android: displaying progress dialog when waiting for connection

I am trying to add a progress dialog when a new activity is launched that has to wait for a response from the internet. At the moment the screen just goes black while it is waiting. Does any one know where it needs to be placed to work?

this progressDialog:

ProgressDialog dialog = ProgressDialog.show(SearchActivity.this, "", "Loading. Please wait...", true);
dialog.dismiss();

this is in the overlayActivity extends ItemizedOverlay:

@Override
protected boolean onTap(int index) {
    final OverlayItem item = (OverlayItem) items.get(index);
    final Context mContext = context;
    AlertDialog.Builder builder = new AlertDialog.Builder(mContext);
    builder.setTitle(item.getTitle())
    .setCancelable(true)
    .setPositiveButton("View Details", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int id) {
            Intent intent = new Intent(mContext, Profile.class);
            intent.putExtra("id", item.getSnippet());
            mContext.startActivity(intent);
        }
    });
    AlertDialog alert = builder.create();
    alert.show();
    return true;
}

and this is the Profile activity:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.profile);
    Bundle extras = getIntent().getExtras(); 
    String id;

    if (extras != null) {
        id = extras.getString("id");

        String xml = XMLfunctions.getXMLFromBarId(id); // makes httpPost call
        Document doc = XMLfunctions.XMLfromString(xml);
        NodeList nodes = doc.getElementsByTagName("result");
        Element e = (Element)nodes.item(0);

        // rest of profile created here 
    }
}

You should use Progress dialog. Progress dialog should be used in the Profile activity. You can use the following code:

    final ProgressDialog dialog = ProgressDialog.show(MyProfileActivity.this, "","Loading..Wait.." , true);
dialog.show();
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
    public void run() {
        //your code here
                dialog.dismiss();
    }   
}, 3000);  // 3000 milliseconds