Android异步加载图片

对于Android中的异步加载图片，自己总结了两种方式，如下：

1、

/**  * 异步读取图片，需要传递三个参数：Imageview imageView,String imagePath,int maxNumpixels   * @author Bryant  */  public class AsyncLoadImage extends AsyncTask<Object, Object, Void> {      @Override      protected Void doInBackground(Object... params) {          try {              ImageView imageView=(ImageView) params[0];              String path=(String) params[1];              int maxNumOfPixels = (Integer)params[2];                        Bitmap bm = CompressPicture.compress(path,maxNumOfPixels);               publishProgress(new Object[] {imageView, bm});          }catch (Exception e) {              e.printStackTrace();          }                  return null;    }      protected void onProgressUpdate(Object... progress) {          ImageView imageView = (ImageView) progress[0];          Bitmap bm = (Bitmap) progress[1];        if(bm != null){            imageView.setImageBitmap(bm);         }    }  }

2、

/** * 图片异步加载 * @author Bryant * */public class AsyncImageLoader {private Map<String, SoftReference<Bitmap>> imageCache=new HashMap<String, SoftReference<Bitmap>>();private int maxNumPixels;public Bitmap loadBitmap(final String imagePath,int maxNumPixels,final ImageCallback callback){this.maxNumPixels = maxNumPixels;if(imageCache.containsKey(imagePath)){SoftReference<Bitmap> softReference=imageCache.get(imagePath);if(softReference.get()!=null){return softReference.get();}}final Handler handler=new Handler(){@Overridepublic void handleMessage(Message msg) {callback.imageLoaded((Bitmap) msg.obj, imagePath);}};new Thread(){public void run() {Bitmap bitmap=loadImageFromPath(imagePath);imageCache.put(imagePath, new SoftReference<Bitmap>(bitmap));handler.sendMessage(handler.obtainMessage(0,bitmap));};}.start();return null;}protected Bitmap loadImageFromPath(String imagePath) {try {return CompressPicture.compress(imagePath, maxNumPixels);} catch (Exception e) {throw new RuntimeException(e);}}public interface ImageCallback{public void imageLoaded(Bitmap imageBitmap,String imagePath);}}

经过实际使用，AsyncImageLoader的效率比较高，但是调用比较麻烦。

调用示例：

private AsyncImageLoader imageLoader = new AsyncImageLoader();imageLoader.loadBitmap(imagePath,maxNumPixels, new ImageCallback() {public void imageLoaded(Bitmap imageBitmap, String imagePath) {imageView.setImageBitmap(imageBitmap);}});

AsyncLoadImage调用较简单，调用示例如下：

new AsyncLoadImage().execute(new Object[]{imageView,imagePath,maxNumPixels});

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