Where or how is it possible (if it is...) to add some layout to an app with P3???

with Eclipse with or without P3 i can easily , from xml or from code, add a layout to an app. I have tried to do the same with P3 (coding) with this simple code (importing what is needed)

             Activity act;

            act = this.getActivity() // which is "said" an error by P3, i dont understand why as this is the way to do in a fragment
            //yet does not matter as it compiles....

            layout = new LinearLayout(act);

                tv = new TextView(act);
            layout.setLayoutParams(new ViewGroup.LayoutParams(-1,-1));
                tv.setLayoutParams(new ViewGroup.LayoutParams(-1,-2));
                 tv.setText("Hello world!");
            tv.setId(2);

                layout.addView(tv);

---- not any error in the console ----the sketch is launched "successfully" ---- the app crashes on the device (real one) ---- not any error message returned....

-----then i have tried to create manually and put some layout: :: but where ??? -----i have created a layout folder in res, given an hard coded id to the layout but when i want to inflate it (in another fragment) i get an error saying that this resource does not exist