Lottie is a powerful library that parses After Effects animations and makes mobile (and web) apps more user friendly, enhancing them with beautiful animations and interactions.
It’s common for Android projects to fail during build due to incompatible versions of Lottie, or any other library, used by different dependencies.
Developers often resort to solutions such as:
configurations.all {
resolutionStrategy {
force("com.airbnb.android:lottie:your-desired-version")
}
}
Or removing transitive dependencies
implementation("your.library:dependency") {
exclude(group = "com.airbnb.android", module = "lottie")
}
However, these solutions can lead to runtime issues, including crashes.
Using a resolution strategy that forces a version in a conflict can lead to runtime error.
A more robust way to handle this issue is through Dependency Shadowing.
Dependency Shadowing involves taking a dependency and renaming its package to avoid conflicts.
You might think about forking the repository and changing the package name, but there’s a more efficient approach that doesn’t require maintaining a fork.
There is a well-known Java plugin that does this shadowing but doesn’t work quite well will Android projects. So in order to have a better experience in Android development, a Gradle plugin should be created.
Dependency Shadowing
Gradle comes to our rescue
We’ll create a Gradle plugin that enables us to easily shadow dependencies like this:
add("shadowAARImplementation", "com.airbnb.android:lottie:6.1.0")
Here, shadowAARImplementation is a configuration that processes the dependency, shadows it, and adds it to your project. In order to create our plugin. let’s create a buildSrc folder inside your Android project, and inside the folder a structure like the one showed below.
The content of the AddShadowedAARDependenciesPlugin.kt can be found at my public gist.
And the content of the build.gradle.kts file is
plugins {
`kotlin-dsl`
}
repositories {
gradlePluginPortal()
}
dependencies {
implementation("com.github.johnrengelman:shadow:8.1.1") // https://github.com/GradleUp/shadow
}
Using the AddShadowedARRDependencies Plugin
In your project’s build.gradle.kts file add the import to the plugin
import com.eaceto.android.plugins.shadow.AddShadowedAARDependenciesPlugin
import com.eaceto.android.plugins.shadow.AddShadowedAARDependenciesPluginExtension
Then in the dependencies block add your dependency with
add("shadowAARImplementation", "com.airbnb.android:lottie:6.1.0")
Once that is done, add a configuration block in order to rename the package of (Lottie) dependency, with a custom one. I will use for this example com.eaceto.shadowed.lottie
extensions.getByType(AddShadowedAARDependenciesPluginExtension::class.java).apply {
relocations.set(
mutableListOf(
listOf("com.airbnb.lottie", "com.my.package.shadow.lottie"),
),
)
}
If you sync & build your Android project you will find a lot of error related to missing com.airbnb.lottie. This is because now you will find all the Lottie classes under com.eaceto.shadowed.lottie.
Adopting Lottie Compose
The above solution works great for Lottie and other libraries but the GradleUp/Shadow plugin has a few problems with top-level functions. The Lottie-Compose package is full of these functions, so the workaround is:
- Copy all the Lottie Compose functions to a package in your code
- Modify the imports to match the shadowed package
- Add @SuppressLint(“RestrictedApi”) where needed
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