Android串口操作方法实例

1.首先下载一个libserial_port.so，新建目录libs/armeabi,将so文件放到该目录下。
2.定义串口类，在类的构建函数中修改权限，打开设备，创建输入流和输出流，通过native接口访问串口打开关闭函数

public class SerialPort {

 /*Do not remove or rename the field mFd: it is used by native method close();*/

 public SerialPort(File device, int baudrate, int flags) throws SecurityException, IOException, InvalidParameterException{

//如果串口权限不够，改变权限

  /* Check access permission */

  if (!device.canRead() || !device.canWrite()) {

   try {

    /* Missing read/write permission, trying to chmod the file */

    Process su;

    su = Runtime.getRuntime().exec("/system/bin/su");

    String cmd = "chmod 666 " + device.getAbsolutePath() + "\n"

      + "exit\n";

    su.getOutputStream().write(cmd.getBytes());

    if ((su.waitFor() != 0) || !device.canRead()

      || !device.canWrite()) {

     throw new SecurityException();

    }

   } catch (Exception e) {

    e.printStackTrace();

    throw new SecurityException();

   }

  }

  mFd = open(device.getAbsolutePath(), baudrate, flags);//打开串口

  if (mFd == null) {

   Log.e(TAG, "native open returns null");

   throw new IOException();

  }

  mFileInputStream = new FileInputStream(mFd);//串口输入流

  mFileOutputStream = new FileOutputStream(mFd);//串口输出流

 }

 // Getters and setters

 public InputStream getInputStream() {

  return mFileInputStream;

 }

 public OutputStream getOutputStream() {

  return mFileOutputStream;

 }

 // JNI

 private native static FileDescriptor open(String path, int baudrate, int flags);//c文件中的串口open()函数

 public native void close();//c文件中的串口close()函数

 static {

  System.loadLibrary("serial_port");//加载串口库

 }

}

}

public abstract class ServerData {

 protected SerialPort mSerialPort;

 protected OutputStream mOutputStream;

 private InputStream mInputStream;

 private ReadThread mReadThread;

 private class ReadThread extends Thread {

  @Override

  //在线程中读取数据并处理数据

  public void run() {

   super.run();

   byte[] buffer = new byte[128];

   int size;

   while(true) {

    try {

     if (mInputStream == null) return;

     size = mInputStream.read(buffer);//读取数据

     if (size > 0) {

      onDataReceived(buffer, size);//处理数据

     }

    } catch (IOException e) {

     e.printStackTrace();

     return;

    }

   }

  }

 }

4.实例化串口类，输出流和输入流，实例化读取线程并开始执行该线程

[code]

 public ServerData(String path, int baudrate){

  try {

   mSerialPort = new SerialPort(new File(path), baudrate, 0); 

   mOutputStream = mSerialPort.getOutputStream();

   mInputStream = mSerialPort.getInputStream();

   /* Create a receiving thread */

   mReadThread = new ReadThread();

   mReadThread.start();

  } catch (SecurityException e) {

  } catch (IOException e) {

  } catch (InvalidParameterException e) {

  }

 }

 protected abstract void onDataReceived(final byte[] buffer, final int size);

}

package View;

//导入R类，所在包不同，不能直接饮用，需要导入才可以使用

import android_serialport_api.sample.R;

/* EtcView类，Etc界面管理 */

public class SerialView {

 private Activity context = null;

 private Serial mEtcServer = null;

 /* Etc界面构造函数 */

 public SerialView(Activity context) {

  this.context = context;

 }

 public void EtcInitView() {

  //这样才可以找到android_serialport_api.sample包下的id

  TextView mytext=(TextView)context.findViewById(R.id.mytext);

  mEtcServer = new Serial("/dev/s3c2410_serial3", 9600);

 }

 public void EtcRefresh() {

  //返回串口线程读取的数据

  byte[] buffer = mEtcServer.getdata();

  String recString=new String(buffer);//将byte[]的数组转换成字符串string

  mytext.setText(recString);//设置字符文本

  buffer = null;

 }

}