Error while jumping screens

Same problem

java.lang.RuntimeException: Unable to start activity ComponentInfo{appinventor.ai_pmesystem.Bilgiler/io.kodular.pmesystem.Bilgiler.Screen1}: java.util.ConcurrentModificationException
at Source:591)
at Source:36)
at Source:57)
at Source:99)
at Source:34)
at$H.handleMessage(Unknown Source:43)
at android.os.Handler.dispatchMessage(Unknown Source:21)
at android.os.Looper.loop(Unknown Source:210)
at Source:107)
at java.lang.reflect.Method.invoke(Native Method)
at$ Source:11)
at Source:281)
Caused by: java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextNode(
at java.util.HashMap$
at android.widget.SeekBar.onProgressRefresh(Unknown Source:9)
at android.widget.ProgressBar.doRefreshProgress(Unknown Source:65)
at android.widget.ProgressBar.refreshProgress(Unknown Source:21)
at android.widget.ProgressBar.setProgressInternal(Unknown Source:30)
at android.widget.ProgressBar.setProgress(Unknown Source:2)
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(
at gnu.expr.PrimProcedure.apply(
at gnu.mapping.CallContext.runUntilDone(
at gnu.mapping.CallContext.runUntilValue(
at gnu.kawa.reflect.Invoke.applyN(
at gnu.mapping.ProcedureN.apply2(
at io.kodular.pmesystem.Bilgiler.Screen1.$define(Screen1.yail:10248)
at Source:16)
at Source:1)
at Source:3)
at Source:368)
… 11 more


How do you know this is related with the problem from the original post? I see you imported an aia from app inventor into kodular.

Hi Peter,

I started my project on ai2 in ~2013 then i switch to other ai2 platforms for new features.

its work before update. There is a problem with switching screens. When i was return to screen 1 my app fc.

Don’t hijack this topic. I created a new one.

How did you get get message?

See here: Only one Slider with Slider.PositionChanged event is possibe on a screen since Eagle

Thanks for mention,I use 2 slider at Screen1 maybe problem source is slider.

If you use the two sliders only on Screen1, this problem should not occur because Screen1 never needs to be reopened.

We need use Kodular reccommed screen swithing methods.If we dont use it some components not work correctly like notifier.

So screen1 closed and reopened on my app

Yes, then your problem should be there too.

Thanks you find problem source.I disable one of the sliders position changed block and compiled my app.Its working

Fine, but I have 4-6 sliders in many of my apps that are all needed. So we have to wait for a bugfix …

Try this ,its new

Ok, thanks, I’ll take a look at that later … and test …

I tried it, and the app does not crash, fine, but it does not store / get the correct values of the TinyDB, when switching screen … check it

maybe am wrong … I am now a bit confused …



sliderBug2.aia (27.1 KB)

Companion works, APK not. Tested on Android 5 / 9.

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Yes its works on companion and its not work on real app.I wiil test it on ai2 and if its not work i will report to ai2 team

Thanks, I checked it and it works on AI2.

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Yes its works on ai2.

@KodularCreator Can you check this bug guys?

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