We can have a listener for dialog in Android :

dialog.setOnKeyListener(new Dialog.OnKeyListener() {

  @Override
  public boolean onKey(DialogInterface arg0, int keyCode,KeyEvent event)
  {
     if (keyCode == KeyEvent.KEYCODE_BACK) {
           /* The user pressed back button - do whatever here.
           Normally you dismiss the dialog like dialog.dismiss(); */

         }
        return true;
        }
    });

How we can do that for AlertDialog in jetpack compose?

@Composable
    private fun DisplayAlertDialog() {
        val openDialog = remember { mutableStateOf(true) }
        if (openDialog.value) {
            AlertDialog(
                onDismissRequest = {  },
                title = {
                    Text(
                        text = stringResource(id = R.string.settings),
                        fontSize = 18.sp
                    )
                },
                confirmButton = {
                    TextButton(
                        onClick = {
                            openDialog.value = false
                        }
                    ) {
                        Text(stringResource(id = R.string.yes))
                    }
                },
                dismissButton = {
                    TextButton(
                        onClick = {
                            openDialog.value = false
                        }
                    ) {
                        Text(stringResource(id = R.string.no))
                    }
                },
                backgroundColor = Color.White,
                contentColor = Color.Black
            )
        }
    }

CodePudding user response：

Check out details of Modifier.onKeyEvent usage in this answer.

In this case requestFocus has to be called from inside AlertDialog to make sure it already appeared.

In my example I use a text field to show that the modifier is not interrupted.

var displayed by remember { mutableStateOf(true) }
if (displayed) {
    val requester = remember { FocusRequester() }
    AlertDialog(
        onDismissRequest = {
            println("dismissOnClickOutside")
            displayed = false
        },
        buttons = {
            var text by remember { mutableStateOf("") }
            TextField(value = text, onValueChange = {text = it})
            LaunchedEffect(Unit) {
                requester.requestFocus()
            }
        },
        properties = DialogProperties(
            dismissOnBackPress = false,
        ),
        modifier = Modifier
            .focusRequester(requester)
            .focusable()
            .onKeyEvent {
                if (it.nativeKeyEvent.keyCode != KeyEvent.KEYCODE_BACK) {
                    return@onKeyEvent false
                }
                println("dismissOnBackPress")
                displayed = false
                false
            }
    )
}