Memory Leak with Bitmaps and Custom Image Views (Android)

Question

In my Android app, I am using a custom ImageView class (Banner) to display images pulled from Facebook Events. While running the app, I notice that there is a large heap size (120 MB) while running the app. I used MAT and I think I've narrowed it down to byte[] and then finally to ImageView. Please check the pictures below to see how I came to this conclusion.

Now, I've read similar posts and I tried recycling my bitmap, using WeakReferences, creating a cache, but nothing seems to be reducing the memory size. However, recycling my bitmap threw me an error which said that I can't use a recycled bitmap (I feel like that may be a hint because it's keeping my bitmap in memory?).

The app isn't running slowly on my phone (It even only says a CPU usage of 1.5% even though the memory is on average 100 MB). I will post my Banner subclass and how I download the images to see if anyone can help me.

Banner.java:

public class Banner extends ImageView {
    public Banner(Context context) {
        super(context);
    }

    public Banner(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public Banner(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = 400;
        if (getDrawable() != null && getDrawable().getIntrinsicWidth() != 0){
            height = width * getDrawable().getIntrinsicHeight() / getDrawable().getIntrinsicWidth();
            if (height < 500)
                height = 700;
        }
        setMeasuredDimension(width, height);
        setColorFilter(Color.rgb(123, 123, 123), android.graphics.PorterDuff.Mode.MULTIPLY);
    }
    public void onDestroy(){
        Drawable drawable = this.getDrawable();
        if (drawable instanceof BitmapDrawable) {
            BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
            Bitmap bitmap = bitmapDrawable.getBitmap();
            bitmap.recycle();
        }
        this.setImageBitmap(null);
    }
}

BannerLoader.java:

public class BannerLoader{
    private String url;
    private WeakReference<ImageView> cover;
    private LruCache<String, WeakReference<Bitmap>> mMemoryCache;
    final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
    final int cacheSize = maxMemory / 8;
    public BannerLoader(String cover_url, WeakReference<ImageView> cover, Drawable defaultDrawable) {
        this.url = cover_url;
        this.cover = cover;
        cover.get().setBackground(defaultDrawable);
        mMemoryCache = new LruCache<String, WeakReference<Bitmap>>(cacheSize) {
            @Override
            protected int sizeOf(String key, WeakReference<Bitmap> bitmap) {
                // The cache size will be measured in kilobytes rather than
                // number of items.
                return bitmap.get().getByteCount() / 1024;
            }
        };
        new DownloadImage().execute();
    }
    public void addBitmapToMemoryCache(String key, WeakReference<Bitmap> bitmap) {
        if (getBitmapFromMemCache(key) == null) {
            mMemoryCache.put(key, bitmap);
        }
    }
    public WeakReference<Bitmap> getBitmapFromMemCache(String key) {
        return mMemoryCache.get(key);
    }
    class DownloadImage extends AsyncTask<Void, Void, WeakReference<Bitmap>>{
        protected WeakReference<Bitmap> doInBackground(Void... params){
            try {
                final WeakReference<Bitmap> cachedBitmap = getBitmapFromMemCache(url);
                if (cachedBitmap != null){
                    return cachedBitmap;
                } else{
                    URL pictureURL = new URL(url);
                    HttpGet httpRequest = null;

                    httpRequest = new HttpGet(pictureURL.toURI());

                    HttpClient httpclient = new DefaultHttpClient();
                    HttpResponse response = (HttpResponse) httpclient
                            .execute(httpRequest);

                    HttpEntity entity = response.getEntity();
                    BufferedHttpEntity b_entity = new BufferedHttpEntity(entity);
                    InputStream input = b_entity.getContent();

                    WeakReference<Bitmap> bitmap = new WeakReference<Bitmap>(BitmapFactory.decodeStream(input));
                    addBitmapToMemoryCache(url, bitmap);
                    return bitmap;
                }
            } catch(Exception ex){
                ex.printStackTrace();
            }
            return null;
        }
        public void onPostExecute(WeakReference<Bitmap> image){
            if (image != null && cover.get() != null){
                cover.get().setImageBitmap(image.get());
            }
        }
    }
}

So, as an example, I download an image like this:

new BannerLoader(tempEvent.getCover_url(), new WeakReference<ImageView>(thumb_image), context.getResources().getDrawable(R.drawable.placeholder));

Thanks for the help!