either version of webviewextras might help (they both allow for
javascript injection).
what you really need to debug webview is to add a chromeclient.
if there is an error, you'll see it in your log. webviewextras offers
a chromeclient (i presume version2 also provides it)
post the code for the populate() function. i'm a little confused;
if you don't want the user to do anything, why provide a button in
the first place? in any case, let's see how you implemented the
click(). if i invent my own implementation to see what happens
on android 11, the result may not be the same as for your way.