Android应用层操作底层gpio来控制led

    具体实现过程：

    process = Runtime.getRuntime().exec("su");
   dos = new DataOutputStream(process.getOutputStream());
   //打开gpio引脚74，即status_led连接的引脚
   dos.writeBytes("echo 74 > /sys/class/gpio/export"+"\n");
   
   dos.flush(); 
   //设置引脚功能为输出
   dos.writeBytes("echo out > /sys/class/gpio/gpio74/direction"+"\n");
   dos.flush(); 

   
   dos.close();

//led开：

private void cmdLedOn() {
  // TODO Auto-generated method stub
  DataOutputStream dos = null;
  
  
  try {
   process = Runtime.getRuntime().exec("su");
   dos = new DataOutputStream(process.getOutputStream());
   dos.writeBytes("echo 1 > /sys/class/gpio/gpio74/value"+"\n");
   
   dos.flush();
   dos.close();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } 
  
 }

//led关

private void cmdLedOff() {
  // TODO Auto-generated method stub
  DataOutputStream dos = null;
  
  try {
   process = Runtime.getRuntime().exec("su");
   dos = new DataOutputStream(process.getOutputStream());
   dos.writeBytes("echo 0 > /sys/class/gpio/gpio74/value"+"\n");
   
   dos.flush();
   dos.close();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } 
 }