本人使用环境

CH340转接头

Android5.1，RK3188

Android6.0，RK3288

关于CH34官方的jar包与使用存在的问题(官方地址)

最大的问题是无法修改串口波特率，一直以19200运行，但我的传感器为9600,理论上应该可以修改，可是就连官方的APK都无法修改，我只好另寻他发

最终解决方案

初始化

在你的build.gradle(project)中添加

allprojects {

repositories {

...

maven { url 'https://jitpack.io' }

}

}

添加依赖

dependencies {

implementation 'com.github.mik3y:usb-serial-for-android:2.2.2'

}

添加权限

在res/xml/下添加 device_filter.xml，CH340官网的工程Demo内也有。并要在AndroidManifest中补全代码

android:name="..."

...>

android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"

android:resource="@xml/device_filter" />

使用

创建单独的温度传感器类

class TemperMoudle {

private final static String TAG = "MainActivity";

private static final int TEMPERATURE_USB_VENDOR_ID = 6790; //供应商id

private static final int TEMPERATURE_USB_PRODUCT_ID = 29987; //产品id

private Context context;

private List usbSerialDrivers = null;

private List usbSerialPorts = new ArrayList<>();

private UsbSerialPort temperatureUsbPort = null;

private SerialInputOutputManager serialIoManager;

private SerialInputOutputManager.Listener serialListener;

private ExecutorService executor = Executors.newSingleThreadExecutor();

TemperMoudle(Context context) {

this.context = context;

}

/**

* 初始化，获取目标端口

*/

UsbSerialPort init(SerialInputOutputManager.Listener listener) {

this.serialListener = listener;

//获取全部设备

UsbManager usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);

if (usbManager != null) {

usbSerialDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(usbManager);

}

//获取全部端口

if (usbSerialDrivers != null) {

for (UsbSerialDriver driver : usbSerialDrivers) {

usbSerialPorts.addAll(driver.getPorts());

}

}

//校验端口设备，获得目标端口

for (UsbSerialPort port : usbSerialPorts) {

UsbDevice device = port.getDriver().getDevice();

if (device.getVendorId() == TEMPERATURE_USB_VENDOR_ID && device.getProductId() == TEMPERATURE_USB_PRODUCT_ID) {

UsbDeviceConnection connection = usbManager.openDevice(device);

try {

temperatureUsbPort = port;

temperatureUsbPort.open(connection);

temperatureUsbPort.setParameters(9600, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);

//我这里需要开启RTS,否则无法读取数据，但务必记得在temperatureUsbPort.close之前置位false，否则再次启动程序无法读取端口！

temperatureUsbPort.setRTS(true);

} catch (IOException e) {

Log.e(TAG, "打开端口失败");

try {

temperatureUsbPort.setRTS(false);

temperatureUsbPort.close();

} catch (IOException e2) {

e.printStackTrace();

}

}

}

}

return temperatureUsbPort;

}

/**

* 设置数据监听器

*

* @param listener 监听器

*/

void setSerialListener(SerialInputOutputManager.Listener listener) {

this.serialListener = listener;

}

private void startIoManager() {

if (temperatureUsbPort != null) {

serialIoManager = new SerialInputOutputManager(temperatureUsbPort, serialListener);

executor.submit(serialIoManager);

}

}

private void stopIoManager() {

if (serialIoManager != null) {

serialIoManager.stop();

serialIoManager = null;

}

}

/**

* 重新开启USB管理器

*/

void onDeviceStateChange() {

stopIoManager();

startIoManager();

}

void onPause() {

stopIoManager();

if (temperatureUsbPort != null) {

try {

temperatureUsbPort.setRTS(false);

temperatureUsbPort.close();

temperatureUsbPort = null;

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

主函数使用

TemperMoudle temperMoudle;

UsbSerialPort temperUsbPort;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//获取温度传感器数据端口

temperMoudle = new TemperMoudle(this);

temperUsbPort = temperMoudle.init(temperListener);

//发送查询温度的指令

if (temperUsbPort != null) {

try {

temperUsbPort.write(Str16ToBytes("01 03 00 00 00 01 84 0A", " "), 200);

} catch (IOException e) {

e.printStackTrace();

}

}

}

/**

* 监听USB端口数据

*/

SerialInputOutputManager.Listener temperListener = new SerialInputOutputManager.Listener() {

@Override

public void onNewData(byte[] data) {

String[] dataStrings = BytesToStrs16(data);

for (String dataString : dataStrings) {

Log.d(TAG, "dataString: " + dataString);

}

}

@Override

public void onRunError(Exception e) {

e.printStackTrace();

}

};

/**

* 用于检测usb插入状态的BroadcasReceiver

*/

private final BroadcastReceiver usbReceiver = new BroadcastReceiver() {

public void onReceive(Context context, Intent intent) {

if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(intent.getAction())) {

Log.e(TAG, "设备移除");

temperMoudle.onPause();

finish();

}

}

};

@Override

protected void onResume() {

super.onResume();

IntentFilter usbFilter = new IntentFilter();

usbFilter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);

registerReceiver(usbReceiver, usbFilter);

temperMoudle.onDeviceStateChange();

}

@Override

protected void onPause() {

super.onPause();

temperMoudle.onPause();

unregisterReceiver(usbReceiver);

}

/**

* 16进制字符串转byte数组

*

* @param str 需要转换的字符串

* @param splitChare 中断间隔符

* @return 转换好的byte[]数组

*/

public byte[] Str16ToBytes(String str, String splitChare) {

String[] string = str.trim().split(splitChare);

byte[] bytes = new byte[string.length];

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

bytes[i] = (byte) (Integer.parseInt(string[i], 16) & 0xff);

}

return bytes;

}

/**

* 十进制bytes转16进制strings

*

* @param bytes 十进制bytes

* @return 16进制strings

*/

public String[] BytesToStrs16(byte[] bytes) {

String[] strs = new String[bytes.length];

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

strs[i] = Integer.toHexString(bytes[i] & 0xff);

}

return strs;

}