效果图:
类ImageLoader.class：
/******************************************************************************* * Copyright 2011-2013 Sergey Tarasevich * * 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.nostra13.universalimageloader.core;import android.graphics.Bitmap;import android.text.TextUtils;import android.view.View;import android.view.ViewGroup.LayoutParams;import android.widget.ImageView;import android.widget.ImageView.ScaleType;import com.nostra13.universalimageloader.cache.disc.DiscCacheAware;import com.nostra13.universalimageloader.cache.memory.MemoryCacheAware;import com.nostra13.universalimageloader.core.assist.*;import com.nostra13.universalimageloader.core.display.BitmapDisplayer;import com.nostra13.universalimageloader.core.display.FakeBitmapDisplayer;import com.nostra13.universalimageloader.utils.ImageSizeUtils;import com.nostra13.universalimageloader.utils.L;/** * Singletone for image loading and displaying at {@link ImageView ImageViews} * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before any other method. * * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) * @since 1.0.0 */public class ImageLoader { public static final String TAG = ImageLoader.class.getSimpleName(); static final String LOG_INIT_CONFIG = "Initialize ImageLoader with configuration"; static final String LOG_DESTROY = "Destroy ImageLoader"; static final String LOG_LOAD_IMAGE_FROM_MEMORY_CACHE = "Load image from memory cache [%s]"; private static final String WARNING_RE_INIT_CONFIG = "Try to initialize ImageLoader which had already been initialized before. " + "To re-init ImageLoader with new configuration call ImageLoader.destroy() at first."; private static final String ERROR_WRONG_ARGUMENTS = "Wrong arguments were passed to displayImage() method (ImageView reference must not be null)"; private static final String ERROR_NOT_INIT = "ImageLoader must be init with configuration before using"; private static final String ERROR_INIT_CONFIG_WITH_NULL = "ImageLoader configuration can not be initialized with null"; private ImageLoaderConfiguration configuration; private ImageLoaderEngine engine; private final ImageLoadingListener emptyListener = new SimpleImageLoadingListener(); private final BitmapDisplayer fakeBitmapDisplayer = new FakeBitmapDisplayer(); private volatile static ImageLoader instance; /** Returns singleton class instance */ public static ImageLoader getInstance() { if (instance == null) { synchronized (ImageLoader.class) { if (instance == null) { instance = new ImageLoader(); } } } return instance; } protected ImageLoader() { } /** * Initializes ImageLoader instance with configuration. * If configurations was set before ( {@link #isInited()} == true) then this method does nothing. * To force initialization with new configuration you should {@linkplain #destroy() destroy ImageLoader} at first. * * @param configuration {@linkplain ImageLoaderConfiguration ImageLoader configuration} * @throws IllegalArgumentException if configuration parameter is null */ public synchronized void init(ImageLoaderConfiguration configuration) { if (configuration == null) { throw new IllegalArgumentException(ERROR_INIT_CONFIG_WITH_NULL); } if (this.configuration == null) { if (configuration.writeLogs) L.d(LOG_INIT_CONFIG); engine = new ImageLoaderEngine(configuration); this.configuration = configuration; } else { L.w(WARNING_RE_INIT_CONFIG); } } /** * Returns true - if ImageLoader {@linkplain #init(ImageLoaderConfiguration) is initialized with * configuration}; false - otherwise */ public boolean isInited() { return configuration != null; } /** * Adds display image task to execution pool. Image will be set to ImageView when it's turn. * Default {@linkplain DisplayImageOptions display image options} from {@linkplain ImageLoaderConfiguration * configuration} will be used. * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before this method call * * @param uri Image URI (i.e. "http://site.com/image.png", "file:///mnt/sdcard/image.png") * @param imageView {@link ImageView} which should display image * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before * @throws IllegalArgumentException if passed imageView is null */ public void displayImage(String uri, ImageView imageView) { displayImage(uri, imageView, null, null); } /** * Adds display image task to execution pool. Image will be set to ImageView when it's turn. * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before