title: When will MeasureSpec.UNSPECIFIED and MeasureSpec.AT_MOST be applied?
body: <p>I am a bit confused about <code>MeasureSpec.UNSPECIFIED</code> and <code>MeasureSpec.AT_MOST</code>.
  I know that when <code>match_parent</code> or an constant dimension value is set to <code>layout_width</code> or <code>layout_height</code>, <code>MeasureSpec.EXACTLY</code> will be applied when measuring the view.</p>
  
  <p>Then, how about <code>MeasureSpec.UNSPECIFIED</code> and <code>MeasureSpec.AT_MOST</code>?</p>
  
  <p>My understanding is that, when <code>layout_width</code> or <code>layout_height</code> is set to <code>wrap_content</code>, <code>MeasureSpec.UNSPECIFIED</code> will be applied, because <code>wrap_content</code> means the height or width of a view can be any size depending on the content. But many articles said that <code>wrap_content</code> means <code>MeasureSpec.AT_MOST</code>. So I am confused. I don't know when <code>MeasureSpec.AT_MOST</code> should be applied.</p>