ImageFetcher.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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.
 */

package com.ustc.dystu.dandelion.utils.image;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import android.content.Context;
import android.graphics.Bitmap;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

import com.ustc.dystu.dandelion.BuildConfig;
import com.ustc.dystu.dandelion.utils.Logger;


/**
 * A simple subclass of {@link ImageResizer} that fetches and resizes images
 * fetched from a URL.
 */
public class ImageFetcher extends ImageResizer {
	private static final String TAG = "ImageFetcher";
	private static final int HTTP_CACHE_SIZE = 10 * 1024 * 1024; // 10MB
	public static final String HTTP_CACHE_DIR = "http";

	/**
	 * Initialize providing a target image width and height for the processing
	 * images.
	 * 
	 * @param context
	 * @param imageWidth
	 * @param imageHeight
	 */
	public ImageFetcher(Context context, int imageWidth, int imageHeight) {
		super(context, imageWidth, imageHeight);
		init(context);
	}

	/**
	 * Initialize providing a single target image size (used for both width and
	 * height);
	 * 
	 * @param context
	 * @param imageSize
	 */
	public ImageFetcher(Context context, int imageSize) {
		super(context, imageSize);
		init(context);
	}

	private void init(Context context) {
		checkConnection(context);
	}

	/**
	 * Simple network connection check.
	 * 
	 * @param context
	 */
	private void checkConnection(Context context) {
		final ConnectivityManager cm = (ConnectivityManager) context
				.getSystemService(Context.CONNECTIVITY_SERVICE);
		final NetworkInfo networkInfo = cm.getActiveNetworkInfo();
		if (networkInfo == null || !networkInfo.isConnectedOrConnecting()) {
			/*
			 * Toast.makeText(context, "No network connection found.",
			 * Toast.LENGTH_LONG).show(); Log.e(TAG,
			 * "checkConnection - no connection found");
			 */
		}
	}

	/**
	 * The main process method, which will be called by the ImageWorker in the
	 * VdiskAsyncTask background thread.
	 * 
	 * @param data
	 *            The data to load the bitmap, in this case, a regular http URL
	 * @return The downloaded and resized bitmap
	 */
	private Bitmap processBitmap(String data) {
		if (BuildConfig.DEBUG) {
			// Log.d(TAG, "processBitmap - " + data);
		}

		// Download a bitmap, write it to a file
		final File f = downloadBitmap(mContext, data);

		if (f != null) {
			// Return a sampled down version
			return decodeSampledBitmapFromFile(f.toString(), mImageWidth,
					mImageHeight);
		}

		return null;
	}

	@Override
	protected Bitmap processBitmap(Object data) {
		return processBitmap(String.valueOf(data));
	}

	/**
	 * Download a bitmap from a URL, write it to a disk and return the File
	 * pointer. This implementation uses a simple disk cache.
	 * 
	 * @param context
	 *            The context to use
	 * @param urlString
	 *            The URL to fetch
	 * @return A File pointing to the fetched bitmap
	 */
	public static File downloadBitmap(Context context, String urlString) {
		final File cacheDir = DiskLruCache.getDiskCacheDir(context,
				HTTP_CACHE_DIR);

		final DiskLruCache cache = DiskLruCache.openCache(context, cacheDir,
				HTTP_CACHE_SIZE);

		if (cache == null) {
			return null;
		}

		Logger.d(TAG, "downloadBitmap urlString: " + urlString);

		final File cacheFile = new File(cache.createFilePath(urlString));

		if (cache.containsKey(urlString)) {
			if (BuildConfig.DEBUG) {
				// Log.d(TAG, "downloadBitmap - found in http cache - "
				// + urlString);
			}
			return cacheFile;
		}

		if (BuildConfig.DEBUG) {
			// Log.d(TAG, "downloadBitmap - downloading - " + urlString);
		}

		if (urlString.startsWith("file://")) {
			BufferedOutputStream out = null;
			InputStream in = null;
			try {
				in = new BufferedInputStream(new FileInputStream(new File(
						urlString.substring("file://".length()))),
						Utils.IO_BUFFER_SIZE);
				out = new BufferedOutputStream(new FileOutputStream(cacheFile),
						Utils.IO_BUFFER_SIZE);

				int b;
				while ((b = in.read()) != -1) {
					out.write(b);
				}
				out.flush();

				return cacheFile;

			} catch (FileNotFoundException e) {
				e.printStackTrace();
			} catch (IOException e) {
				e.printStackTrace();
			} finally {
				if (in != null) {
					try {
						in.close();
					} catch (IOException e) {
						e.printStackTrace();
					}
				}
				if (out != null) {
					try {
						out.close();
					} catch (IOException e) {
						e.printStackTrace();
					}
				}
			}
		} else {
			String downloadUrl = urlString;

			Logger.d(TAG, "thumbnail downloadurl: " + downloadUrl);

			Utils.disableConnectionReuseIfNecessary();
			HttpURLConnection urlConnection = null;
			InputStream in = null;
			BufferedOutputStream out = null;

			try {
				Logger.d(TAG, "thumbnail downloadurl: " + downloadUrl);
				final URL url = new URL(downloadUrl);
				urlConnection = (HttpURLConnection) url.openConnection();
				urlConnection.setReadTimeout(100 * 1000);
				urlConnection.setConnectTimeout(100 * 1000);
				urlConnection.setUseCaches(false);
				in = new BufferedInputStream(urlConnection.getInputStream(),
						Utils.IO_BUFFER_SIZE);
				out = new BufferedOutputStream(new FileOutputStream(cacheFile),
						Utils.IO_BUFFER_SIZE);

				int b;
				while ((b = in.read()) != -1) {
					out.write(b);
				}

				return cacheFile;

			} catch (Exception e) {
				Logger.e(TAG, "Error in downloadBitmap - " + e);
			} finally {
				if (urlConnection != null) {
					try {
						urlConnection.disconnect();
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
				if (in != null) {
					try {
						in.close();
					} catch (IOException e) {
						e.printStackTrace();
					}
				}
				if (out != null) {
					try {
						out.close();
					} catch (Exception e) {
						Logger.e(TAG, "Error in downloadBitmap - " + e);
					}
				}
			}
		}

		return null;
	}
}