this method call * * @param uri Image URI (i.e. "http://site.com/image.png", "file:///mnt/sdcard/image.png") * @param imageView {@link ImageView} which should display image * @param options {@linkplain DisplayImageOptions Display image options} for image displaying. If null - * default display image options * {@linkplain ImageLoaderConfiguration.Builder#defaultDisplayImageOptions(DisplayImageOptions) from * configuration} will be used. * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before * @throws IllegalArgumentException if passed imageView is null */ public void displayImage(String uri, ImageView imageView, DisplayImageOptions options) { displayImage(uri, imageView, options, null); } /** * Adds display image task to execution pool. Image will be set to ImageView when it's turn. * Default {@linkplain DisplayImageOptions display image options} from {@linkplain ImageLoaderConfiguration * configuration} will be used. * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before this method call * * @param uri Image URI (i.e. "http://site.com/image.png", "file:///mnt/sdcard/image.png") * @param imageView {@link ImageView} which should display image * @param listener {@linkplain ImageLoadingListener Listener} for image loading process. Listener fires events on UI * thread. * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before * @throws IllegalArgumentException if passed imageView is null */ public void displayImage(String uri, ImageView imageView, ImageLoadingListener listener) { displayImage(uri, imageView, null, listener); } /** * Adds display image task to execution pool. Image will be set to ImageView when it's turn. * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before this method call * * @param uri Image URI (i.e. "http://site.com/image.png", "file:///mnt/sdcard/image.png") * @param imageView {@link ImageView} which should display image * @param options {@linkplain DisplayImageOptions Display image options} for image displaying. If null - * default display image options * {@linkplain ImageLoaderConfiguration.Builder#defaultDisplayImageOptions(DisplayImageOptions) from * configuration} will be used. * @param listener {@linkplain ImageLoadingListener Listener} for image loading process. Listener fires events on UI * thread. * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before * @throws IllegalArgumentException if passed imageView is null */ public void displayImage(String uri, ImageView imageView, DisplayImageOptions options, ImageLoadingListener listener) { checkConfiguration(); if (imageView == null) { throw new IllegalArgumentException(ERROR_WRONG_ARGUMENTS); } if (listener == null) { listener = emptyListener; } if (options == null) { options = configuration.defaultDisplayImageOptions; } if (TextUtils.isEmpty(uri)) { engine.cancelDisplayTaskFor(imageView); listener.onLoadingStarted(uri, imageView); if (options.shouldShowImageForEmptyUri()) { imageView.setImageResource(options.getImageForEmptyUri()); } else { imageView.setImageDrawable(null); } listener.onLoadingComplete(uri, imageView, null); return; } ImageSize targetSize = ImageSizeUtils.defineTargetSizeForView(imageView, configuration.maxImageWidthForMemoryCache, configuration.maxImageHeightForMemoryCache); String memoryCacheKey = MemoryCacheUtil.generateKey(uri, targetSize); engine.prepareDisplayTaskFor(imageView, memoryCacheKey); listener.onLoadingStarted(uri, imageView); Bitmap bmp = configuration.memoryCache.get(memoryCacheKey); if (bmp != null && !bmp.isRecycled()) { if (configuration.writeLogs) L.d(LOG_LOAD_IMAGE_FROM_MEMORY_CACHE, memoryCacheKey); if (options.shouldPostProcess()) { ImageLoadingInfo imageLoadingInfo = new ImageLoadingInfo(uri, imageView, targetSize, memoryCacheKey, options, listener, engine.getLockForUri(uri)); ProcessAndDisplayImageTask displayTask = new ProcessAndDisplayImageTask(engine, bmp, imageLoadingInfo, options.getHandler()); engine.submit(displayTask); } else { options.getDisplayer().display(bmp, imageView, LoadedFrom.MEMORY_CACHE); listener.onLoadingComplete(uri, imageView, bmp); } } else { if (options.shouldShowStubImage()) { imageView.setImageResource(options.getStubImage()); } else { if (options.isResetViewBeforeLoading()) { imageView.setImageDrawable(null); } } ImageLoadingInfo imageLoadingInfo = new ImageLoadingInfo(uri, imageView, targetSize, memoryCacheKey, options, listener, engine.getLockForUri(uri)); LoadAndDisplayImageTask displayTask = new