Android串口通信實例分析【附源碼】

Android 串口通信實例分析，用的時開源的android-serialport-api

這個是用android ndk實現的串口通信，我把他做了一個簡化，適合於一般的程序的串口通信移植，歡迎拍磚～～～～～～～～～

先說jni接口吧，原本文件太多，其實只需要SerialPort.c和Android.mk就可以實現

Serialport.c

1. #include <stdio.h>
2. #include <stdlib.h>
3. #include <unistd.h>
4. #include <sys/types.h>
5. #include <sys/stat.h>
6. #include <fcntl.h>
7. #include <termios.h>
8. #include <errno.h>
9. #include <jni.h>
10. #include <android/log.h>
12. #define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "", __VA_ARGS__))//在logcat上打印信息用
13. //#define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, TAG, fmt, ##args)
14. //#define LOGE(fmt, args...) __android_log_print(ANDROID_LOG_ERROR, TAG, fmt, ##args)
16. static speed_t getBaudrate(jint baudrate)
17. {
18. switch(baudrate) {
19. case 0: return B0;
20. case 50: return B50;
21. case 75: return B75;
22. case 110: return B110;
23. case 134: return B134;
24. case 150: return B150;
25. case 200: return B200;
26. case 300: return B300;
27. case 600: return B600;
28. case 1200: return B1200;
29. case 1800: return B1800;
30. case 2400: return B2400;
31. case 4800: return B4800;
32. case 9600: return B9600;
33. case 19200: return B19200;
34. case 38400: return B38400;
35. case 57600: return B57600;
36. case 115200: return B115200;
37. case 230400: return B230400;
38. case 460800: return B460800;
39. case 500000: return B500000;
40. case 576000: return B576000;
41. case 921600: return B921600;
42. case 1000000: return B1000000;
43. case 1152000: return B1152000;
44. case 1500000: return B1500000;
45. case 2000000: return B2000000;
46. case 2500000: return B2500000;
47. case 3000000: return B3000000;
48. case 3500000: return B3500000;
49. case 4000000: return B4000000;
50. default: return -1;
51. }
52. }
54. /*
55. * Class: com.huangcheng.serial.SerialPort
56. * Method: open
57. * Signature: (Ljava/lang/String;II)Ljava/io/FileDescriptor;
58. *
59. * 用於打開串口，配置串口參數，包括的參數有path(需要打開的串口設備文件路徑)，baudrate(波特率),flags(打開串口的參數，如O_NONBLOCK之類的，可以隨不同情況設置)
60. * 其串口數據的讀取是用FileDescriptor來實現的
61. *
62. */
63. JNIEXPORT jobject JNICALL Java_com_huangcheng_serial_SerialPort_open
64. (JNIEnv *env, jclass thiz, jstring path, jint baudrate, jint flags)
65. {
66. int fd;
67. speed_t speed;
68. jobject mFileDescriptor;
70. /* Check arguments */
71. {
72. speed = getBaudrate(baudrate);
73. if (speed == -1) {
74. /* TODO: throw an exception */
75. LOGI("Invalid baudrate");
76. return NULL;
77. }
78. }
80. /* Opening device */
81. {
82. jboolean iscopy;
83. const char *path_utf = (*env)->GetStringUTFChars(env, path, &iscopy);
84. LOGI("Opening serial port %s with flags 0x%x", path_utf, O_RDWR | flags);
85. fd = open(path_utf, O_RDWR | flags);
86. LOGI("open() fd = %d", fd);
87. (*env)->ReleaseStringUTFChars(env, path, path_utf);
88. if (fd == -1)
89. {
90. /* Throw an exception */
91. LOGI("Cannot open port");
92. /* TODO: throw an exception */
93. return NULL;
94. }
95. }
97. /* Configure device */
98. {
99. struct termios cfg;
100. LOGI("Configuring serial port");
101. if (tcgetattr(fd, &cfg))
102. {
103. LOGI("tcgetattr() failed");
104. close(fd);
105. /* TODO: throw an exception */
106. return NULL;
107. }
109. cfmakeraw(&cfg);
110. cfsetispeed(&cfg, speed);
111. cfsetospeed(&cfg, speed);
113. if (tcsetattr(fd, TCSANOW, &cfg))
114. {
115. LOGI("tcsetattr() failed");
116. close(fd);
117. /* TODO: throw an exception */
118. return NULL;
119. }
120. }
122. /* Create a corresponding file descriptor */
123. {
124. jclass cFileDescriptor = (*env)->FindClass(env, "java/io/FileDescriptor");
125. jmethodID iFileDescriptor = (*env)->GetMethodID(env, cFileDescriptor, "<init>", "()V");
126. jfieldID descriptorID = (*env)->GetFieldID(env, cFileDescriptor, "descriptor", "I");
127. mFileDescriptor = (*env)->NewObject(env, cFileDescriptor, iFileDescriptor);
128. (*env)->SetIntField(env, mFileDescriptor, descriptorID, (jint)fd);
129. }
131. return mFileDescriptor;
132. }
134. /*
135. * Class: com.huangcheng.serial.SerialPort
136. * Method: close
137. * Signature: ()V
138. *
139. * 用於串口關閉
140. */
141. JNIEXPORT void JNICALL Java_com_huangcheng_serial_SerialPort_close
142. (JNIEnv *env, jobject thiz)
143. {
144. jclass SerialPortClass = (*env)->GetObjectClass(env, thiz);
145. jclass FileDescriptorClass = (*env)->FindClass(env, "java/io/FileDescriptor");
147. jfieldID mFdID = (*env)->GetFieldID(env, SerialPortClass, "mFd", "Ljava/io/FileDescriptor;");
148. jfieldID descriptorID = (*env)->GetFieldID(env, FileDescriptorClass, "descriptor", "I");
150. jobject mFd = (*env)->GetObjectField(env, thiz, mFdID);
151. jint descriptor = (*env)->GetIntField(env, mFd, descriptorID);
153. LOGI("close(fd = %d)", descriptor);
154. close(descriptor);
155. }