Try putting the ImageView
inside a LinearLayout
...then inflate that layout.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<ImageButton
android:id="@+id/btnTourStartGame"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="32dp"
android:background="@drawable/tour_btn_start"/>
</LinearLayout>
Inflate as follows...
View view = inflater.inflate(R.layout.button_tour_start, ltTourScreenLast, false);
ImageButton startButton = (ImageButton)view.findViewById(R.id.btnTourStartGame);
startButton.setOnClickListener(this);
ltTourScreenLast.addView(view);