Android中怎么实现串口读写
这篇文章给大家介绍Android中怎么实现串口读写，内容非常详细，感兴趣的小伙伴们可以参考借鉴，希望对大家能有所帮助。
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1、SerialPort.cpp
#include#include #include #include #include #include #include #include #include #include #include #include "android/log.h" static const char *TAG = "serial_port"; #define LOGI(fmt, args...) __android_log_print(ANDROID_LOG_INFO, TAG, fmt, ##args) #define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, TAG, fmt, ##args) #define LOGE(fmt, args...) __android_log_print(ANDROID_LOG_ERROR, TAG, fmt, ##args) static speed_t getBaudrate(jint baudrate) { switch (baudrate) { case 0: return B0; case 50: return B50; case 75: return B75; case 110: return B110; case 134: return B134; case 150: return B150; case 200: return B200; case 300: return B300; case 600: return B600; case 1200: return B1200; case 1800: return B1800; case 2400: return B2400; case 4800: return B4800; case 9600: return B9600; case 19200: return B19200; case 38400: return B38400; case 57600: return B57600; case 115200: return B115200; case 230400: return B230400; case 460800: return B460800; case 500000: return B500000; case 576000: return B576000; case 921600: return B921600; case 1000000: return B1000000; case 1152000: return B1152000; case 1500000: return B1500000; case 2000000: return B2000000; case 2500000: return B2500000; case 3000000: return B3000000; case 3500000: return B3500000; case 4000000: return B4000000; default: return -1; } } /* * Class: cedric_serial_SerialPort * Method: open * Signature: (Ljava/lang/String;)V */ JNIEXPORT jobject JNICALL native_open(JNIEnv *env, jobject thiz, jstring path,jint baudrate) { int fd; speed_t speed; jobject mFileDescriptor; LOGD("init native Check arguments"); /* Check arguments */ { speed = getBaudrate(baudrate); if (speed == -1) { /* TODO: throw an exception */ LOGE("Invalid baudrate"); return NULL; } } LOGD("init native Opening device!"); /* Opening device */ { jboolean iscopy; const char *path_utf = env->GetStringUTFChars(path, &iscopy); LOGD("Opening serial port %s", path_utf); // fd = open(path_utf, O_RDWR | O_DIRECT | O_SYNC); fd = open(path_utf, O_RDWR | O_NOCTTY | O_NONBLOCK | O_NDELAY); LOGD("open() fd = %d", fd); env->ReleaseStringUTFChars(path, path_utf); if (fd == -1) { /* Throw an exception */ LOGE("Cannot open port %d",baudrate); /* TODO: throw an exception */ return NULL; } } LOGD("init native Configure device!"); /* Configure device */ { struct termios cfg; if (tcgetattr(fd, &cfg)) { LOGE("Configure device tcgetattr() failed 1"); close(fd); return NULL; } cfmakeraw(&cfg); cfsetispeed(&cfg, speed); cfsetospeed(&cfg, speed); if (tcsetattr(fd, TCSANOW, &cfg)) { LOGE("Configure device tcsetattr() failed 2"); close(fd); /* TODO: throw an exception */ return NULL; } } /* Create a corresponding file descriptor */ { jclass cFileDescriptor = env->FindClass("java/io/FileDescriptor"); jmethodID iFileDescriptor = env->GetMethodID(cFileDescriptor," ", "()V"); jfieldID descriptorID = env->GetFieldID(cFileDescriptor,"descriptor", "I"); mFileDescriptor = env->NewObject(cFileDescriptor,iFileDescriptor); env->SetIntField(mFileDescriptor, descriptorID, (jint) fd); } return mFileDescriptor; } /* * Class: cedric_serial_SerialPort * Method: close * Signature: ()V */ JNIEXPORT jint JNICALL native_close(JNIEnv * env, jobject thiz) { jclass SerialPortClass = env->GetObjectClass(thiz); jclass FileDescriptorClass = env->FindClass("java/io/FileDescriptor"); jfieldID mFdID = env->GetFieldID(SerialPortClass, "mFd", "Ljava/io/FileDescriptor;"); jfieldID descriptorID = env->GetFieldID(FileDescriptorClass, "descriptor", "I"); jobject mFd = env->GetObjectField(thiz, mFdID); jint descriptor = env->GetIntField(mFd, descriptorID); LOGD("close(fd = %d)", descriptor); close(descriptor); return 1; } static JNINativeMethod gMethods[] = { { "open", "(Ljava/lang/String;I)Ljava/io/FileDescriptor;",(void*) native_open }, { "close", "()I",(void*) native_close }, }; /* * 为某一个类注册本地方法 */ static int registerNativeMethods(JNIEnv* env, const char* className, JNINativeMethod* gMethods, int numMethods) { jclass clazz; clazz = env->FindClass(className); if (clazz == NULL) { return JNI_FALSE; } if (env->RegisterNatives(clazz, gMethods, numMethods) < 0) { return JNI_FALSE; } return JNI_TRUE; } /* * 为所有类注册本地方法 */ static int registerNatives(JNIEnv* env) { const char* kClassName = "com/jerome/serialport/SerialPort"; //指定要注册的类 return registerNativeMethods(env, kClassName, gMethods, sizeof(gMethods) / sizeof(gMethods[0])); } /* * System.loadLibrary("lib")时调用 * 如果成功返回JNI版本, 失败返回-1 */ JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM* vm, void* reserved) { JNIEnv* env = NULL; jint result = -1; if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) { return -1; } assert(env != NULL); if (!registerNatives(env)) { //注册 return -1; } //成功 result = JNI_VERSION_1_4; return result; }
