement repository settings.
settings.gradle.kts
// ...
pluginManagement {
repositories {
google()
mavenCentral()
gradlePluginPortal()
}
}
// ...
Apply the plugin to your app module.
app/build.gradle.kts
plugins {
id("io.github.irgaly.remove-unused-resources") version "1.2.0"
}
Ensure your lintOptions is correctly set for UnusedResources rule.
isCheckGeneratedSources = trueis required, if you use code generation such as DataBinding or Epoxy.- This is required to each projects that uses code generation.
isCheckDependencies = trueis required, if you use multi module project.- This option let lint to analyze all resources in all module.
- This option is default to true since AGP 7.1.0.
- This is required only in app project.
app/build.gradle.kts
lintOptions {
// isCheckGeneratedSources is slow down Android Lint analysing.
// It is recommended to disable this when you analyse other lint rules but UnusedResources rule.
isCheckGeneratedSources = true
// for multi module. This is default to true since AGP 7.1.0
isCheckDependencies = true
}
othermodule/build.gradle.kts
lintOptions {
// if a module uses code generation, this is required each project.
isCheckGeneratedSources = true
}
Run Android Lint, that contains UnusedResources analyser.
% ./gradlew :app:lintDebug
Run clean up task, then unused resources are deleted.
% ./gradlew :app:removeUnusedResources -Prur.lintVariant="debug"
console outputs like:
> Task :app:removeUnusedResources
delete resource file: /src/app/src/main/res/drawable/usused_drawable.xml
delete resource element: R.color.usused_color in /src/app/src/main/res/values/colors.xml
delete resource element: R.color.usused_color_with_night_theme in /src/app/src/main/res/values-night/colors.xml
delete resource file because of empty: /src/app/src/main/res/values-night/colors.xml
delete resource element: R.color.usused_color_with_night_theme in /src/app/src/main/res/values/colors.xml
modified XML exmaple:
Only modifies unused resource tag, preserve others (XML indent, spaces, special reference characters...) as it is.
Plugin Sample -
unused
© = ©
">
--- a/sample/src/main/res/values/strings.xml +++ b/sample/src/main/res/values/strings.xml @@ -1,7 +1,6 @@Plugin Sample -unused © = ©
Run lint only for UnusedResources
This plugin provides simple utility for lint, that overrides lint options.
For example, this command let lint to check only UnusedResources rule.
% ./gradlew :app:lintDebug -Prur.lint.onlyUnusedResources
The -Prur.lint.onlyUnusedResources overrides lint options by settings below:
lintOptions {
// These settings are applied automatically by the plugin, when -Prur.lint.onlyUnusedResources is specified,
// so you don't have to add these settings in build.gradle.kts.
xmlReport = true // only app project
isCheckDependencies = true // only app project
isCheckGeneratedSources = true
checkOnly.clear()
checkOnly("UnusedResources")
warning("UnusedResources")
}
Disable or Overrides lintConfig
This command disables to load default lint.xml.
% ./gradlew :app:lintDebug -Prur.lint.disableLintConfig
The -Prur.lint.disableLintConfig overrides lint options by settings below:
lintOptions {
lintConfig = File("") // invalid file, so it is disabled to load lint.xml
}
Also you can overrides a single lintConfig file for all projects.
% ./gradlew :app:lintDebug -Prur.lint.overrideLintConfig="./lint.unusedresources.xml"
The details of lint.xml format is here .
Recommended CI usage with one liner
This is recommended one liner for CI.
% ./gradlew :app:lintDebug :app:removeUnusedResources -Prur.lint.onlyUnusedResources -Prur.lint.disableLintConfig -Prur.lintVariant="debug"
This executes:
- Run Android Lint with
checkOnly("UnusedResources")and ignoring lint.xml config.- Disabling lint.xml is recommended, because lint.xml settings conflicts checkOnly option.
- Report will be saved to
app/build/reports/lint-results-debug.xml.
- Clean up unused resources by lint result (
app/build/reports/lint-results-debug.xml)
Exclude Resources rules
There are options to set exclude resource ID rules or file path rules.
See Gradle configuration syntax section.
