Bug? B4XPages - GetPage crashes if pageid does not exists

Robert Valentino

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• Apr 22, 2021

• #1

I am not sure if this is a Bug or Intended?

I have some pages that are only created based on options selected.

if you do a B4XPages.GetPage("Nothing") and Nothing page id does not exists B4XPages crashes

B4X:

Error: page id not found: Nothing
Ids: (ArrayList) [mainpage, pplaying, pplayqueue, pplayfrom, pdatabaselist, psettings, pscreensaver]

Seems like returning a Null Page would be better or some type of command like B4XPages.DoesPageExist("Nothing")

BobVal

 

LucaMs

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• Apr 22, 2021

• #2

You can get if a B4XPage is "open":

B4X:

Dim PageIDAdded As Boolean = B4XPages.GetManager.mStackOfPageIds.Contains("SomePageID")

 

Erel

B4X founder

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• Apr 23, 2021

• #3

This is the designed behavior.

You are expected to add all pages once when the program starts. The pages are "lazy loaded", which means that you don't need to worry about performance. B4XPage_Created will only be called when the page is first shown (unless you add pages with the sometimes useful AddPageAndCreate method).

 

Sandman

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• Apr 23, 2021

• #4

Erel said:

You are expected to add all pages once when the program starts.

Click to expand...

I don't think I've seen that expectation anywhere before. Hence my thread a while back. So I'd suggest adding that expectation to the list in the initial B4XPages post.

 

Erel

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• Apr 25, 2021

• #5

It is not a forced requirement. You are required to add the page before you can get it with B4XPages.GetPage.

 

Robert Valentino

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• Apr 25, 2021

• #6

Understood.
I just feel that B4XPages shouldn't crash.
If it returned null and I didn't check for it and I crash that is fine.
But the umbrella that B4XPages is providing should never crash - should be bullet proof.

 

W

walt61

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• Jun 25, 2021

• #7

+1, agree with @Robert Valentino, would be good if Null would be returned