public void displayImages(
 final List<String> urls,
 final ImageView imageView, 
 final MergeCallBack mergeCallBack
)

 public String getNewUrlByList(List<String> urls, String mark) {
 StringBuilder sb = new StringBuilder();
 for (String url : urls) {
  sb.append(url + mark);
 }
 return sb.toString();
 }

 public void displayImages(final List<String> urls, final ImageView imageView, final MergeCallBack mergeCallBack, final int dstWidth, final int dstHeight) {
 if (urls == null || urls.size() <= 0) {
  throw new IllegalArgumentException("url不能为空");
 }
 if (mergeCallBack == null) {
  throw new IllegalArgumentException("mergeCallBack 不能为空");
 }
 final String url = getNewUrlByList(urls, mergeCallBack.getMark());
 imageView.setTag(IMG_URL, url);
 //内存中加载
 Bitmap bitmap = loadFromMemory(url);
 if (bitmap != null) {
  LogUtil.e(Tag, "displayImages this is from Memory");
  imageView.setImageBitmap(bitmap);
  return;
 }
 try {
  //磁盘中加载
  bitmap = loadFromDiskCache(url, dstWidth, dstHeight);
  if (bitmap != null) {
  LogUtil.e(Tag, "displayImages this is from Disk");
  imageView.setImageBitmap(bitmap);
  return;
  }
 } catch (Exception e) {
  e.printStackTrace();
 }
 //设置一张默认图
 bitmap = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.ic_launcher_round);
 imageView.setImageBitmap(bitmap);
 LogUtil.e(Tag, "displayImages this is from default");
 //开启一个新的线程，同步加载所有的图片。如果加载成功，则返回。
 Runnable loadBitmapTask = new Runnable() {
  @Override
  public void run() {
  ArrayList<Bitmap> bitmaps = loadBitMaps(urls, dstWidth, dstHeight);
  if (bitmaps != null && bitmaps.size() > 0) {
   Result result;
   if (mergeCallBack != null) {
   Bitmap mergeBitmap = mergeCallBack.merge(bitmaps, mContext, imageView);
   if (urls.size() == bitmaps.size()) {
    //加入缓存
    try {
    saveDru(url, mergeBitmap);
    } catch (IOException e) {
    e.printStackTrace();
    }
   } else {
    LogUtil.e(Tag, "size change. so can not save");
   }
   LogUtil.e(Tag, "displayImages this is from Merge");
   result = new Result(mergeBitmap, url, imageView);
   } else {
   result = new Result(bitmaps.get(0), url, imageView);
   }
   Message msg = mMainHandler.obtainMessage(MESSAGE_SEND_RESULT, result);
   msg.sendToTarget();
  }
  }
 };
 threadPoolExecutor.execute(loadBitmapTask);
 }

 private ArrayList<Bitmap> loadBitMaps(List<String> urls, int dstWidth, int dstHeight) {
 ArrayList<Bitmap> bitmaps = new ArrayList<>();
 for (String url : urls) {
  //同步获得所有图像
  Bitmap bitmap = loadBitMap(url, dstWidth, dstHeight);
  if (bitmap != null) {
  bitmaps.add(bitmap);
  }
 }
 return bitmaps;
 }

 private Bitmap loadBitMap(String url, int dstWidth, int dstHeight) {
 //内存
 Bitmap bitmap = loadFromMemory(url);
 if (bitmap != null) {
  LogUtil.e(Tag, "this is from Memory");
  return bitmap;
 }
 try {
  //磁盘
  bitmap = loadFromDiskCache(url, dstWidth, dstHeight);
  if (bitmap != null) {
  LogUtil.e(Tag, "this is from Disk");
  return bitmap;
  }
  //网络
  bitmap = loadFromNet(url, dstWidth, dstHeight);
  LogUtil.e(Tag, "this is from Net");
  if (bitmap == null) {
  LogUtil.e(Tag, "bitmap null network error");
  }
 } catch (Exception e) {
  e.printStackTrace();
 }
 return bitmap;
 }

Bitmap mergeBitmap = mergeCallBack.merge(bitmaps, mContext, imageView);
if (urls.size() == bitmaps.size()) {
 //加入缓存
 try {
  saveDru(url, mergeBitmap);
 } catch (IOException e) {
  e.printStackTrace();
 }
} 

@Override
public Bitmap merge(List<Bitmap> bitmapArray, Context context, ImageView imageView) {
 this.context = context;
 // 画布的宽
 ViewGroup.LayoutParams lp = imageView.getLayoutParams();
 int tempWidth;
 int tempHeight;
 if (lp != null) {
 tempWidth = dip2px(context, lp.width);
 tempHeight = dip2px(context, lp.height);
 } else {
 //否则给一个默认的高度
 tempWidth = dip2px(context, 70);
 tempHeight = dip2px(context, 70);
 }
 return CombineBitmapTools.combimeBitmap(context, tempWidth, tempHeight,
  bitmapArray);
}

 public static Bitmap combimeBitmap(Context context, int combineWidth,
     int combineHeight, List<Bitmap> bitmaps) {
 if (bitmaps == null || bitmaps.size() == 0)
  return null;

 if (bitmaps.size() >= 9) {
  bitmaps = bitmaps.subList(0, 9);
 }
 Bitmap resultBitmap = null;
 int len = bitmaps.size();
 // 绘制数据，这里记录所有的绘制坐标。
 List<CombineBitmapEntity> combineBitmapEntities = CombineNineRect
  .generateCombineBitmapEntity(combineWidth, combineHeight, len);
 // 缩略图
 List<Bitmap> thumbnailBitmaps = new ArrayList<Bitmap>();
 for (int i = 0; i < len; i++) {
  thumbnailBitmaps.add(ThumbnailUtils.extractThumbnail(bitmaps.get(i),
   (int) combineBitmapEntities.get(i).width,
   (int) combineBitmapEntities.get(i).height));
 }
 // 合成
 resultBitmap = getCombineBitmaps(combineBitmapEntities,
  thumbnailBitmaps, combineWidth, combineHeight);

 return resultBitmap;
 }
 private static Bitmap getCombineBitmaps(
  List<CombineBitmapEntity> mEntityList, List<Bitmap> bitmaps,
  int width, int height) {
 Bitmap newBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
 for (int i = 0; i < mEntityList.size(); i++) {
  //合并图像
  newBitmap = mixtureBitmap(newBitmap, bitmaps.get(i), new PointF(
   mEntityList.get(i).x, mEntityList.get(i).y));
 }
 return newBitmap;
 }

 private static Bitmap mixtureBitmap(Bitmap first, Bitmap second,
     PointF fromPoint) {
 if (first == null || second == null || fromPoint == null) {
  return null;
 }
 Bitmap newBitmap = Bitmap.createBitmap(first.getWidth(),
  first.getHeight(), Bitmap.Config.ARGB_8888);
 Canvas cv = new Canvas(newBitmap);
 cv.drawBitmap(first, 0, 0, null);
 cv.drawBitmap(second, fromPoint.x, fromPoint.y, null);
 cv.save(Canvas.ALL_SAVE_FLAG);
 cv.restore();
 if (first != null) {
  first.recycle();
  first = null;
 }
 if (second != null) {
  second.recycle();
  second = null;
 }
 return newBitmap;
 }