AsyncImageLoader.java

package com.threeH.MyExhibition.tools;

import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Handler;

public class AsyncImageLoader {
    public Map<String, SoftReference<Drawable>> imageCache = new HashMap<String, SoftReference<Drawable>>();

    private ExecutorService executorService = Executors.newFixedThreadPool(5);
    private final Handler handler = new Handler();

    public Drawable loadDrawable(final String imageUrl,
                                 final ImageCallback callback) {
        if (imageCache.containsKey(imageUrl)) {
            SoftReference<Drawable> softReference = imageCache.get(imageUrl);
            if (softReference.get() != null) {
                return softReference.get();
            }
        }
        executorService.submit(new Runnable() {
            public void run() {
                try {
                    final Drawable drawable = loadImageFromUrl(imageUrl);
                    imageCache.put(imageUrl, new SoftReference<Drawable>(
                            drawable));
                    handler.post(new Runnable() {
                        public void run() {
                            callback.imageLoaded(drawable);
                        }
                    });
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }
        });
        return null;
    }

    protected Drawable loadImageFromUrl(String imageUrl) {
        try {
            URL url = new URL(imageUrl);
            InputStream is = url.openStream();
            System.out.println("" + is.toString().length());
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inPreferredConfig = Config.RGB_565;
            options.inPurgeable = true;
            options.inInputShareable = true;
            options.inSampleSize = 1;
            Bitmap bitmap = BitmapFactory.decodeStream(is, null, options);
            return new BitmapDrawable(bitmap);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public interface ImageCallback {
        public void imageLoaded(Drawable imageDrawable);
    }
}