I’ve been working with newer versions of Android Studio and noticed that the dependency declarations in build.gradle files have changed. The old compile keyword seems to be replaced with different options like implementation and api. Same thing happened with test dependencies where testCompile became testImplementation.
Here’s what I see in new projects:
api 'androidx.appcompat:appcompat:1.4.0'
implementation 'com.google.android.material:material:1.5.0'
testImplementation 'org.junit.jupiter:junit-jupiter:5.8.2'
Compared to the old way:
compile 'androidx.appcompat:appcompat:1.4.0'
compile 'com.google.android.material:material:1.5.0'
testCompile 'org.junit.jupiter:junit-jupiter:5.8.2'
I’m confused about when to use each one. Can someone explain the practical differences between these dependency types and help me understand which one I should choose for different scenarios? Does it affect how dependencies are exposed to other modules?
Gradle switched from compile to implementation/api for better dependency management. implementation hides your module’s dependencies from other modules that use it, which speeds up builds. When an implementation dependency is updated, Gradle only recompiles your module, not all dependent ones. In contrast, api exposes the dependency to consuming modules; it’s vital when your public API utilizes types from that dependency. Most of the time, you should prefer implementation, using api only when you face compilation issues in dependent modules. This transition significantly improves performance, with some users reporting build times halved on larger projects.
It’s all about dependency visibility and build performance. With implementation, the dependency stays internal to your module - other modules can’t see it directly. This keeps things cleaner and builds faster since Gradle won’t recompile everything when you change an implementation dependency. api exposes the dependency to any module that depends on yours. Only use this when other modules actually need to access classes from that dependency - like when your library returns objects from an external library in its public methods. My approach: start with implementation for everything, then switch to api only when you get compilation errors about missing classes. They deprecated compile because it acted like api but without being explicit about it, which created bloated dependency trees and slower builds.
yep, implementation is for keeping things in-house, while api lets other modules use it too. usually go with implementation unless u need to share. oh, and yeah, compile is totally outdated now.