一、介绍
Android-Universal-Image-Loader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
很早就听过Android-Universal-Image-Loader这一开源框架，之前也试用过，但是一直没有认真地研究。一个好的类库的重要特征就是可配置性强。我们先简单试用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。
1 public class BaseActivity extends Activity { 2 ImageLoader imageLoader; 3 @Override 4 protected void onCreate(Bundle savedInstanceState) { 5 // Create global configuration and initialize ImageLoader with this configuration 6 ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext()) 7 .build(); 8 ImageLoader.getInstance().init(config); 9 super.onCreate(savedInstanceState); 10 } 11 }
1 public class MainActivity extends BaseActivity { 2 3 @Override 4 protected void onCreate(Bundle savedInstanceState) { 5 super.onCreate(savedInstanceState); 6 setContentView(R.layout.activity_main); 7 8 ImageLoader imageLoader = ImageLoader.getInstance(); 9 10 GridView gridView = (GridView) this.findViewById(R.id.grdvImageWall); 11 gridView.setAdapter(new PhotoWallAdapter(Constants.IMAGES)); 12 } 13 14 static class ViewHolder { 15 ImageView imageView; 16 ProgressBar progressBar; 17 } 18 19 public class PhotoWallAdapter extends BaseAdapter { 20 String[] imageUrls; 21 ImageLoader imageLoad; 22 DisplayImageOptions options; 23 LinearLayout gridViewItem; 24 25 public PhotoWallAdapter(String[] imageUrls) { 26 assert imageUrls != null; 27 this.imageUrls = imageUrls; 28 29 options = new DisplayImageOptions.Builder() 30 .showImageOnLoading(R.drawable.ic_stub) // resource or 31 // drawable 32 .showImageForEmptyUri(R.drawable.ic_empty) // resource or 33 // drawable 34 .showImageOnFail(R.drawable.ic_error) // resource or 35 // drawable 36 .resetViewBeforeLoading(false) // default 37 .delayBeforeLoading(1000).cacheInMemory(false) // default 38 .cacheOnDisk(false) // default 39 .considerExifParams(false) // default 40 .imageScaleType(ImageScaleType.IN_SAMPLE_POWER_OF_2) // default 41 .bitmapConfig(Bitmap.Config.ARGB_8888) // default 42 .displayer(new SimpleBitmapDisplayer()) // default 43 .handler(new Handler()) // default 44 .build(); 45 this.imageLoad = ImageLoader.getInstance(); 46 47 } 48 49 @Override 50 public int getCount() { 51 return this.imageUrls.length; 52 } 53 54 @Override 55 public Object getItem(int position) { 56 if (position <= 0 || position >= this.imageUrls.length) { 57 throw new IllegalArgumentException( 58 "position<=0||position>=this.imageUrls.length"); 59 } 60 return this.imageUrls[position]; 61 } 62 63 @Override 64 public long getItemId(int position) { 65 return position; 66 } 67 68 @Override 69 public View getView(int position, View convertView, ViewGroup parent) { 70 // 判断这个image是否已经在缓存当中，如果没有就下载 71 final ViewHolder holder; 72 if (convertView == null) { 73 holder = new ViewHolder(); 74 gridViewItem = (LinearLayout) getLayoutInflater().inflate( 75 R.layout.image_wall_item, null); 76 holder.imageView = (ImageView) gridViewItem 77 .findViewById(R.id.item_image); 78 holder.progressBar = (ProgressBar) gridViewItem 79 .findViewById(R.id.item_process); 80 gridViewItem.setTag(holder); 81 convertView = gridViewItem; 82 } else { 83 holder = (ViewHolder) gridViewItem.getTag(); 84 } 85 this.imageLoad.displayImage(this.imageUrls[position], 86 holder.imageView, options, 87 new SimpleImageLoadingListener() { 88 89 @Override 90 public void onLoadingStarted(String imageUri, View view) { 91 holder.progressBar.setProgress(0); 92 holder.progressBar.setVisibility(View.VISIBLE); 93 } 94 95 @Override 96 public void onLoadingFailed(String imageUri, View view, 97 FailReason failReason) { 98 holder.progressBar.setVisibility(View.GONE); 99 } 100 101 @Override 102 public void onLoadingComplete(String imageUri, 103 View view, Bitmap loadedImage) { 104 holder.progressBar.setVisibility(View.GONE); 105 } 106 107 }, new ImageLoadingProgressListener() { 108 109 @Override 110 public void onProgressUpdate(String imageUri, 111 View view, int current, int total) { 112 holder.progressBar.setProgress(Math.round(100.0f 113 * current / total)); 114 } 115 }); // 通过URL判断图片是否已经下载 116 return convertView; 117 } 118 119 } 120 }
里面主要的对象都用 突出显示了。
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。
1 /******************************************************************************* 2 * Copyright 2011-2013 Sergey Tarasevich 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 *******************************************************************************/ 16 package com.nostra13.universalimageloader.core; 17 18 import android.content.Context; 19 import android.content.res.Resources; 20 import android.util.DisplayMetrics; 21 import com.nostra13.universalimageloader.cache.disc.DiskCache; 22 import com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator; 23 import com.nostra13.universalimageloader.cache.memory.MemoryCache; 24 import com.nostra13.universalimageloader.cache.memory.impl.FuzzyKeyMemoryCache; 25 import com.nostra13.universalimageloader.core.assist.FlushedInputStream; 26 import com.nostra13.universalimageloader.core.assist.ImageSize; 27 import com.nostra13.universalimageloader.core.assist.QueueProcessingType; 28 import com.nostra13.universalimageloader.core.decode.ImageDecoder; 29 import com.nostra13.universalimageloader.core.download.ImageDownloader; 30 import com.nostra13.universalimageloader.core.process.BitmapProcessor; 31 import com.nostra13.universalimageloader.utils.L; 32 import com.nostra13.universalimageloader.utils.MemoryCacheUtils; 33 34 import java.io.IOException; 35 import java.io.InputStream; 36 import java.util.concurrent.Executor; 37 38 /** 39 * Presents configuration for {@link ImageLoader} 40 * 41 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) 42 * @see ImageLoader 