Updating progress bar in ListView

Sample code to demonstrate the idea, worked, but not tested.

public View getView(int position, View convertView, ViewGroup parent) {
    final App app = getItem(position);
    
    ViewHolder holder = ViewHolder.newInstance(context, convertView, parent, resLine);
    
    Picasso.with(context).load(app.icon).placeholder(R.drawable.ic_launcher)
      .into((ImageView)holder.getView(R.id.list_home_app_icon));
    ((TextView)holder.getView(R.id.list_home_app_title)).setText(app.name);
    
    final ProgressBar bar = holder.getView(R.id.list_home_app_progress);
    bar.setTag(app.name);
    final Downloader.ProgressListener listener = new Downloader.ProgressListener() {
      public void onProgressChanged(final int progress) {
        if((String)bar.getTag() == app.name)bar.setProgress(progress);
      }
    };

    if(app.downloader == null){
      bar.setProgress(0);//clear progress
    }else{
      app.downloader.setListener(listener);
    }
    
    Button btn = holder.getView(R.id.list_home_app_download);
    btn.setOnClickListener(new OnClickListener(){
      @Override
      public void onClick(View v) {
        app.setDownloader(context);
        app.downloader.setListener(listener);
        Toast.makeText(context,"Start downloading "+app.downloadUrl, Toast.LENGTH_LONG).show();
        app.startDownload();
      }
    });
    
    return holder.convertView;
  }