IOS black screen on APP switcher

[freedreamer82]

Hi all,

I tried to build my own app for IOS device (iphone 8 with ios 15.5)...everything it works except when I slide up to the app switcher... the app snapshot becomes all black and when I switch back to the app sometimes it works and sometimes I need to go it in the background and reopen to get it working.

I tried the last stable release and the develop branch as well ..but with both I have the same issue.

Any advice ?

PS
build with:
fyne package -os ios -appID com.mqtt.shell -icon ../../assets/mqtt-shell.png -name mqtt-shell
on MacOs Apple M1

fyne version develop : v2.1.4-0.20220602113944-20fbb51896f7
fyne versione stable v2.1.4

Thanks

Marco

[Jacalz]

Please use the issue templates when opening a new issue. It makes sure that we get all the information that we need to be able to help out and triage bugs.

From what I can tell, this should have been fixed, according to #1610, in Fyne 2.0 and later. It looks like this might have popped up again.

EDIT: Sorry for the fuss about the Fyne version. I missed that you had the version written in the text. I was looking for something on the form of "vx.x.x". Using "latest stable release" will get out of date pretty quickly once a new release is out.

[freedreamer82]

edit with the version I tried.
more info:
I build another app (https://github.com/fynelabs/mqttweather) and i have the same issue.. so i guess it's not related to the app but to the way I build or the framework.

[Jacalz]

Thanks. I think it most likely is an issue on our end. Seems like something has made it appear again.

[Jacalz]

Hmm. I actually can't find the commit that was supposed to fix the other issue that I linked above. Could it perhaps be that it never actually landed on develop? cc @andydotxyz

[changkun]

Thanks. I think it most likely is an issue on our end. Seems like something has made it appear again.

It sounds like this was an old issue that had been fixed before but somehow occurred again. Am I correct?

As far as I understood the phenomenon, this is due to the mobile driver (including gomobile) does not yet handle GL context recovering at application switch, which has been a long-standing knowing problem (at least in gomobile).

[andydotxyz]

It sounds like this was an old issue that had been fixed before but somehow occurred again. Am I correct?

Yes this was fixed before. The black screen is not context recovery as it is trying to snapshot in the current context (I think...) but not working on returning to the app may be that.
All of this should be working - and indeed is on my test hardware.

@freedreamer82 this does not look like an iOS screenshot, can you please provide the missing information about what hardware you are running and how to replicate the problem?

[andydotxyz]

The previous fixes are around this issue and it was marked resolved 15 months ago: #1610

[freedreamer82]

It sounds like this was an old issue that had been fixed before but somehow occurred again. Am I correct?

Yes this was fixed before. The black screen is not context recovery as it is trying to snapshot in the current context (I think...) but not working on returning to the app may be that. All of this should be working - and indeed is on my test hardware.

@freedreamer82 this does not look like an iOS screenshot, can you please provide the missing information about what hardware you are running and how to replicate the problem?

actually it is an ios screenshot.
BTW if you clone and build
https://github.com/fynelabs/mqttweather

this repo it happens:

iphone 8 ios 15.5 build on apple macbook M1 with fyne version develop : v2.1.4-0.20220602113944-20fbb51896f7

[andydotxyz]

Aaaah, the old iPhone with almost square corners really confused me as their task switcher takes the shape of the surrounding device!

[freedreamer82]

Aaaah, the old iPhone with almost square corners really confused me as their task switcher takes the shape of the surrounding device!

ahahha "old"... :( if you want to gift me a new iphone , no problem :)

[andydotxyz]

ahahha "old"... :( if you want to gift me a new iphone , no problem :)

It's not young - nearly 5 years old. Apple will stop supporting it next year.
Of course we will still support it... We go back to the iPhone 5s - but your screenshot caught me by surprise.
So it could relate to the graphical memory or the age of the GPU...

[freedreamer82]

ahahha "old"... :( if you want to gift me a new iphone , no problem :)

It's not young - nearly 5 years old. Apple will stop supporting it next year. Of course we will still support it... We go back to the iPhone 5s - but your screenshot caught me by surprise. So it could relate to the graphical memory or the age of the GPU...

I hope apple will support it for one year more... my wife has an iphone 11 ..I can try on it...

[freedreamer82]

in order to help your debug I noticed that when there a screen with infinity bar running the black issues disappears... when the bar is closed the issues comes back again.. I don't think could be a GPU problem.

Marco

[andydotxyz]

I'm sorry can you clarify what an infinity bar is? How can we replicate this case where it works and then stops working?

[freedreamer82]

I'm sorry can you clarify what an infinity bar is? How can we replicate this case where it works and then stops working?

to replicate this you have to build my app for ios:
https://github.com/freedreamer82/mqtt-shell/tree/feature-gui

[freedreamer82]

v2.2.0

same issue.. here a videoclip.

RPReplay_Final1654857105.mov

[andydotxyz]

Can you please try with an app installed from the store that works for others and report whether you see the same issue?
https://apps.apple.com/app/id1568737297

[freedreamer82]

Can you please try with an app installed from the store that works for others and report whether you see the same issue? https://apps.apple.com/app/id1568737297

with the app downloaded from the store it works.

M.

[andydotxyz]

I don't seem to have this issue any more with iOS16.
Not sure what that means...

[inchworks]

I have the same issue with my own app. The demo calculator app installed from the app store doesn't show the problem. However building https://github.com/fyne-io/calculator myself does reproduce the issue. This is with fyne v2.3.4, iOS 16.4.1(a), iPhone 14 Pro. Also with Xcode simulator for iPhone 14 Pro Max, except that the screen is bright magenta instead of black. (I don't suspect the iPhone model but I haven't tried a different one with calculator.)

[freedreamer82]

HI ,

I changed my phone from iphone 8 to iphone 12 mini and....it happens some way. I can confirm that it's not an iphone ram issue. It's something else, at least IMHO.

Marco

[andydotxyz]

Thanks for this extra info.
Can you confirm if the Fyne apps downloaded from store work ok on your new device?

[freedreamer82]

Yes i confirm. the apps downloaded From the store are ok.
M.