43 * @see MemoryCache 44 * @see DiskCache 45 * @see DisplayImageOptions 46 * @see ImageDownloader 47 * @see FileNameGenerator 48 * @since 1.0.0 49 */ 50 public final class ImageLoaderConfiguration { 51 52 final Resources resources; 53 54 final int maxImageWidthForMemoryCache; 55 final int maxImageHeightForMemoryCache; 56 final int maxImageWidthForDiskCache; 57 final int maxImageHeightForDiskCache; 58 final BitmapProcessor processorForDiskCache; 59 60 final Executor taskExecutor; 61 final Executor taskExecutorForCachedImages; 62 final boolean customExecutor; 63 final boolean customExecutorForCachedImages; 64 65 final int threadPoolSize; 66 final int threadPriority; 67 final QueueProcessingType tasksProcessingType; 68 69 final MemoryCache memoryCache; 70 final DiskCache diskCache; 71 final ImageDownloader downloader; 72 final ImageDecoder decoder; 73 final DisplayImageOptions defaultDisplayImageOptions; 74 75 final ImageDownloader networkDeniedDownloader; 76 final ImageDownloader slowNetworkDownloader; 77 78 private ImageLoaderConfiguration(final Builder builder) { 79 resources = builder.context.getResources(); 80 maxImageWidthForMemoryCache = builder.maxImageWidthForMemoryCache; 81 maxImageHeightForMemoryCache = builder.maxImageHeightForMemoryCache; 82 maxImageWidthForDiskCache = builder.maxImageWidthForDiskCache; 83 maxImageHeightForDiskCache = builder.maxImageHeightForDiskCache; 84 processorForDiskCache = builder.processorForDiskCache; 85 taskExecutor = builder.taskExecutor; 86 taskExecutorForCachedImages = builder.taskExecutorForCachedImages; 87 threadPoolSize = builder.threadPoolSize; 88 threadPriority = builder.threadPriority; 89 tasksProcessingType = builder.tasksProcessingType; 90 diskCache = builder.diskCache; 91 memoryCache = builder.memoryCache; 92 defaultDisplayImageOptions = builder.defaultDisplayImageOptions; 93 downloader = builder.downloader; 94 decoder = builder.decoder; 95 96 customExecutor = builder.customExecutor; 97 customExecutorForCachedImages = builder.customExecutorForCachedImages; 98 99 networkDeniedDownloader = new NetworkDeniedImageDownloader(downloader); 100 slowNetworkDownloader = new SlowNetworkImageDownloader(downloader); 101 102 L.writeDebugLogs(builder.writeLogs); 103 } 104 105 /** 106 * Creates default configuration for {@link ImageLoader} <br /> 107 * <b>Default values:</b> 108 * <ul> 109 * <li>maxImageWidthForMemoryCache = device‘s screen width</li> 110 * <li>maxImageHeightForMemoryCache = device‘s screen height</li> 111 * <li>maxImageWidthForDikcCache = unlimited</li> 112 * <li>maxImageHeightForDiskCache = unlimited</li> 113 * <li>threadPoolSize = {@link Builder#DEFAULT_THREAD_POOL_SIZE this}</li> 114 * <li>threadPriority = {@link Builder#DEFAULT_THREAD_PRIORITY this}</li> 115 * <li>allow to cache different sizes of image in memory</li> 116 * <li>memoryCache = {@link DefaultConfigurationFactory#createMemoryCache(int)}</li> 117 * <li>diskCache = {@link com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache}</li> 118 * <li>imageDownloader = {@link DefaultConfigurationFactory#createImageDownloader(Context)}</li> 119 * <li>imageDecoder = {@link DefaultConfigurationFactory#createImageDecoder(boolean)}</li> 120 * <li>diskCacheFileNameGenerator = {@link DefaultConfigurationFactory#createFileNameGenerator()}</li> 121 * <li>defaultDisplayImageOptions = {@link DisplayImageOptions#createSimple() Simple options}</li> 122 * <li>tasksProcessingOrder = {@link QueueProcessingType#FIFO}</li> 123 * <li>detailed logging disabled</li> 124 * </ul> 125 */ 126 public static ImageLoaderConfiguration createDefault(Context context) { 127 return new Builder(context).build(); 128 } 129 130 ImageSize getMaxImageSize() { 131 DisplayMetrics displayMetrics = resources.getDisplayMetrics(); 132 133 int width = maxImageWidthForMemoryCache; 134 if (width <= 0) { 135 width = displayMetrics.widthPixels; 136 } 137 int height = maxImageHeightForMemoryCache; 138 if (height <= 0) { 139 height = displayMetrics.heightPixels; 140 } 141 return new ImageSize(width, height); 142 } 143 144 /** 145 * Builder for {@link ImageLoaderConfiguration} 146 * 147 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) 148 */ 149 public static class Builder { 150 151 private static final String WARNING_OVERLAP_DISK_CACHE_PARAMS = "diskCache(), diskCacheSize() and diskCacheFileCount calls overlap each other"; 152 private static final String WARNING_OVERLAP_DISK_CACHE_NAME_GENERATOR = "diskCache() and diskCacheFileNameGenerator() calls overlap each other"; 153 private static final String WARNING_OVERLAP_MEMORY_CACHE = "memoryCache() and memoryCacheSize() calls overlap each other"; 154 private static final String WARNING_OVERLAP_EXECUTOR = "threadPoolSize(), threadPriority() and tasksProcessingOrder() calls " 155 + "can overlap taskExecutor() and taskExecutorForCachedImages() calls."; 156 157 /** {@value} */ 158 public static final int DEFAULT_THREAD_POOL_SIZE = 3; 159 /** {@value} */ 160 public static final int DEFAULT_THREAD_PRIORITY = Thread.NORM_PRIORITY - 1; 161 /** {@value} */ 162 public static final QueueProcessingType DEFAULT_TASK_PROCESSING_TYPE = QueueProcessingType.FIFO; 163 164 private Context context; 165 166 private int maxImageWidthForMemoryCache = 0; 167 private int maxImageHeightForMemoryCache = 0; 168 private int maxImageWidthForDiskCache = 0; 169 private int maxImageHeightForDiskCache = 0; 170 private BitmapProcessor processorForDiskCache = null; 171 172 private Executor taskExecutor = null; 173 private Executor taskExecutorForCachedImages = null; 174 private boolean customExecutor = false; 175 private boolean customExecutorForCachedImages = false; 176 177 private int