Managing multiple asynctask to download multiple images from html code, leaking ram, any ideas?

Question

I'm developing an android app. Now I'm parsing bbcode to html and display it inside a textview, the textview is inside a custom listview. I use Html.ImageGetter() to display the images downloaded from AsyncTask.

It works great for a low number of pictures. But if the app is asked to download 40-50 pictures, 40-50 tasks are created and it becomes a mess. Each task opens a stream to download the images. After that it decodes the bytes into bitmaps, resize them, save them to the sdcard and recycles the bitmaps.

Now if the app is loading all this images at the same time it uses a huge amount of ram. I managed to make it pass 48 mb. There is a big gap between 16 and 48 :(. I searched on how to solve this. I downloaded AsyncTask code from google:

http://google.com/codesearch/p?hl=en&sa=N&cd=2&ct=rc#uX1GffpyOZk/core/java/android/os/AsyncTask.java&q=lang:java%20AsyncTask

And set the pool size to 3. But this didn't helped. I really can't figure out where I'm loosing ram. As soon as I put a big task queue my ram goes crazy. After a few images are received it gets worst. I don't think it is the images since I can get to 30 mb before any image is displayed. The app itself including the view, information and its service uses 13 mb, all the rest is leaked here.

Does the queue itself make big ram allocations? Or is the Html.ImageGetter() leaking a huge amount of memory somehow? Is there a better way to do this?

Here I load the images:

public void LoadImages(String source) {

    myurl = null;
    try {
        myurl = new URL(source);
    } catch (MalformedURLException e) {
        e.printStackTrace();
    }

    new DownloadImageFromPost().execute(myurl);
}

private class DownloadImageFromPost extends AsyncTask<URL, Integer, Bitmap> {

    @Override
    protected Bitmap doInBackground(URL... params) {
        URL url;
        Log.d(TAG, "Starting new image download");
        try {
            url = params[0];
            HttpURLConnection connection = (HttpURLConnection) url
            .openConnection();
            int length = connection.getContentLength();
            InputStream is = (InputStream) url.getContent();
            byte[] imageData = new byte[length];
            int buffersize = (int) Math.ceil(length / (double) 100);
            int downloaded = 0;
            int read;
            while (downloaded < length) {
                if (length < buffersize) {
                    read = is.read(imageData, downloaded, length);
                } else if ((length - downloaded) <= buffersize) {
                    read = is.read(imageData, downloaded, length
                            - downloaded);
                } else {
                    read = is.read(imageData, downloaded, buffersize);
                }
                downloaded += read;
                publishProgress((downloaded * 100) / length);
            }
            Bitmap bitmap = BitmapFactory.decodeByteArray(imageData, 0,
                    length);
            if (bitmap != null) {
                Log.i(TAG, "Bitmap created");
            } else {
                Log.i(TAG, "Bitmap not created");
            }
            is.close();
            return bitmap;

        } catch (MalformedURLException e) {
            Log.e(TAG, "Malformed exception: " + e.toString());

        } catch (IOException e) {
            Log.e(TAG, "IOException: " + e.toString());

        } catch (Exception e) {

        }


    return null;

}

protected void onPostExecute(Bitmap result) {

        String name = Environment.getExternalStorageDirectory() + "/tempthumbs/" + myurl.toString().hashCode() +".jpg";
        String rname = Environment.getExternalStorageDirectory() + "/tempthumbs/" + myurl.toString().hashCode() +"-t.jpg";
        try {
            if (result != null) {
                    hasExternalStoragePublicPicture(name); 
                    ImageManager manager = new ImageManager(context);
                    Bitmap rezised = manager.resizeBitmap(result, 300, 300);
                    saveToSDCard(result, name,  myurl.toString().hashCode() +".jpg");
                    saveToSDCard(rezised, rname, myurl.toString().hashCode() +"-t.jpg");
                    result.recycle();
                    rezised.recycle();

