Hi Carmen, It was because of your post that I could implement the above code. I found the links from your post itself. Thanks for the links and procedure.
Thanks, Prajakta On Sat, Apr 10, 2010 at 2:52 PM, Carmen Delessio <[email protected]>wrote: > I think this is a recurring topic. Here is something I posted on it > previously. I was looking for a recommended or consensus approach. > Romain mentioned that his technique takes into consideration things like > whether the list is scrolling or not. > > Here are 4 references that I have found for lazy-loading images into a > listview in Android. > The idea is to display a placeholder image, get the actual image in the > background, update the ImageView in the list when the image is available. > > I've tried to do this in the simplest way possible using an AsyncTask in an > Adapter. > The outline of that approach is below. Is it flawed? > Is there an agreed approach to handling this common task? > > Thanks, > Carmen > > http://blog.jteam.nl/2009/09/17/exploring-the-world-of-android-part-2/ > Tom van Zummeren > http://evancharlton.com/thoughts/lazy-loading-images-in-a-listview/ Evan > Charlton > http://code.google.com/p/shelves/ from Romain Guy > http://github.com/commonsguy/cwac-thumbnail from Mark Murphy > > > Approach using AsyncTask within an Adapter > > Somewhere in the Adapter. > Add info about the URL for the image to fetch to the ImageView. > Execute an AsyncTask to get the image in the background and load the > ImageView. > AsyncTask uses the tag to fetch the image. > It uses the tag to find the correct view within the ListView. > ImageView imageViewByTag = (ImageView) myListView.findViewWithTag( > tag); > ImageView is updated. > > Somewhere in the Adapter: > > myImageView.setTag("http://someimage.jpg";); // > try { > new GetImage().execute(myImageView); > } catch(RejectedExecutionException e) { } > > > // Asynctask > private class GetImageInBackground extends AsyncTask<ImageView , ImageView > , Long > { > Drawable drawable; > String tag; > > @Override > protected void onProgressUpdate (ImageView... params){ > if (drawable!=null){ > ImageView imageViewByTag = (ImageView) > myListView.findViewWithTag(tag); // find the ImageView > if (imageViewByTag != null) { > imageViewByTag.setImageDrawable(drawable); //update > it > } > > } > } > > @Override > protected Long doInBackground(ImageView... params) { > tag = (String) params[0].getTag(); // get the tag from the > ImageView > > if (tag==null){ > drawable = getPlaceholder(); // get a default drawable > }else{ > > bm =getDrawablefromURL(String (tag); // a method to get > drawable from a URL > } > publishProgress(params[0]); > return null; > } > > } > > > > On Sat, Apr 10, 2010 at 3:10 PM, Prajakta Shitole <[email protected]>wrote: > >> I was able to resolve the issue, just made simple tweaks like removing the >> drawableMap we just need the imageCache. >> >> >> On Sat, Apr 10, 2010 at 10:51 AM, Prajakta Shitole >> <[email protected]>wrote: >> >>> Forgot to paste my code:- >>> >>> class IconicAdapter extends ArrayAdapter { >>> Activity context; >>> Context context2; >>> HashMap<String,String> ret = new HashMap<String,String>(); >>> AsyncLoader async;// = new AsyncLoader(); >>> private ListView listView; >>> HashMap<String,Bitmap> bit = new HashMap<String,Bitmap>(); >>> >>> >>> IconicAdapter(Activity context) { >>> super(context, R.layout.exclusive, items); >>> this.context=context; >>> async = new AsyncLoader(); >>> } >>> >>> public View getView(final int position, View convertView, >>> ViewGroup parent) { >>> View row_inflated = View.inflate(context, R.layout.exclusive,null); >>> wrapper = new ViewWrapper(row_inflated); >>> row_inflated.setTag(wrapper); >>> >>> wrapper.getSongName().setText(items[position]); >>> wrapper.getSingerName().setText(singer_name[position]); >>> final ImageView imgview = wrapper.getIcon(); >>> imgview.setTag(myRemoteImages[position]); >>> Bitmap cachedImage = async.loadDrawable(myRemoteImages[position], new >>> ImageCallback() { >>> public void imageLoaded(Bitmap imageBitmap, String imageUrl) { >>> imgview.setImageBitmap(imageBitmap); >>> notifyDataSetChanged(); >>> } >>> }); >>> if(cachedImage!