OnBackPressed doesn't work when observe EditText KEys

Question

I have Extension of EditText where I'm listenig to events from keyboard of EditText. I need to know when user press any button for showing (or not showing) error. So I make Observable for keys (rxbinding2) and I'm getting any press but when I press back button and cursor still in this EditText method onBackPressed doesn`t work. How to filter onBack pressed?

fun EditText.changeWithFormatting(formatter: (String) -> String): Observable<String> {
    return Observable.merge(
            afterTextChangeEvents()
                    .map { editableText },
            keys()
                    .filter { it.action == KeyEvent.ACTION_UP }
                    .map { editableText }
    )
            .map { changeText(formatter(it.toString())) }
}

Answer 1

Just listen for the keydown event. This should trigger before it gets handed to your UI element. super will pass it to the parent to go normal flow. I can't remember if it's return true or false, but I think it's true for handled.

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) 
   {
        if ((keyCode == KeyEvent.KEYCODE_BACK)) 
        {
            onBackPressed();
            return true; 
        }
        return super.onKeyDown(keyCode, event);
   }