Ok, I decided to do It in this way. I created the dialog to ask the user for the values, with lineEdits and one button that I decides that will run the process. So, what I was looking for was to launch the other dialog in the redFang button of the main menu. I did It like this:
I added in main.cpp and in btscanning.cpp, the include: #include "redfangdialog.h", and in the slot of the button of the main menu I did:
static Form1 *dialog = new Form1(this);
dialog->show();
dialog->setActiveWindow();
dialog->raise();

and the dialog appears, but it appears in the same window of the other gui, and it hides everything.I want that the dialog appears in another window, how can I do it?