Bluetooth socket won't connect always resulting IOException

819 Views Asked by At

In my application i am detecting Beacons using some libraries after finding the right beacon am using its name to find another Bluetooth device (Android Device 5.0) and then trying to connect to the phone by Bluetooth using the methods and classes provided by google in their sample Bluetooth chat app, but the socket is never connecting it is giving IOException always either (socket closed) or (socket time out ret:-1).

I tried every solution provided online and dozens of questions posted here on Stack Overflow but none worked.

i came to desperate conclusion that maybe using low energy bluetooth and bluetooth at the samee time is causing a conflict, am i right? or absolutely wrong?

Here is my code

BluetoothChatService


    /*
     * Copyright (C) 2014 The Android Open Source Project
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *      http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */

        package com.example.android.bluetoothchat;

        import android.bluetooth.BluetoothAdapter;
        import android.bluetooth.BluetoothDevice;
        import android.bluetooth.BluetoothServerSocket;
        import android.bluetooth.BluetoothSocket;
        import android.content.Context;
        import android.os.Bundle;
        import android.os.Handler;
        import android.os.Message;
        import android.os.ParcelUuid;

        import com.example.android.common.logger.Log;

        import java.io.IOException;
        import java.io.InputStream;
        import java.io.OutputStream;
        import java.util.UUID;

        /**
         * This class does all the work for setting up and managing Bluetooth
         * connections with other devices. It has a thread that listens for
         * incoming connections, a thread for connecting with a device, and a
         * thread for performing data transmissions when connected.
         */
        public class BluetoothChatService {
            // Debugging
            private static final String TAG = "BluetoothChatService";

            // Name for the SDP record when creating server socket
            private static final String NAME_SECURE = "BluetoothChatSecure";
            private static final String NAME_INSECURE = "BluetoothChatInsecure";

            // Unique UUID for this application
            private static final UUID MY_UUID_SECURE =
                    UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
            private static final UUID MY_UUID_INSECURE =
                    UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

            // Member fields
            private final BluetoothAdapter mAdapter;
            private final Handler mHandler;
            private AcceptThread mSecureAcceptThread;
            private AcceptThread mInsecureAcceptThread;


 private ConnectThread mConnectThread;
        private ConnectedThread mConnectedThread;
        private int mState;
        private int mNewState;

        // Constants that indicate the current connection state
        public static final int STATE_NONE = 0;       // we're doing nothing
        public static final int STATE_LISTEN = 1;     // now listening for incoming connections
        public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection
        public static final int STATE_CONNECTED = 3;  // now connected to a remote device

        /**
         * Constructor. Prepares a new BluetoothChat session.
         *
         * @param context The UI Activity Context
         * @param handler A Handler to send messages back to the UI Activity
         */
        public BluetoothChatService(Context context, Handler handler) {
            mAdapter = BluetoothAdapter.getDefaultAdapter();
            mState = STATE_NONE;
            mNewState = mState;
            mHandler = handler;
        }

        /**
         * Update UI title according to the current state of the chat connection
         */
        private synchronized void updateUserInterfaceTitle() {
            mState = getState();
            Log.d(TAG, "updateUserInterfaceTitle() " + mNewState + " -> " + mState);
            mNewState = mState;

            // Give the new state to the Handler so the UI Activity can update
            mHandler.obtainMessage(Constants.MESSAGE_STATE_CHANGE, mNewState, -1).sendToTarget();
        }

        /**
         * Return the current connection state.
         */
        public synchronized int getState() {
            return mState;
        }

        /**
         * Start the chat service. Specifically start AcceptThread to begin a
         * session in listening (server) mode. Called by the Activity onResume()
         */
        public synchronized void start() {
            Log.d(TAG, "start");

            // Cancel any thread attempting to make a connection
            if (mConnectThread != null) {
                mConnectThread.cancel();
                mConnectThread = null;
            }

            // Cancel any thread currently running a connection
            if (mConnectedThread != null) {
                mConnectedThread.cancel();
                mConnectedThread = null;
            }

