public class Upload extends MapActivity{

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.upload_activity);

Button selectPoint = (Button) findViewById(R.id.selectPoint);
        selectPoint.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
//showMapDialog();
Dialog dialog = new Dialog(Upload.this);
dialog.setTitle("Select Map Point");
dialog.setCancelable(true);
dialog.setContentView(R.layout.map_dialog);
dialog.show();
            }
        });

}

}

public class HelloGoogleMaps extends MapActivity {

MapView m = (MapView) findViewById(R.id.YourMapView);
dialog.setContentView(m);