我正在尝试构建一个Android应用程序，它将通过蓝牙串行端口配置文件（SPP）与外部GPS接收器连接。我正在使用运行2.3.3的Nexus One。我设法让我的应用程序从GPS接收数据，但我有两个问题：1）当我连接到设备时，它只在某些时候工作。有时连接只是超时，有时则表示设备正忙或正在使用中。 2）我无法弄清楚如何将数据发送回设备，这可能是我如何使用流的一个问题，因为传入流是阻塞呼叫。
我将相关代码移动到新的Android应用程序进行测试，具体如下：
/res/layout/main.xml（两个按钮和一个textview）
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">
<Button android:id="@+id/btnStart" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Connect"></Button>
<Button android:id="@+id/btnSend" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Send Message"></Button>
<TextView android:id="@+id/textStatus" android:textSize="24sp" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Status Goes Here" />
</LinearLayout>
/src/com.example.bluetoothspp/MainActivity.java
package com.example.bluetoothspp;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.net.SocketTimeoutException;
import java.util.UUID;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
private static final String BTAG = "BTThread";
static final int MSG_BT_GOT_DATA = 1;
static final int MSG_BT_STATUS_MSG = 2;
static final int MSG_BT_FINISHED = 99;
Button btnStart, btnSend;
TextView textStatus;
private BluetoothAdapter mBluetoothAdapter = null;
private BluetoothDevice btdevice = null;
Thread bThread;
BluetoothSocket bsocket;
InputStream bis = null; //Bluetooth input stream
OutputStream bos = null; //Bluetooth output stream
private String MACAddress = "00:01:95:06:1F:32";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btnStart = (Button)findViewById(R.id.btnStart);
btnSend = (Button)findViewById(R.id.btnSend);
textStatus = (TextView)findViewById(R.id.textStatus);
btnStart.setOnClickListener(btnStartListener);
btnSend.setOnClickListener(btnSendListener);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
}
private OnClickListener btnStartListener = new OnClickListener() {
public void onClick(View v){
if(btnStart.getText().equals("Connect")){
Log.i(TAG, "Connect button pressed");
if (mBluetoothAdapter == null) { //No adapter. Fail
Log.e(TAG, "getDefaultAdapter returned null");
textStatus.setText("getDefaultAdapter returned null");
} else {
if (!mBluetoothAdapter.isEnabled()) { //Bluetooth disabled
Log.e(TAG, "Bluetooth is Disabled");
textStatus.setText("Bluetooth is Disabled");
} else {
Log.i(TAG, "Connecting to Device: " + MACAddress);
btdevice = mBluetoothAdapter.getRemoteDevice(MACAddress);
Log.i(TAG, "Device: " + btdevice.getName());
Log.i(TAG, "Trying to Connect...");
textStatus.setText("Trying to Connect...");
Log.i(TAG, "Starting Thread");
try {
bThread = new Thread(new BluetoothClient(btdevice, true));
bThread.start();
} catch (IOException e) {
Log.e(TAG, "Could not create thread for bluetooth: " + e);
textStatus.setText("Could not create thread for bluetooth...");
}
btnStart.setText("Disconnect");
}
}
} else {
Log.i(TAG, "Disconnect button pressed");
btnStart.setText("Connect");
}
}
};
private OnClickListener btnSendListener = new OnClickListener() {
public void onClick(View v){
textStatus.setText("Sending Message to Thread.");
SendDataToBluetooth("something\r\n");
}
};
public class BluetoothClient implements Runnable {
public BluetoothClient(BluetoothDevice device, boolean IsAnHTCDevice) throws IOException {
if (IsAnHTCDevice) {
//This is a workaround for HTC devices, but it likes to throw an IOException "Connection timed out"
try {
Method m = device.getClass().getMethod("createRfcommSocket", new Class[] {int.class});