            // Start the thread to listen on a BluetoothServerSocket
            if (mSecureAcceptThread == null) {
                mSecureAcceptThread = new AcceptThread(true);
                mSecureAcceptThread.start();
            }
            if (mInsecureAcceptThread == null) {
                mInsecureAcceptThread = new AcceptThread(false);
                mInsecureAcceptThread.start();
            }
            // Update UI title
            updateUserInterfaceTitle();
        }

        /**
         * Start the ConnectThread to initiate a connection to a remote device.
         *
         * @param device The BluetoothDevice to connect
         * @param secure Socket Security type - Secure (true) , Insecure (false)
         */
        public synchronized void connect(BluetoothDevice device, boolean secure) {
            Log.d(TAG, "connect to: " + device);

            // Cancel any thread attempting to make a connection
            if (mState == STATE_CONNECTING) {
                if (mConnectThread != null) {
                    mConnectThread.cancel();
                    mConnectThread = null;
                }
            }

            // Cancel any thread currently running a connection
            if (mConnectedThread != null) {
                mConnectedThread.cancel();
                mConnectedThread = null;
            }

            // Start the thread to connect with the given device
            mConnectThread = new ConnectThread(device, secure);
            mConnectThread.start();
            // Update UI title
            updateUserInterfaceTitle();
        }

        /**
         * Start the ConnectedThread to begin managing a Bluetooth connection
         *
         * @param socket The BluetoothSocket on which the connection was made
         * @param device The BluetoothDevice that has been connected
         */
        public synchronized void connected(BluetoothSocket socket, BluetoothDevice
                device, final String socketType) {
            Log.d(TAG, "connected, Socket Type:" + socketType);

            // Cancel the thread that completed the connection
            if (mConnectThread != null) {
                mConnectThread.cancel();
                mConnectThread = null;
            }

            // Cancel any thread currently running a connection
            if (mConnectedThread != null) {
                mConnectedThread.cancel();
                mConnectedThread = null;
            }

            // Cancel the accept thread because we only want to connect to one device
            if (mSecureAcceptThread != null) {
                mSecureAcceptThread.cancel();
                mSecureAcceptThread = null;
            }
            if (mInsecureAcceptThread != null) {
                mInsecureAcceptThread.cancel();
                mInsecureAcceptThread = null;
            }

            // Start the thread to manage the connection and perform transmissions
            mConnectedThread = new ConnectedThread(socket, socketType);
            mConnectedThread.start();

            // Send the name of the connected device back to the UI Activity
            Message msg = mHandler.obtainMessage(Constants.MESSAGE_DEVICE_NAME);
            Bundle bundle = new Bundle();
            bundle.putString(Constants.DEVICE_NAME, device.getName());
            msg.setData(bundle);
            mHandler.sendMessage(msg);
            // Update UI title
            updateUserInterfaceTitle();
        }

        /**
         * Stop all threads
         */
        public synchronized void stop() {
            Log.d(TAG, "stop");

            if (mConnectThread != null) {
                mConnectThread.cancel();
                mConnectThread = null;
            }

            if (mConnectedThread != null) {
                mConnectedThread.cancel();
                mConnectedThread = null;
            }

            if (mSecureAcceptThread != null) {
                mSecureAcceptThread.cancel();
                mSecureAcceptThread = null;
            }

            if (mInsecureAcceptThread != null) {
                mInsecureAcceptThread.cancel();
                mInsecureAcceptThread = null;
            }
            mState = STATE_NONE;
            // Update UI title
            updateUserInterfaceTitle();
        }

        /**
         * Write to the ConnectedThread in an unsynchronized manner
         *
         * @param out The bytes to write
         * @see ConnectedThread#write(byte[])
         */
        public void write(byte[] out) {
            // Create temporary object
            ConnectedThread r;
            // Synchronize a copy of the ConnectedThread
            synchronized (this) {
                if (mState != STATE_CONNECTED) return;
                r = mConnectedThread;
            }
            // Perform the write unsynchronized
            r.write(out);
        }

        /**
         * Indicate that the connection attempt failed and notify the UI Activity.
         */
        private void connectionFailed() {
            // Send a failure message back to the Activity
            Message msg = mHandler.obtainMessage(Constants.MESSAGE_TOAST);
            Bundle bundle = new Bundle();
            bundle.putString(Constants.TOAST, "Unable to connect device");
            msg.setData(bundle);
            mHandler.sendMessage(msg);

            mState = STATE_NONE;
            // Update UI title
            updateUserInterfaceTitle();

