[TOC]

写在前面

AUIL 的特点

• 多线程下载图片(同步异步)
• 提供多种ImageLoader的用户配置(thread executors, downloaders,decoder, memory and disk cache, display image options, etc.)
• 为每一个显示图片的调用提供了非常丰富的配置(stub image, caching switch, decoding options, Bitmap processing and displaying, etc)
• 提供图片的内存和文件缓存
• 图片加载的监听和下载进度的监听

使用

QuickSetup

1. include library

   implementation 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'
   

2. config manifest permission

   manifest>
       <!-- Include following permission if you load images from Internet -->
       <uses-permission android:name="android.permission.INTERNET" />
       <!-- Include following permission if you want to cache images on SD card -->
       <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
       ...
   </manifest>
   

3. config imageloader and initial

   public class MyActivity extends Activity {
       @Override
       public void onCreate() {
           super.onCreate();
   
           // Create global configuration and initialize ImageLoader with this config
           ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(this)
               ...
               .build();
           ImageLoader.getInstance().init(config);
           ...
       }
   }
   

4. Display Options

   // DON'T COPY THIS CODE TO YOUR PROJECT! This is just example of ALL options using.
   // See the sample project how to use ImageLoader correctly.
   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();
   

Usage

可接受的的URI资源示例

"http://site.com/image.png" // from Web
"file:///mnt/sdcard/image.png" // from SD card
"file:///mnt/sdcard/video.mp4" // from SD card (video thumbnail)
"content://media/external/images/media/13" // from content provider
"content://media/external/video/media/13" // from content provider (video thumbnail)
"assets://image.png" // from assets
"drawable://" + R.drawable.img // from drawables (non-9patch images)

NOTE: Use drawable:// only if you really need it! Always consider the native way to load drawables - ImageView.setImageResource(...) instead of using of ImageLoader.

简单使用

// Load image, decode it to Bitmap and display Bitmap in ImageView (or any other view 
//    which implements ImageAware interface)
ImageLoader imageLoader = ImageLoader.getInstance();
imageLoader.loadImage(imageUri, imageview);

// Load image, decode it to Bitmap and return Bitmap to callback
imageLoader.loadImage(imageUri, new SimpleImageLoadingListener() {
    @Override
    public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
        // Do whatever you want with Bitmap
    }
});

// Load image, decode it to Bitmap and return Bitmap synchronously
Bitmap bmp = imageLoader.loadImageSync(imageUri);

完全使用

// Load image, decode it to Bitmap and display Bitmap in ImageView (or any other view 
//    which implements ImageAware interface)
imageLoader.displayImage(imageUri, imageView, options, new ImageLoadingListener() {
    @Override
    public void onLoadingStarted(String imageUri, View view) {
        ...
    }
    @Override
    public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
        ...
    }
    @Override
    public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
        ...
    }
    @Override
    public void onLoadingCancelled(String imageUri, View view) {
        ...
    }
}, new ImageLoadingProgressListener() {
    @Override
    public void onProgressUpdate(String imageUri, View view, int current, int total) {
        ...
    }
});
// Load image, decode it to Bitmap and return Bitmap to callback
ImageSize targetSize = new ImageSize(80, 50); // result Bitmap will be fit to this size
imageLoader.loadImage(imageUri, targetSize, options, new SimpleImageLoadingListener() {
    @Override
    public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
        // Do whatever you want with Bitmap
    }
});

// Load image, decode it to Bitmap and return Bitmap synchronously
ImageSize targetSize = new ImageSize(80, 50); // result Bitmap will be fit to this size
Bitmap bmp = imageLoader.loadImageSync(imageUri, targetSize, options);

Load & Display Task Flow

重要, 这个是AUIL的加载图片流程

用户须知

1. Caching is NOT enabled by default如果需要开启内存或者是磁盘缓存,需要配置DisplayImageOptions

   // Create default options which will be used for every 
   //  displayImage(...) call if no options will be passed to this method
   DisplayImageOptions defaultOptions = new DisplayImageOptions.Builder()
              ...
              .cacheInMemory(true)
              .cacheOnDisk(true)
              ...
              .build();
   ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())
              ...
              .defaultDisplayImageOptions(defaultOptions)
              ...
              .build();
   ImageLoader.getInstance().init(config); // Do it on Application start
   

   // Then later, when you want to display image
   ImageLoader.getInstance().displayImage(imageUrl, imageView); // Default options will be used
   

   或者这样:

   DisplayImageOptions options = new DisplayImageOptions.Builder()
              ...
              .cacheInMemory(true)
              .cacheOnDisk(true)
              ...
              .build();
   ImageLoader.getInstance().displayImage(imageUrl, imageView, options); // Incoming options will be used
   

2. 注意WRITE_EXTERNAL_STORAGE这个权限的申请.

3. 如果发生OOM可以尝试关掉内存缓存, 或减少线程池的大小, 或使用RGB-565的图像配置替换ARGB-8888, 或者裁剪图片显示小图.

4. MemoryChache的配置

   1. 强引用 LruMemoryCache
   2. 强弱引用混用 1,3除外的算法.
   3. 只是用弱引用 WeakMemoryCache

5. DiscChache也是可配置的UnlimitedDiscCache 是最快的,但是占用存储空间

6. 使用RoundedBigmaDisplayer或FadeInbitmapDisplayer 装饰图片加载

7. 为了是ListView or GrideView的性能提升, 使用PauseOnScrollListener

   boolean pauseOnScroll = false; // or true
   boolean pauseOnFling = true; // or false
   PauseOnScrollListener listener = new PauseOnScrollListener(imageLoader, pauseOnScroll, pauseOnFling);
   listView.setOnScrollListener(listener);
   

8. If you see in logs some strange supplement at the end of image URL (e.g. http://anysite.com/images/image.png_230x460) then it doesn’t mean this URL is used in requests. This is just “URL + target size”, also this is key for Bitmap in memory cache. This postfix (_230x460) is NOT used in requests.