Checkbox issues on iOS beta testing

I've just done my first test with iOS beta.
At first I tried to use an existing project. But there were many errors and an immediate crash without error messages.

I then created a new project after I found out by trial and error that the crash is apparently always generated by checkboxes.

Do I make fundamental mistakes or is it a bug here. If the latter applies, I would report it here: iOS Beta Testing

Screen1 blocks


Screen2 blocks


If I disable all block on Screen2, it crashes too:


Note: The Checkbox.Changed event is not triggered on iOS.
To check this: iOS_test_checkboxSwitch.aia (6.0 KB)


Tested on

  • iPhone 6s (iOS 14.0.1)
  • iPad Pro (12.9, 4th generation - iOS 14.0.1)

The problem is probably related to the fact that iOS (Xcode / Swift) does not have a (native) checkbox.

But there are a number of ways to create them, see e.g. here:


We do have the checkbox implemented (see screenshot) but it appears that if you have the Checked property enabled in the designer there is a race condition where we attempt to adjust the layer to be checked before the image is loaded. We're looking into it further.

1 Like

No, I haven't checked either of them in the designer and also see here:

As I said, the Checkbox.Changed event is not triggered.

There are actually a number of issues here, and I think I've assembled fixes for each of them at this point.

  1. CheckBox.Checked crashes the companion. I believe this is because you're setting it in the Initialize method, which is effectively the same as setting it in the designer from the point of view of the event model.
  2. CheckBox.Changed event doesn't fire.
  3. TinyDB serializes true and false as "#t" and "#f" (the Scheme representations) on iOS but as true and false on Android.
  4. unregisterEventForDelegation isn't implemented for handling disabled event blocks

So far I have always used switches instead of the checkboxes in my iOS (Xcode / Swift) apps.
But I also need checkboxes in other of my apps.

So for now I won't use any checkboxes in iOS beta testing and I'll do more tests later.