threadPoolSize = DEFAULT_THREAD_POOL_SIZE; 178 private int threadPriority = DEFAULT_THREAD_PRIORITY; 179 private boolean denyCacheImageMultipleSizesInMemory = false; 180 private QueueProcessingType tasksProcessingType = DEFAULT_TASK_PROCESSING_TYPE; 181 182 private int memoryCacheSize = 0; 183 private long diskCacheSize = 0; 184 private int diskCacheFileCount = 0; 185 186 private MemoryCache memoryCache = null; 187 private DiskCache diskCache = null; 188 private FileNameGenerator diskCacheFileNameGenerator = null; 189 private ImageDownloader downloader = null; 190 private ImageDecoder decoder; 191 private DisplayImageOptions defaultDisplayImageOptions = null; 192 193 private boolean writeLogs = false; 194 195 public Builder(Context context) { 196 this.context = context.getApplicationContext(); 197 } 198 199 /** 200 * Sets options for memory cache 201 * 202 * @param maxImageWidthForMemoryCache Maximum image width which will be used for memory saving during decoding 203 * an image to {@link android.graphics.Bitmap Bitmap}. <b>Default value - device‘s screen width</b> 204 * @param maxImageHeightForMemoryCache Maximum image height which will be used for memory saving during decoding 205 * an image to {@link android.graphics.Bitmap Bitmap}. <b>Default value</b> - device‘s screen height 206 */ 207 public Builder memoryCacheExtraOptions(int maxImageWidthForMemoryCache, int maxImageHeightForMemoryCache) { 208 this.maxImageWidthForMemoryCache = maxImageWidthForMemoryCache; 209 this.maxImageHeightForMemoryCache = maxImageHeightForMemoryCache; 210 return this; 211 } 212 213 /** 214 * @deprecated Use 215 * {@link #diskCacheExtraOptions(int, int, com.nostra13.universalimageloader.core.process.BitmapProcessor)} 216 * instead 217 */ 218 @Deprecated 219 public Builder discCacheExtraOptions(int maxImageWidthForDiskCache, int maxImageHeightForDiskCache, 220 BitmapProcessor processorForDiskCache) { 221 return diskCacheExtraOptions(maxImageWidthForDiskCache, maxImageHeightForDiskCache, processorForDiskCache); 222 } 223 224 /** 225 * Sets options for resizing/compressing of downloaded images before saving to disk cache.<br /> 226 * <b>NOTE: Use this option only when you have appropriate needs. It can make ImageLoader slower.</b> 227 * 228 * @param maxImageWidthForDiskCache Maximum width of downloaded images for saving at disk cache 229 * @param maxImageHeightForDiskCache Maximum height of downloaded images for saving at disk cache 230 * @param processorForDiskCache null-ok; {@linkplain BitmapProcessor Bitmap processor} which process images before saving them in disc cache 231 */ 232 public Builder diskCacheExtraOptions(int maxImageWidthForDiskCache, int maxImageHeightForDiskCache, 233 BitmapProcessor processorForDiskCache) { 234 this.maxImageWidthForDiskCache = maxImageWidthForDiskCache; 235 this.maxImageHeightForDiskCache = maxImageHeightForDiskCache; 236 this.processorForDiskCache = processorForDiskCache; 237 return this; 238 } 239 240 /** 241 * Sets custom {@linkplain Executor executor} for tasks of loading and displaying images.<br /> 242 * <br /> 243 * <b>NOTE:</b> If you set custom executor then following configuration options will not be considered for this 244 * executor: 245 * <ul> 246 * <li>{@link #threadPoolSize(int)}</li> 247 * <li>{@link #threadPriority(int)}</li> 248 * <li>{@link #tasksProcessingOrder(QueueProcessingType)}</li> 249 * </ul> 250 * 251 * @see #taskExecutorForCachedImages(Executor) 252 */ 253 public Builder taskExecutor(Executor executor) { 254 if (threadPoolSize != DEFAULT_THREAD_POOL_SIZE || threadPriority != DEFAULT_THREAD_PRIORITY || tasksProcessingType != DEFAULT_TASK_PROCESSING_TYPE) { 255 L.w(WARNING_OVERLAP_EXECUTOR); 256 } 257 258 this.taskExecutor = executor; 259 return this; 260 } 261 262 /** 263 * Sets custom {@linkplain Executor executor} for tasks of displaying <b>cached on disk</b> images (these tasks 264 * are executed quickly so UIL prefer to use separate executor for them).<br /> 265 * <br /> 266 * If you set the same executor for {@linkplain #taskExecutor(Executor) general tasks} and 267 * tasks about cached images (this method) then these tasks will be in the 268 * same thread pool. So short-lived tasks can wait a long time for their turn.<br /> 269 * <br /> 270 * <b>NOTE:</b> If you set custom executor then following configuration options will not be considered for this 271 * executor: 272 * <ul> 273 * <li>{@link #threadPoolSize(int)}</li> 274 * <li>{@link #threadPriority(int)}</li> 275 * <li>{@link #tasksProcessingOrder(QueueProcessingType)}</li> 276 * </ul> 277 * 278 * @see #taskExecutor(Executor) 279 */ 280 public Builder taskExecutorForCachedImages(Executor executorForCachedImages) { 281 if (threadPoolSize != DEFAULT_THREAD_POOL_SIZE || threadPriority != DEFAULT_THREAD_PRIORITY || tasksProcessingType != DEFAULT_TASK_PROCESSING_TYPE) { 282 L.w(WARNING_OVERLAP_EXECUTOR); 283 } 284 285 this.taskExecutorForCachedImages = executorForCachedImages; 286 return this; 287 } 288 289 /** 290 * Sets thread pool size for image display tasks.