Thread in Android causes phone crash

I have no idea what fails in this code because I have trouble reading the crash logs. We are not talking about a app-crash but a phone crash probably caused by either a deadlocked thread or a lock-up of some kind. Suggestions are welcomed!

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Background:

When I initiate my connection a dialog shows and when I press the Back button the dialog freezes and after awhile the phone crashes...

Code:

This is the thread that handles the connection with the device. I have no issues connecting to a device at all. What I know is that mmSocket.connect() running when I press the back button. Think the problem lies there somewhere...

class ConnectThread extends Thread {

/**
 * 
 */
private Handler threadhandler;
private BluetoothDevice mmDevice;
private volatile BluetoothSocket mmSocket;
private Message toMain;
//      private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

public ConnectThread(Handler threadhandler, BluetoothDevice device) {

    this.threadhandler = threadhandler;
    this.mmDevice = device;


    // Get a BluetoothSocket to connect with the given BluetoothDevice
    try {
        Method m = mmDevice.getClass().getMethod("createRfcommSocket", new Class[] {int.class});
        mmSocket = (BluetoothSocket) m.invoke(mmDevice, 1);

    }catch (NoSuchMethodException e) {

        e.printStackTrace();
    } catch (IllegalArgumentException e) {

        e.printStackTrace();
    } catch (IllegalAccessException e) {

        e.printStackTrace();
    } catch (InvocationTargetException e) {

        e.printStackTrace();
    }

}

public void run() {
    Looper.prepare();
    try {
        // Connect the device through the socket. This will block
        // until it succeeds or throws an exception

        mmSocket.connect();

        toMain = threadhandler.obtainMessage();
        toMain.arg1 = 开发者_如何学C1;
        threadhandler.sendMessage(toMain);


    } catch (SecurityException e) {

        Log.e("SecurityExcep", "Oh noes" , e);
        toMain = threadhandler.obtainMessage();
        toMain.arg1 = 2;
        threadhandler.sendMessage(toMain);
        Log.w("MESSAGE", e.getMessage());

    }catch (IOException e) {
        //Bad connection, let's get the hell outta here
        try {
            Log.e("IOExcep", "Oh noes" , e);
            Log.w("MESSAGE", e.getMessage());

            mmSocket.close();
            toMain = threadhandler.obtainMessage();
            toMain.arg1 = 2;
            toMain.obj = e.getMessage();
            threadhandler.sendMessage(toMain);


            return;
        } catch (IOException e1) {
            Log.e("IOExcep2", "Oh noes" , e);
        }
    }
    try {
        mmSocket.close();
    } catch (IOException e) {
        Log.d("CONNECT_CONSTRUCTOR", "Unable to close the socket", e);
    }

    toMain = threadhandler.obtainMessage();
    toMain.arg1 = 3;
    threadhandler.sendMessage(toMain);

    Looper.loop();
    return;
    // Now it should be paired.. only thing to do now is let the user commit to the rest
}

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

}

Next code is a snippet from the dialog creator, the thread is called d:

(...)

        case DIALOG_BT_ADDING:
        search_dialog = new ProgressDialog(this);
        search_dialog.setTitle(R.string.adding);
        search_dialog.setMessage(res.getText(R.string.bluetooth_add_accept));
        search_dialog.setIndeterminate(true);           
        search_dialog.setCancelable(true);
        search_dialog.setOnCancelListener(new OnCancelListener() {

            @Override
            public void onCancel(DialogInterface dialog) {
                Log.i("THREAD CONNECT", "Is it alive?: " + d.isAlive());
                if(d != null && d.isAlive()){
                    d.cancel();
                    //d = null;
                }
                if(d2 != null && d2.isAlive()){
                    d2.cancel(false);
                    //d2 = null;

                }
                search_dialog.dismiss();
                showDialog(DIALOG_NEW_DEVICE_FOUND);

            }
        });         
        return search_dialog;
(...)

Here is a snippet of the code executing the ConnectThread-class

private void connectBluetooth(boolean nextstage, IOException e1){
    if(!nextstage){
        showDialog(DIALOG_BT_ADDING);

        d = new ConnectThread(threadhandler, selected_car.getDevice());
        d.start();

    }
    else{
        if(e1 != null){

            d2 = new BluetoothCheckThread(checkthreadhandler,mBluetoothAdapter, 
                    5000, car_bt, after_bt);
            d2.start();
            search_dialog.dismiss();
        }
        else{
            showDialog(DIALOG_BT_ADDING_FAILED);
        }
    }
}

Hope you guys can help me!, thanks for any feedback

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Okay, you're calling BluetoothSocket.close() from what looks like the UI thread. This is probably causing the "freeze".

When you say the phone "crashes" do you mean it reboots? If so is this a full reboot (screen goes back to what happens when you first turn the phone on) or a runtime restart (phone typically shows some sort of animation, on Nexus devices, its the four-color particle spray)? If its not a reboot, do you mean you just get a dialog allowing you to kill the app?

In either case you may want to get a reference to the Thread that is calling BluetoothSocket.connect() and call Thread.interrupt(). I'm not sure if a BluetoothSocket is interruptible, but let's hope. Then after interrupting, call close(), which probably shouldn't be called on the main thread.

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try to use dialog.setOnKeyListener() in that on keyCode_BACK cancel the thread. try this will work.

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It looks like you're calling connect and close on BluetoothSocket which is a "no no". It seems to cause a deadlock. See this link for more info.