Karl, I'm not sure you will see this as it is month after the original post, but I'm running into the same problem. according to the mobile API reference, I believe that my basic code should work. Its just a button that has the code as following:
this.getField("number").value = "01"
It seems that the API reference is not accurate. I have tried my same code in multiple different mobile pdf readers, on both android and apple.
The API Reference is accurate. It's specific to the Adobe viewers, not PDF in general.
Could the implementation of the code be the problem? I have it as a button that writes to the empty text field. It works just fine on a desktop version but when I open it up on the android version of adobe reader, the button does nothing. Could it be that buttons aren't supported on the mobile adobe reader?
I only tested on iOS. It might be a bug but the documentation is accurate.
Could you send me the document that you tested on an iOS device? I would like to test it out on my android to see if it is an issue with my implementation or if it is an issue with the android version of adobe reader. Hopefully I just screwed something up and can learn from the document you made.