I had seen Jim once say about this ```val activity = LocalCo

Question

I had seen Jim once say about this ```val activity = LocalContext current as Activity``` But I never found the answer

Adam Powell · Answer

If you re writing platform dependent code that needs an activity you can t exactly just not use it and laundering platform specific usage through other abstractions is sometimes useful sometimes YAGNI

Adam Powell · Answer

But it s worth noting that often the `LocalContext` is not an `Activity` but instead it can be a chain of `ContextWrapper`s where the ` baseContext` leads to an `Activity` eventually

Adam Powell · Answer

this can often happen if a `ContextThemeWrapper` has been used to change the theme mid view hierarchy If you use the `android theme` attribute in layout xml one of these is created for you If a `ComposeView` is placed as a child of such a subtree `LocalContext` will be one of these wrappers

Adam Powell · Answer

That said depending on what you re doing with the activity you might find it more useful to pass a ` gt Unit` callback or similar to your composable and provide a lambda that makes the actual activity call This can often aid in testability

Adam Powell · Answer

<https cs android com androidx platform frameworks support + androidx main activity activity compose src main java androidx activity compose ActivityComposeUtils kt l=22|https cs android com androidx platform frameworks support + androidx main activity n java androidx activity compose ActivityComposeUtils kt l=22> shows the unwrapping ContextWrappers approach and is used by the activity result API in the androidx activity library

Rafiul Islam · Answer

Actually I have been using a onFinish gt Unit callback for my code to finish the activity from composable functions for a while

Rafiul Islam · Answer

I am a little bit confused just if you make it clear So LocalContext will eventually get the activity it might go through multiple loops But it will return the activity right Or is there any possibility it won t return the activity

Adam Powell · Answer

If there is no activity to return then it won t return one It s entirely possible to create a `ContextThemeWrapper` around a `Service` context `getSystemService` to get the `WindowManager` and add a `ComposeView` to it as a top level window with the right lifecycle dependencies configured At that point you have no activity but you have a perfectly functional compose ui

Adam Powell · Answer

Android Auto projected mode operates more or less this way as well

Rafiul Islam · Answer

Yep I got it Thanks Adam