本源代码实现的是在屏幕上移动一辆自行车。自行车移动的同时旋转它的脚蹬。实现的方法为：绘制出一个完整的自行车映像，以及一系列脚蹬处于不同位置的较小映像，绘制完后按照一定的顺序重复显示这些映像，以达到动画的目的。-source code is realized on the screen a mobile bicycle. Mobile bicycle while rotating the sneaking. The way to achieve : mapping out a complete bicycle mapping, and a series of pedals at various locations in smaller mapping, After drawing with a repeated sequence of these images, animation to achieve the purpose.