<br /> 291 * Default value - {@link #DEFAULT_THREAD_POOL_SIZE this} 292 */ 293 public Builder threadPoolSize(int threadPoolSize) { 294 if (taskExecutor != null || taskExecutorForCachedImages != null) { 295 L.w(WARNING_OVERLAP_EXECUTOR); 296 } 297 298 this.threadPoolSize = threadPoolSize; 299 return this; 300 } 301 302 /** 303 * Sets the priority for image loading threads. Should be <b>NOT</b> greater than {@link Thread#MAX_PRIORITY} or 304 * less than {@link Thread#MIN_PRIORITY}<br /> 305 * Default value - {@link #DEFAULT_THREAD_PRIORITY this} 306 */ 307 public Builder threadPriority(int threadPriority) { 308 if (taskExecutor != null || taskExecutorForCachedImages != null) { 309 L.w(WARNING_OVERLAP_EXECUTOR); 310 } 311 312 if (threadPriority < Thread.MIN_PRIORITY) { 313 this.threadPriority = Thread.MIN_PRIORITY; 314 } else { 315 if (threadPriority > Thread.MAX_PRIORITY) { 316 this.threadPriority = Thread.MAX_PRIORITY; 317 } else { 318 this.threadPriority = threadPriority; 319 } 320 } 321 return this; 322 } 323 324 /** 325 * When you display an image in a small {@link android.widget.ImageView ImageView} and later you try to display 326 * this image (from identical URI) in a larger {@link android.widget.ImageView ImageView} so decoded image of 327 * bigger size will be cached in memory as a previous decoded image of smaller size.<br /> 328 * So <b>the default behavior is to allow to cache multiple sizes of one image in memory</b>. You can 329 * <b>deny</b> it by calling <b>this</b> method: so when some image will be cached in memory then previous 330 * cached size of this image (if it exists) will be removed from memory cache before. 331 */ 332 public Builder denyCacheImageMultipleSizesInMemory() { 333 this.denyCacheImageMultipleSizesInMemory = true; 334 return this; 335 } 336 337 /** 338 * Sets type of queue processing for tasks for loading and displaying images.<br /> 339 * Default value - {@link QueueProcessingType#FIFO} 340 */ 341 public Builder tasksProcessingOrder(QueueProcessingType tasksProcessingType) { 342 if (taskExecutor != null || taskExecutorForCachedImages != null) { 343 L.w(WARNING_OVERLAP_EXECUTOR); 344 } 345 346 this.tasksProcessingType = tasksProcessingType; 347 return this; 348 } 349 350 /** 351 * Sets maximum memory cache size for {@link android.graphics.Bitmap bitmaps} (in bytes).<br /> 352 * Default value - 1/8 of available app memory.<br /> 353 * <b>NOTE:</b> If you use this method then 354 * {@link com.nostra13.universalimageloader.cache.memory.impl.LruMemoryCache LruMemoryCache} will be used as 355 * memory cache. You can use {@link #memoryCache(MemoryCache)} method to set your own implementation of 356 * {@link MemoryCache}. 357 */ 358 public Builder memoryCacheSize(int memoryCacheSize) { 359 if (memoryCacheSize <= 0) throw new IllegalArgumentException("memoryCacheSize must be a positive number"); 360 361 if (memoryCache != null) { 362 L.w(WARNING_OVERLAP_MEMORY_CACHE); 363 } 364 365 this.memoryCacheSize = memoryCacheSize; 366 return this; 367 } 368 369 /** 370 * Sets maximum memory cache size (in percent of available app memory) for {@link android.graphics.Bitmap 371 * bitmaps}.<br /> 372 * Default value - 1/8 of available app memory.<br /> 373 * <b>NOTE:</b> If you use this method then 374 * {@link com.nostra13.universalimageloader.cache.memory.impl.LruMemoryCache LruMemoryCache} will be used as 375 * memory cache. You can use {@link #memoryCache(MemoryCache)} method to set your own implementation of 376 * {@link MemoryCache}. 377 */ 378 public Builder memoryCacheSizePercentage(int availableMemoryPercent) { 379 if (availableMemoryPercent <= 0 || availableMemoryPercent >= 100) { 380 throw new IllegalArgumentException("availableMemoryPercent must be in range (0 < % < 100)"); 381 } 382 383 if (memoryCache != null) { 384 L.w(WARNING_OVERLAP_MEMORY_CACHE); 385 } 386 387 long availableMemory = Runtime.getRuntime().maxMemory(); 388 memoryCacheSize = (int) (availableMemory * (availableMemoryPercent / 100f)); 389 return this; 390 } 391 392 /** 393 * Sets memory cache for {@link android.graphics.Bitmap bitmaps}.<br /> 394 * Default value - {@link com.nostra13.universalimageloader.cache.memory.impl.LruMemoryCache LruMemoryCache} 395 * with limited memory cache size (size = 1/8 of available app memory)<br /> 396 * <br /> 397 * <b>NOTE:</b> If you set custom memory cache then following configuration option will not be considered: 398 * <ul> 399 * <li>{@link #memoryCacheSize(int)}</li> 400 * </ul> 401 */ 402 public Builder memoryCache(MemoryCache memoryCache) { 403 if (memoryCacheSize != 0) { 404 L.w(WARNING_OVERLAP_MEMORY_CACHE); 405 } 406 407 this.memoryCache = memoryCache; 408 return this; 409 } 410 411 /** @deprecated Use {@link #diskCacheSize(int)} instead */ 412 @Deprecated 413 public Builder discCacheSize(int maxCacheSize) { 414 return diskCacheSize(maxCacheSize); 415 } 416 417 /** 418 * Sets maximum disk cache size for images (in bytes).<br /> 419 * By default: disk cache is unlimited.<br /> 420 * <b>NOTE:</b> If you use this method then 421 * {@link com.nostra13.universalimageloader.cache.disc.impl.ext.LruDiscCache LruDiscCache} 422 * will be used as disk cache. You can use {@link #diskCache(DiskCache)} method for introduction your own 423 * implementation of {@link DiskCache} 424 */ 425 public Builder diskCacheSize(int maxCacheSize) { 426 if (maxCacheSize <= 0) throw new IllegalArgumentException("maxCacheSize must be a positive number"); 427 428 if (diskCache != null) { 429 L.w(WARNING_OVERLAP_DISK_CACHE_PARAMS); 430 } 431 432 this.diskCacheSize = maxCacheSize; 433 return this; 434 } 435 436 /** @deprecated Use {@link #diskCacheFileCount(int)} instead */ 437 @Deprecated 438 public Builder discCacheFileCount(int maxFileCount) { 439 return diskCacheFileCount(maxFileCount); 440 } 441 442 /** 443 * Sets maximum file count in disk cache directory.<br /> 444 * By default: disk cache is unlimited.