我不想回答我自己的问题，但是......我明白了。我只是混淆了我的阅读和写作。此外，该设备不喜欢我在命令末尾使用的 '\n'。它似乎与 '\r' 相处得更好。
我最终使用 android 的 bulkTransfer 进行读写。我的写作看起来像这样。
try {
device.getWriter().write(command + "\r");
device.getWriter().flush();
} catch (IOException e) {
throw new RuntimeException(e);
}
我的 BufferedWriter 的重写写入方法：
@覆盖
public void write(char[] buf, int offset, int count) throws IOException {
byte[] buffer = new String(buf, offset, count).getBytes(Charset.forName("US-ASCII"));
int byteCount = connection.bulkTransfer(endpoint, buffer, buffer.length, TIMEOUT);
}
读数相似：
char[] buffer = new char[BUF_SIZE];
try {
BufferedReader reader = device.getReader();
int readBytes = reader.read(buffer);
Log.d(TAG, "BYTES READ: " + readBytes);
} catch (IOException e) {
throw new RuntimeException(e);
}
String strBuf = new String(buffer).trim();
if (DEBUG) {
Log.d(TAG, "Read: " + strBuf);
}
和：
@Override
public int read(char[] buf, int offset, int count) throws IOException {
byte[] buffer = new byte[count];
int byteCount = connection.bulkTransfer(endpoint, buffer, buffer.length, TIMEOUT);
if (byteCount < 0) {
throw new IOException();
}
char[] charBuffer = new String(buffer, Charset.forName("US-ASCII")).toCharArray();
System.arraycopy(charBuffer, 0, buf, offset, byteCount);
return byteCount;
}
这一切都是在这样的一个线程中开始的：
new Thread() {
@Override
public void run() {
String command = "go";
write(command);
while (true) {
String coords = read();
}
}
}.start();
显然这只是通讯的东西，我现在需要用它做点什么（把它放在一个可以使用处理程序报告回顶级 UI 活动的服务中）。但这部分已经弄清楚了。
非常感谢从事 rosjava ( http://code.google.com/p/rosjava/ ) 工作的人们...他们已经完成了很多很棒的项目，他们的代码非常有帮助。
添加我的设备类以帮助澄清事情。
import com.google.common.base.Preconditions;
import android.hardware.usb.UsbConstants;
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbEndpoint;
import android.hardware.usb.UsbInterface;
import android.util.Log;
import java.io.BufferedReader;
import java.io.BufferedWriter;
/* This class represents a USB device that supports the adb protocol. */
public class BKDevice {
// private static final int TIMEOUT = 3000;
private final UsbDeviceConnection usbDeviceConnection;
private final BufferedReader reader;
private final BufferedWriter writer;
public static final String TAG = "AcmDevice";
public BKDevice(UsbDeviceConnection usbDeviceConnection,
UsbInterface usbInterface) {
Preconditions.checkState(usbDeviceConnection.claimInterface(
usbInterface, true));
this.usbDeviceConnection = usbDeviceConnection;
UsbEndpoint epOut = null;
UsbEndpoint epIn = null;
// look for our bulk endpoints
for (int i = 0; i < usbInterface.getEndpointCount(); i++) {
UsbEndpoint ep = usbInterface.getEndpoint(i);
Log.d(TAG, "EP " + i + ": " + ep.getType());
if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
if (ep.getDirection() == UsbConstants.USB_DIR_OUT) {
epOut = ep;
} else if (ep.getDirection() == UsbConstants.USB_DIR_IN) {
epIn = ep;
}
}
}
if (epOut == null || epIn == null) {
throw new IllegalArgumentException("Not all endpoints found.");
}
BKReader acmReader = new BKReader(usbDeviceConnection, epIn);
BKWriter acmWriter = new BKWriter(usbDeviceConnection, epOut);
reader = new BufferedReader(acmReader);
writer = new BufferedWriter(acmWriter);
}
public BufferedReader getReader() {
return reader;
}
public BufferedWriter getWriter() {
return writer;
}
}
添加 BKReader 代码：
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbEndpoint;
import android.util.Log;
import java.io.IOException;
import java.io.Reader;
import java.nio.charset.Charset;
public class BKReader extends Reader {
private static final int TIMEOUT = 1000;
private final UsbDeviceConnection connection;
private final UsbEndpoint endpoint;
public BKReader(UsbDeviceConnection connection, UsbEndpoint endpoint) {
this.connection = connection;
this.endpoint = endpoint;
}
@Override
public int read(char[] buf, int offset, int count) throws IOException {
byte[] buffer = new byte[count];
int byteCount = connection.bulkTransfer(endpoint, buffer, buffer.length, TIMEOUT);
if (byteCount < 0) {
throw new IOException();
}
char[] charBuffer = new String(buffer, Charset.forName("US-ASCII")).toCharArray();
System.arraycopy(charBuffer, 0, buf, offset, byteCount);
return byteCount;
}
@Override
public void close() throws IOException {
}
}