Oh, I think I see what you're trying to do now: was your intent to eventually reuse the same popup both for 'Go to line' and for 'Find'? If so, the minimal change in the light of my previous comment could be:
    
    final int lineNo = findView.lineNumber;
    if (lineNo != null) {
        // go to line
    } else {
      // find
    }

However, I think trying to merge the two will adversely impact both usability (can't preserve/show the previously entered value for both 'find' and 'goto'; can't set a restricting 'only numbers' pattern for 'goto'; what are we going to do when we start adding 'find' options such as regexps -- doesn't make sense for 'goto'; etc.) and coding (trying to behave as both things at once is hard/messy). Why not just have separate popups?