DownloadImageTask.java

package com.pinecone.technology.mcommerce.learning.android.chapter06.asyncTask;

import java.io.IOException;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.util.EntityUtils;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.ImageView;
import android.widget.TextView;

import com.pinecone.technology.mcommerce.learning.android.chapter06.R;

public class DownloadImageTask extends AsyncTask<String, Integer, Bitmap> {
	private Context mContext; // reference to the calling Activity
	int progress = -1;
	Bitmap downloadedImage = null;

	DownloadImageTask(Context context) {
		mContext = context;
	}

	// Called from main thread to re-attach
	protected void setContext(Context context) {
		mContext = context;
		if (progress >= 0) {
			publishProgress(this.progress);
		}
	}

	protected void onPreExecute() {
		progress = 0;
		// We could do some other setup work here before doInBackground() runs
	}

	protected Bitmap doInBackground(String... urls) {
		Log.v("doInBackground", "doing download of image...");
		return downloadImage(urls);
	}

	protected void onProgressUpdate(Integer... progress) {
		TextView mText = (TextView) ((Activity) mContext)
				.findViewById(R.id.text);
		mText.setText("Progress so far: " + progress[0]);
	}

	protected void onPostExecute(Bitmap result) {
		if (result != null) {
			downloadedImage = result;
			setImageInView();
		} else {
			TextView errorMsg = (TextView) ((Activity) mContext)
					.findViewById(R.id.errorMsg);
			errorMsg.setText("Problem downloading image. Please try later.");
		}
	}

	public Bitmap downloadImage(String... urls) {
		HttpClient httpClient = CustomHttpClient.getHttpClient();
		try {
			HttpGet request = new HttpGet(urls[0]);
			HttpParams params = new BasicHttpParams();
			HttpConnectionParams.setSoTimeout(params, 60000); // 1 minute
			request.setParams(params);

			setProgress(25);

			HttpResponse response = httpClient.execute(request);

			setProgress(50);

			sleepFor(5000); // five second sleep

			byte[] image = EntityUtils.toByteArray(response.getEntity());

			setProgress(75);

			Bitmap mBitmap = BitmapFactory.decodeByteArray(image, 0,
					image.length);

			setProgress(100);

			return mBitmap;
		} catch (IOException e) {
			// covers:
			// ClientProtocolException
			// ConnectTimeoutException
			// ConnectionPoolTimeoutException
			// SocketTimeoutException
			e.printStackTrace();
		}
		return null;
	}

	private void setProgress(int progress) {
		this.progress = progress;
		publishProgress(this.progress);
	}

	protected void setImageInView() {
		if (downloadedImage != null) {
			ImageView mImage = (ImageView) ((Activity) mContext)
					.findViewById(R.id.image);
			mImage.setImageBitmap(downloadedImage);
		}
	}

	private void sleepFor(long msecs) {
		try {
			Thread.sleep(msecs);
		} catch (InterruptedException e) {
			Log.v("sleep", "interrupted");
		}
	}
}