实现android相机通过重力感应自动对焦，支持闪光灯、相册浏览，解决相机程序在不同型号手机无法自动对焦的问题。-Android camera through gravity sensing autofocus, support flash, album browsing, to solve the camera program in different types of mobile phones can not focus automatically.

iOS系统提供的Animation简单demo，为小球添加重力、弹力动画，每次点击时在点击位置投下一个小球