text: import React from 'react';
  import { TabNavigator } from 'react-navigation';
  import SessionList   from '../page/SessionList';
  import FriendList    from '../page/FriendList';
  import RequestList   from '../page/RequestList';
  
  export default TabNav = TabNavigator({
      SessionList:{ 
          screen:SessionList,
          navigationOptions:{
              tabBarLabel: '聊天',
          }
      },
      FriendList:{
          screen:FriendList,
          navigationOptions:{
              tabBarLabel: '好友',
          }
      },
      RequestList:{
          screen:RequestList,
          navigationOptions:{
              tabBarLabel: '好友申请',
          }
      }
  },{
      tabBarPosition: 'bottom',
      inactiveBackgroundColor: 'white',
  });