3D手机游戏开发教学 编写一个继承于Canvas类的子类，并且实现Runnable接口，在run方法中绘制屏幕中一个小方块，通过游戏动作键（上下左右）控制方块的移动-3D mobile phone game developers to prepare a succession of teaching in the Canvas sub-class category, and the realization of Runnable interface, in the run method of d