模仿饿了么加载效果

#System Requirement

Android API 11+， Because of the use of ValueAnimation， if you want use it on API 8, please use NineoldAndroids library in your project.

#Usage

    loadingView.addBitmap(R.mipmap.v4);
    
    or
    
    loadingView.addBitmap(bitmap);
    
    or
    
    loadingView.addBitmaps(mBitmapList);
    
    //set the shadow color
    loadingView.setShadowColor(Color.LTGRAY);
    
    //set the duration of animation
    loadingView.setDuration(800);

    loadingView.start();