在getView中动态隐藏/显示ImageView

Question

我试图检查一个目录是否存在，如果确实存在，我想让listview中的imageview可见。由于某种原因，即使目录存在，也不会将imageview设置为可见。有谁知道问题是什么？

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View row = convertView;

    LayoutInflater inflater = ((Activity) context).getLayoutInflater(); 
    row = inflater.inflate(layoutResourceId, parent, false);


    String item = data.get(position);
    ImageView ib = (ImageView)row.findViewById(R.id.alreadyDownloaded);
    TextView textView = (TextView)row.findViewById(R.id.fontTextView);
    textView.setText(data.get(position));

    File dfDir = new File(Environment.getExternalStorageDirectory() + "/DownloadedFonts"+ (data.get(position)));

    if(dfDir.isDirectory()) {
  //if (item.equals("Helvetica") ){ if i use this it hides the image properly
        ib.setVisibility(View.VISIBLE);
    }    

    return row;

}