DownloadImageTask.java

package main;

import java.io.InputStream;
import java.util.Hashtable;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.widget.ImageView;

public class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {

	ImageView bmImage;
	static Hashtable<String, Bitmap> images;

    public DownloadImageTask(ImageView bmImage) {
    	this.bmImage = bmImage;
    	if(images == null){
    		images = new Hashtable<String, Bitmap>();
    	}
    }

    protected Bitmap doInBackground(String... urls) {
    	Bitmap image = images.get(urls[0]);
    	if(image!=null){
    		return image;
    	}
    	
        String urldisplay = urls[0];
        Bitmap mIcon11 = null;
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon11 = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
//            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        if(mIcon11!=null){
        	images.put(urldisplay, mIcon11);
        }
        return mIcon11;
    }

    protected void onPostExecute(Bitmap result) {
        bmImage.setImageBitmap(result);
    }
    
    public static void showImage(ImageView iv, String url){
    	if(url!=null && !url.equals(""))
    		new DownloadImageTask(iv).execute(url);
	}
    
}