LoadAndDisplayImageTask(engine, imageLoadingInfo, options.getHandler()); engine.submit(displayTask); } } /** * Adds load image task to execution pool. Image will be returned with * {@link ImageLoadingListener#onLoadingComplete(String, android.view.View, android.graphics.Bitmap)} callback}. * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before this method call * * @param uri Image URI (i.e. "http://site.com/image.png", "file:///mnt/sdcard/image.png") * @param listener {@linkplain ImageLoadingListener Listener} for image loading process. Listener fires events on UI * thread. * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before */ public void loadImage(String uri, ImageLoadingListener listener) { loadImage(uri, null, null, listener); } /** * Adds load image task to execution pool. Image will be returned with * {@link ImageLoadingListener#onLoadingComplete(String, android.view.View, android.graphics.Bitmap)} callback}. * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before this method call * * @param uri Image URI (i.e. "http://site.com/image.png", "file:///mnt/sdcard/image.png") * @param minImageSize Minimal size for {@link Bitmap} which will be returned in * {@linkplain ImageLoadingListener#onLoadingComplete(String, android.view.View, android.graphics.Bitmap)} callback}. Downloaded image will be decoded * and scaled to {@link Bitmap} of the size which is equal or larger (usually a bit larger) than * incoming minImageSize . * @param listener {@linkplain ImageLoadingListener Listener} for image loading process. Listener fires events on UI * thread. * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before */ public void loadImage(String uri, ImageSize minImageSize, ImageLoadingListener listener) { loadImage(uri, minImageSize, null, listener); } /** * Adds load image task to execution pool. Image will be returned with * {@link ImageLoadingListener#onLoadingComplete(String, android.view.View, android.graphics.Bitmap)} callback}. * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before this method call * * @param uri Image URI (i.e. "http://site.com/image.png", "file:///mnt/sdcard/image.png") * @param options {@linkplain DisplayImageOptions Display image options} for image displaying. If null - * default display image options * {@linkplain ImageLoaderConfiguration.Builder#defaultDisplayImageOptions(DisplayImageOptions) from * configuration} will be used. * Incoming options should contain {@link FakeBitmapDisplayer} as displayer. * @param listener {@linkplain ImageLoadingListener Listener} for image loading process. Listener fires events on UI * thread. * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before */ public void loadImage(String uri, DisplayImageOptions options, ImageLoadingListener listener) { loadImage(uri, null, options, listener); } /** * Adds load image task to execution pool. Image will be returned with * {@link ImageLoadingListener#onLoadingComplete(String, android.view.View, android.graphics.Bitmap)} callback}. * NOTE: {@link #init(ImageLoaderConfiguration)} method must be called before this method call * * @param uri Image URI (i.e. "http://site.com/image.png", "file:///mnt/sdcard/image.png") * @param targetImageSize Minimal size for {@link Bitmap} which will be returned in * {@linkplain ImageLoadingListener#onLoadingComplete(String, android.view.View, android.graphics.Bitmap)} callback}. Downloaded image will be decoded * and scaled to {@link Bitmap} of the size which is equal or larger (usually a bit larger) than * incoming minImageSize . * @param options {@linkplain DisplayImageOptions Display image options} for image displaying. If null - * default display image options * {@linkplain ImageLoaderConfiguration.Builder#defaultDisplayImageOptions(DisplayImageOptions) from * configuration} will be used. * Incoming options should contain {@link FakeBitmapDisplayer} as displayer. * @param listener {@linkplain ImageLoadingListener Listener} for image loading process. Listener fires events on UI * thread. * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before */ public void loadImage(String uri, ImageSize targetImageSize, DisplayImageOptions options, ImageLoadingListener listener) { checkConfiguration(); if (targetImageSize == null) { targetImageSize = new ImageSize(configuration.maxImageWidthForMemoryCache, configuration.maxImageHeightForMemoryCache); } if (options == null) { options = configuration.defaultDisplayImageOptions; } DisplayImageOptions