title: How to make a GridLayout fit screen size
body: <p>The <code>GridLayout</code> API docs is very difficult to learn ...... <br>is there any one who can teach me how to set child <code>View</code>s to have something like "weight" of <code>LinearLayout</code> ?</p>
  
  <p>Right now it looks like all are placed on the left hand side, <br>I have tried many times and still can not make it like each one the half width of the screen.</p>
  
  <p>Edited :  I don't know what can I do for when the childen are all <code>wrap_content</code> ......
      even if I want to set some image in specific size , this class helps me to make <code>ImageView</code> <code>wrap_content</code> .........it cannot operate normal , did I miss some setting ?!?</p>