Java tutorial
package com.normalexception.app.rx8club.handler; /************************************************************************ * NormalException.net Software, and other contributors * http://www.normalexception.net * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ************************************************************************/ import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.net.SocketTimeoutException; import java.util.Collections; import java.util.Map; import java.util.WeakHashMap; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.log4j.LogManager; import org.apache.log4j.Logger; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.widget.ImageView; import com.normalexception.app.rx8club.Log; import com.normalexception.app.rx8club.R; import com.normalexception.app.rx8club.cache.FileCache; import com.normalexception.app.rx8club.cache.MemoryCache; import com.normalexception.app.rx8club.html.LoginFactory; import com.normalexception.app.rx8club.httpclient.ClientUtils; import com.normalexception.app.rx8club.utils.Utils; public class AvatarLoader { private MemoryCache memoryCache = new MemoryCache(); private FileCache fileCache; private Map<ImageView, String> imageViews = Collections.synchronizedMap(new WeakHashMap<ImageView, String>()); private ExecutorService executorService; private final Logger TAG = LogManager.getLogger(this.getClass()); // The default icon should an image not be found private final int stub_id = R.drawable.rotor_icon; /** * Constructor * @param context Source context */ public AvatarLoader(Context context) { fileCache = new FileCache(context); executorService = Executors.newFixedThreadPool(5); } /** * Once we get the image, we actually want to display it * @param url The url of the image * @param imageView The view to put the image in */ public void DisplayImage(String url, ImageView imageView) { imageViews.put(imageView, url); Bitmap bitmap = memoryCache.get(url); if (bitmap != null) imageView.setImageBitmap(bitmap); else { queuePhoto(url, imageView); imageView.setImageResource(stub_id); } } /** * Queue up the next photo to load * @param url The url of hte photo * @param imageView The view to load it to */ private void queuePhoto(String url, ImageView imageView) { PhotoToLoad p = new PhotoToLoad(url, imageView); executorService.submit(new PhotosLoader(p)); } /** * Grab the image url as a bitmap * @param url The url to grab the bitmap from * @return The image as a bitmap object */ private Bitmap getBitmap(String url) { File f = fileCache.getFile(url); // First check our cache to see if the // image exists Bitmap b = decodeFile(f); if (b != null) return b; // If we got here, the image wasn't cached try { Bitmap bitmap = null; HttpClient httpclient = LoginFactory.getInstance().getClient(); HttpGet hget = ClientUtils.getHttpGet(url); HttpResponse response = httpclient.execute(hget, LoginFactory.getInstance().getHttpContext()); InputStream is = response.getEntity().getContent(); OutputStream os = new FileOutputStream(f); Utils.copyStream(is, os); os.close(); bitmap = decodeFile(f); return bitmap; } catch (IllegalStateException iex) { // No big deal, the image doesn't exist return null; } catch (SocketTimeoutException ex) { Log.w(TAG, "Socket Timedout When Reading " + url); return null; } catch (Exception ex) { Log.e(TAG, ex.getMessage(), ex); return null; } } /** * Decode the image from memory, and reduce the file size * @param f The file * @return The image as a bitmap */ private Bitmap decodeFile(File f) { try { //decode image size BitmapFactory.Options o = new BitmapFactory.Options(); o.inJustDecodeBounds = true; BitmapFactory.decodeStream(new FileInputStream(f), null, o); //Find the correct scale value. It should be the power of 2. final int REQUIRED_SIZE = 70; int width_tmp = o.outWidth, height_tmp = o.outHeight; int scale = 1; while (true) { if (width_tmp / 2 < REQUIRED_SIZE || height_tmp / 2 < REQUIRED_SIZE) break; width_tmp /= 2; height_tmp /= 2; scale *= 2; } //decode with inSampleSize BitmapFactory.Options o2 = new BitmapFactory.Options(); o2.inSampleSize = scale; return BitmapFactory.decodeStream(new FileInputStream(f), null, o2); } catch (FileNotFoundException e) { } return null; } //Task for the queue private class PhotoToLoad { public String url; public ImageView imageView; public PhotoToLoad(String u, ImageView i) { url = u; imageView = i; } } class PhotosLoader implements Runnable { PhotoToLoad photoToLoad; PhotosLoader(PhotoToLoad photoToLoad) { this.photoToLoad = photoToLoad; } @Override public void run() { if (imageViewReused(photoToLoad)) return; Bitmap bmp = getBitmap(photoToLoad.url); memoryCache.put(photoToLoad.url, bmp); if (imageViewReused(photoToLoad)) return; BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad); Activity a = (Activity) photoToLoad.imageView.getContext(); a.runOnUiThread(bd); } } boolean imageViewReused(PhotoToLoad photoToLoad) { String tag = imageViews.get(photoToLoad.imageView); if (tag == null || !tag.equals(photoToLoad.url)) return true; return false; } //Used to display bitmap in the UI thread class BitmapDisplayer implements Runnable { Bitmap bitmap; PhotoToLoad photoToLoad; public BitmapDisplayer(Bitmap b, PhotoToLoad p) { bitmap = b; photoToLoad = p; } public void run() { if (imageViewReused(photoToLoad)) return; if (bitmap != null) photoToLoad.imageView.setImageBitmap(bitmap); else photoToLoad.imageView.setImageResource(stub_id); } } public void clearCache() { memoryCache.clear(); fileCache.clear(); } }