Mega Code Archive
Image Loader
<![CDATA[
//package com.discogs.cupcake.utils;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Queue;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.widget.ImageView;
public class ImageLoader
{
static private ImageLoader _instance;
static public ImageLoader getInstance()
{
if (_instance == null)
{
_instance = new ImageLoader();
}
return _instance;
}
private HashMap<String , Bitmap> _urlToBitmap;
private Queue<Group> _queue;
private DownloadThread _thread;
private Bitmap _missing;
private boolean _busy;
/**
* Constructor
*/
private ImageLoader ()
{
_urlToBitmap = new HashMap<String , Bitmap>();
_queue = new LinkedList<Group>();
_busy = false;
}
public Bitmap get(String url)
{
return _urlToBitmap.get(url);
}
public void load(ImageView image, String url)
{
load(image, url, false);
}
public void load(ImageView image, String url, boolean cache)
{
if (_urlToBitmap.get(url) != null)
{
if (image!=null)
{
image.setImageBitmap(_urlToBitmap.get(url));
}
}
else
{
image.setImageBitmap(null);
queue(image, url, cache);
}
}
public void queue(ImageView image, String url, boolean cache)
{
Iterator<Group> it = _queue.iterator();
if (image!=null)
{
while (it.hasNext())
{
if (it.next().image.equals(image))
{
it.remove();
break;
}
}
}
else if (url!=null)
{
while (it.hasNext())
{
if (it.next().url.equals(url))
{
it.remove();
break;
}
}
}
_queue.add(new Group(image, url, null, cache));
loadNext();
}
public void clearQueue()
{
_queue = new LinkedList<Group>();
}
public void clearCache()
{
_urlToBitmap = new HashMap<String , Bitmap>();
}
public void cancel()
{
clearQueue();
if ( _thread != null )
{
_thread.disconnect();
_thread = null;
}
}
public void setMissingBitmap(Bitmap bitmap)
{
_missing = bitmap;
}
private void loadNext()
{
Iterator<Group> it = _queue.iterator();
if (!_busy && it.hasNext())
{
_busy = true;
Group group = it.next();
it.remove();
// double check image availability
if (_urlToBitmap.get(group.url) != null)
{
if (group.image!=null)
{
group.image.setImageBitmap(_urlToBitmap.get(group.url));
}
_busy = false;
loadNext();
}
else
{
_thread = new DownloadThread(group);
_thread.start();
}
}
}
private void onLoad()
{
if (_thread != null)
{
Group group = _thread.group;
if (group.bitmap != null)
{
if (group.cache)
{
_urlToBitmap.put(group.url, group.bitmap);
}
if (group.image != null)
{
group.image.setImageBitmap(group.bitmap);
}
}
else if (_missing != null)
{
if (group.image != null)
{
group.image.setImageBitmap(_missing);
}
}
}
_thread = null;
_busy = false;
loadNext();
}
private class Group
{
public Group(ImageView image, String url, Bitmap bitmap, boolean cache)
{
this.image = image;
this.url = url;
this.bitmap = bitmap;
this.cache = cache;
}
public ImageView image;
public String url;
public Bitmap bitmap;
public boolean cache;
}
private class DownloadThread extends Thread
{
final Handler threadHandler = new Handler();
final Runnable threadCallback = new Runnable()
{
public void run()
{
onLoad();
}
};
private HttpURLConnection _conn;
public Group group;
public DownloadThread(Group group)
{
this.group = group;
}
@Override
public void run()
{
InputStream inStream = null;
_conn = null;
try
{
_conn = (HttpURLConnection) new URL(group.url).openConnection();
_conn.setDoInput(true);
_conn.connect();
inStream = _conn.getInputStream();
group.bitmap = BitmapFactory.decodeStream(inStream);
inStream.close();
_conn.disconnect();
inStream = null;
_conn = null;
}
catch (Exception ex)
{
// nothing
}
if (inStream != null)
{
try
{
inStream.close();
}
catch (Exception ex)
{
}
}
disconnect();
inStream = null;
_conn = null;
threadHandler.post(threadCallback);
}
public void disconnect()
{
if (_conn != null)
{
_conn.disconnect();
}
}
}
}
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