How does one go about hijacking the back button the same way a DropdownMenu or AlertDialog does? `Ba...

# compose

[dewildte]

How does one go about hijacking the back button the same way
a DropdownMenu or AlertDialog does?
BackHandler?

[Ian Lake]

BackHandler is precisely for handling the back button in a composable, yes

[dewildte]

@Ian Lake Thanks!
If the host activity does not call super.onBackPressed() it won’t work correct?

[dewildte]

NVM I answered my own question.
The answer is yes.

[dewildte]

@Colton Idle ☝️

[Ian Lake]

Correct, none of the default behavior, such as dispatching to the activity's OnBackPressedDispatcher will occur if you don't call super.onBackPressed()

[Ian Lake]

tl/dr: it is 2021, you shouldn't be overriding onBackPressed() at all - you should only be using the OnBackPressedDispatcher APIs and those built on top of it

[Ian Lake]

There's also docs on using those APIs in the non-Compose world: https://developer.android.com/guide/navigation/navigation-custom-back

[dewildte]

Oh fantastic!

[dewildte]

I am building a launcher and custom alert dialogs so this is super handy!

[Ian Lake]

Yeah, just keep in mind how key events dispatch works on Android - keys are sent to the topmost window. This is how a PopupWindow or android.app.Dialog will steal the back button before your activity (and its OnBackPressedDispatcher) receives the key event

[Ian Lake]

That generally means that you should avoid having a back stack in any temporary windows

[dewildte]

Noted!