Android 蓝牙错误

我对使用蓝牙的应用程序有问题。该应用程序工作良好，除了在少数情况下，但我不能确定问题。这是蓝牙的活动：

public class Bluetooth extends Activity implements OnItemClickListener{

public static void disconnect(){
    if (connectedThread != null) {
        connectedThread.cancel(); 
        connectedThread = null;
    }
}

public static void gethandler(Handler handler){//Bluetooth handler
    mHandler = handler;
}
static Handler mHandler = new Handler();

static ConnectedThread connectedThread;
public static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
protected static final int SUCCESS_CONNECT = 0;
protected static final int MESSAGE_READ = 1;
ArrayAdapter<String> listAdapter;
ListView listView;
static BluetoothAdapter btAdapter;
Set<BluetoothDevice> devicesArray;
ArrayList<String> pairedDevices;
ArrayList<BluetoothDevice> devices;
IntentFilter filter;
BroadcastReceiver receiver;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_bluetooth);
    init();
    if (btAdapter==null){
        Toast.makeText(getApplicationContext(), "No bluetooth detected", 0).show();
        finish();
    }else{
        if (!btAdapter.isEnabled()){
            turnOnBT();
        }
        getPairedDevices();
        startDiscovery();
    }

}


private void startDiscovery() {
    // TODO Auto-generated method stub
    btAdapter.cancelDiscovery();
    btAdapter.startDiscovery();
}

private void turnOnBT() {
    Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
    startActivityForResult(intent, 1);
}

private void getPairedDevices() {
    devicesArray = btAdapter.getBondedDevices();
    if (devicesArray.size()>0){
        for(BluetoothDevice device:devicesArray){
            pairedDevices.add(device.getName());
        }
    }
}

private void init(){
    listView = (ListView)findViewById(R.id.listView);
    listView.setOnItemClickListener(this);
    listAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,0);
    listView.setAdapter(listAdapter);
    btAdapter = BluetoothAdapter.getDefaultAdapter();
    pairedDevices = new ArrayList<String>();
    filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
    devices = new ArrayList<BluetoothDevice>(); 
    receiver = new BroadcastReceiver(){
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (BluetoothDevice.ACTION_FOUND.equals(action)){
                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                devices.add(device);
                String s = "";
                for(int a=0;a<pairedDevices.size();a++){
                    if (device.getName().equals(pairedDevices.get(a))){
                        //append
                        s = "(Paired)";
                        break;
                    }
                }
                listAdapter.add(device.getName()+" "+s+" "+"\n"+device.getAddress());

            }else if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)){

            }else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)){

            }else if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)){
                if (btAdapter.getState() == btAdapter.STATE_OFF){
                    turnOnBT();
                }
            }  
        }

    };

    registerReceiver(receiver, filter);
    IntentFilter filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
    registerReceiver(receiver, filter);
    filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
    registerReceiver(receiver, filter);
    filter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
}

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    unregisterReceiver(receiver);
}

protected void onActivityResult(int requestCode, int resultCode, Intent data){
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_CANCELED){
        Toast.makeText(getApplicationContext(), "Bluetooth must be enabled to continue", Toast.LENGTH_SHORT).show();
        finish();
    }
}

@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
    // TODO Auto-generated method stub
    if (btAdapter.isDiscovering()){
        btAdapter.cancelDiscovery();
    }
    if (listAdapter.getItem(arg2).contains("(Paired)")){

        BluetoothDevice selectedDevice = devices.get(arg2);
        ConnectThread connect = new ConnectThread(selectedDevice);
        connect.start();
    }else {
        Toast.makeText(getApplicationContext(), "device is not paired", 0).show();
    }
}

private class ConnectThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final BluetoothDevice mmDevice;

    public ConnectThread(BluetoothDevice device) {
        // Use a temporary object that is later assigned to mmSocket,
        // because mmSocket is final
        BluetoothSocket tmp = null;
        mmDevice = device;

        // Get a BluetoothSocket to connect with the given BluetoothDevice
        try {
            // MY_UUID is the app's UUID string, also used by the server code
            tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
        } catch (IOException e) { }
        mmSocket = tmp;
    }

    public void run() {
        // Cancel discovery because it will slow down the connection
        btAdapter.cancelDiscovery();

        try {
            // Connect the device through the socket. This will block
            // until it succeeds or throws an exception
            mmSocket.connect();
            //connectedThread = new ConnectedThread(mmSocket);
        } catch (IOException connectException) {
            // Unable to connect; close the socket and get out
            try {
                mmSocket.close();
            } catch (IOException closeException) { }
            return;
        }

        // Do work to manage the connection (in a separate thread)
        mHandler.obtainMessage(SUCCESS_CONNECT, mmSocket).sendToTarget();
    }

    /** Will cancel an in-progress connection, and close the socket */
    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) { }
    }
}

static class ConnectedThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final InputStream mmInStream;
    private final OutputStream mmOutStream;

    public ConnectedThread(BluetoothSocket socket) {
        mmSocket = socket;
        InputStream tmpIn = null;
        OutputStream tmpOut = null;

        // Get the input and output streams, using temp objects because
        // member streams are final
        try {
            tmpIn = socket.getInputStream();
            tmpOut = socket.getOutputStream();
        } catch (IOException e) { }

        mmInStream = tmpIn;
        mmOutStream = tmpOut;
    }
    StringBuffer sbb = new StringBuffer();
    public void run() {

        byte[] buffer;  // buffer store for the stream
        int bytes; // bytes returned from read()

        // Keep listening to the InputStream until an exception occurs
        while (true) {
            try {
                try {
                    sleep(30);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

                buffer = new byte[1024];
                // Read from the InputStream
                bytes = mmInStream.read(buffer);
                // Send the obtained bytes to the UI activity
                mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer).sendToTarget();
            } catch (IOException e) {
                break;
            }
        }
    }

    /* Call this from the main activity to send data to the remote device */
    public void write(String income) {

        try {
            mmOutStream.write(income.getBytes());
            for(int i=0;i<income.getBytes().length;i++)
            Log.v("outStream"+Integer.toString(i),Character.toString((char)(Integer.parseInt(Byte.toString(income.getBytes()[i])))));
            try {
                Thread.sleep(20);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        } catch (IOException e) { }
    }

    /* Call this from the main activity to shutdown the connection */
    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) { }
    }
}

}

编辑

我注意到当活动是蓝牙时崩溃，我按下后退按钮。即使不总是这样。

---

有人能帮我吗？谢谢。

问题是您正在onCreate中注册收件人，并且应该在onResume上。情况就是这样：

您的活动开始：接收者已注册； 您移动到另一个屏幕或屏幕被锁定：接收器未注册； 您回到活动：接收者仍然未注册； 移动到另一个屏幕：您尝试注销接收器，但它未注册。 因此，要解决这个问题，请尝试将接收器注册移动到onResume（如果可以的话）。如果不能在try/catch语句中包装该调用：

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    try {
        unregisterReceiver(receiver);
    } catch (IllegalArgumentException e) {
        // ignored    
    }
}

---

你能给我举个try/catch的例子吗@Salem@davix10在答案中添加了一个示例。

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();
    try {
        unregisterReceiver(receiver);
    } catch (IllegalArgumentException e) {
        // ignored    
    }
}