高效率下载图片——防止内存溢出(4)

        imageView.setTag(imageUrl); 
         
        //设置下载项 
        ImageDownloadItem item = new ImageDownloadItem(); 
        item.imageUrl = imageUrl; 
        //如果是无需显示图片的情况（如预下载），无需设置item.callback，即让item.callback = null 
        item.callback = new ImageDownloadCallback() { 
            @Override 
            public void update(Bitmap bitmap, String imageUrl) { 
                ImageView imageViewByTag = (ImageView)imageView.findViewWithTag(imageUrl); 
                if (imageViewByTag != null) imageViewByTag.setImageBitmap(bitmap); 
            } 
        }; 
         
        ImageDownloadThread imageDownloadThread = ImageDownloadThread.getInstance(); 
        Bitmap bitmap = imageDownloadThread.downloadWithCache(item); 
        if (bitmap != null) {//从缓存中取到 
            imageView.setImageBitmap(bitmap); 
        } 
        return imageView; 
    } 

作者“程序人生”