问FrameLayout未显示在文本视图下

EN

public class MyRLayout extends android.support.v4.app.Fragment {

    public MyRLayout() {}

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        return inflater.inflate(R.layout.my_relativelayout, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        View v = getView();
        assert v != null;

        RelativeLayout relativelayout = v.findViewById(RelativeLayout_custom);

        RelativeLayout.LayoutParams rlp1 = new RelativeLayout.LayoutParams(GridLayout.LayoutParams.MATCH_PARENT, GridLayout.LayoutParams.WRAP_CONTENT);
        RelativeLayout.LayoutParams paramsP1 = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.WRAP_CONTENT);

        // add text view
        TextView tv1 = new TextView(getActivity());
        tv1.setText("Hello World");
        TextViewCompat.setTextAppearance(tv1, android.R.style.TextAppearance_Medium);
        tv1.setTextColor(Color.WHITE);
        tv1.setGravity(Gravity.CENTER);

        // set view for drawing1
        FrameLayout frameLayoutP1 = new FrameLayout(getActivity());
        paramsP1.height = fortyDp;
        Drawing1 cvDrawing1 = new Drawing1(getActivity());
        cvDrawing1.setLayoutParams(paramsP1);
        frameLayoutP1.addView(cvDrawing1);

        // generate IDs for views
        tv1.setId(View.generateViewId());
        frameLayoutP1.setId(View.generateViewId());

        // set RelativeLayout rules for views
        paramsP1.addRule(RelativeLayout.BELOW, tv1.getId());

        // setLayoutParams for views
        tv1.setLayoutParams(rlp1);

        // add views to RelativeLayout
        relativelayout.addView(tv1);
        relativelayout.addView(frameLayoutP1);

        super.onActivityCreated(savedInstanceState);
    }
}