电子/物联 Android中通过串口操作蓝牙

文章目录 [隐藏]

本文档针对特定Android开发板-Pad-整理。Pad中集成了一个蓝牙Mesh模块；Pad默认开放了蓝牙广播，名称为“UART”。
新安装的蓝牙模块在Android系统中映射为一个串口文件，所以操作这个蓝牙模块转变为对串口的操作，形式上就是读和写。

一.Android板

1.依赖

这里使用了一个第三方库。


dependencies {
   implementation "com.deemons.serialport:serialport:1.2.0"
}

dependencies {

implementation "com.deemons.serialport:serialport:1.2.0"

}

2.必须的root权限


private boolean requestRootPermission() {
   Process process = null;
   DataOutputStream os = null;
   try {
       String cmd = "chmod 777 /dev/ttyS4";       // 目标串口文件
       process = Runtime.getRuntime().exec("su"); // 切换到root帐号
       os = new DataOutputStream(process.getOutputStream());
       os.writeBytes(cmd + "\n");
       os.writeBytes("exit\n");
       os.flush();
       process.waitFor();
   } catch (Exception e) {
       return false;
   } finally {
       try {
           if (os != null) {
               os.close();
           }
           process.destroy();
       } catch (Exception e) {
       }
   }
   return true;
}

private boolean requestRootPermission() {

Process process = null;

DataOutputStream os = null;

try {

String cmd = "chmod 777 /dev/ttyS4"; // 目标串口文件

process = Runtime.getRuntime().exec("su"); // 切换到root帐号

os = new DataOutputStream(process.getOutputStream());

os.writeBytes(cmd + "\n");

os.writeBytes("exit\n");

os.flush();

process.waitFor();

} catch (Exception e) {

return false;

} finally {

try {

if (os != null) {

os.close();

}

process.destroy();

} catch (Exception e) {

}

return true;

}

3.初始化串口


try {
   SerialPort.setSuPath("/system/bin/su"); // root文件路径

   //SerialPortFinder serialPortFinder = new SerialPortFinder();
   //String[] allDevices = serialPortFinder.getAllDevices();
   //String[] allDevicesPath = serialPortFinder.getAllDevicesPath();
   //
   //for (int i = 0; i < allDevices.length; i++) {
   //    String device1 = allDevices[i];
   //    Log.e("ard", "设备：" + device1);
   //}
   //for (int i = 0; i < allDevicesPath.length; i++) {
   //    String path = allDevicesPath[i];
   //    Log.e("ard", "Path：" + path);
   //}

   File device = new File("/dev/ttyS4");// 对应特定的蓝牙串口设备文件
   int baudRate = 115200;               // 波特率
   int parity = 0;                      // 奇偶校验，0 None（默认）； 1 Odd； 2 Even
   int dataBits = 8;                    // 数据位，5 ~ 8  （默认8）
   int stopBit = 1;                     // 停止位，1 或 2  （默认 1）
   int flags = 0;                       // 标记 0（默认）
   serialPort = new SerialPort(device, baudRate, parity, dataBits, stopBit, flags);

   inputStream = serialPort.getInputStream();   // 读串口的通道
   outputStream = serialPort.getOutputStream(); // 写串口的通道

} catch (IOException e) {
   e.printStackTrace();
   Log.e("ard", "IOException：" + e.getMessage());
}

try {

SerialPort.setSuPath("/system/bin/su"); // root文件路径

//SerialPortFinder serialPortFinder = new SerialPortFinder();

//String[] allDevices = serialPortFinder.getAllDevices();

//String[] allDevicesPath = serialPortFinder.getAllDevicesPath();

//for (int i = 0; i < allDevices.length; i++) {

// String device1 = allDevices[i];

// Log.e("ard", "设备：" + device1);

//}

//for (int i = 0; i < allDevicesPath.length; i++) {

// String path = allDevicesPath[i];

// Log.e("ard", "Path：" + path);

//}

File device = new File("/dev/ttyS4");// 对应特定的蓝牙串口设备文件

int baudRate = 115200; // 波特率

int parity = 0; // 奇偶校验，0 None（默认）； 1 Odd； 2 Even

int dataBits = 8; // 数据位，5 ~ 8 （默认8）

int stopBit = 1; // 停止位，1 或 2 （默认 1）

int flags = 0; // 标记 0（默认）

serialPort = new SerialPort(device, baudRate, parity, dataBits, stopBit, flags);

inputStream = serialPort.getInputStream(); // 读串口的通道

outputStream = serialPort.getOutputStream(); // 写串口的通道

} catch (IOException e) {

e.printStackTrace();

Log.e("ard", "IOException：" + e.getMessage());

}

4.向串口写数据-写给蓝牙


try {
   String string = messageEditText.getText().toString();
   if (!TextUtils.isEmpty(string)) {
       string = string.trim();
   } else {
       string = "123456";
   }

   byte[] bytes = hexToByteArray(string2HexString(string)); // 目标设备收到这个bytes，先转为16进制字符串，再从16进制转为字符串
   bytes = hexToByteArray(string); // 这里要求string即一个16进制字符串。每个元素取值为0-f。

   outputStream.write(bytes);
   outputStream.flush();
} catch (IOException e) {
   e.printStackTrace();
   Log.e("ard", "IOException：" + e.getMessage());
}

try {

String string = messageEditText.getText().toString();

if (!TextUtils.isEmpty(string)) {

string = string.trim();

} else {

string = "123456";

}

byte[] bytes = hexToByteArray(string2HexString(string)); // 目标设备收到这个bytes，先转为16进制字符串，再从16进制转为字符串

bytes = hexToByteArray(string); // 这里要求string即一个16进制字符串。每个元素取值为0-f。

outputStream.write(bytes);

outputStream.flush();

