Android 7.1 串口通信 - 使用 Java 和 USB API 实现读写

要在 Android 7.1 上编写一个读写串口的应用程序，你可以使用 Java 编写应用程序，并使用 Android 串口 API 进行串口通信。\n\n下面是一个简单的示例代码，用于打开和配置串口连接，并读取和写入数据：\n\njava\nimport android.hardware.usb.UsbDevice;\nimport android.hardware.usb.UsbDeviceConnection;\nimport android.hardware.usb.UsbManager;\n\nimport java.io.IOException;\nimport java.io.InputStream;\nimport java.io.OutputStream;\n\npublic class SerialPortHelper {\n private UsbManager usbManager;\n private UsbDevice usbDevice;\n private UsbDeviceConnection connection;\n private InputStream inputStream;\n private OutputStream outputStream;\n\n public SerialPortHelper(UsbManager usbManager, UsbDevice usbDevice) {\n this.usbManager = usbManager;\n this.usbDevice = usbDevice;\n }\n\n public void openSerialPort() throws IOException {\n connection = usbManager.openDevice(usbDevice);\n inputStream = connection.openInputStream();\n outputStream = connection.openOutputStream();\n }\n\n public void closeSerialPort() throws IOException {\n if (inputStream != null) {\n inputStream.close();\n }\n if (outputStream != null) {\n outputStream.close();\n }\n if (connection != null) {\n connection.close();\n }\n }\n\n public void writeData(byte[] data) throws IOException {\n outputStream.write(data);\n }\n\n public int readData(byte[] buffer) throws IOException {\n return inputStream.read(buffer);\n }\n}\n\n\n在你的 MainActivity 中，你可以通过以下方式使用 SerialPortHelper 类：\n\njava\nimport android.hardware.usb.UsbDevice;\nimport android.hardware.usb.UsbManager;\n\npublic class MainActivity extends AppCompatActivity {\n private SerialPortHelper serialPortHelper;\n\n @Override\n protected void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.activity_main);\n\n // 获取 UsbManager 实例\n UsbManager usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);\n\n // 获取连接的 USB 设备\n UsbDevice usbDevice = ...;\n\n // 创建 SerialPortHelper 实例\n serialPortHelper = new SerialPortHelper(usbManager, usbDevice);\n\n try {\n // 打开串口连接\n serialPortHelper.openSerialPort();\n\n // 写入数据\n byte[] data = "Hello, Serial!".getBytes();\n serialPortHelper.writeData(data);\n\n // 读取数据\n byte[] buffer = new byte[1024];\n int bytesRead = serialPortHelper.readData(buffer);\n if (bytesRead > 0) {\n String receivedData = new String(buffer, 0, bytesRead);\n Log.d("SerialPort", "Received data: " + receivedData);\n }\n } catch (IOException e) {\n e.printStackTrace();\n } finally {\n try {\n // 关闭串口连接\n serialPortHelper.closeSerialPort();\n } catch (IOException e) {\n e.printStackTrace();\n }\n }\n }\n}\n\n\n请注意，上述代码仅为示例，并且假设你已经获得了连接的 USB 设备。在实际开发中，你需要使用 UsbManager 和 UsbDevice 类来获取连接的 USB 设备。\n\n此外，你还需要在 AndroidManifest.xml 文件中添加以下权限：\n\nxml\n<uses-feature android:name="android.hardware.usb.host" />\n<uses-permission android:name="android.permission.USB_PERMISSION" />\n\n\n希望这可以帮助到你！