毕加索显示进度甚至已下载的图像

Question

我正在使用Picasso库将图像加载到ImageView中，就像我在ListView中只有一个项目一样，因此它显示进度加载器甚至图像已成功下载并在ImageView中可见。

那我怎么能控制它？

        viewHolder.progressBar.setVisibility(View.VISIBLE);

        Picasso.with(MainActivity.this)
        .load(imageURL) // web image URL
        .fit().centerInside()
        .transform(transformation)
        .error(R.drawable.ic_launcher)
        .placeholder(R.drawable.ic_launcher)
        .rotate(90)
        .into(viewHolder.imageViewReport , new Callback() {

            @Override
            public void onSuccess() {
                // TODO Auto-generated method stub
                viewHolder.progressBar.setVisibility(View.GONE);
            }

            @Override
            public void onError() {
                // TODO Auto-generated method stub
                viewHolder.progressBar.setVisibility(View.GONE);
            }
        });

通常，我面临第一个列表项的问题......

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        // convert view = design
        View view = convertView;
        if (view == null) {
            viewHolder = new ViewHolder();
            view = layoutInflater.inflate(Resource, null);

            viewHolder.imageView = (ImageView) view.findViewById(R.id.imageView);               

            viewHolder.progressBar = (ProgressBar) view.findViewById(R.id.progressBar1);

            view.setTag(viewHolder);

        } else {
            viewHolder = (ViewHolder) view.getTag();
        }

        final Transformation transformation = new Transformation() {
            @Override 
            public Bitmap transform(Bitmap source) {

              int targetWidth = viewHolder.imageViewReport.getWidth();
              double aspectRatio = (double) source.getHeight() / (double) source.getWidth();
              int targetHeight = (int) (targetWidth  * aspectRatio);

              Bitmap result = Bitmap.createScaledBitmap(source, targetWidth, targetHeight, false);

              if (result != source) {
                  // Same bitmap is returned if sizes are the same
                  source.recycle();
              }

              return result;

            }

            @Override
            public String key() {
                // TODO Auto-generated method stub
                return null;
            }
        };