Hi folks. Is there a way to customize back button ...

# compose

[Denis]

Hi folks. Is there a way to customize back button behavior with navigation-compose?

I want to make a list with multiple selection like in the GMail app. On back button press navigation-compose goes to the previous destination, but I want it to unselect all selected items. I did it with a boolean optional argument "items?selected={selected}", but I think it really smells. I suppose it's better to override the default behavior of back button, but I just can't find a solution. Or is there a better approach to the problem?

[Ian Lake]

You'd want to add your own OnBackPressedCallback ala https://kotlinlang.slack.com/archives/CJLTWPH7S/p1604158427082300

[Ian Lake]

We've talked about making this part of Compose here: https://kotlinlang.slack.com/archives/CJLTWPH7S/p1604266607160300 (and that has a link to the issue you can star)

[Denis]

Thanks a lot, Ian!

The @Vinay Gaba’s message you shared lead me to his full implementation of BackButtonHandler that works perfectly for me. Vinay, thank you for it!

[Denis]

Oh, and there's https://github.com/vinaygaba/Learn-Jetpack-Compose-By-Example/blob/master/app/src/main/java/com/example/jetpackcompose/state/backpress/BackButtonHandler.kt and https://github.com/vinaygaba/Learn-Jetpack-Compose-By-Example/blob/master/app/src/main/java/com/example/jetpackcompose/state/backpress/BackPressActivity.kt. I was focused on navigation-compose and didn't look at anything else.

[Vinay Gaba]

@Denis The implementation in Showcase is correct - https://github.com/airbnb/Showkase/blob/9301d3dc49fa3174b813931a332d56c5565ea8ad/showkase/src/main/java/com/airbnb/android/showkase/ui/BackButtonHandler.kt#L48. I’ll update the example in Learn Jetpack Compose repo as it uses a less than ideal approach that is also being discussed in the thread that Ian pointed to.