我已成功与蓝牙设备配对并连接。我现在有兴趣接收在 2 之间传输的所有数据并查看是什么。
我正在从套接字获取输入流并尝试读取它。我退回并记录它。
根据我所读的内容,我知道这样做的唯一方法就是使用字节缓冲区进行读取以返回一个 int。但是我应该有大量数据通过。我怎样才能连续读出正在传输的数据,并将格式设置为字节而不是 int。
谢谢。
完整代码如下:
public class ConnectThread {
private BluetoothSocketWrapper bluetoothSocket;
private BluetoothDevice device;
private boolean secure;
private BluetoothAdapter adapter;
private List<UUID> uuidCandidates;
private int candidate;
/**
* @param device the device
* @param secure if connection should be done via a secure socket
* @param adapter the Android BT adapter
* @param uuidCandidates a list of UUIDs. if null or empty, the Serial PP id is used
*/
public ConnectThread(BluetoothDevice device, boolean secure, BluetoothAdapter adapter,
List<UUID> uuidCandidates) {
this.device = device;
this.secure = secure;
this.adapter = adapter;
this.uuidCandidates = uuidCandidates;
if (this.uuidCandidates == null || this.uuidCandidates.isEmpty()) {
this.uuidCandidates = new ArrayList<UUID>();
this.uuidCandidates.add(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));
}
}
public BluetoothSocketWrapper connect() throws IOException {
boolean success = false;
while (selectSocket()) {
adapter.cancelDiscovery();
try {
bluetoothSocket.connect();
success = true;
break;
} catch (IOException e) {
//try the fallback
try {
bluetoothSocket = new FallbackBluetoothSocket(bluetoothSocket.getUnderlyingSocket());
Thread.sleep(500);
bluetoothSocket.connect();
success = true;
break;
} catch (FallbackException e1) {
Log.w("BT", "Could not initialize FallbackBluetoothSocket classes.", e);
} catch (InterruptedException e1) {
Log.w("BT", e1.getMessage(), e1);
} catch (IOException e1) {
Log.w("BT", "Fallback failed. Cancelling.", e1);
}
}
}
if (!success) {
throw new IOException("Could not connect to device: "+ device.getAddress());
}
receiveData(bluetoothSocket);
return bluetoothSocket;
}
private boolean selectSocket() throws IOException {
if (candidate >= uuidCandidates.size()) {
return false;
}
BluetoothSocket tmp;
UUID uuid = uuidCandidates.get(candidate++);
Log.i("BT", "Attempting to connect to Protocol: "+ uuid);
if (secure) {
tmp = device.createRfcommSocketToServiceRecord(uuid);
} else {
tmp = device.createInsecureRfcommSocketToServiceRecord(uuid);
}
bluetoothSocket = new NativeBluetoothSocket(tmp);
return true;
}
public static interface BluetoothSocketWrapper {
InputStream getInputStream() throws IOException;
OutputStream getOutputStream() throws IOException;
String getRemoteDeviceName();
void connect() throws IOException;
String getRemoteDeviceAddress();
void close() throws IOException;
BluetoothSocket getUnderlyingSocket();
}
public static class NativeBluetoothSocket implements BluetoothSocketWrapper {
private BluetoothSocket socket;
public NativeBluetoothSocket(BluetoothSocket tmp) {
this.socket = tmp;
}
@Override
public InputStream getInputStream() throws IOException {
return socket.getInputStream();
}
@Override
public OutputStream getOutputStream() throws IOException {
return socket.getOutputStream();
}
@Override
public String getRemoteDeviceName() {
return socket.getRemoteDevice().getName();
}
@Override
public void connect() throws IOException {
socket.connect();
}
@Override
public String getRemoteDeviceAddress() {
return socket.getRemoteDevice().getAddress();
}
@Override
public void close() throws IOException {
socket.close();
}
@Override
public BluetoothSocket getUnderlyingSocket() {
return socket;
}
}
public class FallbackBluetoothSocket extends NativeBluetoothSocket {
private BluetoothSocket fallbackSocket;
public FallbackBluetoothSocket(BluetoothSocket tmp) throws FallbackException {
super(tmp);
try
{
Class<?> clazz = tmp.getRemoteDevice().getClass();
Class<?>[] paramTypes = new Class<?>[] {Integer.TYPE};
Method m = clazz.getMethod("createRfcommSocket", paramTypes);
Object[] params = new Object[] {Integer.valueOf(1)};
fallbackSocket = (BluetoothSocket) m.invoke(tmp.getRemoteDevice(), params);
}
catch (Exception e)
{
throw new FallbackException(e);
}
}
@Override
public InputStream getInputStream() throws IOException {
return fallbackSocket.getInputStream();
}
@Override
public OutputStream getOutputStream() throws IOException {
return fallbackSocket.getOutputStream();
}
@Override
public void connect() throws IOException {
fallbackSocket.connect();
}
@Override
public void close() throws IOException {
fallbackSocket.close();
}
}
public static class FallbackException extends Exception {
/**
*
*/
private static final long serialVersionUID = 1L;
public FallbackException(Exception e) {
super(e);
}
}
public void sendData(BluetoothSocketWrapper socket, int data) throws IOException{
ByteArrayOutputStream output = new ByteArrayOutputStream(4);
output.write(data);
OutputStream outputStream = socket.getOutputStream();
outputStream.write(output.toByteArray());
}
public int receiveData(BluetoothSocketWrapper socket) throws IOException{
byte[] buffer = new byte[256];
ByteArrayInputStream input = new ByteArrayInputStream(buffer);
InputStream inputStream = socket.getInputStream();
inputStream.read(buffer);
return input.read();
}
}
最佳答案
首先,停止使用 ByteArrayInputStream
和 ByteArrayOutputStream
以获得更多控制。
如果套接字发送/接收文本,执行此操作。
发送:
String text = "My message";
socketOutputStream.write(text.getBytes());
接收:
int length = socketInputStream.read(buffer);
String text = new String(buffer, 0, length);
socketOutputStream
应该是您的 bluetoothSocket.getOutputStream()
。
如果套接字发送/接收大量数据,关键是while循环防止内存不足异常。数据将按 block (例如每 4KB 缓冲区大小)读取,当您选择缓冲区大小时,请考虑堆大小,如果您是直播媒体,还要考虑延迟和质量。
发送:
int length;
while ((length = largeDataInputStream.read(buffer)) != -1) {
socketOutputStream.write(buffer, 0, length);
}
接收:
int length;
//socketInputStream never returns -1 unless connection is broken
while ((length = socketInputStream.read(buffer)) != -1) {
largeDataOutputStream.write(buffer, 0, length);
if (progress >= dataSize) {
break; //Break loop if progress reaches the limit
}
}
常见问题解答:
- 如何获取接收数据的大小?您必须自己实现以通知远程设备准备好接收数据(包括文件大小),这将需要至少一个双套接字连接(2 个套接字,1 个设备),例如,1 个文本套接字 fragment 和自定义命令,以及 1 个用于大数据(如文件或流媒体)的套接字。
- 什么是
largeDataInputStream
和largeDataOutputStream
?这些流可以是普通的 I/O 流、FileInputStream
/FileOutputStream
等。 - 为什么
BluetoothSocket
的 while 循环永远不会结束?套接字输入持续接收数据,read()
方法会阻塞自身,直到检测到数据。为防止阻塞该行中的代码,必须中断 while 循环。
注意:此答案可能需要修改。我的母语不是英语。
关于java - Android:蓝牙 - 如何读取传入数据,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/44593085/