In noble future when compose is released, activities, fragments, views will be annotated with `@Depr...

# compose

[Grigorii Yurkov]

In noble future when compose is released, activities, fragments, views will be annotated with @Deprecated?

[Fudge]

I think those things will be treated like Java. While we all feel Java is deprecated, people can still use it because that’s what they know/have/like.

[Luca Nicoletti]

I don’t think so, we still want to use activities: https://kotlinlang.slack.com/archives/CJLTWPH7S/p1572535685186500?thread_ts=1572532607.179200&cid=CJLTWPH7S

[Luca Nicoletti]

And @Composable could be used with @GenerateView (which is not implemented yet) to generate a View subclass which you then can use in your .xml file

[Luca Nicoletti]

So I don’t think they will deprecated core components of Android

[Michal Bacik]

I can't imagine that Activity will be deprecated, if new UI shall work on old devices with existing framework. Activity is one thing that probably can't be replaced. It's base thing that works with Window, needed for UI.

[Fudge]

Compose doesn’t use activities afaik

[Luca Nicoletti]

Well, in Compose the Activity is used as a starting point for setContent, but setContent itself doesn’t use the Activity, as you said it used Window

[Luca Nicoletti]

So, if you can provide the Window without using the Activity the Activity could become not necessary anymore

[Michal Bacik]

And this is I think not possible. Android won't show Window for an app without Activity.
Also, does compose offer lifecycle events that we know from Activity: onResume, onStart, onCreate, etc?

[Luca Nicoletti]

No, it has its own lifecycle callbacks

[Luca Nicoletti]

onCommit, onActive, onDispose

[Luca Nicoletti]

@Michal Bacik maybe the Application can provide the Window 🙂

[Grigorii Yurkov]

I understand that activity is base element in android. I mean that we will not use activity directly.

[Grigorii Yurkov]

It will be under compose hood

[Luca Nicoletti]

hmm, I don’t think so 🙂 read the link I posted above

[Pablichjenkov]

It is always convenient to have an entry point for system events. At the end, an Activity is a common sink from some sensors and configuration changes. So leaving it wouldn't hurt.
Now Fragments, they are strong candidates to be outs.
In fact they are already out.

[Michal Bacik]

Also note that Compose will allow to be integrated gradually - maybe only for some views, or for all UI in existing Activity which will still use activity lifecycle. It's not expected that we'll rewrite apps completely just because compose arrives.

[Pablichjenkov]

It should. I hope one day Android adopts kind of a micro-service oriented strategy, where inserting a new service don't need to touch existing ones.
As of now, every Google IO, Android Summit has become basically a nightmare for devs. After the event you just realize how much code you have to migrate. 🧌

[Adam Powell]

The Activity will still exist, the idea behind expressing one as a single @Composable function with some additional annotation is indeed that you would not manually write an Activity subclass and we would treat it as abstracted boilerplate.