title: confused between gravity, alignparent, aligncomponent,
body: <p>I'm new to Android programming, and I try to do a simple app first, but I need to understand how to arrange items with one another. There are xml attributes called gravity, layout_gravity, alignParentLeft, alignComponent, ... </p>
  
  <p>It seems to me that, for instance, gravity="left" and alignParentRight="true" will be contradictory. Am I wrong? What's the difference between these alignment attributes?</p>
  
  <p>Thanks</p>