Loading images using web service and Picasso, how to add inSampling size?

问题

I am using Picasso library to load and display images in a ViewPager. The images being loaded have high resolution, I would like to add an insampling size to them. I do not know, however, how or where I should add this insampling size attribute. My ViewPagerAdapter.java class has the following.

@Override
public Object instantiateItem(ViewGroup container, int position) {
   ImageView iv_page_image;
   inflater = (LayoutInflater) mContext
      .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   View itemView = inflater.inflate(R.layout.viewpager_item, container,false);
   iv_page_image = (ImageView) itemView.findViewById(R.id.iv_page_image);
   String path = pageList.get(position).getPageImage();
   path = path.replaceAll(" ", "%20");
   if (path != null && !(path.equalsIgnoreCase(""))) {
      Picasso.with(mContext).load(path)
         .placeholder(R.drawable.placeholder_empty)
         .into(iv_page_image, new Callback() {
         @Override
         public void onSuccess() {

         }
         @Override
         public void onError() {
         }
      });
    }
((ViewPager) container).addView(itemView);
return itemView;
}

I would like to add something like the following to the images

private static int calculateInSampleSize(BitmapFactory.Options options,
        int reqWidth, int reqHeight) {

    final int height = options.outHeight;
    final int width = options.outWidth;
    int inSampleSize = 1;

    if (height > reqHeight || width > reqWidth) {

        // Calculate ratios of height and width to requested height and
        // width
        final int heightRatio = Math.round((float) height
                / (float) reqHeight);
        final int widthRatio = Math.round((float) width / (float) reqWidth);

        // Choose the smallest ratio as inSampleSize value, this will
        // guarantee
        // a final image with both dimensions larger than or equal to the
        // requested height and width.
        inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
    }
    return inSampleSize;
}

回答1:

Just add .fit() to your call to Picasso and it will automatically calculate the appropriate inSampleSize to use when decoding the image.

You will also probably want to use either .centerInside() or .centerCrop() to ensure the aspect ratio of the image is not altered when automatically resized.

来源：https://stackoverflow.com/questions/26518116/loading-images-using-web-service-and-picasso-how-to-add-insampling-size

标签

android

bitmap

picasso