问题
I'm trying to develop an Android application which transfers images from one device to another. The received image would then be shown on the ImageView inside my application. To achieve my task, I thought to send a byte array of the bitmap. I'm able to get the first image on the imageview. But, as soon as I click on the button to send another image the application fails to send the bitmap. It shows me an exception "java.io.IOException: Service fiscovery failed." To send any image successfully I need to restart my application on the receiving/remote device. Can anyone please suggest a solution to mu problem. The logcat has also been included below.
Code to establish the connection:
private class StartConnectionThread extends Thread{
private final BluetoothSocket bluetoothSocket;
private final BluetoothDevice bluetoothDevice;
public StartConnectionThread(BluetoothDevice device){
BluetoothSocket tempBluetoothSocket=null;
bluetoothDevice=device;
try
{
System.out.println(uuid);
tempBluetoothSocket=device.createRfcommSocketToServiceRecord(uuid);
}
catch(IOException ioException)
{
}
bluetoothSocket=tempBluetoothSocket;
}
@Override
public void run() {
// TODO Auto-generated method stub
bluetoothAdapter.cancelDiscovery();
try
{
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
bluetoothSocket.connect();
}
catch(IOException ioException)
{
System.out.println("bluetoothSocketInThread failed");
try
{
bluetoothSocket.close();
}
catch(IOException cancelIOException)
{
}
return;
}
manageConnectedSocket(bluetoothSocket);
}
public void cancel()
{
try
{
bluetoothSocket.close();
}
catch(IOException ioException)
{
}
}
}
Code to accept the connection:
private class AcceptConnectionThread extends Thread
{
private final BluetoothServerSocket bluetoothServerSocket;
public AcceptConnectionThread() {
// TODO Auto-generated constructor stub
System.out.println("constructor");
BluetoothServerSocket tempBluetoothServerSocket=null;
try
{
tempBluetoothServerSocket=bluetoothAdapter.listenUsingRfcommWithServiceRecord("My Souvenirs", uuid);
}
catch(IOException ioException)
{
}
bluetoothServerSocket=tempBluetoothServerSocket;
}
@Override
public void run() {
// TODO Auto-generated method stub
BluetoothSocket bluetoothSocket=null;
while(true)
{
try
{
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(bluetoothServerSocket);
if(bluetoothServerSocket!=null)
{
bluetoothSocket=bluetoothServerSocket.accept();
}
System.out.println("accept");
}
catch(IOException ioException){
break;
}
if(bluetoothSocket!=null)
{
manageConnectedSocket(bluetoothSocket);
try {
bluetoothServerSocket.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
break;
}
}
}
public void cancel()
{
try{
bluetoothServerSocket.close();
}
catch(IOException ioException){
}
}
}
Code to manage the connection:
private class ManageConnectedDevicesThread extends Thread
{
private final BluetoothSocket connectedBluetoothSocket;
public ManageConnectedDevicesThread(BluetoothSocket socket) {
// TODO Auto-generated constructor stub
connectedBluetoothSocket=socket;
InputStream tempInputStream=null;
OutputStream tempOutputStream=null;
try
{
tempInputStream=socket.getInputStream();
tempOutputStream=socket.getOutputStream();
}
catch(IOException ioException)
{
}
inputStream=tempInputStream;
outputStream=tempOutputStream;
}
@Override
public void run() {
// TODO Auto-generated method stub
byte[] buffer=new byte[1024*8];
int bytes;
while(true)
{
try
{
bytes=inputStream.read(buffer);
handler.obtainMessage(MESSAGE_READ,bytes,-1,buffer).sendToTarget();
System.out.println("handler");
}
catch(IOException ioException)
{
System.out.println("for handler:" +ioException);
break;
}
}
}
public void write(byte[] bytes)
{
try
{
outputStream.write(bytes);
}
catch(IOException ioException){
System.out.println("exception in wrie tatement of managing connections");
}
}
public void close()
{
try {
connectedBluetoothSocket.close();
} catch (IOException e) {
// TODO: handle exception
}
}
}
Code to reset the connection:
void resetConnection()
{
if(inputStream!=null)
{
try {
inputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(outputStream!=null)
{
try {
outputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(startConnectionThread!=null)
{
System.out.println("start wala active tha");
startConnectionThread.cancel();
}
if(acceptConnectionThread!=null)
{
System.out.println("accept wala active tha");
acceptConnectionThread.cancel();
}
if(manageConnectedDevicesThread!=null)
{
System.out.println("manage wala active tha");
manageConnectedDevicesThread.close();
}
}
}
code for handler is shown below:
private final Handler handler=new Handler(){
public void handleMessage(Message msg) {
switch (msg.what) {
case MESSAGE_READ:
System.out.println("MESSAGE_READ");
byte[] readBuf = (byte[]) msg.obj;
// construct a string from the valid bytes in the buffer
String readMessage = new String(readBuf, 0, msg.arg1);
byte[] b=readMessage.getBytes();
Bitmap bitmap1=BitmapFactory.decodeByteArray(readBuf, 0, readBuf.length);
imageView.setImageBitmap(bitmap1);
break;
}
};
The logcat shows the following:
01-25 14:49:31.800: D/dalvikvm(9451): Debugger has detached; object registry had 1 entries
01-25 14:49:38.380: V/BluetoothSocket.cpp(9451): initSocketNative
01-25 14:49:38.380: V/BluetoothSocket.cpp(9451): ...fd 40 created (RFCOMM, lm = 26)
01-25 14:49:38.380: V/BluetoothSocket.cpp(9451): initSocketFromFdNative
01-25 14:49:40.420: D/BluetoothUtils(9451): isSocketAllowedBySecurityPolicy start : device null
01-25 14:49:41.680: I/System.out(9451): bluetoothSocketInThread failed
01-25 14:49:41.680: V/BluetoothSocket.cpp(9451): abortNative
01-25 14:49:41.680: V/BluetoothSocket.cpp(9451): ...asocket_abort(40) complete
01-25 14:49:41.680: V/BluetoothSocket.cpp(9451): destroyNative
01-25 14:49:41.680: V/BluetoothSocket.cpp(9451): ...asocket_destroy(40) complete
Thanks in advance.
回答1:
Maybe you can try adding thread.sleep for a second? See this discussion:
"The only way I've been able to fix the problem is by adding a thread.sleep for a second before closing the connection."
also see dan's two consecutive comments on this thread:
"I was able to get this to run only after separating the calls to findBT(); openBT();
Otherwise, mmSocket.connect(); throws an exception, “Service discovery failed”
but if I put findBT() in onCreate() and just use the button for openBT(); it works fine.
Or, if I make a second button, one for each, it works fine.
Suggestions?"
the excerpts from the second comment:
Set pairedDevices = mBluetoothAdapter.getBondedDevices(); mmDevice = mBluetoothAdapter.getRemoteDevice(“00:06:66:46:5A:91″); if (pairedDevices.contains(mmDevice)) { statusText.setText(“Bluetooth Device Found, address: ” + mmDevice.getAddress() ); Log.d(“ArduinoBT”, “BT is paired”); }where I entered the address of my Bluetooth device. The original code finds the device and returns the correct address, but mmSocket.connect(); generates an exception “java.io.IOException: Service discovery failed”
Suggestions?
来源：https://stackoverflow.com/questions/21348789/android-bluetooth-java-io-ioexception-service-discovery-failed