Trying to import an MIT App Inventor project in Kodular... May be a WebViewer bug is found!

My Project worked OK just about 2 weeks ago for about 2 years, and suddenly it becomes very unstable. There are 3 instances of WebViewer in my project. Most of the time, they works OK. But suddenly 1 instance would try to reload its content again and again automatically when I selected an item from its list, then the other 2 instances will also do the same thing together automatically. Curiously, this problem will be fixed by itself within 15 seconds or more, or by touching the screen of instance 1 (very strange).

At first, I think I had created a bug, but I still couldn't find anything wrong with my coding after a few days. Having no hope to fix the problem, I decided to recompile the project in Kodular.
When I imported my aia version from my computer, I got the following error message:

"A problem occurred while loading this project. Unable to load project with Web version 7 (maximum known version is 6)."

Everything seems OK when I run the Kodular version. This problem can't be created intentionally, and it seems very difficult to debug. And if Kodular update with your new Web version later, I have no way to go !

Yours truely,
Anthony Chow

Hi @Anthony_Chow Welcome
You should show relevant blocks.


My project is a big project. There are hundreds of blocks in it, and lots of javascript coding. Just don't know what to show.

Anthony Chow

Blocks related to web viewer.

yup ! everyone does have hundreds of blocks in their projects so do you
for sharing your blocks :- right click in the blocks screen , then select "Download blocks as image" and they all will be converted in a png image & u can share that


Nearly all the blocks' operations are for WebViewers except file operations. I think you should check if your team had updated your version recently. Sorry, I just can't help with so many & long coding.

Anthony Chow

But I am not an MIT Staff member.
Let's wait for Staff's answer.

Once you imported your MIT App Inventor 2 project to Kodular Anthony, you probably corrupted the Project aia. When you reloaded that Project using App Inventor 2, it no longer loads on the AI2 server. Once AI2 projects are imported to Kodular, they take on the characteristics of Kodular. A guess is that Web version 7 is not available in AI2.

As a test, load an aia you previously created on AI2 (but did not export to Kodular); does that Project load and run properly Anthony? The rule is do not mix and match compilers.

Steve to go back to your most recent backup. There is an advanced Web View for App Inventor by vknow360:

Hi Steve,

I just have one aia file in my computer download from AI2, so I did an experiment: import the same file to AI2 and to Kodular and then created two different apk files and installed into my phone. The result is: the one from AI2 has that problem once a while, and the other has no such problem.

Steve, I am actually the guy who helped you to debug similar problem a year ago when AI2 upgrade to android 9. At that time, I could create a small project for you to debug. But this time, the case is so unstable, and I am sorry that I am not able to do that.

Thanks in advance.

Yours truely,
Anthony Chow

This happens when you load the Kodular aia into MIT App Inventor? ... that appears to be what you said. Has Android 9 recently been upgraded and no longer compatible with App Inventor's WebView? I don't know...a possibility.

Without a test project, there is little possibly that anyone will be able to help you. You are using WebVIewers, the issue might be related to url's. One of the developers might comment w.r.t. which WebViewer AI2 supports.

Edit: Have you tried your app on an Android version other than 9 ? It would be interesting to know if
all is ok on a lower version number.

Hi Steve,

"A problem occurred while loading this project. Unable to load project with Web version 7 (maximum known version is 6)."

This happens when I load the MIT App Inventor aia file into Kodular. That means (according to the error message) the Web version in AI2 is 7, and Kodular is 6.

Today, I found that the Kodular version is not in a perfect stable state, I saw the same problem appeared once (but the problem appears all the time in the AI2 version).

I have a Xiaomi phone installed with android 7, and as what you expected, everything works perfect on that phone.

I will try to make a small project to see if I can create the same problem.

Anthony Chow

if you try to load a MIT App Inventor project in another builder, be ready to get issues...
the builder are not 100% compatible...

in your case if you really want to move to Kodular you first might want to remove all webviewer blocks in your App Inventor proejct before importing it into Kodular...
alternatively start your project from scratch there...


Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by Taifun.

I am confused. You talk about there being 3 WebViewers in your app, then start talking about how you get a warning about upgrading the Web component. These are two different components and an error with one really has no bearing on the other (unless you've combined them in some way in your app). Unfortunately, we can't do too much to help you without seeing an example of the code and what the error is. Does it happen on every device? If so, what manufacturers and what versions of Android? Does it happen in the emulator? If you just create an app with three web viewers with the home URLs set and no other, do you get the erratic behavior?

Hi Taifun & ewpatton,

I did my coding using AI2 and then used Kodular (through aia) to make apk files for testing for already more than a month. But recently, I found that your team already solved my problem (seems like a memory leak problem) accidentally. So now I moved back to AI2 for making apk files. THANKS GUYS !!!

By the way, the apk file generated from AI2 is about 2000 kb less than that generated from Kodular for my app. Also, I nearly switched all my WebViewers (now I have 7 Webviewers in my app) to CustomerWebViewer to get better results in graphics.

Yours truly,
Anthony Chow

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