?串口通訊的步驟：
1.打開串口。
2.串口處于監(jiān)聽狀態(tài)
3.想串口寫入數(shù)據(jù)吁讨，串口接收到數(shù)據(jù)返回數(shù)據(jù)
串口的一個基本結(jié)構(gòu)：
SerialPort類所在的包一定要和上圖包名一直峦朗，因為串口通訊需要使用jni中的函數(shù)。
SerialPort類：
package android_serialport_api;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import com.fx.serialporttest.L;
public class SerialPort {
/*
* Do not remove or rename the field mFd: it is used by native method
* close();
*/
private FileDescriptor mFd;
private FileInputStream mFileInputStream;
private FileOutputStream mFileOutputStream;
/**
* 構(gòu)造方法
* @param device 串口地址
* @param baurate 波特率
* @param flags
* @throws IOException
* @throws InterruptedException
*/
public SerialPort(File device,int baudrate,int flags) {
/*
* 檢測是否有訪問權(quán)限
*/
if(!device.canRead()||!device.canWrite()){
//如果沒有讀寫權(quán)限橄维，嘗試chmod命令這個文件
L.tag("沒有讀寫權(quán)限");
Process su;
try {
su = Runtime.getRuntime().exec("/system/bin/su");//獲取root讀寫權(quán)限
String cmd = "chmod 777"+device.getAbsolutePath()+"\n"+"exit\n";
su.getOutputStream().write(cmd.getBytes()); //向此路徑文件寫入命令
if((su.waitFor()!=0||!device.canRead()||!device.canWrite())){
throw new SecurityException();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
mFd = open(device.getAbsolutePath(),baudrate,flags);
if(mFd==null){
mFd = open(device.getAbsolutePath(),baudrate,flags);
L.tag("native open return null");
}
mFileInputStream = new FileInputStream(mFd);
mFileOutputStream = new FileOutputStream(mFd);
}
public FileInputStream getmFileInputStream() {
return mFileInputStream;
}
public void setmFileInputStream(FileInputStream mFileInputStream) {
this.mFileInputStream = mFileInputStream;
}
public FileOutputStream getmFileOutputStream() {
return mFileOutputStream;
}
public void setmFileOutputStream(FileOutputStream mFileOutputStream) {
this.mFileOutputStream = mFileOutputStream;
}
//JNI
private native static FileDescriptor open(String path,int baudrate,int flags);
public native void close();
static {
System.loadLibrary("serial_port");
}
}
SerialPortFinger類：
package android_serialport_api;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import com.fx.serialporttest.L;
public? class SerialPortFinger {
private static ReadThread readThread;
private static FileInputStream mFileInputStream;
private static FileOutputStream mFileOutputStream;
static String path = "/dev/ttyS0";//設(shè)備主板的串口地址争舞，地址有所不同
public? void startListener(){
SerialPort serialPort = new SerialPort(new File(path), 9600, 0);//9600是波特率澈灼，這個也是有所不同，具體要看設(shè)備
mFileInputStream = serialPort.getmFileInputStream();
mFileOutputStream = serialPort.getmFileOutputStream();//獲取串口寫入流
readThread? = new ReadThread();
readThread.start();//開啟監(jiān)聽
}
/**
* 發(fā)送指令到串口
*
* @param cmd
* @return
*/
public boolean sendCmds(String cmd) {
boolean result = true;
byte[] mBuffer = (cmd+"\r\n").getBytes();
try {
if (mFileOutputStream != null) {
mFileOutputStream.write(mBuffer);
} else {
result = false;
}
} catch (IOException e) {
e.printStackTrace();
result = false;
}
return result;
}
static class ReadThread extends Thread{
@Override
public void run() {
// TODO Auto-generated method stub
super.run();
int len;
StringBuffer sb = new StringBuffer("");
while(true){ //循環(huán)監(jiān)聽串口，讀取返回的數(shù)據(jù)
byte[] buffer = new byte[1024];
if(mFileInputStream==null){
return;
}
try {
len = mFileInputStream.read(buffer);
if(len>0){
sb.append(new String(buffer, 0, len));
}
if(!sb.toString().equals(""))
{
L.tag(sb.toString());//收到串口的返回數(shù)據(jù)者疤，在日志中打印出來
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
L.tag("接受完成");
}
}
}
}
