Android-Universal-Image-Loader三大组件DisplayImageOptions、ImageLoader、ImageLoaderConfiguration详解

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一、介绍

 Android-Universal-Image-Loader(github地址)是一个开源的UI组件程序,该项目的目的是提供一个可重复使用的仪器为异步图像加载,缓存和显示。所以,如果你的程序里需要这个功能的话,那么不妨试试它。因为已经封装好了一些类和方法。我们 可以直接拿来用了。而不用重复去写了。其实,写一个这方面的程序还是比较麻烦的,要考虑多线程缓存,内存溢出等很多方面。

二、具体使用

一个好的类库的重要特征就是可配置性强。我们先简单使用Android-Universal-Image-Loader,一般情况下使用默认配置就可以了。

下面的实例利用Android-Universal-Image-Loader将网络图片加载到图片墙中。

public class BaseActivity extends Activity {    ImageLoader imageLoader;    protected void onCreate(Bundle savedInstanceState) {          // Create global configuration and initialize ImageLoader with this configuration        ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())            .build();        ImageLoader.getInstance().init(config);        super.onCreate(savedInstanceState);    }}

public class MainActivity extends BaseActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);          ImageLoader imageLoader = ImageLoader.getInstance();        GridView gridView = (GridView) this.findViewById(R.id.grdvImageWall);        gridView.setAdapter(new PhotoWallAdapter(Constants.IMAGES));    }    static class ViewHolder {        ImageView imageView;        ProgressBar progressBar;    }    public class PhotoWallAdapter extends BaseAdapter {        String[] imageUrls;        ImageLoader imageLoad;        DisplayImageOptions options;        LinearLayout gridViewItem;        public PhotoWallAdapter(String[] imageUrls) {            assert imageUrls != null;            this.imageUrls = imageUrls;            options = new DisplayImageOptions.Builder()                    .showImageOnLoading(R.drawable.ic_stub) // resource or                                                            // drawable                    .showImageForEmptyUri(R.drawable.ic_empty) // resource or                                                                // drawable                    .showImageOnFail(R.drawable.ic_error) // resource or                                                            // drawable                    .resetViewBeforeLoading(false) // default                    .delayBeforeLoading(1000).cacheInMemory(false) // default                    .cacheOnDisk(false) // default                    .considerExifParams(false) // default                    .imageScaleType(ImageScaleType.IN_SAMPLE_POWER_OF_2) // default                    .bitmapConfig(Bitmap.Config.ARGB_8888) // default                    .displayer(new SimpleBitmapDisplayer()) // default                    .handler(new Handler()) // default                    .build();            this.imageLoad = ImageLoader.getInstance();        }        @Override        public int getCount() {            return this.imageUrls.length;        }        @Override        public Object getItem(int position) {            if (position <= 0 || position >= this.imageUrls.length) {                throw new IllegalArgumentException(                        "position<=0||position>=this.imageUrls.length");            }            return this.imageUrls[position];        }        @Override        public long getItemId(int position) {            return position;        }        @Override        public View getView(int position, View convertView, ViewGroup parent) {            // 判断这个image是否已经在缓存当中,如果没有就下载            final ViewHolder holder;            if (convertView == null) {                holder = new ViewHolder();                gridViewItem = (LinearLayout) getLayoutInflater().inflate(                        R.layout.image_wall_item, null);                holder.imageView = (ImageView) gridViewItem                        .findViewById(R.id.item_image);                holder.progressBar = (ProgressBar) gridViewItem                        .findViewById(R.id.item_process);                gridViewItem.setTag(holder);                convertView = gridViewItem;            } else {                holder = (ViewHolder) gridViewItem.getTag();            }            this.imageLoad.displayImage(this.imageUrls[position],                    holder.imageView, options,                    new SimpleImageLoadingListener() {                        @Override                        public void onLoadingStarted(String imageUri, View view) {                            holder.progressBar.setProgress(0);                            holder.progressBar.setVisibility(View.VISIBLE);                        }                        @Override                        public void onLoadingFailed(String imageUri, View view,                                FailReason failReason) {                            holder.progressBar.setVisibility(View.GONE);                        }                        @Override                        public void onLoadingComplete(String imageUri,                                View view, Bitmap loadedImage) {                            holder.progressBar.setVisibility(View.GONE);                        }                    }, new ImageLoadingProgressListener() {                        @Override                        public void onProgressUpdate(String imageUri,                                View view, int current, int total) {                            holder.progressBar.setProgress(Math.round(100.0f                                    * current / total));                        }                    }); // 通过URL判断图片是否已经下载            return convertView;        }    }}



三者的关系

ImageLoaderConfiguration是针对图片缓存的全局配置,主要有线程类、缓存大小、磁盘大小、图片下载与解析、日志方面的配置。

ImageLoader是具体下载图片,缓存图片,显示图片的具体执行类,它有两个具体的方法displayImage(...)、loadImage(...),但是其实最终他们的实现都是displayImage(...)。

DisplayImageOptions用于指导每一个Imageloader根据网络图片的状态(空白、下载错误、正在下载)显示对应的图片,是否将缓存加载到磁盘上,下载完后对图片进行怎么样的处理。

从三者的协作关系上看,他们有点像厨房规定、厨师、客户个人口味之间的关系。ImageLoaderConfiguration就像是厨房里面的规定,每一个厨师要怎么着装,要怎么保持厨房的干净,这是针对每一个厨师都适用的规定,而且不允许个性化改变。ImageLoader就像是具体做菜的厨师,负责具体菜谱的制作。DisplayImageOptions就像每个客户的偏好,根据客户是重口味还是清淡,每一个imageLoader根据DisplayImageOptions的要求具体执行。

 

ImageLoaderConfiguration

在上面的示例代码中,我们使用ImageLoaderConfiguration的默认配置,下面给出ImageLoaderConfiguration比较详尽的配置,从下面的配置中,可以看出ImageLoaderConfiguration的配置主要是全局性的配置,主要有线程类、缓存大小、磁盘大小、图片下载与解析、日志方面的配置。


ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(context)        .memoryCacheExtraOptions(480, 800) // default = device screen dimensions        .diskCacheExtraOptions(480, 800, null)        .taskExecutor(...)        .taskExecutorForCachedImages(...)        .threadPoolSize(3) // default        .threadPriority(Thread.NORM_PRIORITY - 1) // default        .tasksProcessingOrder(QueueProcessingType.FIFO) // default        .denyCacheImageMultipleSizesInMemory()        .memoryCache(new LruMemoryCache(2 * 1024 * 1024))        .memoryCacheSize(2 * 1024 * 1024)        .memoryCacheSizePercentage(13) // default        .diskCache(new UnlimitedDiscCache(cacheDir)) // default        .diskCacheSize(50 * 1024 * 1024)        .diskCacheFileCount(100)        .diskCacheFileNameGenerator(new HashCodeFileNameGenerator()) // default        .imageDownloader(new BaseImageDownloader(context)) // default        .imageDecoder(new BaseImageDecoder()) // default        .defaultDisplayImageOptions(DisplayImageOptions.createSimple()) // default        .writeDebugLogs()        .build();

ImageLoaderConfiguration的主要职责就是记录相关的配置,它的内部其实就是一些字段的集合(如下面的源代码)。它有一个builder的内部类,这个类中的字段跟ImageLoaderConfiguration中的字段完全一致,它有一些默认值,通过修改builder可以配置ImageLoaderConfiguration。