<br /> 445 * <b>NOTE:</b> If you use this method then 446 * {@link com.nostra13.universalimageloader.cache.disc.impl.ext.LruDiscCache LruDiscCache} 447 * will be used as disk cache. You can use {@link #diskCache(DiskCache)} method for introduction your own 448 * implementation of {@link DiskCache} 449 */ 450 public Builder diskCacheFileCount(int maxFileCount) { 451 if (maxFileCount <= 0) throw new IllegalArgumentException("maxFileCount must be a positive number"); 452 453 if (diskCache != null) { 454 L.w(WARNING_OVERLAP_DISK_CACHE_PARAMS); 455 } 456 457 this.diskCacheFileCount = maxFileCount; 458 return this; 459 } 460 461 /** @deprecated Use {@link #diskCacheFileNameGenerator(com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator)} */ 462 @Deprecated 463 public Builder discCacheFileNameGenerator(FileNameGenerator fileNameGenerator) { 464 return diskCacheFileNameGenerator(fileNameGenerator); 465 } 466 467 /** 468 * Sets name generator for files cached in disk cache.<br /> 469 * Default value - 470 * {@link com.nostra13.universalimageloader.core.DefaultConfigurationFactory#createFileNameGenerator() 471 * DefaultConfigurationFactory.createFileNameGenerator()} 472 */ 473 public Builder diskCacheFileNameGenerator(FileNameGenerator fileNameGenerator) { 474 if (diskCache != null) { 475 L.w(WARNING_OVERLAP_DISK_CACHE_NAME_GENERATOR); 476 } 477 478 this.diskCacheFileNameGenerator = fileNameGenerator; 479 return this; 480 } 481 482 /** @deprecated Use {@link #diskCache(com.nostra13.universalimageloader.cache.disc.DiskCache)} */ 483 @Deprecated 484 public Builder discCache(DiskCache diskCache) { 485 return diskCache(diskCache); 486 } 487 488 /** 489 * Sets disk cache for images.<br /> 490 * Default value - {@link com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache 491 * BaseDiscCache}. Cache directory is defined by 492 * {@link com.nostra13.universalimageloader.utils.StorageUtils#getCacheDirectory(Context) 493 * StorageUtils.getCacheDirectory(Context)}.<br /> 494 * <br /> 495 * <b>NOTE:</b> If you set custom disk cache then following configuration option will not be considered: 496 * <ul> 497 * <li>{@link #diskCacheSize(int)}</li> 498 * <li>{@link #diskCacheFileCount(int)}</li> 499 * <li>{@link #diskCacheFileNameGenerator(FileNameGenerator)}</li> 500 * </ul> 501 */ 502 public Builder diskCache(DiskCache diskCache) { 503 if (diskCacheSize > 0 || diskCacheFileCount > 0) { 504 L.w(WARNING_OVERLAP_DISK_CACHE_PARAMS); 505 } 506 if (diskCacheFileNameGenerator != null) { 507 L.w(WARNING_OVERLAP_DISK_CACHE_NAME_GENERATOR); 508 } 509 510 this.diskCache = diskCache; 511 return this; 512 } 513 514 /** 515 * Sets utility which will be responsible for downloading of image.<br /> 516 * Default value - 517 * {@link com.nostra13.universalimageloader.core.DefaultConfigurationFactory#createImageDownloader(Context) 518 * DefaultConfigurationFactory.createImageDownloader()} 519 */ 520 public Builder imageDownloader(ImageDownloader imageDownloader) { 521 this.downloader = imageDownloader; 522 return this; 523 } 524 525 /** 526 * Sets utility which will be responsible for decoding of image stream.<br /> 527 * Default value - 528 * {@link com.nostra13.universalimageloader.core.DefaultConfigurationFactory#createImageDecoder(boolean) 529 * DefaultConfigurationFactory.createImageDecoder()} 530 */ 531 public Builder imageDecoder(ImageDecoder imageDecoder) { 532 this.decoder = imageDecoder; 533 return this; 534 } 535 536 /** 537 * Sets default {@linkplain DisplayImageOptions display image options} for image displaying. These options will 538 * be used for every {@linkplain ImageLoader#displayImage(String, android.widget.ImageView) image display call} 539 * without passing custom {@linkplain DisplayImageOptions options}<br /> 540 * Default value - {@link DisplayImageOptions#createSimple() Simple options} 541 */ 542 public Builder defaultDisplayImageOptions(DisplayImageOptions defaultDisplayImageOptions) { 543 this.defaultDisplayImageOptions = defaultDisplayImageOptions; 544 return this; 545 } 546 547 /** 548 * Enables detail logging of {@link ImageLoader} work. To prevent detail logs don‘t call this method. 549 * Consider {@link com.nostra13.universalimageloader.utils.L#disableLogging()} to disable 550 * ImageLoader logging completely (even error logs) 551 */ 552 public Builder writeDebugLogs() { 553 this.writeLogs = true; 554 return this; 555 } 556 557 /** Builds configured {@link ImageLoaderConfiguration} object */ 558 public ImageLoaderConfiguration build() { 559 initEmptyFieldsWithDefaultValues(); 560 return new ImageLoaderConfiguration(this); 561 } 562 563 private void initEmptyFieldsWithDefaultValues() { 564 if (taskExecutor == null) { 565 taskExecutor = DefaultConfigurationFactory 566 .createExecutor(threadPoolSize, threadPriority, tasksProcessingType); 567 } else { 568 customExecutor = true; 569 } 570 if (taskExecutorForCachedImages == null) { 571 taskExecutorForCachedImages = DefaultConfigurationFactory 572 .createExecutor(threadPoolSize, threadPriority, tasksProcessingType); 573 } else { 574 customExecutorForCachedImages = true; 575 } 576 if (diskCache == null) { 577 if (diskCacheFileNameGenerator == null) { 578 diskCacheFileNameGenerator = DefaultConfigurationFactory.createFileNameGenerator(); 579 } 580 diskCache = DefaultConfigurationFactory 581 .createDiskCache(context, diskCacheFileNameGenerator, diskCacheSize, diskCacheFileCount); 582 } 583 if (memoryCache == null) { 584 memoryCache = DefaultConfigurationFactory.createMemoryCache(memoryCacheSize); 585 } 586 if (denyCacheImageMultipleSizesInMemory) { 587 memoryCache = new FuzzyKeyMemoryCache(memoryCache, MemoryCacheUtils.createFuzzyKeyComparator()); 588 } 589 if (downloader == null) { 590 downloader = DefaultConfigurationFactory.createImageDownloader(context); 591 } 592 if (decoder == null) { 593 decoder = DefaultConfigurationFactory.createImageDecoder(writeLogs); 594 } 595 if (defaultDisplayImageOptions == null) { 596 defaultDisplayImageOptions = DisplayImageOptions.createSimple(); 597 } 598 } 599 } 600 601 /** 602 * Decorator. Prevents downloads from network (throws {@link IllegalStateException exception}).