optionsWithFakeDisplayer; if (options.getDisplayer() instanceof FakeBitmapDisplayer) { optionsWithFakeDisplayer = options; } else { optionsWithFakeDisplayer = new DisplayImageOptions.Builder().cloneFrom(options).displayer(fakeBitmapDisplayer).build(); } ImageView fakeImage = new ImageView(configuration.context); fakeImage.setLayoutParams(new LayoutParams(targetImageSize.getWidth(), targetImageSize.getHeight())); fakeImage.setScaleType(ScaleType.CENTER_CROP); displayImage(uri, fakeImage, optionsWithFakeDisplayer, listener); } /** * Checks if ImageLoader's configuration was initialized * * @throws IllegalStateException if configuration wasn't initialized */ private void checkConfiguration() { if (configuration == null) { throw new IllegalStateException(ERROR_NOT_INIT); } } /** * Returns memory cache * * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before */ public MemoryCacheAware getMemoryCache() { checkConfiguration(); return configuration.memoryCache; } /** * Clears memory cache * * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before */ public void clearMemoryCache() { checkConfiguration(); configuration.memoryCache.clear(); } /** * Returns disc cache * * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before */ public DiscCacheAware getDiscCache() { checkConfiguration(); return configuration.discCache; } /** * Clears disc cache. * * @throws IllegalStateException if {@link #init(ImageLoaderConfiguration)} method wasn't called before */ public void clearDiscCache() { checkConfiguration(); configuration.discCache.clear(); } /** Returns URI of image which is loading at this moment into passed {@link ImageView} */ public String getLoadingUriForView(ImageView imageView) { return engine.getLoadingUriForView(imageView); } /** * Cancel the task of loading and displaying image for passed {@link ImageView}. * * @param imageView {@link ImageView} for which display task will be cancelled */ public void cancelDisplayTask(ImageView imageView) { engine.cancelDisplayTaskFor(imageView); } /** * Denies or allows ImageLoader to download images from the network. * * If downloads are denied and if image isn't cached then * {@link ImageLoadingListener#onLoadingFailed(String, View, FailReason)} callback will be fired with * {@link FailReason.FailType#NETWORK_DENIED} * * @param denyNetworkDownloads pass true - to deny engine to download images from the network; false - * to allow engine to download images from network. */ public void denyNetworkDownloads(boolean denyNetworkDownloads) { engine.denyNetworkDownloads(denyNetworkDownloads); } /** * Sets option whether ImageLoader will use {@link FlushedInputStream} for network downloads to handle this known problem or not. * * @param handleSlowNetwork pass true - to use {@link FlushedInputStream} for network downloads; false * - otherwise. */ public void handleSlowNetwork(boolean handleSlowNetwork) { engine.handleSlowNetwork(handleSlowNetwork); } /** * Pause ImageLoader. All new "load&display" tasks won't be executed until ImageLoader is {@link #resume() resumed}. * Already running tasks are not paused. */ public void pause() { engine.pause(); } /** Resumes waiting "load&display" tasks */ public void resume() { engine.resume(); } /** * Cancels all running and scheduled display image tasks. * ImageLoader still can be used after calling this method. */ public void stop() { engine.stop(); } /** * {@linkplain #stop() Stops ImageLoader} and clears current configuration. * You can {@linkplain #init(ImageLoaderConfiguration) init} ImageLoader with new configuration after calling this * method. */ public void destroy() { if (configuration != null && configuration.writeLogs) L.d(LOG_DESTROY); stop(); engine = null; configuration = null; }} 调用方法：
public boolean onOptionsItemSelected(MenuItem item) { // TODO Auto-generated method stub switch (item.getItemId()) { case R.id.menu_about: break; case R.id.menu_setting: break; case R.id.menu_history: break; case R.id.menu_feedback: break; case R.id.menu_exit: showAlertDialog("退出程序", "确定退出高仿京东商城？", "确定", new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub AppManager.getInstance().AppExit(getApplicationContext()); ImageLoader.getInstance().clearMemoryCache(); } }, "取消", new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // TODO Auto-generated method stub dialog.dismiss(); } }); break; case R.id.menu_help: break; default: break; } return true; } 出自：高仿京东商城