/******************************************************************************* * 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.content.Context;import android.content.res.Resources;import android.util.DisplayMetrics;import com.nostra13.universalimageloader.cache.disc.DiskCache;import com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator;import com.nostra13.universalimageloader.cache.memory.MemoryCache;import com.nostra13.universalimageloader.cache.memory.impl.FuzzyKeyMemoryCache;import com.nostra13.universalimageloader.core.assist.FlushedInputStream;import com.nostra13.universalimageloader.core.assist.ImageSize;import com.nostra13.universalimageloader.core.assist.QueueProcessingType;import com.nostra13.universalimageloader.core.decode.ImageDecoder;import com.nostra13.universalimageloader.core.download.ImageDownloader;import com.nostra13.universalimageloader.core.process.BitmapProcessor;import com.nostra13.universalimageloader.utils.L;import com.nostra13.universalimageloader.utils.MemoryCacheUtils;import java.io.IOException;import java.io.InputStream;import java.util.concurrent.Executor;/** * Presents configuration for {@link ImageLoader} * * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) * @see ImageLoader * @see MemoryCache * @see DiskCache * @see DisplayImageOptions * @see ImageDownloader * @see FileNameGenerator * @since 1.0.0 */public final class ImageLoaderConfiguration {    final Resources resources;    final int maxImageWidthForMemoryCache;    final int maxImageHeightForMemoryCache;    final int maxImageWidthForDiskCache;    final int maxImageHeightForDiskCache;    final BitmapProcessor processorForDiskCache;    final Executor taskExecutor;    final Executor taskExecutorForCachedImages;    final boolean customExecutor;    final boolean customExecutorForCachedImages;    final int threadPoolSize;    final int threadPriority;    final QueueProcessingType tasksProcessingType;    final MemoryCache memoryCache;    final DiskCache diskCache;    final ImageDownloader downloader;    final ImageDecoder decoder;    final DisplayImageOptions defaultDisplayImageOptions;    final ImageDownloader networkDeniedDownloader;    final ImageDownloader slowNetworkDownloader;    private ImageLoaderConfiguration(final Builder builder) {        resources = builder.context.getResources();        maxImageWidthForMemoryCache = builder.maxImageWidthForMemoryCache;        maxImageHeightForMemoryCache = builder.maxImageHeightForMemoryCache;        maxImageWidthForDiskCache = builder.maxImageWidthForDiskCache;        maxImageHeightForDiskCache = builder.maxImageHeightForDiskCache;        processorForDiskCache = builder.processorForDiskCache;        taskExecutor = builder.taskExecutor;        taskExecutorForCachedImages = builder.taskExecutorForCachedImages;        threadPoolSize = builder.threadPoolSize;        threadPriority = builder.threadPriority;        tasksProcessingType = builder.tasksProcessingType;        diskCache = builder.diskCache;        memoryCache = builder.memoryCache;        defaultDisplayImageOptions = builder.defaultDisplayImageOptions;        downloader = builder.downloader;        decoder = builder.decoder;        customExecutor = builder.customExecutor;        customExecutorForCachedImages = builder.customExecutorForCachedImages;        networkDeniedDownloader = new NetworkDeniedImageDownloader(downloader);        slowNetworkDownloader = new SlowNetworkImageDownloader(downloader);        L.writeDebugLogs(builder.writeLogs);    }    /**     * Creates default configuration for {@link ImageLoader} <br />     * <b>Default values:</b>     * <ul>     * <li>maxImageWidthForMemoryCache = device's screen width</li>     * <li>maxImageHeightForMemoryCache = device's screen height</li>     * <li>maxImageWidthForDikcCache = unlimited</li>     * <li>maxImageHeightForDiskCache = unlimited</li>     * <li>threadPoolSize = {@link Builder#DEFAULT_THREAD_POOL_SIZE this}</li>     * <li>threadPriority = {@link Builder#DEFAULT_THREAD_PRIORITY this}</li>     * <li>allow to cache different sizes of image in memory</li>     * <li>memoryCache = {@link DefaultConfigurationFactory#createMemoryCache(int)}</li>     * <li>diskCache = {@link com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache}</li>     * <li>imageDownloader = {@link DefaultConfigurationFactory#createImageDownloader(Context)}</li>     * <li>imageDecoder = {@link DefaultConfigurationFactory#createImageDecoder(boolean)}</li>     * <li>diskCacheFileNameGenerator = {@link DefaultConfigurationFactory#createFileNameGenerator()}</li>     * <li>defaultDisplayImageOptions = {@link DisplayImageOptions#createSimple() Simple options}</li>     * <li>tasksProcessingOrder = {@link QueueProcessingType#FIFO}</li>     * <li>detailed logging disabled</li>     * </ul>     */    public static ImageLoaderConfiguration createDefault(Context context) {        return new Builder(context).build();    }    ImageSize getMaxImageSize() {        DisplayMetrics displayMetrics = resources.getDisplayMetrics();        int width = maxImageWidthForMemoryCache;        if (width <= 0) {            width = displayMetrics.widthPixels;        }        int height = maxImageHeightForMemoryCache;        if (height <= 0) {            height = displayMetrics.heightPixels;        }        return new ImageSize(width, height);    }    /**     * Builder for {@link ImageLoaderConfiguration}     *     * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)     */    public static class Builder {        private static final String WARNING_OVERLAP_DISK_CACHE_PARAMS = "diskCache(), diskCacheSize() and diskCacheFileCount calls overlap each other";        private static final String WARNING_OVERLAP_DISK_CACHE_NAME_GENERATOR = "diskCache() and diskCacheFileNameGenerator() calls overlap each other";        private static final String WARNING_OVERLAP_MEMORY_CACHE = "memoryCache() and memoryCacheSize() calls overlap each other";        private static final String WARNING_OVERLAP_EXECUTOR = "threadPoolSize(), threadPriority() and tasksProcessingOrder() calls "                + "can overlap taskExecutor() and taskExecutorForCachedImages() calls.";        /** {@value} */        public static final int DEFAULT_THREAD_POOL_SIZE = 3;        /** {@value} */        public static final int DEFAULT_THREAD_PRIORITY = Thread.NORM_PRIORITY - 1;        /** {@value} */        public static final QueueProcessingType DEFAULT_TASK_PROCESSING_TYPE = QueueProcessingType.FIFO;        private Context context;        private int maxImageWidthForMemoryCache = 0;        private int maxImageHeightForMemoryCache = 0;        private int maxImageWidthForDiskCache = 0;        private int maxImageHeightForDiskCache = 0;        private BitmapProcessor processorForDiskCache = null;        private Executor taskExecutor = null;        private Executor taskExecutorForCachedImages = null;        private boolean customExecutor = false;        private boolean customExecutorForCachedImages = false;        private int threadPoolSize = DEFAULT_THREAD_POOL_SIZE;        private int threadPriority = DEFAULT_THREAD_PRIORITY;        private boolean denyCacheImageMultipleSizesInMemory = false;        private QueueProcessingType tasksProcessingType = DEFAULT_TASK_PROCESSING_TYPE;        private int memoryCacheSize = 0;        private long diskCacheSize = 0;        private int diskCacheFileCount = 0;        private MemoryCache memoryCache = null;        private DiskCache diskCache = null;        private FileNameGenerator diskCacheFileNameGenerator = null;        private ImageDownloader downloader = null;        private ImageDecoder decoder;        private DisplayImageOptions defaultDisplayImageOptions = null;        private boolean writeLogs = false;        public Builder(Context context) {            this.context = context.getApplicationContext();        }        /**         * Sets options for memory cache         *         * @param maxImageWidthForMemoryCache  Maximum image width which will be used for memory saving during decoding         *                                     an image to {@link android.graphics.Bitmap Bitmap}. <b>Default value - device's screen width</b>         * @param maxImageHeightForMemoryCache Maximum image height which will be used for memory saving during decoding         *                                     an image to {@link android.graphics.Bitmap Bitmap}. <b>Default value</b> - device's screen height         */        public Builder memoryCacheExtraOptions(int maxImageWidthForMemoryCache, int maxImageHeightForMemoryCache) {            this.maxImageWidthForMemoryCache = maxImageWidthForMemoryCache;            this.maxImageHeightForMemoryCache = maxImageHeightForMemoryCache;            return this;        }        /**         * @deprecated Use         * {@link #diskCacheExtraOptions(int, int, com.nostra13.universalimageloader.core.process.BitmapProcessor)}         * instead         */        @Deprecated        public Builder discCacheExtraOptions(int maxImageWidthForDiskCache, int maxImageHeightForDiskCache,                BitmapProcessor processorForDiskCache) {            return diskCacheExtraOptions(maxImageWidthForDiskCache, maxImageHeightForDiskCache, processorForDiskCache);        }        /**         * Sets options for resizing/compressing of downloaded images before saving to disk cache.<br />         * <b>NOTE: Use this option only when you have appropriate needs. It can make ImageLoader slower.</b>         *         * @param maxImageWidthForDiskCache  Maximum width of downloaded images for saving at disk cache         * @param maxImageHeightForDiskCache Maximum height of downloaded images for saving at disk cache         * @param processorForDiskCache      null-ok; {@linkplain BitmapProcessor Bitmap processor} which process images before saving them in disc cache         */        public Builder diskCacheExtraOptions(int maxImageWidthForDiskCache, int maxImageHeightForDiskCache,                BitmapProcessor processorForDiskCache) {            this.maxImageWidthForDiskCache = maxImageWidthForDiskCache;            this.maxImageHeightForDiskCache = maxImageHeightForDiskCache;            this.processorForDiskCache = processorForDiskCache;            return this;        }        /**         * Sets custom {@linkplain Executor executor} for tasks of loading and displaying images.<br />         * <br />         * <b>NOTE:</b> If you set custom executor then following configuration options will not be considered for this         * executor:         * <ul>         * <li>{@link #threadPoolSize(int)}</li>         * <li>{@link #threadPriority(int)}</li>         * <li>{@link #tasksProcessingOrder(QueueProcessingType)}</li>         * </ul>         *         * @see #taskExecutorForCachedImages(Executor)         */        public Builder taskExecutor(Executor executor) {            if (threadPoolSize != DEFAULT_THREAD_POOL_SIZE || threadPriority != DEFAULT_THREAD_PRIORITY || tasksProcessingType != DEFAULT_TASK_PROCESSING_TYPE) {                L.w(WARNING_OVERLAP_EXECUTOR);            }            this.taskExecutor = executor;            return this;        }        /**         * Sets custom {@linkplain Executor executor} for tasks of displaying <b>cached on disk</b> images (these tasks         * are executed quickly so UIL prefer to use separate executor for them).<br />         * <br />         * If you set the same executor for {@linkplain #taskExecutor(Executor) general tasks} and         * tasks about cached images (this method) then these tasks will be in the         * same thread pool. So short-lived tasks can wait a long time for their turn.<br />         * <br />         * <b>NOTE:</b> If you set custom executor then following configuration options will not be considered for this         * executor:         * <ul>         * <li>{@link #threadPoolSize(int)}</li>         * <li>{@link #threadPriority(int)}</li>         * <li>{@link #tasksProcessingOrder(QueueProcessingType)}</li>         * </ul>         *         * @see #taskExecutor(Executor)         */        public Builder taskExecutorForCachedImages(Executor executorForCachedImages) {            if (threadPoolSize != DEFAULT_THREAD_POOL_SIZE || threadPriority != DEFAULT_THREAD_PRIORITY || tasksProcessingType != DEFAULT_TASK_PROCESSING_TYPE) {                L.w(WARNING_OVERLAP_EXECUTOR);            }            this.taskExecutorForCachedImages = executorForCachedImages;            return this;        }        /**         * Sets thread pool size for image display tasks.<br />         * Default value - {@link #DEFAULT_THREAD_POOL_SIZE this}         */        public Builder threadPoolSize(int threadPoolSize) {            if (taskExecutor != null || taskExecutorForCachedImages != null) {                L.w(WARNING_OVERLAP_EXECUTOR);            }            this.threadPoolSize = threadPoolSize;            return this;        }        /**         * Sets the priority for image loading threads. Should be <b>NOT</b> greater than {@link Thread#MAX_PRIORITY} or         * less than {@link Thread#MIN_PRIORITY}<br />         * Default value - {@link #DEFAULT_THREAD_PRIORITY this}         */        public Builder threadPriority(int threadPriority) {            if (taskExecutor != null || taskExecutorForCachedImages != null) {                L.w(WARNING_OVERLAP_EXECUTOR);            }            if (threadPriority < Thread.MIN_PRIORITY) {                this.threadPriority = Thread.MIN_PRIORITY;            } else {                if (threadPriority > Thread.MAX_PRIORITY) {                    this.threadPriority = Thread.MAX_PRIORITY;                } else {                    this.threadPriority = threadPriority;                }            }            return this;        }        /**         * When you display an image in a small {@link android.widget.ImageView ImageView} and later you try to display         * this image (from identical URI) in a larger {@link android.widget.ImageView ImageView} so decoded image of         * bigger size will be cached in memory as a previous decoded image of smaller size.