<br /> 603 * In most cases this downloader shouldn‘t be used directly. 604 * 605 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) 606 * @since 1.8.0 607 */ 608 private static class NetworkDeniedImageDownloader implements ImageDownloader { 609 610 private final ImageDownloader wrappedDownloader; 611 612 public NetworkDeniedImageDownloader(ImageDownloader wrappedDownloader) { 613 this.wrappedDownloader = wrappedDownloader; 614 } 615 616 @Override 617 public InputStream getStream(String imageUri, Object extra) throws IOException { 618 switch (Scheme.ofUri(imageUri)) { 619 case HTTP: 620 case HTTPS: 621 throw new IllegalStateException(); 622 default: 623 return wrappedDownloader.getStream(imageUri, extra); 624 } 625 } 626 } 627 628 /** 629 * Decorator. Handles <a href="http://code.google.com/p/android/issues/detail?id=6066">this problem</a> on slow networks 630 * using {@link com.nostra13.universalimageloader.core.assist.FlushedInputStream}. 631 * 632 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) 633 * @since 1.8.1 634 */ 635 private static class SlowNetworkImageDownloader implements ImageDownloader { 636 637 private final ImageDownloader wrappedDownloader; 638 639 public SlowNetworkImageDownloader(ImageDownloader wrappedDownloader) { 640 this.wrappedDownloader = wrappedDownloader; 641 } 642 643 @Override 644 public InputStream getStream(String imageUri, Object extra) throws IOException { 645 InputStream imageStream = wrappedDownloader.getStream(imageUri, extra); 646 switch (Scheme.ofUri(imageUri)) { 647 case HTTP: 648 case HTTPS: 649 return new FlushedInputStream(imageStream); 650 default: 651 return imageStream; 652 } 653 } 654 } 655 }
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。
1 public final class DisplayImageOptions { 2 3 private final int imageResOnLoading; 4 private final int imageResForEmptyUri; 5 private final int imageResOnFail; 6 private final Drawable imageOnLoading; 7 private final Drawable imageForEmptyUri; 8 private final Drawable imageOnFail; 9 private final boolean resetViewBeforeLoading; 10 private final boolean cacheInMemory; 11 private final boolean cacheOnDisk; 12 private final ImageScaleType imageScaleType; 13 private final Options decodingOptions; 14 private final int delayBeforeLoading; 15 private final boolean considerExifParams; 16 private final Object extraForDownloader; 17 private final BitmapProcessor preProcessor; 18 private final BitmapProcessor postProcessor; 19 private final BitmapDisplayer displayer; 20 private final Handler handler; 21 private final boolean isSyncLoading; 22 23 private DisplayImageOptions(Builder builder) { 24 imageResOnLoading = builder.imageResOnLoading; 25 imageResForEmptyUri = builder.imageResForEmptyUri; 26 imageResOnFail = builder.imageResOnFail; 27 imageOnLoading = builder.imageOnLoading; 28 imageForEmptyUri = builder.imageForEmptyUri; 29 imageOnFail = builder.imageOnFail; 30 resetViewBeforeLoading = builder.resetViewBeforeLoading; 31 cacheInMemory = builder.cacheInMemory; 32 cacheOnDisk = builder.cacheOnDisk; 33 imageScaleType = builder.imageScaleType; 34 decodingOptions = builder.decodingOptions; 35 delayBeforeLoading = builder.delayBeforeLoading; 36 considerExifParams = builder.considerExifParams; 37 extraForDownloader = builder.extraForDownloader; 38 preProcessor = builder.preProcessor; 39 postProcessor = builder.postProcessor; 40 displayer = builder.displayer; 41 handler = builder.handler; 42 isSyncLoading = builder.isSyncLoading; 43 } 44 45 public boolean shouldShowImageOnLoading() { 46 return imageOnLoading != null || imageResOnLoading != 0; 47 } 48 49 public boolean shouldShowImageForEmptyUri() { 50 return imageForEmptyUri != null || imageResForEmptyUri != 0; 51 } 52 53 public boolean shouldShowImageOnFail() { 54 return imageOnFail != null || imageResOnFail != 0; 55 } 56 57 public boolean shouldPreProcess() { 58 return preProcessor != null; 59 } 60 61 public boolean shouldPostProcess() { 62 return postProcessor != null; 63 } 64 65 public boolean shouldDelayBeforeLoading() { 66 return delayBeforeLoading > 0; 67 } 68 69 public Drawable getImageOnLoading(Resources res) { 70 return imageResOnLoading != 0 ? res.getDrawable(imageResOnLoading) : imageOnLoading; 71 } 72 73 public Drawable getImageForEmptyUri(Resources res) { 74 return imageResForEmptyUri != 0 ? res.getDrawable(imageResForEmptyUri) : imageForEmptyUri; 75 } 76 77 public Drawable getImageOnFail(Resources res) { 78 return imageResOnFail != 0 ? res.getDrawable(imageResOnFail) : imageOnFail; 79 } 80 81 public boolean isResetViewBeforeLoading() { 82 return resetViewBeforeLoading; 83 } 84 85 public boolean isCacheInMemory() { 86 return cacheInMemory; 87 } 88 89 public boolean isCacheOnDisk() { 90 return cacheOnDisk; 91 } 92 93 public ImageScaleType getImageScaleType() { 94 return imageScaleType; 95 } 96 97 public Options getDecodingOptions() { 98 return decodingOptions; 99 } 100 101 public int getDelayBeforeLoading() { 102 return delayBeforeLoading; 103 } 104 105 public boolean isConsiderExifParams() { 106 return considerExifParams; 107 } 108 109 public Object getExtraForDownloader() { 110 return extraForDownloader; 111 } 112 113 public BitmapProcessor getPreProcessor() { 114 return preProcessor; 115 } 116 117 public BitmapProcessor getPostProcessor() { 118 return postProcessor; 119 } 120 121 public BitmapDisplayer getDisplayer() { 122 return displayer; 123 } 124 125 public Handler getHandler() { 126 return handler; 127 } 128 129 boolean isSyncLoading() { 130 return isSyncLoading; 131 } 132 133 /** 134 * Builder for {@link