content: function init()
    m.category_list=m.top.findNode("category_list")
  	m.category_list.setFocus(true)
  	m.top.observeField("visible", "onVisibleChange")
  end function
  
  ' set proper focus to rowList in case if return from Details Screen
  sub onVisibleChange()
    if m.top.visible = true then
      m.category_list.setFocus(true)
    end if
  end sub
  
  function updateConfig(params)
  	categories = params.config.categories
  	contentNode = createObject("roSGNode","ContentNode")
    for each category in categories
      node = createObject("roSGNode","category_node")
      node.title = category.title
      node.feed_url = params.config.host + category.feed_url
      contentNode.appendChild(node)
    end for
  	m.category_list.content = contentNode
  end function
  