ImageLoader初始化以及调用

1、首先在当前程序的Application中调用ImageLoader的初始化init()方法

private void initImageLoader() {  
    ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(this).imageDownloader(  
        new BaseImageDownloader(this, 60 * 1000, 60 * 1000)) // connectTimeout超时时间  
            .build();  
    ImageLoader.getInstance().init(config);  
 }  

2、下载图片的参数选项配置

/** 
  * 调用该方法下载图片 
  * 配置imageLoader图片选项 
  * @param iv  显示图片控件 
  * @param url  网络或本地图片地址 
  * @param defaultPic  默认图片 
  * @param isRound  true为圆形，false不处理 
  * @param cacheOnDisk true缓存到SD卡，false不缓存到SD卡 
  */  
public static void displayImages(ImageView iv,String url,int defaultPic,boolean isRound,boolean cacheOnDisk){  
    //配置一些图片选项  
    DisplayImageOptions options = new DisplayImageOptions.Builder()  
    .showImageOnLoading(defaultPic)// 设置图片在下载期间显示的图片  
    .showImageForEmptyUri(defaultPic)// 设置图片Uri为空或是错误的时候显示的图片  
    .showImageOnFail(defaultPic)// 设置图片加载/解码过程中错误时候显示的图片  
    .cacheInMemory(false)// 设置下载的图片是否缓存在内存中  
    .cacheOnDisk(cacheOnDisk)// 设置下载的图片是否缓存在SD卡中  
    .considerExifParams(true)//是否考虑JPEG图像EXIF参数（旋转，翻转）  
    .displayer(isRound ? new CircleBitmapDisplayer() : new SimpleBitmapDisplayer())//FadeInBitmapDisplayer(200)listview加载闪烁问题  
    .imageScaleType(ImageScaleType.IN_SAMPLE_POWER_OF_2)//图片将降低2倍，直到下一减少步骤，使图像更小的目标大小  
    .bitmapConfig(Bitmap.Config.RGB_565)//图片色彩565  
    .build();  
    imageLoader.displayImage(url, iv, options);  //加载网络图片url

3、扩展，图片显示方式，圆角；CircleBitmapDisplayer()

private static class CircleBitmapDisplayer implements BitmapDisplayer {  
    final int margin ;  
    public CircleBitmapDisplayer() {  
        this(0);  
    }  
    public CircleBitmapDisplayer(int margin) {  
        this.margin = margin;  
    }  
    @Override  
    public void display(Bitmap bitmap, ImageAware imageAware, LoadedFrom loadedFrom) {  
        if (!(imageAware instanceof ImageViewAware)) {  
             throw new IllegalArgumentException("ImageAware should wrap ImageView. ImageViewAware is expected.");
        }
        imageAware.setImageBitmap(ToRoundBitmap.toRoundBitmap(bitmap));  
    }  
 }

4、返回圆形bitmap；toRoundBitmap()

public static  Bitmap toRoundBitmap(Bitmap bitmap) {  
         int width = bitmap.getWidth();  
         int height = bitmap.getHeight();  
         float roundPx;  
         float left,top,right,bottom,dst_left,dst_top,dst_right,dst_bottom;  
         if (width <= height) {  
              roundPx = width / 2;  
              top = 0;  
              left = 0;  
              bottom = width;  
              right = width;  
              height = width;  
              dst_left = 0;  
              dst_top = 0;  
              dst_right = width;  
              dst_bottom = width;  
          } else {  
              roundPx = height / 2;  
              float clip = (width - height) / 2;  
              left = clip;  
              right = width - clip;  
              top = 0;  
              bottom = height;  
              width = height;  
              dst_left = 0;  
              dst_top = 0;  
              dst_right = height;  
              dst_bottom = height;  
         }  
  
            Bitmap output = Bitmap.createBitmap(width,height, Config.ARGB_8888);  
            Canvas canvas = new Canvas(output);  
              
            final int color = 0xff424242;  
            final Paint paint = new Paint();  
            final Rect src = new Rect((int)left, (int)top, (int)right, (int)bottom);  
            final Rect dst = new Rect((int)dst_left, (int)dst_top, (int)dst_right, (int)dst_bottom);  
            final RectF rectF = new RectF(dst);  
  
            paint.setAntiAlias(true);  
 
            canvas.drawARGB(0, 0, 0, 0);  
            paint.setColor(Color.WHITE);  
            paint.setStrokeWidth(4);   
            canvas.drawRoundRect(rectF, roundPx, roundPx, paint);  
            paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));  
            canvas.drawBitmap(bitmap, src, dst, paint);  
            return output ;   
}

5、根据图片uri返回bitmap；此缓存位置为内存

public static Bitmap getBitmapUtils(String imgUri){  
    return imageLoader.getMemoryCache().get(imgUri);  
 }

6、根据图片uri返回File；此缓存位置为sd卡

public static File getFileUtils(String imgUri){  
    return imageLoader.getDiskCache().get(imgUri);  
}

7、获取imageloader缓存所有图片总计大小

public static long getCacheFileSize(){  
    File disCacheFile = imageLoader.getDiskCache().getDirectory();  
    long size = 0;  
    for(int i=0; i<disCacheFile.listFiles().length; i++){  
        size += disCacheFile.listFiles()[i].length();  
              }  
 return size;  
}

8、清除图片缓存

public static void clearImageCache(){  
    imageLoader.clearDiskCache();//清除磁盘缓存  
    imageLoader.clearMemoryCache();//清除内存缓存  
}