Dealing with Thread, Handler and message: "Restart" a thread

Question

Hi,

    public class Connection extends Activity implements Runnable {

            public static final int CONNECTION_ERROR = 1;
            public static final int CONNECTION_DONE = 3;



            @Override
            public void onCreate(Bundle icicle) {
                super.onCreate(icicle);
                createConnection();
            }

            public void createConnection() {
                m_ProgressDialog = ProgressDialog.show(this, "Please wait...","Connection ...", true, false);
                thread = new Thread(this);
                thread.start();
            }

            public void run() {
                int i = connecTion();
                handler.sendEmptyMessage(i);
            }

            private Handler handler = new Handler() {

                @Override
                public void handleMessage(Message msg) {
                 if (msg.what == CONNECTION_ERROR) {                
                        m_ProgressDialog.dismiss();

                        AlertDialog.Builder alt_bld = new AlertDialog.Builder(thisA);
                        alt_bld.setMessage("Failed to connect to the server");
                        alt_bld.setCancelable(false);                                       
                        alt_bld.setNegativeButton("Quit",new DialogInterface.OnClickListener() {public void onClick(DialogInterface dialog, int id) {finish();}});
                        alt_bld.setPositiveButton("Try Again",new DialogInterface.OnClickListener() {
                                    public void onClick(DialogInterface dialog, int id) { 
//HERE IS THE PROBLEM
                                        /*m_ProgressDialog.show(thisA, "Please wait...", "Connection ...", true, false);
                                        connecTion();*/
                                    }
                                });

                        AlertDialog alert = alt_bld.create();
                        alert.setTitle("ChatApp");
                        alert.setIcon(R.drawable.icon);
                        alert.show();
                    }
                    else {          
                    m_ProgressDialog.dismiss();
                    finish();
                    }
                }
            };

            private int connecTion() {      
                /** Create a connection */        
                try {

                           //Function to create the connection (throwing error if there is a pb)

                } catch (Exception e) {
                    Log.e("App","Failed to connect");
                    return CONNECTION_ERROR;
                }               
                //If no error left, everything is OK
                return CONNECTION_DONE;

            }

I want to realize a "Try Again" button which launch again the thread to create the connection and the ProgressDialog in parallel. How can I kill the "old" thread and create the new one properly? Is it better to keep the same thread alive and just dealing with Handler and Messages? Use service?

Thank you !