Bug: CacheableContainer::cachedBitmapId is not initialized by constructor

[Klemens_Pleiner_STE]

Hi,

I came across the missing implementation of CacheableContainer::cachedBitmapId in the following situation:

• My application starts with a screen where CacheableContainers are used. This first time everything works fine.
• Then the application switches to another screen.
• The other screen switches back to the first screen with the CacheableContainers. Now nothing is displayed for the CacheableContainers :(

First I thought the problem is caused somewhere in my code. But I could not find any bug in my code. Then I reviewed the CacheableContainer sources and bingo:

When a screen is placed in a portion of memory that was used to house another screen, the private member CacheableContainer::cachedBitmapId might not be initialized as expected.

This bug is solved by calling setCacheBitmap(BITMAP_INVALID) in the constructor of the first screen. (The source of CacheableContainer.hpp and .cpp led me to this fix.)

=> Could you please add a constructor to CacheableContainer and initialize all members which are introduced in CacheableContainer to default values that let the CacheableContainer work correctly?

Thanks & kind regards,

Klemens Pleiner

[Martin KJELDSEN]

Hi Klemens!

Thanks for investigating, i'll look into it. Do you have a small project that shows the issue i can look at?

/Martin

[Klemens_Pleiner_STE]

Hi Martin,

I'm sorry, I've no small project that demonstrates the problem. If you really need one, I'd have to create on that does the following:

• Enter a page where a CacheableContainer is used.
• Enter another page that uses that bit of memory where the CacheableContainer resided in. This new page must set that region of memory to 0 where cachedBitmapId resided.
• Return to the first Screen. CacheableContainer::cachedBitmapId is not initialized and thus it uses the value 0.

Just tell me, if you really need such an example.

KR, Klemens

[Martin KJELDSEN]

​Please do! Thanks :)

[Romain DIELEMAN]

Hi Klemens,

Could you also add this input to the "idea zone" section of this forum ? This will help us track it and forward it internally.

/Romain

[Klemens_Pleiner_STE]

Hi Romain,

done: https://community.st.com/s/ideazone#0873W000000PAvCQAW

KR, Klemens