Android: How to download a .png file using Async and set it to ImageView?

Question

I've got the URL of a .png image, that needs to be downloaded and set as a source of an ImageView. I'm a beginner so far, so there are a few things I don't understand: 1) Where do I store the file? 2) How do I set it to the ImageView in java code? 3) How to correctly override the AsyncTask methods?

Thanks in advance, will highly appreciate any kind of help.

Answer 1

I'm not sure you can explicity build a png from a download. However, here is what I use to download images and display them into Imageviews :

First, you download the image :

protected static byte[] imageByter(Context ctx, String strurl) {
    try {
        URL url = new URL(urlContactIcon + strurl);
        InputStream is = (InputStream) url.getContent();
        byte[] buffer = new byte[8192];
        int bytesRead;
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        while ((bytesRead = is.read(buffer)) != -1) {
            output.write(buffer, 0, bytesRead);
        }
        return output.toByteArray();
    } catch (MalformedURLException e) {
        e.printStackTrace();
    return null;
    } catch (IOException e) {
        e.printStackTrace();
        return null;
    }
}

And then, create a BitMap and associate it to the Imageview :

bytes = imagebyter(this, mUrl);
bm = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
yourImageview.setImageBitmap(bm);

And that's it.

EDIT
Actually, you can save the file by doing this :

File file = new File(fileName);
FileOutputStream fos = new FileOutputStream(file);
fos.write(imagebyter(this, mUrl));
fos.close();