Question

I have an Android Gallery widget that displays several ImageViews with pictures from the web. The images are stored as jpgs, and get converted to bitmap before added to the ImageViews. Each jpg is 8kb. I’m not doing any scaling on the images.

When I use the gallery with 1 or 2 pictures, it works fine, scrolling is smooth, etc. With 3, it starts to get a little choppy, and at 5 or 10 pictures the application is pretty much unusable.

Does anyone have any ideas as to why the performance is so bad? Does anyone have suggestions for alternatives? Thank you-

@elevine: my method to construct bitmap from jpg url:

private Bitmap getBitmapFromURL(String input) throws IOException {
        URL url = new URL(input);
        URLConnection conn = url.openConnection();
        conn.connect();
        InputStream is = conn.getInputStream();
        BufferedInputStream bis = new BufferedInputStream(is);
        Bitmap bm = BitmapFactory.decodeStream(bis);
        bis.close();
        is.close();
        return bm;
    }

This is my getView method from my ImageAdapter. I’m beginning to suspect this is where my problem lies… Am I grabbing the images way too many times? Thanks for your help!

public View getView(int position, View convertView, ViewGroup parent) {
            ImageView imageView = new ImageView(mContext);

            Bitmap bm;
            try {
                imageView.setImageBitmap(getBitmapFromURL(urls.get(position)));
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            //mageView.
            imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
            imageView.setLayoutParams(new Gallery.LayoutParams(100,100));
            return imageView;
        }

Answer 1

If you are calling getBitmapFromURL from your Activity, then it might be blocking the UI thread. Make sure this code runs on a separate Thread or inside an AsyncTask. You may also want to cache the Bitmaps inside a WeakHashmap. Check for the image inside the cache before grabbing it from the network.