title: Selecting child view at index using Espresso
body: <p>With Espresso when using a custom widget view with child image views, which Matcher type can I use to select the nth child?
  Example:</p>
  
  <pre><code>+---------&gt;NumberSlider{id=2131296844, res-name=number_slider, visibility=VISIBLE, width=700, height=95, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=false, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=10.0, y=0.0, child-count=7}
  |
  +----------&gt;NumberView{id=-1, visibility=VISIBLE, width=99, height=95, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=0.0, y=0.0}
  |
  +----------&gt;NumberView{id=-1, visibility=VISIBLE, width=100, height=95, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=99.0, y=0.0}
  |
  +----------&gt;NumberView{id=-1, visibility=VISIBLE, width=100, height=95, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=199.0, y=0.0}
  |
  +----------&gt;NumberView{id=-1, visibility=VISIBLE, width=100, height=95, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=299.0, y=0.0}
  |
  +----------&gt;NumberView{id=-1, visibility=VISIBLE, width=100, height=95, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=399.0, y=0.0}
  |
  +----------&gt;NumberView{id=-1, visibility=VISIBLE, width=100, height=95, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=499.0, y=0.0}
  |
  +----------&gt;NumberView{id=-1, visibility=VISIBLE, width=100, height=95, has-focus=false, has-focusable=false, has-window-focus=true, is-clickable=true, is-enabled=true, is-focused=false, is-focusable=false, is-layout-requested=false, is-selected=false, root-is-layout-requested=false, has-input-connection=false, x=599.0, y=0.0}
  </code></pre>