=null) >>> imgview.setImageBitmap(cachedImage); >>> return(row_inflated); >>> } >>> } >>> >>> >>> ====================================================================== >>> AsynLoader is as below:- >>> >>> public class AsyncLoader{ >>> HashMap<String,Bitmap> bit = new HashMap<String,Bitmap>(); >>> private HashMap<String, SoftReference<Bitmap>> imageCache; >>> private HashMap<String, SoftReference<Bitmap>> drawableMap; >>> public AsyncLoader() { >>> drawableMap = new HashMap<String, SoftReference<Bitmap>>(); >>> imageCache = new HashMap<String, SoftReference<Bitmap>>(); >>> } >>> public Bitmap loadDrawable(final String imageUrl, final ImageCallback >>> imageCallback) { >>> if (drawableMap.containsKey(imageUrl)) { >>> SoftReference<Bitmap> softReference = >>> imageCache.get(imageUrl); >>> Bitmap drawable = softReference.get(); >>> if (drawable != null) { >>> return drawable; >>> } >>> } >>> final Handler handler = new Handler() { >>> @Override >>> public void handleMessage(Message message) { >>> imageCallback.imageLoaded((Bitmap) message.obj, >>> imageUrl); >>> } >>> }; >>> new Thread() { >>> @Override >>> public void run() { >>> Bitmap bitMap = loadImageFromUrl(imageUrl); >>> imageCache.put(imageUrl, new >>> SoftReference<Bitmap>(bitMap)); >>> Message message = handler.obtainMessage(0, bitMap); >>> handler.sendMessage(message); >>> } >>> }.start(); >>> return null; >>> } >>> >>> public static Bitmap loadImageFromUrl(String url){ >>> >>> >>> URL aURL; >>> Bitmap bitmap=null;//=this.bm; >>> try { >>> aURL = new URL(url); >>> URLConnection conn; >>> conn = aURL.openConnection(); >>> conn.connect(); >>> InputStream is= conn.getInputStream(); >>> BufferedInputStream bis = new BufferedInputStream(is); >>> bitmap = BitmapFactory.decodeStream(bis); >>> // bitMap.put(p,bm); >>> bis.close(); >>> is.close(); >>> >>> >>> } catch (MalformedURLException e) { >>> e.printStackTrace(); >>> } catch (IOException e) { >>> e.printStackTrace(); >>> } >>> return bitmap; >>> } >>> >>> public interface ImageCallback { >>> public void imageLoaded(Bitmap imageBitmap, String imageUrl); >>> } >>> } >>> >>> >>> Thanks, >>> Prajakta >>> >>> >>> >>> On Sat, Apr 10, 2010 at 10:21 AM, praj <[email protected]> wrote: >>> >>>> Hi, >>>> >>>> I was trying to implement the lazy loading of images in the list view. >>>> For implementing this i was referring to post by Tom van Zummeren. >>>> (http://blog.jteam.nl/2009/09/17/exploring-the-world-of-android- >>>> part-2/<http://blog.jteam.nl/2009/09/17/exploring-the-world-of-android-part-2/>), >>>> but my images keep on changing in the list. Please can >>>> anyone let me know if they were able to get this working properly >>>> without having the images drawn again and again or let me know if I >>>> have missed on anything or doing something wrong. >>>> >>>> Thanks, >>>> Prajakta >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Android Developers" group. >>>> To post to this group, send email to >>>> [email protected] >>>> To unsubscribe from this group, send email to >>>> [email protected]<android-developers%[email protected]> >>>> For more options, visit this group at >>>> http://groups.google.com/group/android-developers?hl=en >>>> >>>> To unsubscribe, reply using "remove me" as the subject. >>>> >>> >>> >> -- >> You received this message because you are subscribed to the Google >> Groups "Android Developers" group. >> To post to this group, send email to [email protected] >> To unsubscribe from this group, send email to >> [email protected]<android-developers%[email protected]> >> For more options, visit this group at >> http://groups.google.com/group/android-developers?hl=en >> > > > > -- > Carmen > http://www.twitter.com/CarmenDelessio > http://www.talkingandroid.com > http://www.facebook.com/BFFPhoto > http://www.twitter.com/DroidDrop > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected]<android-developers%[email protected]> > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. 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