iOS Question XUI timing conflict with b4xpages

[bobbruns]

This code works on b4a:

Sub sign_up_back_Click
xui.MsgboxAsync("sign up cancelled","'No Touch' Orienteering")
B4XPages.ShowPageAndRemovePreviousPages("MainPage")
End Sub

but on B4i the following error is thrown:
setViewControllers:animated: called on <B4INavigationController 0x103815600> while an existing transition or presentation is occurring; the navigation stack will not be updated.

I added a delay:

back click with delay:

Sub sign_up_back_Click
xui.MsgboxAsync("sign up cancelled","'No Touch' Orienteering")
    #if b4i
    Sleep(500) '390 is too short! 400 works
    #End If
B4XPages.ShowPageAndRemovePreviousPages("MainPage")
End Sub

the error message is gone

 

[William Lancee]

Asynchronous means that execution continues after "showing" the message. Not after the user responds.
In your case you need to wait for user response.

See https://www.b4x.com/android/forum/threads/how-to-use-msgboxasync-with-wait-for.86902/

 

[Erel]

Moved to the questions forum.

 

[bobbruns]

Asynchronous means that execution continues after "showing" the message. Not after the user responds.
In your case you need to wait for user response.

See https://www.b4x.com/android/forum/threads/how-to-use-msgboxasync-with-wait-for.86902/

I do not need to wait for user response on android, and the page you referenced seems to indicate that too.

 

[bobbruns]

This is still a problem. I cannot wait for xui.MsgboxAsync The wait for is for xui.Msgbox2Async

 

[William Lancee]

I don't know why it works in Android and not in iOS. I thought that the next statement caused the problem.

Can you use B4XPages.ShowPage("MainPage") without removing previous pages?
In other words why do you need to remove previous pages? They just sit in the stack, where they don't do any harm.

In any case someone else might have a better idea.

 

[agraham]

I cannot wait for xui.MsgboxAsync

Yes you can, . It is the same as for xui.Msgbox2Async

 

[bobbruns]

Yes you can, . It is the same as for xui.Msgbox2Async

#if b4a
xui.MsgBoxAsync("message","title")
#else if b4i
wait for xui.MsgBoxAsync("message","title")
#end if
B4xpages.ShowPageandRemovePreviousPages("Mainpage")

Should I do it this way? or just add a "wait for" in front of all message boxes so it will run on Apple too?

Wouldn't use of a synchronous message block be better on ios? In other words, never use xui.MsgBoxAsync on iOS.

 

[bobbruns]

Yes you can, . It is the same as for xui.Msgbox2Async

I don't know why it works in Android and not in iOS. I thought that the next statement caused the problem.

Can you use B4XPages.ShowPage("MainPage") without removing previous pages?
In other words why do you need to remove previous pages? They just sit in the stack, where they don't do any harm.

In any case someone else might have a better idea.

I have verified that the same behavior is with "showpage". Either way the log error is generated. Also the same behavior is with both debug and compiled versions. Again, only with Apple, Android works fine, no issues. iPhone SE iOS 15.6. Both local builder and hosted builder exhibit identical behavior.. Local builder is Mac mini M1. B4i 8.00. I have spend hours with this issue. The code: sleep(500) seems to be an easy workaround with the fewest keystrokes.

 

[Alexander Stolte]

Should I do it this way? or just add a "wait for" in front of all message boxes so it will run on Apple too?

Dim sf As Object = xui.MsgboxAsync("Delete file?", "Title")
Wait For (sf) Msgbox_Result (Result As Int)

 

[bobbruns]

Dim sf As Object = xui.MsgboxAsync("Delete file?", "Title")
Wait For (sf) Msgbox_Result (Result As Int)

Thanks. Only on Apple, right?

 

[agraham]

Thanks. Only on Apple, right?

No. It's good practice on Android as well otherwise any code after the Msgbox runs immediately which can produce unexpected results .

 

[bobbruns]

No. It's good practice on Android as well otherwise any code after the Msgbox runs immediately which can produce unexpected results .

Unexpected results is why I use the debugger.