            // Start the service over to restart listening mode
            BluetoothChatService.this.start();
        }

        /**
         * Indicate that the connection was lost and notify the UI Activity.
         */
        private void connectionLost() {
            // Send a failure message back to the Activity
            Message msg = mHandler.obtainMessage(Constants.MESSAGE_TOAST);
            Bundle bundle = new Bundle();
            bundle.putString(Constants.TOAST, "Device connection was lost");
            msg.setData(bundle);
            mHandler.sendMessage(msg);

            mState = STATE_NONE;
            // Update UI title
            updateUserInterfaceTitle();

            // Start the service over to restart listening mode
            BluetoothChatService.this.start();
        }

        /**
         * This thread runs while listening for incoming connections. It behaves
         * like a server-side client. It runs until a connection is accepted
         * (or until cancelled).
         */
        private class AcceptThread extends Thread {
            // The local server socket
            private final BluetoothServerSocket mmServerSocket;
            private String mSocketType;

            public AcceptThread(boolean secure) {
                BluetoothServerSocket tmp = null;
                mSocketType = secure ? "Secure" : "Insecure";

                // Create a new listening server socket
                try
                {
                    if (secure) {
                        tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME_SECURE,
                                MY_UUID_SECURE);
                    } else {
                        tmp = mAdapter.listenUsingInsecureRfcommWithServiceRecord(
                                NAME_INSECURE, MY_UUID_INSECURE);
                    }
                } catch (IOException e) {
                    Log.e(TAG, "Socket Type: " + mSocketType + "listen() failed", e);
                }
                mmServerSocket = tmp;
                mState = STATE_LISTEN;
            }

            public void run() {
                Log.d(TAG, "Socket Type: " + mSocketType +
                        "BEGIN mAcceptThread" + this);
                setName("AcceptThread" + mSocketType);

                BluetoothSocket socket = null;

                // Listen to the server socket if we're not connected
                while (mState != STATE_CONNECTED) {
                    try {
                        // This is a blocking call and will only return on a
                        // successful connection or an exception
                        socket = mmServerSocket.accept();
                    } catch (IOException e) {
                        Log.e(TAG, "Socket Type: " + mSocketType + "accept() failed", e);
                        break;
                    }

                    // If a connection was accepted
                    if (socket != null) {
                        synchronized (BluetoothChatService.this) {
                            switch (mState) {
                                case STATE_LISTEN:
                                case STATE_CONNECTING:
                                    // Situation normal. Start the connected thread.
                                    connected(socket, socket.getRemoteDevice(),
                                            mSocketType);
                                    break;
                                case STATE_NONE:
                                case STATE_CONNECTED:
                                    // Either not ready or already connected. Terminate new socket.
                                    try {
                                        socket.close();
                                    } catch (IOException e) {
                                        Log.e(TAG, "Could not close unwanted socket", e);
                                    }
                                    break;
                            }
                        }
                    }
                }
                Log.i(TAG, "END mAcceptThread, socket Type: " + mSocketType);

            }

            public void cancel() {
                Log.d(TAG, "Socket Type" + mSocketType + "cancel " + this);
                try {
                    mmServerSocket.close();
                } catch (IOException e) {
                    Log.e(TAG, "Socket Type" + mSocketType + "close() of server failed", e);
                }
            }
        }


        /**
         * This thread runs while attempting to make an outgoing connection
         * with a device. It runs straight through; the connection either
         * succeeds or fails.
         */
        private class ConnectThread extends Thread {
            private final BluetoothSocket mmSocket;
            private final BluetoothDevice mmDevice;
            private String mSocketType;

            public ConnectThread(BluetoothDevice device, boolean secure) {
                mmDevice = device;
                BluetoothSocket tmp = null;
                mSocketType = secure ? "Secure" : "Insecure";