<br />         * So <b>the default behavior is to allow to cache multiple sizes of one image in memory</b>. You can         * <b>deny</b> it by calling <b>this</b> method: so when some image will be cached in memory then previous         * cached size of this image (if it exists) will be removed from memory cache before.         */        public Builder denyCacheImageMultipleSizesInMemory() {            this.denyCacheImageMultipleSizesInMemory = true;            return this;        }        /**         * Sets type of queue processing for tasks for loading and displaying images.<br />         * Default value - {@link QueueProcessingType#FIFO}         */        public Builder tasksProcessingOrder(QueueProcessingType tasksProcessingType) {            if (taskExecutor != null || taskExecutorForCachedImages != null) {                L.w(WARNING_OVERLAP_EXECUTOR);            }            this.tasksProcessingType = tasksProcessingType;            return this;        }        /**         * Sets maximum memory cache size for {@link android.graphics.Bitmap bitmaps} (in bytes).<br />         * Default value - 1/8 of available app memory.<br />         * <b>NOTE:</b> If you use this method then         * {@link com.nostra13.universalimageloader.cache.memory.impl.LruMemoryCache LruMemoryCache} will be used as         * memory cache. You can use {@link #memoryCache(MemoryCache)} method to set your own implementation of         * {@link MemoryCache}.         */        public Builder memoryCacheSize(int memoryCacheSize) {            if (memoryCacheSize <= 0) throw new IllegalArgumentException("memoryCacheSize must be a positive number");            if (memoryCache != null) {                L.w(WARNING_OVERLAP_MEMORY_CACHE);            }            this.memoryCacheSize = memoryCacheSize;            return this;        }        /**         * Sets maximum memory cache size (in percent of available app memory) for {@link android.graphics.Bitmap         * bitmaps}.<br />         * Default value - 1/8 of available app memory.<br />         * <b>NOTE:</b> If you use this method then         * {@link com.nostra13.universalimageloader.cache.memory.impl.LruMemoryCache LruMemoryCache} will be used as         * memory cache. You can use {@link #memoryCache(MemoryCache)} method to set your own implementation of         * {@link MemoryCache}.         */        public Builder memoryCacheSizePercentage(int availableMemoryPercent) {            if (availableMemoryPercent <= 0 || availableMemoryPercent >= 100) {                throw new IllegalArgumentException("availableMemoryPercent must be in range (0 < % < 100)");            }            if (memoryCache != null) {                L.w(WARNING_OVERLAP_MEMORY_CACHE);            }            long availableMemory = Runtime.getRuntime().maxMemory();            memoryCacheSize = (int) (availableMemory * (availableMemoryPercent / 100f));            return this;        }        /**         * Sets memory cache for {@link android.graphics.Bitmap bitmaps}.<br />         * Default value - {@link com.nostra13.universalimageloader.cache.memory.impl.LruMemoryCache LruMemoryCache}         * with limited memory cache size (size = 1/8 of available app memory)<br />         * <br />         * <b>NOTE:</b> If you set custom memory cache then following configuration option will not be considered:         * <ul>         * <li>{@link #memoryCacheSize(int)}</li>         * </ul>         */        public Builder memoryCache(MemoryCache memoryCache) {            if (memoryCacheSize != 0) {                L.w(WARNING_OVERLAP_MEMORY_CACHE);            }            this.memoryCache = memoryCache;            return this;        }        /** @deprecated Use {@link #diskCacheSize(int)} instead */        @Deprecated        public Builder discCacheSize(int maxCacheSize) {            return diskCacheSize(maxCacheSize);        }        /**         * Sets maximum disk cache size for images (in bytes).<br />         * By default: disk cache is unlimited.<br />         * <b>NOTE:</b> If you use this method then         * {@link com.nostra13.universalimageloader.cache.disc.impl.ext.LruDiscCache LruDiscCache}         * will be used as disk cache. You can use {@link #diskCache(DiskCache)} method for introduction your own         * implementation of {@link DiskCache}         */        public Builder diskCacheSize(int maxCacheSize) {            if (maxCacheSize <= 0) throw new IllegalArgumentException("maxCacheSize must be a positive number");            if (diskCache != null) {                L.w(WARNING_OVERLAP_DISK_CACHE_PARAMS);            }            this.diskCacheSize = maxCacheSize;            return this;        }        /** @deprecated Use {@link #diskCacheFileCount(int)} instead */        @Deprecated        public Builder discCacheFileCount(int maxFileCount) {            return diskCacheFileCount(maxFileCount);        }        /**         * Sets maximum file count in disk cache directory.<br />         * By default: disk cache is unlimited.<br />         * <b>NOTE:</b> If you use this method then         * {@link com.nostra13.universalimageloader.cache.disc.impl.ext.LruDiscCache LruDiscCache}         * will be used as disk cache. You can use {@link #diskCache(DiskCache)} method for introduction your own         * implementation of {@link DiskCache}         */        public Builder diskCacheFileCount(int maxFileCount) {            if (maxFileCount <= 0) throw new IllegalArgumentException("maxFileCount must be a positive number");            if (diskCache != null) {                L.w(WARNING_OVERLAP_DISK_CACHE_PARAMS);            }            this.diskCacheFileCount = maxFileCount;            return this;        }        /** @deprecated Use {@link #diskCacheFileNameGenerator(com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator)} */        @Deprecated        public Builder discCacheFileNameGenerator(FileNameGenerator fileNameGenerator) {            return diskCacheFileNameGenerator(fileNameGenerator);        }        /**         * Sets name generator for files cached in disk cache.<br />         * Default value -         * {@link com.nostra13.universalimageloader.core.DefaultConfigurationFactory#createFileNameGenerator()         * DefaultConfigurationFactory.createFileNameGenerator()}         */        public Builder diskCacheFileNameGenerator(FileNameGenerator fileNameGenerator) {            if (diskCache != null) {                L.w(WARNING_OVERLAP_DISK_CACHE_NAME_GENERATOR);            }            this.diskCacheFileNameGenerator = fileNameGenerator;            return this;        }        /** @deprecated Use {@link #diskCache(com.nostra13.universalimageloader.cache.disc.DiskCache)} */        @Deprecated        public Builder discCache(DiskCache diskCache) {            return diskCache(diskCache);        }        /**         * Sets disk cache for images.