Android setMultiChoiceItems with no space between items

Question

I'm using an android AlertDialog (setMultiChoiceItems) to show a list of items. If I use target 26 in gradle there is no separetion line and the items are very close to each other. If I use a ListView I can put a separetion line but I have the same problem for spacing between items.

Any suggestions?

Thanks

base setMultiChoiceItems

adb_scelta = new AlertDialog.Builder(MainActivity.this);
                            adb_scelta.setTitle(getResources().getText(R.string.adb_scelta_title));
                            adb_scelta.setMultiChoiceItems(lista_con_num, selections,new DialogSelectionClick());
                            adb_scelta.setPositiveButton(getResources().getText(R.string.prosegui_min), new ClickPositiveButton());
                            adb_scelta.create();
                            adb_scelta.show();

ListView setMultiChoiceItems

 final CharSequence[] tags =lista_con_num;
                            adb_scelta = new AlertDialog.Builder(MainActivity.this);
                            adb_scelta.setMultiChoiceItems(tags, selections,new DialogSelectionClick());
                            adb_scelta.setPositiveButton(getResources().getText(R.string.prosegui_min), new ClickPositiveButton());
                            AlertDialog alertDialogObject = adb_scelta.create();
                            ListView listView_=alertDialogObject.getListView();
                            listView_.setDivider(new ColorDrawable(ContextCompat.getColor(getBaseContext(), R.color.Grigio_leggero))); // set color
                            listView_.setDividerHeight(2); // set height
                            alertDialogObject.show();

base setMultiChoiceItems image

ListView setMultiChoiceItems image