Thanks a lot for alpha11 release. It solved all my...

# compose

[Kshitij Patil]

Thanks a lot for alpha11 release. It solved all my keyboard related issues 🥳🥳 Can’t wait to see what’s cooking up next. Just tried out this snippet to pre-focus a TextField on First load and it worked like charm. Let me know if anything is wrong doing it this way

val fieldFocus = remember { FocusRequester() }
LaunchedEffect(key1 = Unit) {
    addressFocus.requestFocus()
}

[Zach Klippenstein (he/him) [MOD]]

If you don’t need a coroutine (and I don’t think requestFocus is suspending), I would use SideEffect instead of LaunchedEffect.

[grandstaish]

Zach do you mean DisposableEffect? I think SideEffect runs after every recomposition. (Asking bc I’m using DisposableEffect to replace my onCommit calls, but having an empty onDispose lambda feels weird to me, so want to check I’m not missing an obvious API)

[Ian Lake]

onCommit -> SideEffect. It is supposed to feel wrong using DisposableEffect if you have nothing to dispose

[Zach Klippenstein (he/him) [MOD]]

My bad, i remembered incorrectly (thought SideEffect replaced onActive, not onCommit).

[grandstaish]

onCommit took a subject though right? Which SideEffect doesn’t as far as I can see

[grandstaish]

so it seems like I’m forced to use:

DisposableEffect(Unit) {
  // do thing
  onDispose { } 
}

[Ian Lake]

DisposableEffect(Unit) is the equivalent to onActive, looking at the commit that made the changes: https://android-review.googlesource.com/c/platform/frameworks/support/+/1548515

[Andrew Neal]

It may feel wrong to have an empty onDispose, but I think that is the correct way to handle things right now. There isn't another effect api to use in place of it at the moment. If you want to save yourself some typing, you could make your own DisposableEffect with an empty onDispose and just import that one when you need it. Here are some examples with empty onDispose calls:

Modifier.focusable
Swipeable.rememberSwipeableStateFor
Modifier.swipeable
NavHost
DemoFilter.FilterField

[grandstaish]

thanks all, good to know

[Ian Lake]

Yup, having no cleanup isn't a problem, just note as per the deprecation messages on onCommit, etc that using DisposableEffect without any parameters is "usually incorrect" to use @Adam Powell's words

[Adam Powell]

Yeah, as is using it with an empty onDispose clause

[Adam Powell]

Empty onDispose with keys often means you're trying to use composition as an event dispatch mechanism, which is a road that spirals into hacks to fix the hacks 🙂

[Adam Powell]

Or that you're trying to get composition to enforce idempotence in your state object APIs that would be better implemented in those objects themselves

[Adam Powell]

If you can better hoist that focus requester and call it at a more domain-appropriate event point you'll probably have a better time

[Mantas Varnagiris]

So if I want to request a focus on the text field when the screen is first shown - what would be the recommended approach for that?

[Kshitij Patil]

I want to have TextField pre-focused, that's the only logic here. Where could I hoist the focus requester in this case? I picked LaunchedEffect because it's called once at the start and on subject changed afterwards, which in my case is Unit

[allan.conda]

@Kshitij Patil what kind of issues did you have that were fixed?

[Kshitij Patil]

All mainly related to opening and closing of keyboard.
1) Keyboard used to get stuck sometimes and didn't hide when clicked outside
2) Keyboard doesn't show up when TextField focused
3) It wasn't possible to pre-focus a TextField prior alpha11. It's now possible with the snippet I shared.
4) I'm not sure whether we do have to explicitly use imePadding() or navigationBarsWithImePadding() to prevent TextField from getting hidden by the Keyboard but now I'm using it everywhere I've TextField . This wasn't a case with native xml layouts. softInputMode=adjustResize in AndroidManifest and fitsSystemWindow=true used to do the job for us.

[allan.conda]

omg, that’s good news! We’ve been tracking these issues for a long time and gives a bad impression. I’m excited to update.
Any critical issues when you updated?

[Kshitij Patil]

No issues so far.

[Shakil Karim]

@Adam Powell Is this the valid case of using DisposableEffect?
ColorToApply : Color which will change
colorPrimary: Default color

DisposableEffect(ColorToApply) {
    systemUIController.setStatusBarColor(ColorToApply)
    onDispose {
        systemUIController.setStatusBarColor(colorPrimary)
    }
}

[Adam Powell]

That'll probably get you pretty far. For something library-grade I'd probably try to give that sysuiController class an add/dispose mechanism with some sort of disambiguation for cases when more than one of these snippets is present in the composition at the same time. There would be cases where you wouldn't want to go back to the default, but instead you'd want to fall back to the other contributor.

[Adam Powell]

e.g.:
Enter A(red)
Enter B(blue) // what color is the bar now and why?
Leave A or B // what color is the bar now and why?

[Adam Powell]

This is where this kind of inverted control, where potentially multiple children in the composition contribute something to a single parent element, needs to be thought through carefully. Often the first question should be, "do I really need this?" and if you can have one piece of code consuming the various states that might affect the status bar color and emitting it directly in one place, things can be simpler.

[Shakil Karim]

Thank you, for detail answer, I agree it would be problem if multiple composable use this code at same time, but in my case only screen level composable uses this snippet.