How to load image from url

Question

I am writing a little picture frame app for android that is using opengl for part of the UI. This portion needs to get images from flickr and load them into a texture. The code I have below is functional most of the time, but it has a Thread.sleep() kludge in between getting the input stream from the connection and the bitmap factory decoding the stream:

            URL url = new URL("http://farm5.static.flickr.com/4132/5168797476_7a85deb2be_b.jpg");
            URLConnection con = url.openConnection();
            InputStream is = con.getInputStream();
            Thread.sleep(250); //What am I actually waiting for?
            sourceBitmap = BitmapFactory.decodeStream(is);

How do I get around using the sleep() method in favor of something that makes logical sense?

I am testing on a samsung galaxy tab not in the emulator

score 0 · Answer 1 · answered Dec 01 '10 at 06:53

I think you should implement AsyncTask. Refer this: http://developer.android.com/resources/articles/painless-threading.html

public void onClick(View v) {
  new DownloadImageTask().execute("http://example.com/image.png");
}

private class DownloadImageTask extends AsyncTask<string, void,="" bitmap=""> {
     protected Bitmap doInBackground(String... urls) {
         return loadImageFromNetwork(urls[0]);
     }

     protected void onPostExecute(Bitmap result) {
         mImageView.setImageBitmap(result);
     }
 }

I hope it helps you !!

Downloading the images asynchronously is of course a good idea, however, it doesn't really address the actual question — Mr Bell, Dec 02 '10 at 03:41

score 0 · Accepted Answer · answered Dec 02 '10 at 04:45

This seems less than ideal, but if you read the stream byte by byte into a buffer and then pass the byte array to the BitmapFactory it works correctly.

            URL url = new URL("http://farm5.static.flickr.com/4132/5168797476_7a85deb2be_b.jpg");
            URLConnection con = url.openConnection();
            con.connect();
            int fileLength = con.getContentLength();
            InputStream is = con.getInputStream();
            byte[] bytes = new byte[fileLength];
            for(int i=0;i<fileLength;i++) {
                bytes[i] = (byte)is.read();
            }
            sourceBitmap = BitmapFactory.decodeByteArray(bytes, 0, fileLength);

I tried reading the bytes into the buffer all at once with is.read(bytes, 0, fileLength) but it did not reliably fill the buffer completely unless I waited a moment before calling the read. Is it possible that android implementation of InputStream's read method is flawed causing the BitmapFactory's decodeStream method to fail due to incomplete data?

How to load image from url

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