<br />         * Default value - {@link com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache         * BaseDiscCache}. Cache directory is defined by         * {@link com.nostra13.universalimageloader.utils.StorageUtils#getCacheDirectory(Context)         * StorageUtils.getCacheDirectory(Context)}.<br />         * <br />         * <b>NOTE:</b> If you set custom disk cache then following configuration option will not be considered:         * <ul>         * <li>{@link #diskCacheSize(int)}</li>         * <li>{@link #diskCacheFileCount(int)}</li>         * <li>{@link #diskCacheFileNameGenerator(FileNameGenerator)}</li>         * </ul>         */        public Builder diskCache(DiskCache diskCache) {            if (diskCacheSize > 0 || diskCacheFileCount > 0) {                L.w(WARNING_OVERLAP_DISK_CACHE_PARAMS);            }            if (diskCacheFileNameGenerator != null) {                L.w(WARNING_OVERLAP_DISK_CACHE_NAME_GENERATOR);            }            this.diskCache = diskCache;            return this;        }        /**         * Sets utility which will be responsible for downloading of image.<br />         * Default value -         * {@link com.nostra13.universalimageloader.core.DefaultConfigurationFactory#createImageDownloader(Context)         * DefaultConfigurationFactory.createImageDownloader()}         */        public Builder imageDownloader(ImageDownloader imageDownloader) {            this.downloader = imageDownloader;            return this;        }        /**         * Sets utility which will be responsible for decoding of image stream.<br />         * Default value -         * {@link com.nostra13.universalimageloader.core.DefaultConfigurationFactory#createImageDecoder(boolean)         * DefaultConfigurationFactory.createImageDecoder()}         */        public Builder imageDecoder(ImageDecoder imageDecoder) {            this.decoder = imageDecoder;            return this;        }        /**         * Sets default {@linkplain DisplayImageOptions display image options} for image displaying. These options will         * be used for every {@linkplain ImageLoader#displayImage(String, android.widget.ImageView) image display call}         * without passing custom {@linkplain DisplayImageOptions options}<br />         * Default value - {@link DisplayImageOptions#createSimple() Simple options}         */        public Builder defaultDisplayImageOptions(DisplayImageOptions defaultDisplayImageOptions) {            this.defaultDisplayImageOptions = defaultDisplayImageOptions;            return this;        }        /**         * Enables detail logging of {@link ImageLoader} work. To prevent detail logs don't call this method.         * Consider {@link com.nostra13.universalimageloader.utils.L#disableLogging()} to disable         * ImageLoader logging completely (even error logs)         */        public Builder writeDebugLogs() {            this.writeLogs = true;            return this;        }        /** Builds configured {@link ImageLoaderConfiguration} object */        public ImageLoaderConfiguration build() {            initEmptyFieldsWithDefaultValues();            return new ImageLoaderConfiguration(this);        }        private void initEmptyFieldsWithDefaultValues() {            if (taskExecutor == null) {                taskExecutor = DefaultConfigurationFactory                        .createExecutor(threadPoolSize, threadPriority, tasksProcessingType);            } else {                customExecutor = true;            }            if (taskExecutorForCachedImages == null) {                taskExecutorForCachedImages = DefaultConfigurationFactory                        .createExecutor(threadPoolSize, threadPriority, tasksProcessingType);            } else {                customExecutorForCachedImages = true;            }            if (diskCache == null) {                if (diskCacheFileNameGenerator == null) {                    diskCacheFileNameGenerator = DefaultConfigurationFactory.createFileNameGenerator();                }                diskCache = DefaultConfigurationFactory                        .createDiskCache(context, diskCacheFileNameGenerator, diskCacheSize, diskCacheFileCount);            }            if (memoryCache == null) {                memoryCache = DefaultConfigurationFactory.createMemoryCache(memoryCacheSize);            }            if (denyCacheImageMultipleSizesInMemory) {                memoryCache = new FuzzyKeyMemoryCache(memoryCache, MemoryCacheUtils.createFuzzyKeyComparator());            }            if (downloader == null) {                downloader = DefaultConfigurationFactory.createImageDownloader(context);            }            if (decoder == null) {                decoder = DefaultConfigurationFactory.createImageDecoder(writeLogs);            }            if (defaultDisplayImageOptions == null) {                defaultDisplayImageOptions = DisplayImageOptions.createSimple();            }        }    }    /**     * Decorator. Prevents downloads from network (throws {@link IllegalStateException exception}).<br />     * In most cases this downloader shouldn't be used directly.     *     * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)     * @since 1.8.0     */    private static class NetworkDeniedImageDownloader implements ImageDownloader {        private final ImageDownloader wrappedDownloader;        public NetworkDeniedImageDownloader(ImageDownloader wrappedDownloader) {            this.wrappedDownloader = wrappedDownloader;        }        @Override        public InputStream getStream(String imageUri, Object extra) throws IOException {            switch (Scheme.ofUri(imageUri)) {                case HTTP:                case HTTPS:                    throw new IllegalStateException();                default:                    return wrappedDownloader.getStream(imageUri, extra);            }        }    }    /**     * Decorator. Handles <a href="http://code.google.com/p/android/issues/detail?id=6066">this problem</a> on slow networks     * using {@link com.nostra13.universalimageloader.core.assist.FlushedInputStream}.     *     * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)     * @since 1.8.1     */    private static class SlowNetworkImageDownloader implements ImageDownloader {        private final ImageDownloader wrappedDownloader;        public SlowNetworkImageDownloader(ImageDownloader wrappedDownloader) {            this.wrappedDownloader = wrappedDownloader;        }        @Override        public InputStream getStream(String imageUri, Object extra) throws IOException {            InputStream imageStream = wrappedDownloader.getStream(imageUri, extra);            switch (Scheme.ofUri(imageUri)) {                case HTTP:                case HTTPS:                    return new FlushedInputStream(imageStream);                default:                    return imageStream;            }        }    }}

