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    <p>High performance loader - after examining the methods suggested here, I used <a href="http://negativeprobability.blogspot.com/2011/08/lazy-loading-of-images-in-listview.html" rel="noreferrer">Ben's solution</a> with some changes - </p> <ol> <li><p>I realized that working with drawables is faster that with bitmaps so I uses drawables instead</p></li> <li><p>Using SoftReference is great, but it makes the cached image to be deleted too often, so I added a Linked list that holds images references, preventing from the image to be deleted, until it reached a predefined size</p></li> <li><p>To open the InputStream I used java.net.URLConnection which allows me to use web cache (you need to set a response cache first, but that's another story)</p></li> </ol> <p>My code:</p> <pre><code>import java.util.Map; import java.util.HashMap; import java.util.LinkedList; import java.util.Collections; import java.util.WeakHashMap; import java.lang.ref.SoftReference; import java.util.concurrent.Executors; import java.util.concurrent.ExecutorService; import android.graphics.drawable.Drawable; import android.widget.ImageView; import android.os.Handler; import android.os.Message; import java.io.InputStream; import java.net.MalformedURLException; import java.io.IOException; import java.net.URL; import java.net.URLConnection; public class DrawableBackgroundDownloader { private final Map&lt;String, SoftReference&lt;Drawable&gt;&gt; mCache = new HashMap&lt;String, SoftReference&lt;Drawable&gt;&gt;(); private final LinkedList &lt;Drawable&gt; mChacheController = new LinkedList &lt;Drawable&gt; (); private ExecutorService mThreadPool; private final Map&lt;ImageView, String&gt; mImageViews = Collections.synchronizedMap(new WeakHashMap&lt;ImageView, String&gt;()); public static int MAX_CACHE_SIZE = 80; public int THREAD_POOL_SIZE = 3; /** * Constructor */ public DrawableBackgroundDownloader() { mThreadPool = Executors.newFixedThreadPool(THREAD_POOL_SIZE); } /** * Clears all instance data and stops running threads */ public void Reset() { ExecutorService oldThreadPool = mThreadPool; mThreadPool = Executors.newFixedThreadPool(THREAD_POOL_SIZE); oldThreadPool.shutdownNow(); mChacheController.clear(); mCache.clear(); mImageViews.clear(); } public void loadDrawable(final String url, final ImageView imageView,Drawable placeholder) { mImageViews.put(imageView, url); Drawable drawable = getDrawableFromCache(url); // check in UI thread, so no concurrency issues if (drawable != null) { //Log.d(null, "Item loaded from mCache: " + url); imageView.setImageDrawable(drawable); } else { imageView.setImageDrawable(placeholder); queueJob(url, imageView, placeholder); } } private Drawable getDrawableFromCache(String url) { if (mCache.containsKey(url)) { return mCache.get(url).get(); } return null; } private synchronized void putDrawableInCache(String url,Drawable drawable) { int chacheControllerSize = mChacheController.size(); if (chacheControllerSize &gt; MAX_CACHE_SIZE) mChacheController.subList(0, MAX_CACHE_SIZE/2).clear(); mChacheController.addLast(drawable); mCache.put(url, new SoftReference&lt;Drawable&gt;(drawable)); } private void queueJob(final String url, final ImageView imageView,final Drawable placeholder) { /* Create handler in UI thread. */ final Handler handler = new Handler() { @Override public void handleMessage(Message msg) { String tag = mImageViews.get(imageView); if (tag != null &amp;&amp; tag.equals(url)) { if (imageView.isShown()) if (msg.obj != null) { imageView.setImageDrawable((Drawable) msg.obj); } else { imageView.setImageDrawable(placeholder); //Log.d(null, "fail " + url); } } } }; mThreadPool.submit(new Runnable() { @Override public void run() { final Drawable bmp = downloadDrawable(url); // if the view is not visible anymore, the image will be ready for next time in cache if (imageView.isShown()) { Message message = Message.obtain(); message.obj = bmp; //Log.d(null, "Item downloaded: " + url); handler.sendMessage(message); } } }); } private Drawable downloadDrawable(String url) { try { InputStream is = getInputStream(url); Drawable drawable = Drawable.createFromStream(is, url); putDrawableInCache(url,drawable); return drawable; } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return null; } private InputStream getInputStream(String urlString) throws MalformedURLException, IOException { URL url = new URL(urlString); URLConnection connection; connection = url.openConnection(); connection.setUseCaches(true); connection.connect(); InputStream response = connection.getInputStream(); return response; } } </code></pre>
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    1. POLazy load of images in ListView
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    1. USGaurav Shah
    1. USAsaf Pinhassi
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    1. COWorks great! BTW there's a typo in the class name.
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      1. USMullins
    2. COIn case it saves someone else the time: `import java.util.Map; import java.util.HashMap; import java.util.LinkedList; import java.util.Collections; import java.util.WeakHashMap; import java.lang.ref.SoftReference; import java.util.concurrent.Executors; import java.util.concurrent.ExecutorService; import android.graphics.drawable.Drawable; import android.widget.ImageView; import android.os.Handler; import android.os.Message; import java.io.InputStream; import java.net.MalformedURLException; import java.io.IOException; import java.net.URL; import java.net.URLConnection;`
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      1. USMichael Reed
    3. COThanks very much, this is a nice implementation. I also put a different placeholder for when the drawable is being loaded so the user can get some feedback.
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      1. USJuan Hernandez
 

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