其实为ImageViewZoomHelper，这样方便索引。(with a helper called ImageViewZoomHelper can easily handle interactive Actions )
A simple ImageView which can pan,scale image.一个安卓ImageView 控件的辅助类，可以手势缩放，平移，双击之后恢复到原始状态。
iv 为ImageView 此处为初始化辅助类。（iv is a ImageView and a line below for Initializing a Helper Handling Pan,Scale Actions.)
imageViewZoomHelper.SetImageEx("File path"); 是显示一张图片。（imageViewZoomHelper.SetImageEx("File path"); Displaying a Image 。）
下面则是控制上一张图或者下一张图片的操作（The following codes shows you how to set a next or previous image when you have a image array to display. ）
