Android Open Source - SocketTest Image Download Task

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License

The source code is released under:

MIT License

Java Source Code

package com.talsockettest;
//Based on Chapter 11 of the book Pro Android 3
/*  w w w .j a  va2 s  .co m*/
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.view.View;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.TextView;

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

  ImageDownloadTask(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;
    clearImageInView();
  }

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

  protected void onProgressUpdate(Integer... progress) {    
    ProgressBar pBar = (ProgressBar)
        ((Activity) mContext).findViewById(R.id.progressBar1);
    
    if(progress[0] > 0 && progress[0] < 100){
      pBar.setVisibility(View.VISIBLE);
      pBar.setProgress(progress[0]);
    }
    else{
      pBar.setVisibility(View.INVISIBLE);    
    }
  }

  protected void onPostExecute(Bitmap result) {
    if(result != null) {
      downloadedImage = result;
      setImageInView();
    }
    else {
      TextView errorMsg = (TextView)
          ((Activity) mContext).findViewById(R.id.error_text);
      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);

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

      setProgress(75);

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

      setProgress(100);

      return mBitmap;
      
    } 
    catch (IOException e) {
      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.imageView1);
      mImage.setImageBitmap(downloadedImage);
    }
  }
  
  protected void clearImageInView() {
      ImageView mImage = (ImageView)
          ((Activity) mContext).findViewById(R.id.imageView1);
      mImage.setImageDrawable(null);
  }
}

Java Source Code List

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