                // Get a BluetoothSocket for a connection with the
                // given BluetoothDevice
                try {
                    ParcelUuid parcelUuid = device.getUuids()[0];
                    parcelUuid.getUuid();
                    if (secure) {
                        tmp = device.createRfcommSocketToServiceRecord(MY_UUID_SECURE);
                    } else {
                        tmp = device.createInsecureRfcommSocketToServiceRecord(
                               MY_UUID_INSECURE);
                    }
                } catch (IOException e) {
                    Log.e(TAG, "Socket Type: " + mSocketType + "create() failed", e);
                }
                mmSocket = tmp;
                mState = STATE_CONNECTING;
            }

            public void run() {
                Log.i(TAG, "BEGIN mConnectThread SocketType:" + mSocketType);
                setName("ConnectThread" + mSocketType);

                // Always cancel discovery because it will slow down a connection
                mAdapter.cancelDiscovery();

                // Make a connection to the BluetoothSocket
                try {
                    // This is a blocking call and will only return on a
                    // successful connection or an exception
                    mmSocket.connect();
                } catch (IOException e) {
                    // Close the socket
                    try {
                        mmSocket.close();
                    } catch (IOException e2) {
                        Log.e(TAG, "unable to close() " + mSocketType +
                                " socket during connection failure", e2);
                    }
                    connectionFailed();
                    return;
                }

                // Reset the ConnectThread because we're done
                synchronized (BluetoothChatService.this) {
                    mConnectThread = null;
                }

                // Start the connected thread
                connected(mmSocket, mmDevice, mSocketType);
            }

            public void cancel() {
                try {
                    mmSocket.close();
                } catch (IOException e) {
                    Log.e(TAG, "close() of connect " + mSocketType + " socket failed", e);
                }
            }
        }

        /**
         * This thread runs during a connection with a remote device.
         * It handles all incoming and outgoing transmissions.
         */
        private class ConnectedThread extends Thread {
            private final BluetoothSocket mmSocket;
            private final InputStream mmInStream;
            private final OutputStream mmOutStream;

            public ConnectedThread(BluetoothSocket socket, String socketType) {
                Log.d(TAG, "create ConnectedThread: " + socketType);
                mmSocket = socket;
                InputStream tmpIn = null;
                OutputStream tmpOut = null;

                // Get the BluetoothSocket input and output streams
                try {
                    tmpIn = socket.getInputStream();
                    tmpOut = socket.getOutputStream();
                } catch (IOException e) {
                    Log.e(TAG, "temp sockets not created", e);
                }

                mmInStream = tmpIn;
                mmOutStream = tmpOut;
                mState = STATE_CONNECTED;
            }

            public void run() {
                Log.i(TAG, "BEGIN mConnectedThread");
                byte[] buffer = new byte[1024];
                int bytes;

                // Keep listening to the InputStream while connected
                while (mState == STATE_CONNECTED) {
                    try {
                        // Read from the InputStream
                        bytes = mmInStream.read(buffer);

                        // Send the obtained bytes to the UI Activity
                        mHandler.obtainMessage(Constants.MESSAGE_READ, bytes, -1, buffer)
                                .sendToTarget();
                    } catch (IOException e) {
                        Log.e(TAG, "disconnected", e);
                        connectionLost();
                        break;
                    }
                }
            }

            /**
             * Write to the connected OutStream.
             *
             * @param buffer The bytes to write
             */
            public void write(byte[] buffer) {
                try {
                    mmOutStream.write(buffer);

                    // Share the sent message back to the UI Activity
                    mHandler.obtainMessage(Constants.MESSAGE_WRITE, -1, -1, buffer)
                            .sendToTarget();
                } catch (IOException e) {
                    Log.e(TAG, "Exception during write", e);
                }
            }

            public void cancel() {
                try {
                    mmSocket.close();
                } catch (IOException e) {
                    Log.e(TAG, "close() of connect socket failed", e);
                }
            }
        }
    }
1

There are 1 best solutions below

1
On

You included a lot of unnecessary code but none of the relevant parts. How are you performing the B-LE scanning and the Bluetooth discovery? Without this code is hard to offer more suggestions but you should watch out for the following:

  • Bluetooth LE scanning and regular Bluetooth discovery cannot be performed at the same time.
  • You cannot connect using regular Bluetooth if the device has been discovered via Bluetooth LE. You have to discover the device via regular Bluetooth discovery for the connection to be successful.