My site has breadcrumbs which highlight which stage in a process the user has reached. The breadcrumbs rely on the browser history to tell which stage should be highlighted when
You can put check on inside onBackPressed method of the activity and before calling super.onBackPressed(); trigger the method to call javascript method.
for e.g:
override fun onBackPressed() {
if (handleBackPress) {
myWebView.loadUrl("javascript:backButtonPressed()")
}else {
super.onBackPressed()
}
}
in the above example if handleBackPress boolean variable is true, then it will try to call backButtonPressed() method of javascript file in the webview.
Let me know if you need any explanation or help.