title: Is it possible to center a layout/view inside CoordinatorLayout?
body: <p>I have a <code>FrameLayout</code> inside <code>CoordinatorLayout</code> to inflate my fragments which contain <code>RecyclerView</code>. The thing is, I want to display a progress bar when loading the <code>RecyclerView</code>, but the progress bar is always at the top of the screen under the <code>Toolbar</code>. I have tried various layouts, setting <code>gravity</code> or <code>centerInParent</code> but none had worked. So is there any way to achieve this?</p>