net.potterpcs.recipebook.DownloadImageTask.java Source code

Introduction

Here is the source code for net.potterpcs.recipebook.DownloadImageTask.java

Source

/*
 *    Copyright 2012 Michael Potter
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */

/*
 * DownloadImageTask.java - Async image downloader that caches frequently-used
 * images into the database. 
 */

package net.potterpcs.recipebook;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.apache.http.HttpResponse;
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.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.net.http.AndroidHttpClient;
import android.os.AsyncTask;
import android.widget.ImageView;

public class DownloadImageTask extends AsyncTask<String, Integer, Bitmap> {
    // Tag for logging
    //   private static final String TAG = "DownloadImageTask";

    // Handle for the parent activity
    Activity parent;

    // Handle for the ImageView that we will fill
    ImageView view;

    public DownloadImageTask(Activity a, ImageView v) {
        parent = a;
        view = v;
    }

    @Override
    protected Bitmap doInBackground(String... params) {
        return downloadImage(params);
    }

    private Bitmap downloadImage(String... urls) {
        Bitmap bitmap = null;
        RecipeData data = ((RecipeBook) parent.getApplication()).getData();

        AndroidHttpClient client = AndroidHttpClient.newInstance("A to Z Recipes for Android");

        if (data.isCached(urls[0])) {
            // Retrieve a cached image if we have one
            String pathName = data.findCacheEntry(urls[0]);
            Uri pathUri = Uri.fromFile(new File(parent.getCacheDir(), pathName));
            try {
                bitmap = RecipeBook.decodeScaledBitmap(parent, pathUri);
            } catch (IOException e) {
                e.printStackTrace();
                bitmap = null;
            }
        } else {
            try {
                // If the image isn't in the cache, we have to go and get it.
                // First, we set up the HTTP request.
                HttpGet request = new HttpGet(urls[0]);
                HttpParams params = new BasicHttpParams();
                HttpConnectionParams.setSoTimeout(params, 60000);
                request.setParams(params);

                // Let the UI know we're working.
                publishProgress(25);

                // Retrieve the image from the network.
                HttpResponse response = client.execute(request);
                publishProgress(50);

                // Create a bitmap to put in the ImageView.
                byte[] image = EntityUtils.toByteArray(response.getEntity());
                bitmap = BitmapFactory.decodeByteArray(image, 0, image.length);
                publishProgress(75);

                // Cache the file for offline use, and to lower data usage.
                File cachePath = parent.getCacheDir();
                String cacheFile = "recipecache-" + Long.toString(System.currentTimeMillis());
                if (bitmap.compress(Bitmap.CompressFormat.PNG, 0,
                        new FileOutputStream(new File(cachePath, cacheFile)))) {
                    RecipeData appData = ((RecipeBook) parent.getApplication()).getData();
                    appData.insertCacheEntry(urls[0], cacheFile);
                }
                //            Log.v(TAG, cacheFile);

                // We're done!
                publishProgress(100);
            } catch (IOException e) {
                // TODO Maybe a dialog?
            }

        }
        client.close();
        return bitmap;
    }

    @Override
    protected void onPostExecute(Bitmap result) {
        // UI changes happen here
        view.setImageBitmap(result);
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        // TODO If the download is going to take a while, pop up a dialog
        //      Log.v(TAG, values[0].toString());
    }

    public static void doDownload(Activity a, String url, ImageView view) {
        new DownloadImageTask(a, view).execute(url);
    }
}