Android text (s) superimposed on a button

inside the linear layout I need to overlay some text views with a transparent button that fills the entire layout size (width / height). I tried with the layout properties of the parent layout, but this does not work. Thank you for your help.

<LinearLayout
                android:id="@+id/layout1"
                android:layout_width="38dp"
                android:layout_height="match_parent"
                android:gravity="bottom"
                android:orientation="vertical" >

                <TextView
                    android:id="@+id/TVBlack"
                    android:layout_width="28dp"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center|bottom"
                    android:background="@color/black"
                    android:text="test"
                    android:textColor="@color/white" />

                <TextView
                    android:id="@+id/TVWhite"
                    android:layout_width="28dp"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center|bottom"
                    android:text="test"
                    android:textColor="@color/black" />

                <Button
                    android:id="@+id/button1"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:background="@null"
                    android:text="Button" />

            </LinearLayout>