I was able to find a mitigation, but need to investigate further on why it is happening.
To fix the issue on any imported AI2 app, follow these steps:
- Open the Settings modal for the App
- In General, check and uncheck the following properties (or uncheck and check, if you want them enabled):
- Splash Enabled
- RTL Support
- In Publishing, select Min SDK 21 (I did not test without this, but should be ok to just set it).
- Now export the app.
For some reason, when importing an AI2 app, those properties get set with the incorrect types in YAIL. Then, at runtime, they fail to get initialized correctly.
Basically, forcing a mutation of those properties causes the app to get its types properly refreshed, hence fixing the issue.
Can you try if it works for you?
EDIT: The issue seems to be related to how AI2 saves projects.
This is the projects.properties and Screen1.scm files when no component is added yet:
#
#Mon Aug 11 19:46:30 UTC 2025
sizing=Fixed
color.primary.dark=0
color.primary=0
color.accent=0
aname=
defaultfilescope=App
main=appinventor.ai_diego_barreiro_perez.CleanProjectTest.Screen1
source=../src
actionbar=false
useslocation=false
assets=../assets
build=../build
name=CleanProjectTest
showlistsasjson=false
theme=AppTheme.Light.DarkActionBar
versioncode=1
versionname=1.0
#|
$JSON
{"authURL":[],"YaVersion":"232","Source":"Form","Properties":{"$Name":"Screen1","$Type":"Form","$Version":"31","Uuid":"0","Title":"Screen1","AppName":"CleanProjectTest","Theme":"AppTheme.Light.DarkActionBar"}}
|#
This is how those files go after adding and deleting a component:
#
#Mon Aug 11 19:46:41 UTC 2025
sizing=Responsive
color.primary.dark=&HFF303F9F
color.primary=&HFF3F51B5
color.accent=&HFFFF4081
aname=CleanProjectTest
defaultfilescope=App
main=appinventor.ai_diego_barreiro_perez.CleanProjectTest.Screen1
source=../src
actionbar=True
useslocation=False
assets=../assets
build=../build
name=CleanProjectTest
showlistsasjson=True
theme=AppTheme.Light.DarkActionBar
versioncode=1
versionname=1.0
#|
$JSON
{"authURL":["ai2.appinventor.mit.edu"],"YaVersion":"232","Source":"Form","Properties":{"$Name":"Screen1","$Type":"Form","$Version":"31","ActionBar":"True","AppName":"CleanProjectTest","Title":"Screen1","Uuid":"0"}}
|#
Importing a project with the first set of files works fine, but importing one with the ones below fails to start.