Display Options

每一个ImageLoader.displayImage(...)都可以使用Display Options


DisplayImageOptions options = new DisplayImageOptions.Builder()        .showImageOnLoading(R.drawable.ic_stub) // resource or drawable        .showImageForEmptyUri(R.drawable.ic_empty) // resource or drawable        .showImageOnFail(R.drawable.ic_error) // resource or drawable        .resetViewBeforeLoading(false)  // default        .delayBeforeLoading(1000)        .cacheInMemory(false) // default        .cacheOnDisk(false) // default        .preProcessor(...)        .postProcessor(...)        .extraForDownloader(...)        .considerExifParams(false) // default        .imageScaleType(ImageScaleType.IN_SAMPLE_POWER_OF_2) // default        .bitmapConfig(Bitmap.Config.ARGB_8888) // default        .decodingOptions(...)        .displayer(new SimpleBitmapDisplayer()) // default        .handler(new Handler()) // default        .build();


Display Options的主要职责就是记录相关的配置,它的内部其实就是一些字段的集合(如下面的源代码)。它有一个builder的内部类,这个类中的字段跟DisplayOption中的字段完全一致,它有一些默认值,通过修改builder可以配置DisplayOptions。


public final class DisplayImageOptions {    private final int imageResOnLoading;    private final int imageResForEmptyUri;    private final int imageResOnFail;    private final Drawable imageOnLoading;    private final Drawable imageForEmptyUri;    private final Drawable imageOnFail;    private final boolean resetViewBeforeLoading;    private final boolean cacheInMemory;    private final boolean cacheOnDisk;    private final ImageScaleType imageScaleType;    private final Options decodingOptions;    private final int delayBeforeLoading;    private final boolean considerExifParams;    private final Object extraForDownloader;    private final BitmapProcessor preProcessor;    private final BitmapProcessor postProcessor;    private final BitmapDisplayer displayer;    private final Handler handler;    private final boolean isSyncLoading;    private DisplayImageOptions(Builder builder) {        imageResOnLoading = builder.imageResOnLoading;        imageResForEmptyUri = builder.imageResForEmptyUri;        imageResOnFail = builder.imageResOnFail;        imageOnLoading = builder.imageOnLoading;        imageForEmptyUri = builder.imageForEmptyUri;        imageOnFail = builder.imageOnFail;        resetViewBeforeLoading = builder.resetViewBeforeLoading;        cacheInMemory = builder.cacheInMemory;        cacheOnDisk = builder.cacheOnDisk;        imageScaleType = builder.imageScaleType;        decodingOptions = builder.decodingOptions;        delayBeforeLoading = builder.delayBeforeLoading;        considerExifParams = builder.considerExifParams;        extraForDownloader = builder.extraForDownloader;        preProcessor = builder.preProcessor;        postProcessor = builder.postProcessor;        displayer = builder.displayer;        handler = builder.handler;        isSyncLoading = builder.isSyncLoading;    }    public boolean shouldShowImageOnLoading() {        return imageOnLoading != null || imageResOnLoading != 0;    }    public boolean shouldShowImageForEmptyUri() {        return imageForEmptyUri != null || imageResForEmptyUri != 0;    }    public boolean shouldShowImageOnFail() {        return imageOnFail != null || imageResOnFail != 0;    }    public boolean shouldPreProcess() {        return preProcessor != null;    }    public boolean shouldPostProcess() {        return postProcessor != null;    }    public boolean shouldDelayBeforeLoading() {        return delayBeforeLoading > 0;    }    public Drawable getImageOnLoading(Resources res) {        return imageResOnLoading != 0 ? res.getDrawable(imageResOnLoading) : imageOnLoading;    }    public Drawable getImageForEmptyUri(Resources res) {        return imageResForEmptyUri != 0 ? res.getDrawable(imageResForEmptyUri) : imageForEmptyUri;    }    public Drawable getImageOnFail(Resources res) {        return imageResOnFail != 0 ? res.getDrawable(imageResOnFail) : imageOnFail;    }    public boolean isResetViewBeforeLoading() {        return resetViewBeforeLoading;    }    public boolean isCacheInMemory() {        return cacheInMemory;    }    public boolean isCacheOnDisk() {        return cacheOnDisk;    }    public ImageScaleType getImageScaleType() {        return imageScaleType;    }    public Options getDecodingOptions() {        return decodingOptions;    }    public int getDelayBeforeLoading() {        return delayBeforeLoading;    }    public boolean isConsiderExifParams() {        return considerExifParams;    }    public Object getExtraForDownloader() {        return extraForDownloader;    }    public BitmapProcessor getPreProcessor() {        return preProcessor;    }    public BitmapProcessor getPostProcessor() {        return postProcessor;    }    public BitmapDisplayer getDisplayer() {        return displayer;    }    public Handler getHandler() {        return handler;    }    boolean isSyncLoading() {        return isSyncLoading;    }    /**     * Builder for {@link DisplayImageOptions}     *     * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)     */    public static class Builder {        private int imageResOnLoading = 0;        private int imageResForEmptyUri = 0;        private int imageResOnFail = 0;        private Drawable imageOnLoading = null;        private Drawable imageForEmptyUri = null;        private Drawable imageOnFail = null;        private boolean resetViewBeforeLoading = false;        private boolean cacheInMemory = false;        private boolean cacheOnDisk = false;        private ImageScaleType imageScaleType = ImageScaleType.IN_SAMPLE_POWER_OF_2;        private Options decodingOptions = new Options();        private int delayBeforeLoading = 0;        private boolean considerExifParams = false;        private Object extraForDownloader = null;        private BitmapProcessor preProcessor = null;        private BitmapProcessor postProcessor = null;        private BitmapDisplayer displayer = DefaultConfigurationFactory.createBitmapDisplayer();        private Handler handler = null;        private boolean isSyncLoading = false;        public Builder() {            decodingOptions.inPurgeable = true;            decodingOptions.inInputShareable = true;        }        /**         * Stub image will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} during image loading         *         * @param imageRes Stub image resource         * @deprecated Use {@link #showImageOnLoading(int)} instead         */        @Deprecated        public Builder showStubImage(int imageRes) {            imageResOnLoading = imageRes;            return this;        }        /**         * Incoming image will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} during image loading         *         * @param imageRes Image resource         */        public Builder showImageOnLoading(int imageRes) {            imageResOnLoading = imageRes;            return this;        }        /**         * Incoming drawable will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} during image loading.         * This option will be ignored if {@link DisplayImageOptions.Builder#showImageOnLoading(int)} is set.         */        public Builder showImageOnLoading(Drawable drawable) {            imageOnLoading = drawable;            return this;        }        /**         * Incoming image will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} if empty URI (null or empty         * string) will be passed to <b>ImageLoader.displayImage(...)</b> method.         *         * @param imageRes Image resource         */        public Builder showImageForEmptyUri(int imageRes) {            imageResForEmptyUri = imageRes;            return this;        }        /**         * Incoming drawable will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} if empty URI (null or empty         * string) will be passed to <b>ImageLoader.displayImage(...)</b> method.         * This option will be ignored if {@link DisplayImageOptions.Builder#showImageForEmptyUri(int)} is set.         */        public Builder showImageForEmptyUri(Drawable drawable) {            imageForEmptyUri = drawable;            return this;        }        /**         * Incoming image will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} if some error occurs during         * requested image loading/decoding.         *         * @param imageRes Image resource         */        public Builder showImageOnFail(int imageRes) {            imageResOnFail = imageRes;            return this;        }        /**         * Incoming drawable will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} if some error occurs during         * requested image loading/decoding.         * This option will be ignored if {@link DisplayImageOptions.Builder#showImageOnFail(int)} is set.         */        public Builder showImageOnFail(Drawable drawable) {            imageOnFail = drawable;            return this;        }        /**         * {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} will be reset (set <b>null</b>) before image loading start         *         * @deprecated Use {@link #resetViewBeforeLoading(boolean) resetViewBeforeLoading(true)} instead         */        public Builder resetViewBeforeLoading() {            resetViewBeforeLoading = true;            return this;        }        /**         * Sets whether {@link com.nostra13.universalimageloader.core.imageaware.ImageAware         * image aware view} will be reset (set <b>null</b>) before image loading start         */        public Builder resetViewBeforeLoading(boolean resetViewBeforeLoading) {            this.resetViewBeforeLoading = resetViewBeforeLoading;            return this;        }        /**         * Loaded image will be cached in memory         *         * @deprecated Use {@link #cacheInMemory(boolean) cacheInMemory(true)} instead         */        @Deprecated        public Builder cacheInMemory() {            cacheInMemory = true;            return this;        }        /** Sets whether loaded image will be cached in memory */        public Builder cacheInMemory(boolean cacheInMemory) {            this.cacheInMemory = cacheInMemory;            return this;        }        /**         * Loaded image will be cached on disk         *         * @deprecated Use {@link #cacheOnDisk(boolean) cacheOnDisk(true)} instead         */        @Deprecated        public Builder cacheOnDisc() {            return cacheOnDisk(true);        }        /**         * Sets whether loaded image will be cached on disk         *         * @deprecated Use {@link #cacheOnDisk(boolean)} instead         */        @Deprecated        public Builder cacheOnDisc(boolean cacheOnDisk) {            return cacheOnDisk(cacheOnDisk);        }        /** Sets whether loaded image will be cached on disk */        public Builder cacheOnDisk(boolean cacheOnDisk) {            this.cacheOnDisk = cacheOnDisk;            return this;        }        /**         * Sets {@linkplain ImageScaleType scale type} for decoding image. This parameter is used while define scale         * size for decoding image to Bitmap. Default value - {@link ImageScaleType#IN_SAMPLE_POWER_OF_2}         */        public Builder imageScaleType(ImageScaleType imageScaleType) {            this.imageScaleType = imageScaleType;            return this;        }        /** Sets {@link Bitmap.Config bitmap config} for image decoding. Default value - {@link Bitmap.Config#ARGB_8888} */        public Builder bitmapConfig(Bitmap.Config bitmapConfig) {            if (bitmapConfig == null) throw new IllegalArgumentException("bitmapConfig can't be null");            decodingOptions.inPreferredConfig = bitmapConfig;            return this;        }        /**         * Sets options for image decoding.<br />         * <b>NOTE:</b> {@link Options#inSampleSize} of incoming options will <b>NOT</b> be considered. Library         * calculate the most appropriate sample size itself according yo {@link #imageScaleType(ImageScaleType)}         * options.<br />         * <b>NOTE:</b> This option overlaps {@link #bitmapConfig(android.graphics.Bitmap.Config) bitmapConfig()}         * option.         */        public Builder decodingOptions(Options decodingOptions) {            if (decodingOptions == null) throw new IllegalArgumentException("decodingOptions can't be null");            this.decodingOptions = decodingOptions;            return this;        }        /** Sets delay time before starting loading task. Default - no delay. */        public Builder delayBeforeLoading(int delayInMillis) {            this.delayBeforeLoading = delayInMillis;            return this;        }        /** Sets auxiliary object which will be passed to {@link ImageDownloader#getStream(String, Object)} */        public Builder extraForDownloader(Object extra) {            this.extraForDownloader = extra;            return this;        }        /** Sets whether ImageLoader will consider EXIF parameters of JPEG image (rotate, flip) */        public Builder considerExifParams(boolean considerExifParams) {            this.considerExifParams = considerExifParams;            return this;        }        /**         * Sets bitmap processor which will be process bitmaps before they will be cached in memory. So memory cache         * will contain bitmap processed by incoming preProcessor.<br />         * Image will be pre-processed even if caching in memory is disabled.         */        public Builder preProcessor(BitmapProcessor preProcessor) {            this.preProcessor = preProcessor;            return this;        }        /**         * Sets bitmap processor which will be process bitmaps before they will be displayed in         * {@link com.nostra13.universalimageloader.core.imageaware.ImageAware image aware view} but         * after they'll have been saved in memory cache.         */        public Builder postProcessor(BitmapProcessor postProcessor) {            this.postProcessor = postProcessor;            return this;        }        /**         * Sets custom {@link BitmapDisplayer displayer} for image loading task. Default value -         * {@link DefaultConfigurationFactory#createBitmapDisplayer()}         */        public Builder displayer(BitmapDisplayer displayer) {            if (displayer == null) throw new IllegalArgumentException("displayer can't be null");            this.displayer = displayer;            return this;        }        Builder syncLoading(boolean isSyncLoading) {            this.isSyncLoading = isSyncLoading;            return this;        }        /**         * Sets custom {@linkplain Handler handler} for displaying images and firing {@linkplain ImageLoadingListener         * listener} events.         */        public Builder handler(Handler handler) {            this.handler = handler;            return this;        }        /** Sets all options equal to incoming options */        public Builder cloneFrom(DisplayImageOptions options) {            imageResOnLoading = options.imageResOnLoading;            imageResForEmptyUri = options.imageResForEmptyUri;            imageResOnFail = options.imageResOnFail;            imageOnLoading = options.imageOnLoading;            imageForEmptyUri = options.imageForEmptyUri;            imageOnFail = options.imageOnFail;            resetViewBeforeLoading = options.resetViewBeforeLoading;            cacheInMemory = options.cacheInMemory;            cacheOnDisk = options.cacheOnDisk;            imageScaleType = options.imageScaleType;            decodingOptions = options.decodingOptions;            delayBeforeLoading = options.delayBeforeLoading;            considerExifParams = options.considerExifParams;            extraForDownloader = options.extraForDownloader;            preProcessor = options.preProcessor;            postProcessor = options.postProcessor;            displayer = options.displayer;            handler = options.handler;            isSyncLoading = options.isSyncLoading;            return this;        }        /** Builds configured {@link DisplayImageOptions} object */        public DisplayImageOptions build() {            return new DisplayImageOptions(this);        }    }    /**     * Creates options appropriate for single displaying:     * <ul>     * <li>View will <b>not</b> be reset before loading</li>     * <li>Loaded image will <b>not</b> be cached in memory</li>     * <li>Loaded image will <b>not</b> be cached on disk</li>     * <li>{@link ImageScaleType#IN_SAMPLE_POWER_OF_2} decoding type will be used</li>     * <li>{@link Bitmap.Config#ARGB_8888} bitmap config will be used for image decoding</li>     * <li>{@link SimpleBitmapDisplayer} will be used for image displaying</li>     * </ul>     * <p/>     * These option are appropriate for simple single-use image (from drawables or from Internet) displaying.     */    public static DisplayImageOptions createSimple() {        return new Builder().build();    }}

转载于:http://www.cnblogs.com/kissazi2/p/3886563.html

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