            } else {

            }
        } catch(NullPointerException e) {
        }

    Log.d(TAG, "Sending images loaded announcement");
    Intent i = new Intent(IMAGE_LOADED);
    i.putExtra("image",  name);
    i.putExtra("source", myurl.toString());
    i.putExtra("class", true);
    context.sendBroadcast(i);

}

}


    private boolean hasExternalStoragePublicPicture(String name) {
    File file = new File(name);
    if (file != null) {
        file.delete();
    }

        try {
            file.createNewFile();

        } catch (IOException e) {
        e.printStackTrace();


        }

    return file.exists();
}

public void saveToSDCard(Bitmap bitmap, String name, String nam) {
    boolean mExternalStorageAvailable = false;
    boolean mExternalStorageWriteable = false;
    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state)) {
        mExternalStorageAvailable = mExternalStorageWriteable = true;
        Log.v(TAG, "SD Card is available for read and write "
                + mExternalStorageAvailable + mExternalStorageWriteable);
        saveFile(bitmap, name, nam);
    } else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
        mExternalStorageAvailable = true;
        mExternalStorageWriteable = false;
        Log.v(TAG, "SD Card is available for read "
                + mExternalStorageAvailable);
    } else {
        mExternalStorageAvailable = mExternalStorageWriteable = false;
        Log.v(TAG, "Please insert a SD Card to save your Video "
                + mExternalStorageAvailable + mExternalStorageWriteable);
    }
}

private void saveFile(Bitmap bitmap, String fullname, String nam) {

    ContentValues values = new ContentValues();

    File outputFile = new File(fullname);
    values.put(MediaStore.MediaColumns.DATA, outputFile.toString());
    values.put(MediaStore.MediaColumns.TITLE, nam);
    values.put(MediaStore.MediaColumns.DATE_ADDED, System
            .currentTimeMillis());
    values.put(MediaStore.MediaColumns.MIME_TYPE, "image/jpg");
    Uri uri = context.getContentResolver().insert(
            android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI,

            values);;

    try {
        OutputStream outStream = context.getContentResolver()
                .openOutputStream(uri);
        bitmap.compress(Bitmap.CompressFormat.JPEG, 95, outStream);

        outStream.flush();
        outStream.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    bitmap.recycle();
}

And here i call Html.ImageGetter(), this is inside a list getView:

holder.content.setText(Html.fromHtml(
   processor.preparePostText(posts.get(position).post_content),
   new Html.ImageGetter() {

      @Override public Drawable getDrawable(String source) {

         Log.d("Forum Service", "image source: " + source);
         if (imageSources.contains(source)) {
            for (int x = 0; x < imageSources.size(); x++) {
               if (source.equals(imageSources.get(x))) {

                  String tmp = oImages.get(x);
                  tmp = tmp.substring(0, tmp.length() - 4);
                  tmp = tmp + "-t.jpg";
                  Drawable d = Drawable.createFromPath(tmp);
                  try {
                     d.setBounds(0, 0, d.getIntrinsicWidth(),
                        d.getIntrinsicHeight());
                  } catch (NullPointerException e) {

                  }
                  Log.d("Forum Service", "Loaded image froms sdcard");
                  return d;
               }
            }

         } else if (notLoadedImages.contains(source)) {
            Log.d("Forum Service", "Waiting for image");
            return null;
         } else {
            notLoadedImages.add(source);
            LoadAllIcons loader = new LoadAllIcons(context);
            loader.LoadImages(source);
            Log.d("Forum Service", "Asked for image");
            return null;
         }
         return null;
      }

   }, null));

Thanks!

Finally the problem was that all Tasks loaded at the same time. Therefor 40 images where allocated in ram while downloading. I managed to limit the amount of running tasks by doing this modifications on AsyncTask:

private static final int CORE_POOL_SIZE = 2;
private static final int MAXIMUM_POOL_SIZE = 2;
private static final int KEEP_ALIVE = 1;

private static final BlockingQueue<Runnable> sWorkQueue =
        new LinkedBlockingQueue<Runnable>(100);

Answer 1

Mateo there goes your answer http://android-developers.blogspot.com/2010/07/multithreading-for-performance.html

And you're done!