DownloadImageTask.java

package com.kaorisan.lazyload;

import java.io.InputStream;
import java.net.URL;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.os.AsyncTask;
import android.view.View;
import android.widget.ImageView;
import android.widget.ProgressBar;

public class DownloadImageTask extends AsyncTask<PbAndImage, Void, Bitmap> {
	ImageView imageView = null;
	ProgressBar pb = null;

	protected Bitmap doInBackground(PbAndImage... pb_and_images) {
		this.imageView = (ImageView) pb_and_images[0].getImg();
		this.pb = (ProgressBar) pb_and_images[0].getPb();
		return getBitmapDownloaded((String) imageView.getTag());
	}

	protected void onPostExecute(Bitmap result) {
		imageView.setVisibility(View.VISIBLE);
		pb.setVisibility(View.GONE); // hide the progressbar after downloading
										// the image.
		imageView.setImageBitmap(result); // set the bitmap to the imageview.
	}

	/** This function downloads the image and returns the Bitmap **/
	private Bitmap getBitmapDownloaded(String url) {
		Bitmap bitmap = null;
		try {
			bitmap = BitmapFactory.decodeStream((InputStream) new URL(url).getContent());
			bitmap = getResizedBitmap(bitmap, 50, 50);
			return bitmap;
		} catch (Exception e) {
			e.printStackTrace();
		}
		return bitmap;
	}

	/** decodes image and scales it to reduce memory consumption **/
	public Bitmap getResizedBitmap(Bitmap bm, int newHeight, int newWidth) {
		int width = bm.getWidth();
		int height = bm.getHeight();
		float scaleWidth = ((float) newWidth) / width;
		float scaleHeight = ((float) newHeight) / height;
		// CREATE A MATRIX FOR THE MANIPULATION
		Matrix matrix = new Matrix();
		// RESIZE THE BIT MAP
		matrix.postScale(scaleWidth, scaleHeight);
		// RECREATE THE NEW BITMAP
		Bitmap resizedBitmap = Bitmap.createBitmap(bm, 0, 0, width, height, matrix, false);
		return resizedBitmap;
	}
}