在编译时注意修改const char* kClassName = "com/jerome/serialport/SerialPort";为你Java层与jni对应得包名；
2、Android.mk
LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) TARGET_PLATFORM := android-3 LOCAL_MODULE := serial_port LOCAL_SRC_FILES := SerialPort.cpp LOCAL_LDLIBS := -llog include $(BUILD_SHARED_LIBRARY)
如果要修改生成so文件的名称，请修改LOCAL_MODULE := serial_port
3、SerialPort.java
package com.jerome.serialport;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class SerialPort {
private static final String TAG = "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;
public SerialPort(File device, int baudrate) throws SecurityException, IOException {
mFd = open(device.getAbsolutePath(), baudrate);
if (mFd == null) {
throw new IOException();
}
mFileInputStream = new FileInputStream(mFd);
mFileOutputStream = new FileOutputStream(mFd);
}
public InputStream getInputStream() {
return mFileInputStream;
}
public OutputStream getOutputStream() {
return mFileOutputStream;
}
private native FileDescriptor open(String path, int baudrate);
public native int close();
static {
System.loadLibrary("serial_port");
}
}4、SerialPortUtil.java
package com.jerome.serialport;
import java.io.BufferedWriter;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
/**
* 串口操作类
*
* @author Jerome
*
*/
public class SerialPortUtil {
private String TAG = SerialPortUtil.class.getSimpleName();
private SerialPort mSerialPort;
private OutputStream mOutputStream;
private InputStream mInputStream;
private ReadThread mReadThread;
private String path = "/dev/ttyMT1";
private int baudrate = 115200;
private static SerialPortUtil portUtil;
private OnDataReceiveListener onDataReceiveListener = null;
private boolean isStop = false;
public interface OnDataReceiveListener {
public void onDataReceive(byte[] buffer, int size);
}
public void setOnDataReceiveListener(
OnDataReceiveListener dataReceiveListener) {
onDataReceiveListener = dataReceiveListener;
}
public static SerialPortUtil getInstance() {
if (null == portUtil) {
portUtil = new SerialPortUtil();
portUtil.onCreate();
}
return portUtil;
}
/**
* 初始化串口信息
*/
public void onCreate() {
try {
mSerialPort = new SerialPort(new File(path), baudrate);
mOutputStream = mSerialPort.getOutputStream();
mInputStream = mSerialPort.getInputStream();
mReadThread = new ReadThread();
isStop = false;
mReadThread.start();
} catch (Exception e) {
e.printStackTrace();
}
initBle();
}
/**
* 发送指令到串口
*
* @param cmd
* @return
*/
public boolean sendCmds(String cmd) {
boolean result = true;
byte[] mBuffer = (cmd+"\r\n").getBytes();
//注意：我得项目中需要在每次发送后面加\r\n，大家根据项目项目做修改，也可以去掉，直接发送mBuffer
try {
if (mOutputStream != null) {
mOutputStream.write(mBuffer);
} else {
result = false;
}
} catch (IOException e) {
e.printStackTrace();
result = false;
}
return result;
}
public boolean sendBuffer(byte[] mBuffer) {
boolean result = true;
String tail = "\r\n";
byte[] tailBuffer = tail.getBytes();
byte[] mBufferTemp = new byte[mBuffer.length+tailBuffer.length];
System.arraycopy(mBuffer, 0, mBufferTemp, 0, mBuffer.length);
System.arraycopy(tailBuffer, 0, mBufferTemp, mBuffer.length, tailBuffer.length);
//注意：我得项目中需要在每次发送后面加\r\n，大家根据项目项目做修改，也可以去掉，直接发送mBuffer
try {
if (mOutputStream != null) {
mOutputStream.write(mBufferTemp);
} else {
result = false;
}
} catch (IOException e) {
e.printStackTrace();
result = false;
}
return result;
}
private class ReadThread extends Thread {
@Override
public void run() {
super.run();
while (!isStop && !isInterrupted()) {
int size;
try {
if (mInputStream == null)
return;
byte[] buffer = new byte[512];
size = mInputStream.read(buffer);
if (size > 0) {
if(MyLog.isDyeLevel()){
MyLog.log(TAG, MyLog.DYE_LOG_LEVEL, "length is:"+size+",data is:"+new String(buffer, 0, size));
}
if (null != onDataReceiveListener) {
onDataReceiveListener.onDataReceive(buffer, size);
}
}
Thread.sleep(10);
} catch (Exception e) {
e.printStackTrace();
return;
}
}
}
}
/**
* 关闭串口
*/
public void closeSerialPort() {
sendShellCommond1();
isStop = true;
if (mReadThread != null) {
mReadThread.interrupt();
}
if (mSerialPort != null) {
mSerialPort.close();
}
}
}5、使用方法：
a、配置ndk开发环境，具体百度一下；
b、工程根目录下新建jni文件夹，将Android.mk和SerialPort.cpp放进去；
c、ndk中进入jni目录，编译生成so文件，默认so生成在libs/armeabi下；
d、新建com.jerom.serialport目录，将SerialPort和SerialPortUtil放进去；
f、在你要使用的地方初始化SerialPortUtil，实现回调接口OnDataReceiveListener即可接受数据；
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