bsocket = (BluetoothSocket) m.invoke(device, Integer.valueOf(1));
} catch (Exception e) {
Log.e(BTAG, "Error at HTC/createRfcommSocket: " + e);
e.printStackTrace();
handler.sendMessage(handler.obtainMessage(MSG_BT_STATUS_MSG, "MethodException: " + e));
}
} else {
//This is the normal method, but on a Nexus One it almost always throws an IOException "Service discovery failed" message
try {
UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
bsocket = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (Exception e) {
Log.e(BTAG, "Error at createRfcommSocketToServiceRecord: " + e);
e.printStackTrace();
handler.sendMessage(handler.obtainMessage(MSG_BT_STATUS_MSG, "MethodException: " + e));
}
}
}
public void run() {
try {
Log.i(BTAG, "Cancelling Discovery");
mBluetoothAdapter.cancelDiscovery();
Log.i(BTAG, "Connecting to Socket");
bsocket.connect();
bis = bsocket.getInputStream();
bos = bsocket.getOutputStream();
Log.i(BTAG, "Socket created, streams assigned");
handler.sendMessage(handler.obtainMessage(MSG_BT_STATUS_MSG, "Device Connected"));
Log.i(BTAG, "Waiting for data...");
byte[] buffer = new byte[4096];
int read = bis.read(buffer, 0, 4096); // This is blocking
Log.i(BTAG, "Getting data...");
while (read != -1) {
byte[] tempdata = new byte[read];
System.arraycopy(buffer, 0, tempdata, 0, read);
handler.sendMessage(handler.obtainMessage(MSG_BT_GOT_DATA, tempdata));
read = bis.read(buffer, 0, 4096); // This is blocking
}
} catch (SocketTimeoutException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
} finally {
Log.i(BTAG, "Finished");
handler.sendMessage(handler.obtainMessage(MSG_BT_FINISHED));
}
}
}
public void SendDataToBluetooth(String cmd) { // You run this from the main thread.
try {
if (bsocket != null) {
bos.write(cmd.getBytes());
}
} catch (Exception e) {
Log.e("SendDataToBluetooth", "Message send failed. Caught an exception: " + e);
}
}
public Handler handler = new Handler() { // Handler for data coming from the network and bluetooth sockets
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_BT_GOT_DATA:
Log.i("handleMessage", "MSG_BT_GOT_DATA: " + (String) msg.obj);
textStatus.setText((String) msg.obj);
break;
case MSG_BT_STATUS_MSG:
Log.i("handleMessage", "MSG_BT_STATUS_MSG: " + (String) msg.obj);
textStatus.setText((String) msg.obj);
break;
case MSG_BT_FINISHED:
Log.i("handleMessage", "MSG_BT_FINISHED");
btnStart.setText("Connect");
break;
default:
super.handleMessage(msg);
}
}
};
@Override
protected void onDestroy() {
super.onDestroy();
if (bThread != null) { // If the thread is currently running, close the socket and interrupt it.
Log.i(BTAG, "Killing BT Thread");
try {
bis.close();
bos.close();
bsocket.close();
bsocket = null;
} catch (IOException e) {
Log.e(BTAG, "IOException");
e.printStackTrace();
} catch (Exception e) {
Log.e(BTAG, "Exception");
e.printStackTrace();
}
try {
Thread moribund = bThread;
bThread = null;
moribund.interrupt();
} catch (Exception e) {}
Log.i(BTAG, "BT Thread Killed");
}
}
}
我发现使用普通的“bsocket = device.createRfcommSocketToServiceRecord（MY_UUID）;”方法通常会导致我的“服务发现失败”消息，所以我也尝试了“bsocket =（BluetoothSocket）m.invoke（device，Integer.valueOf（1））;”方法。这种情况更常见，但在我尝试连接时喜欢超时。
我在这里做错了什么？
答案 0 :(得分：2)
尝试侦听传入的数据并在单独的线程中写入设备。通过这种方式，您可以分离阻止呼叫 你看过蓝牙聊天样本了吗？该示例使用类似的线程技术。
答案 1 :(得分：0)
如果你的目标是2.3及以上（当前安装了on over 50%的Android设备）你可以使用createInsecureRfcommSocketToServiceRecord方法与设备进行通信，这肯定会让它更好，更可连接