PhotoWallFallsDemoAndroid瀑布流照片墙实现，或者说是图片墙，体验Android的不规则布局，里面包括对图片进行管理的类，图片缓存技术的核心类，用于缓存在瀑布流中所显示的图片，在程序内存达到设定值时会将最少最近使用的图片移除掉。以及ImageLoader的实例，将一张图片存储到LruCache中，从LruCache中获取一张图片，如果不存在就返回null。第一次解析将inJustDecodeBounds设置为true，来获取图片大校自定义的ScrollView，在其中动态地对图片进行添加。

　　@param key

　　LruCache的键，这里传入图片的URL地址。

　　@return 对应传入键的Bitmap对象，或者null。

　　一些关键性的初始化操作，获取MyScrollView的高度，以及得到第一列的宽度值。并在这里开始加载第一页的图片，监听用户的触屏事件，如果用户手指离开屏幕则开始进行滚动检测等。-PhotoWallFallsDemoAndroid waterfall stream photo wall achieve, or is the picture wall, experience the irregular layout of Android, which includes the picture management classes, core classes picture caching techniques for caching in the waterfall stream shown in the picture, in the program When memory reaches the set value will remove the least recently used picture out. And ImageLoader instance, a picture will be stored LruCache, gets a picture from LruCache, if it does not exist return null. The first resolution will inJustDecodeBounds set to true, to get the picture Colonel custom ScrollView, in which the picture is dynamically added. @ Param key LruCache key, where the incoming image URL. @ Return the corresponding incoming keys Bitmap object, or null. Some key initialization, get MyScrollView height and width values 琠漀 get the first column. And here the picture on the first page starts loading, monitoring the user' s touch event, if the user' s finger off the screen starts t