} catch (IOException e) {

e.printStackTrace();

Log.e("ard", "IOException：" + e.getMessage());

}

5.从串口读数据-接收蓝牙收到的消息


try {
   while (!isDestroyed()) {
       byte[] buffer = new byte[64];
       if (inputStream == null)
           return;

       int size = inputStream.read(buffer);
       if (size > 0) {
           byte[] bRec = new byte[size];
           for (int i = 0; i < size; i++) {
               byte bf = buffer[i];
               bRec[i] = bf;
           }

           String hex = bytesToHex(bRec);
           Log.e("ard", "通过串口收到蓝牙消息：" + hex);
       }
   }
   Log.e("ard", "recordRunalbe结束");
} catch (IOException e) {
   e.printStackTrace();
   Log.e("ard", "IOException：" + e.getMessage());
}

try {

while (!isDestroyed()) {

byte[] buffer = new byte[64];

if (inputStream == null)

return;

int size = inputStream.read(buffer);

if (size > 0) {

byte[] bRec = new byte[size];

for (int i = 0; i < size; i++) {

byte bf = buffer[i];

bRec[i] = bf;

}

String hex = bytesToHex(bRec);

Log.e("ard", "通过串口收到蓝牙消息：" + hex);

}

Log.e("ard", "recordRunalbe结束");

} catch (IOException e) {

e.printStackTrace();

Log.e("ard", "IOException：" + e.getMessage());

}

6.辅助函数


private String string2HexString(String targert) {
   return strTo16(string2Unicode(targert));
}

/**
* 字符串转换unicode
*/
private String string2Unicode(String string) {
   StringBuffer unicode = new StringBuffer();
   for (int i = 0; i < string.length(); i++) {
       // 取出每一个字符
       char c = string.charAt(i);
       // 转换为unicode
       unicode.append("\\u" + Integer.toHexString(c));
   }
   return unicode.toString();
}

/**
* 字符串转化成为16进制字符串
*/
private String strTo16(String s) {
   String str = "";
   for (int i = 0; i < s.length(); i++) {
       int ch = (int) s.charAt(i);
       String s4 = Integer.toHexString(ch);
       str = str + s4;
   }
   return str;
}

private byte[] hexToByteArray(String inHex) {
   int hexlen = inHex.length();
   byte[] result;
   if (hexlen % 2 == 1) {
       //奇数
       hexlen++;
       result = new byte[(hexlen / 2)];
       inHex = "0" + inHex;
   } else {
       //偶数
       result = new byte[(hexlen / 2)];
   }
   int j = 0;
   for (int i = 0; i < hexlen; i += 2) {
       result[j] = (byte) Integer.parseInt((inHex.substring(i, i + 2)), 16);
       j++;
   }
   return result;
}

private String bytesToHex(byte[] bytes) {
   StringBuffer sb = new StringBuffer();
   for (int i = 0; i < bytes.length; i++) {
       String hex = Integer.toHexString(bytes[i] & 0xFF);
       if (hex.length() < 2) {
           sb.append(0);
       }
       sb.append(hex);
   }
   return sb.toString();
}

private String string2HexString(String targert) {

return strTo16(string2Unicode(targert));

}

/**

* 字符串转换unicode

private String string2Unicode(String string) {

StringBuffer unicode = new StringBuffer();

for (int i = 0; i < string.length(); i++) {

// 取出每一个字符

char c = string.charAt(i);

// 转换为unicode

unicode.append("\\u" + Integer.toHexString(c));

}

return unicode.toString();

}

/**

* 字符串转化成为16进制字符串

private String strTo16(String s) {

String str = "";

for (int i = 0; i < s.length(); i++) {

int ch = (int) s.charAt(i);

String s4 = Integer.toHexString(ch);

str = str + s4;

}

return str;

}

private byte[] hexToByteArray(String inHex) {

int hexlen = inHex.length();

byte[] result;

if (hexlen % 2 == 1) {

//奇数

hexlen++;

result = new byte[(hexlen / 2)];

inHex = "0" + inHex;

} else {

//偶数

result = new byte[(hexlen / 2)];

}

int j = 0;

for (int i = 0; i < hexlen; i += 2) {

result[j] = (byte) Integer.parseInt((inHex.substring(i, i + 2)), 16);

j++;

}

return result;

}

private String bytesToHex(byte[] bytes) {

StringBuffer sb = new StringBuffer();

for (int i = 0; i < bytes.length; i++) {

String hex = Integer.toHexString(bytes[i] & 0xFF);

if (hex.length() < 2) {

sb.append(0);

}

sb.append(hex);

}

return sb.toString();

}

二.手机

手机可以使用原生api连接“UART”，获取其Service（00000001）和此Service下的Characteristic（00000002）及Characteristic（00000003）。对蓝牙的写操作在00000002上，获取蓝牙的消息须打开00000003的Descriptor（00002902）的通知权限。


BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));
boolean b = descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
boolean b1 = currentBluetoothGatt.writeDescriptor(descriptor);
currentBluetoothGatt.setCharacteristicNotification(characteristic, true);

BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));

boolean b = descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);

boolean b1 = currentBluetoothGatt.writeDescriptor(descriptor);

currentBluetoothGatt.setCharacteristicNotification(characteristic, true);

向Android板发收消息同之前的手环操作。可参考http://www.gaohaiyan.com/2256.html

声明

本文由 cuiweiyou 原创，转载请注明出处：http://www.gaohaiyan.com/2259.html

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