Android : Dialog And Nullpointerexception

I have the first activity that call a dialog from second activity with this code : public class negozi extends ListActivity implements dati_punti{ private Context context;

Solution 1:

Why do you create the class popup_segnala that extends Activity? You have to move onCreateDialog(int id) code in your main activity where you will simply call showDialog(OK_INSERT).

Moreover onCreateDialog must return a dialog object.