FAQ¶
How can I incrementally adopt App Platform?¶
App Platform offers many recommendations and best practices and hardly enforces any principles, e.g.
it’s possible to adopt the concept of the module structure without the Scope class or Presenters.
Presenters can be used without Compose UI. This and the fact that App Platform is extensible allows
for an incremental adoption. Apps can leverage the concepts and the framework without migrating all code at
once.
For example, instead of going all in on the unidirectional dataflow, Android apps can start adopting Presenters and
Renderers on an Activity by Activity or Fragment by Fragment basis. Our Android app initially used
Dagger 2 and Anvil as dependency injection framework and
made it interop with kotlin-inject-anvil before switching fully.
Can I use Metro, Dagger 2 or any other DI framework?¶
It depends, but likely yes. We’ve chosen kotlin-inject-anvil because it supports Kotlin Multiplatform and verifies the dependency graph at compile time.
Metro is still fairly new. It seems to be possible to bridge a Metro dependency graph with a kotlin-inject-anvil.
This would allow App Platform to use kotlin-inject-anvil internally, while all user code uses Metro. Long term
we may consider moving App Platform to Metro.
Dagger 2 is more challenging, because it only supports Android and JVM application. That said, App Platform started on
Android we used to use Dagger 2. We bridged the Dagger 2 components with the kotlin-inject-anvil components for
interop and this served us well for a long time until we fully migrated to kotlin-inject-anvil.
How does App Platform compare to Circuit?¶
Circuit shares certain aspects with App Platform in regards to implementing the unidirectional dataflow,
e.g. presenters and decoupling UI. How Screens with Circuit work vs how App Platform relies on composing presenters
and renderers is different.
App Platform goes further and has feature that Circuit doesn’t provide, e.g. the module structure, the strong emphasis on fakes and robots.
At Amazon we built App Platform months before Circuit was released in 2022 and at this point there was no reason for us to migrate off of App Platform and to Circuit.
Help needed
Help from the community for a more in-depth comparison is needed.