Android 串口通信

   可以使用开源usb-serial-for-android 库进行串口通信

1. 添加 usb-serial-for-android 依赖项到项目中。在项目的 build.gradle 文件中添加以下内容：

dependencies {// 其他依赖项...implementation 'com.github.mik3y:usb-serial-for-android:3.5.1'// 其他依赖项...
}

2、在AndroidManifest.xml 文件中添加 USB 权限声明：

<uses-permission android:name="android.permission.USB_PERMISSION" />

  3. 创建一个类来处理串口通信：

import android.content.Context;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbManager;import com.hoho.android.usbserial.driver.CdcAcmSerialDriver;
import com.hoho.android.usbserial.driver.ProbeTable;
import com.hoho.android.usbserial.driver.UsbSerialDriver;
import com.hoho.android.usbserial.driver.UsbSerialPort;
import com.hoho.android.usbserial.driver.UsbSerialProber;import java.io.IOException;
import java.util.List;public class USBSerialHelper {private UsbManager usbManager;private UsbSerialPort usbSerialPort;private UsbDeviceConnection connection;private OnDataReceivedListener onDataReceivedListener;private ReadThread readThread;public interface OnDataReceivedListener {void onDataReceived(byte[] data);}public USBSerialHelper(Context context, OnDataReceivedListener listener) {usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);onDataReceivedListener = listener;}public void openDevice() throws IOException {ProbeTable customTable = new ProbeTable();customTable.addProduct(0x2341, 0x0043, CdcAcmSerialDriver.class);UsbSerialProber prober = new UsbSerialProber(customTable);List<UsbSerialDriver> availableDrivers = prober.findAllDrivers(usbManager);if (!availableDrivers.isEmpty()) {UsbSerialDriver driver = availableDrivers.get(0);UsbDevice device = driver.getDevice();connection = usbManager.openDevice(device);usbSerialPort = driver.getPorts().get(0);usbSerialPort.open(connection);usbSerialPort.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);readThread = new ReadThread();readThread.start();} else {throw new IOException("No USB serial device found");}}public void closeDevice() {if (readThread != null) {readThread.interrupt();readThread = null;}if (usbSerialPort != null) {try {usbSerialPort.close();} catch (IOException e) {e.printStackTrace();}usbSerialPort = null;}if (connection != null) {connection.close();connection = null;}}public void sendData(byte[] data) throws IOException {if (usbSerialPort != null) {usbSerialPort.write(data, 1000);}}private class ReadThread extends Thread {@Overridepublic void run() {byte[] buffer = new byte[1024];int numBytes;while (!isInterrupted()) {try {numBytes = usbSerialPort.read(buffer, 1000);if (numBytes > 0) {byte[] data = new byte[numBytes];System.arraycopy(buffer, 0, data, 0, numBytes);onDataReceivedListener.onDataReceived(data);}} catch (IOException e) {e.printStackTrace();break;}}}
}

4. 在代码中使用串口通信类：

public class MainActivity extends AppCompatActivity implements USBSerialHelper.OnDataReceivedListener {private USBSerialHelper usbSerialHelper;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);usbSerialHelper = new USBSerialHelper(this, this);try {usbSerialHelper.openDevice();} catch (IOException e) {e.printStackTrace();}// 示例：发送数据byte[] sendData = "Hello, USB!".getBytes();try {usbSerialHelper.sendData(sendData);} catch (IOException e) {e.printStackTrace();}}@Overrideprotected void onDestroy() {super.onDestroy();usbSerialHelper.closeDevice();}@Overridepublic void onDataReceived(byte[] data) {// 处理接收到的数据String receivedData = new String(data);Log.d("USBSerialHelper", "Received data: " + receivedData);}
}

在 MainActivity 的 onCreate() 方法中创建了一个 USBSerialHelper 实例，并调用 openDevice() 方法打开 USB 设备进行通信。

然后，使用 sendData() 方法发送数据到 USB 设备。将字符串 "Hello, USB!" 转换为字节数组，并发送给 USB 设备。

最后，在 onDataReceived() 方法中处理接收到的数据。将接收到的字节数组转换为字符串，并打印到日志中。

请确保在使用之前已经获取了 USB 权限，并根据实际的 USB 设备进行相应的配置（例如波特率、数据位、停止位、校验位等）。