DisplayImageOptions} 135 * 136 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com) 137 */ 138 public static class Builder { 139 private int imageResOnLoading = 0; 140 private int imageResForEmptyUri = 0; 141 private int imageResOnFail = 0; 142 private Drawable imageOnLoading = null; 143 private Drawable imageForEmptyUri = null; 144 private Drawable imageOnFail = null; 145 private boolean resetViewBeforeLoading = false; 146 private boolean cacheInMemory = false; 147 private boolean cacheOnDisk = false; 148 private ImageScaleType imageScaleType = ImageScaleType.IN_SAMPLE_POWER_OF_2; 149 private Options decodingOptions = new Options(); 150 private int delayBeforeLoading = 0; 151 private boolean considerExifParams = false; 152 private Object extraForDownloader = null; 153 private BitmapProcessor preProcessor = null; 154 private BitmapProcessor postProcessor = null; 155 private BitmapDisplayer displayer = DefaultConfigurationFactory.createBitmapDisplayer(); 156 private Handler handler = null; 157 private boolean isSyncLoading = false; 158 159 public Builder() { 160 decodingOptions.inPurgeable = true; 161 decodingOptions.inInputShareable = true; 162 } 163 164 /** 165 * Stub image will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 166 * image aware view} during image loading 167 * 168 * @param imageRes Stub image resource 169 * @deprecated Use {@link #showImageOnLoading(int)} instead 170 */ 171 @Deprecated 172 public Builder showStubImage(int imageRes) { 173 imageResOnLoading = imageRes; 174 return this; 175 } 176 177 /** 178 * Incoming image will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 179 * image aware view} during image loading 180 * 181 * @param imageRes Image resource 182 */ 183 public Builder showImageOnLoading(int imageRes) { 184 imageResOnLoading = imageRes; 185 return this; 186 } 187 188 /** 189 * Incoming drawable will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 190 * image aware view} during image loading. 191 * This option will be ignored if {@link DisplayImageOptions.Builder#showImageOnLoading(int)} is set. 192 */ 193 public Builder showImageOnLoading(Drawable drawable) { 194 imageOnLoading = drawable; 195 return this; 196 } 197 198 /** 199 * Incoming image will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 200 * image aware view} if empty URI (null or empty 201 * string) will be passed to <b>ImageLoader.displayImage(...)</b> method. 202 * 203 * @param imageRes Image resource 204 */ 205 public Builder showImageForEmptyUri(int imageRes) { 206 imageResForEmptyUri = imageRes; 207 return this; 208 } 209 210 /** 211 * Incoming drawable will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 212 * image aware view} if empty URI (null or empty 213 * string) will be passed to <b>ImageLoader.displayImage(...)</b> method. 214 * This option will be ignored if {@link DisplayImageOptions.Builder#showImageForEmptyUri(int)} is set. 215 */ 216 public Builder showImageForEmptyUri(Drawable drawable) { 217 imageForEmptyUri = drawable; 218 return this; 219 } 220 221 /** 222 * Incoming image will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 223 * image aware view} if some error occurs during 224 * requested image loading/decoding. 225 * 226 * @param imageRes Image resource 227 */ 228 public Builder showImageOnFail(int imageRes) { 229 imageResOnFail = imageRes; 230 return this; 231 } 232 233 /** 234 * Incoming drawable will be displayed in {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 235 * image aware view} if some error occurs during 236 * requested image loading/decoding. 237 * This option will be ignored if {@link DisplayImageOptions.Builder#showImageOnFail(int)} is set. 238 */ 239 public Builder showImageOnFail(Drawable drawable) { 240 imageOnFail = drawable; 241 return this; 242 } 243 244 /** 245 * {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 246 * image aware view} will be reset (set <b>null</b>) before image loading start 247 * 248 * @deprecated Use {@link #resetViewBeforeLoading(boolean) resetViewBeforeLoading(true)} instead 249 */ 250 public Builder resetViewBeforeLoading() { 251 resetViewBeforeLoading = true; 252 return this; 253 } 254 255 /** 256 * Sets whether {@link com.nostra13.universalimageloader.core.imageaware.ImageAware 257 * image aware view} will be reset (set <b>null</b>) before image loading start 258 */ 259 public Builder resetViewBeforeLoading(boolean resetViewBeforeLoading) { 260 this.resetViewBeforeLoading = resetViewBeforeLoading; 261 return this; 262 } 263 264 /** 265 * Loaded image will be cached in memory 266 * 267 * @deprecated Use {@link #cacheInMemory(boolean) cacheInMemory(true)} instead 268 */ 269 @Deprecated 270 public Builder cacheInMemory() { 271 cacheInMemory = true; 272 return this; 273 } 274 275 /** Sets whether loaded image will be cached in memory */ 276 public Builder cacheInMemory(boolean cacheInMemory) { 277 this.cacheInMemory = cacheInMemory; 278 return this; 279 } 280 281 /** 282 * Loaded image will be cached on disk 283 * 284 * @deprecated Use {@link #cacheOnDisk(boolean) cacheOnDisk(true)} instead 285 */ 286 @Deprecated 287 public Builder cacheOnDisc() { 288 return cacheOnDisk(true); 289 } 290 291 /** 292 * Sets whether loaded image will be cached on disk 293 * 294 * @deprecated Use {@link #cacheOnDisk(boolean)} instead 295 */ 296 @Deprecated 297 public Builder cacheOnDisc(boolean cacheOnDisk) { 298 return cacheOnDisk(cacheOnDisk); 299 } 300 301 /** Sets whether loaded image will be cached on disk */ 302 public Builder cacheOnDisk(boolean cacheOnDisk) { 303 this.cacheOnDisk = cacheOnDisk; 304 return this; 305 } 306 307 /** 308 * Sets {@linkplain ImageScaleType scale type} for decoding image. This parameter is used while define scale 309 * size for decoding image to Bitmap. Default value - {@link ImageScaleType#IN_SAMPLE_POWER_OF_2} 310 */ 311 public Builder imageScaleType(ImageScaleType imageScaleType) { 312 this.imageScaleType = imageScaleType; 313 return this; 314 } 315 316 /** Sets {@link Bitmap.Config bitmap config} for image decoding. Default value - {@link Bitmap.Config#ARGB_8888} */ 317 public Builder bitmapConfig(Bitmap.Config bitmapConfig) { 318 if (bitmapConfig == null) throw new IllegalArgumentException("bitmapConfig can‘t be null"); 319 decodingOptions.inPreferredConfig = bitmapConfig; 320 return this; 321 } 322 323 /** 324 * Sets options for image decoding.