这是一个在android下进行gpio驱动开发的例子，在这个例子中分别从底层驱动代码到测试程序再到android上的JNI层，然后通过java代码调用APP Framework层的接口实现对开发板上led的控制(This is carried out under a gpio android-driven development example, in this case were driven from the bottom to the android code to the test pr