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

@Deprecated

?

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.

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

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.

Compose doesn’t use activities afaik

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

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?

No, it has its own lifecycle callbacks

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

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

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.

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.

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. 🧌

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.