<br /> 325 * <b>NOTE:</b> {@link Options#inSampleSize} of incoming options will <b>NOT</b> be considered. Library 326 * calculate the most appropriate sample size itself according yo {@link #imageScaleType(ImageScaleType)} 327 * options.<br /> 328 * <b>NOTE:</b> This option overlaps {@link #bitmapConfig(android.graphics.Bitmap.Config) bitmapConfig()} 329 * option. 330 */ 331 public Builder decodingOptions(Options decodingOptions) { 332 if (decodingOptions == null) throw new IllegalArgumentException("decodingOptions can‘t be null"); 333 this.decodingOptions = decodingOptions; 334 return this; 335 } 336 337 /** Sets delay time before starting loading task. Default - no delay. */ 338 public Builder delayBeforeLoading(int delayInMillis) { 339 this.delayBeforeLoading = delayInMillis; 340 return this; 341 } 342 343 /** Sets auxiliary object which will be passed to {@link ImageDownloader#getStream(String, Object)} */ 344 public Builder extraForDownloader(Object extra) { 345 this.extraForDownloader = extra; 346 return this; 347 } 348 349 /** Sets whether ImageLoader will consider EXIF parameters of JPEG image (rotate, flip) */ 350 public Builder considerExifParams(boolean considerExifParams) { 351 this.considerExifParams = considerExifParams; 352 return this; 353 } 354 355 /** 356 * Sets bitmap processor which will be process bitmaps before they will be cached in memory. So memory cache 357 * will contain bitmap processed by incoming preProcessor.<br /> 358 * Image will be pre-processed even if caching in memory is disabled. 359 */ 360 public Builder preProcessor(BitmapProcessor preProcessor) { 361 this.preProcessor = preProcessor; 362 return this; 363 } 364 365 /** 366 * Sets bitmap processor which will be process bitmaps before they will be displayed in 367 * {@link com.nostra13.universalimageloader.core.imageaware.ImageAware image aware view} but 368 * after they‘ll have been saved in memory cache. 369 */ 370 public Builder postProcessor(BitmapProcessor postProcessor) { 371 this.postProcessor = postProcessor; 372 return this; 373 } 374 375 /** 376 * Sets custom {@link BitmapDisplayer displayer} for image loading task. Default value - 377 * {@link DefaultConfigurationFactory#createBitmapDisplayer()} 378 */ 379 public Builder displayer(BitmapDisplayer displayer) { 380 if (displayer == null) throw new IllegalArgumentException("displayer can‘t be null"); 381 this.displayer = displayer; 382 return this; 383 } 384 385 Builder syncLoading(boolean isSyncLoading) { 386 this.isSyncLoading = isSyncLoading; 387 return this; 388 } 389 390 /** 391 * Sets custom {@linkplain Handler handler} for displaying images and firing {@linkplain ImageLoadingListener 392 * listener} events. 393 */ 394 public Builder handler(Handler handler) { 395 this.handler = handler; 396 return this; 397 } 398 399 /** Sets all options equal to incoming options */ 400 public Builder cloneFrom(DisplayImageOptions options) { 401 imageResOnLoading = options.imageResOnLoading; 402 imageResForEmptyUri = options.imageResForEmptyUri; 403 imageResOnFail = options.imageResOnFail; 404 imageOnLoading = options.imageOnLoading; 405 imageForEmptyUri = options.imageForEmptyUri; 406 imageOnFail = options.imageOnFail; 407 resetViewBeforeLoading = options.resetViewBeforeLoading; 408 cacheInMemory = options.cacheInMemory; 409 cacheOnDisk = options.cacheOnDisk; 410 imageScaleType = options.imageScaleType; 411 decodingOptions = options.decodingOptions; 412 delayBeforeLoading = options.delayBeforeLoading; 413 considerExifParams = options.considerExifParams; 414 extraForDownloader = options.extraForDownloader; 415 preProcessor = options.preProcessor; 416 postProcessor = options.postProcessor; 417 displayer = options.displayer; 418 handler = options.handler; 419 isSyncLoading = options.isSyncLoading; 420 return this; 421 } 422 423 /** Builds configured {@link DisplayImageOptions} object */ 424 public DisplayImageOptions build() { 425 return new DisplayImageOptions(this); 426 } 427 } 428 429 /** 430 * Creates options appropriate for single displaying: 431 * <ul> 432 * <li>View will <b>not</b> be reset before loading</li> 433 * <li>Loaded image will <b>not</b> be cached in memory</li> 434 * <li>Loaded image will <b>not</b> be cached on disk</li> 435 * <li>{@link ImageScaleType#IN_SAMPLE_POWER_OF_2} decoding type will be used</li> 436 * <li>{@link Bitmap.Config#ARGB_8888} bitmap config will be used for image decoding</li> 437 * <li>{@link SimpleBitmapDisplayer} will be used for image displaying</li> 438 * </ul> 439 * <p/> 440 * These option are appropriate for simple single-use image (from drawables or from Internet) displaying. 441 */ 442 public static DisplayImageOptions createSimple() { 443 return new Builder().build(); 444 } 445 }
参考链接
http://blog.csdn.net/wangjinyu501/article/details/8091623
https://github.com/nostra13/Android-Universal-Image-Loader
Android-Universal-Image-Loader三大组件DisplayImageOptions、ImageLoader、ImageLoaderConfiguration详解