Gradle task and options
Gradle tasks:
| task | description |
|---|---|
| removeUnusedResources | delete unused resources |
Gradle properties:
| property | description | example |
|---|---|---|
| rur.dryRun | only output result, without deletion | ./gradlew :app:removeUnusedResouces -Prur.dryRun |
| rur.lintVariant | the variant for lint result xml path. if lintResultXml is set, lintVariant is ignored. use {buildDir}/reports/lint-results-{default variant}.xml if no variant is specified in AGP 7.0.0 or upper. |
./gradlew :app:removeUnusedResources -Prur.lintVariant=debug |
| rur.lintResultXml | the lint result xml path from rootProject (or full absolute path) | ./gradlew :app:removeUnusedResources -Prur.lintResultXml="./app/build/reports/lint-results-debug.xml" |
| rur.lint.onlyUnusedResources | override lintOptions for checkOnly UnusedResources | ./gradlew :app:lintDebug -Prur.lint.onlyUnusedResources |
| rur.lint.disableLintConfig | override lintOptions.lintConfig to empty to disable lint.xml loading | ./gradlew :app:lintDebug -Prur.lint.disableLintConfig |
| rur.lint.overrideLintConfig | override lintOptions.lintConfig. the path is relative path from rootProject (or full absolute path) | ./gradlew :app:lintDebug -Prur.lint.overrideLintConfig="./lint.unusedresources.xml" |
Gradle configuration syntax
Gradle configuration syntax is also available.
app/build.gradle.kts
removeUnusedResource {
// for dry run
// default: false
dryRun = true
// specify lint target variant for result xml file detection
// if lintResultXml is set, lintVariant is ignored.
// default: not specified (use {buildDir}/reports/lint-results-{default variant}.xml) in AGP 7.0.0 or upper
lintVariant = "debug"
// specify lint result xml directly
// default: not specified (use {buildDir}/reports/lint-results-{default variant}.xml) in AGP 7.0.0 or upper
lintResultXml = file("$buildDir/reports/lint-results-debug.xml")
// exclude resource Id list. match rule: entire match
excludeIds = listOf("R.color.unused_exclude_color")
// regular expression exclude resource Id list. match rule: regular expression entire match
excludeIdPatterns = listOf("R\\..*exclude_pattern.*")
// glob expression exclude file.
// file path is relative path from Project's root directory
excludeFilePatterns = listOf("**/values/exclude_colors.xml")
}
The details of glob pattern is documented in JDK FileSystem#getPathMatcher
Other behaviors
- This plugin does not remove the resources that is outside of rootProject directory.
- Those resources are reported in error message.
Troubleshoots
Could not find com.android.tools.build:gradle:{version}
This error occurs without pluginManagement > repository settings in settings.gradle.kts.
See Usage section, and add pluginManagement settings.
org.gradle.api.internal.artifacts.ivyservice.DefaultLenientConfiguration$ArtifactResolveException: Could not resolve all files for configuration ':app:classpath'.
# ...
Caused by: org.gradle.internal.resolve.ModuleVersionNotFoundException: Could not find com.android.tools.build:gradle:7.0.4.
Searched in the following locations:
- https://plugins.gradle.org/m2/com/android/tools/build/gradle/7.0.4/gradle-7.0.4.pom
If the artifact you are trying to retrieve can be found in the repository but without metadata in 'Maven POM' format, you need to adjust the 'metadataSources { ... }' of the repository declaration.
Required by:
project :app > io.github.irgaly.remove-unused-resources:io.github.irgaly.remove-unused-resources.gradle.plugin:0.9.1 > io.github.irgaly:plugin:0.9.1
Known Issues
- Android Lint Bug (not this plugin's bug)
- When project is multi module project with
android.nonTransitiveRClass=true, and two module has same resource ID, Android Lint can't find out that resource is not used.- I'm find out this behavior with AGP 7.0.1.
- example: moduleA has R.drawable.image (this is used) and moduleB has R.drawable.image (this is not used), Android Lint is not report moduleB's R.drawable.image
- related IssueTracker? https://issuetracker.google.com/issues/188871862
- When project is multi module project with
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