title: Icon not displaying on android screen using react-native-vector-icons
body: <p>I am new to react-native and<a href="https://i.stack.imgur.com/z3YHt.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/z3YHt.png" alt="enter image description here"></a> trying to implement tab navigator. I am using react-native-vector-icons. i tried to display icon in my screen but It isn't showing me any icon.Here is what I did</p>
  
  <blockquote>
    <p>1-npm install react-native-vector-icons --save</p>
    
    <p>2-react-native link react-native-vector-icons</p>
    
    <p>3-Edited android/app/build.gradle</p>
  </blockquote>
  
  <pre><code>  project.ext.vectoricons = [
          iconFontNames: [ 'MaterialIcons.ttf', 'EvilIcons.ttf' ] 
      ]
    apply from: "../../node_modules/react-native-vector-icons/fonts.gradle"
  </code></pre>
  
  <blockquote>
    <p>4- react-native run-android</p>
  </blockquote>
  
  <pre><code>import React, { Component } from 'react'; 
  import { StyleSheet, Text, View,Image,StatusBar,Button,TouchableOpacity} from 'react-native';
  import { createBottomTabNavigator, createAppContainer } from 'react-navigation';
  import Icon from 'react-native-vector-icons/Ionicons';
  import profile from './profile';
  
  export  class test extends Component
  { render()
      { 
          return (
              &lt;View style={styles.container}&gt;
                   &lt;Text style={styles.text}&gt;Test&lt;/Text&gt;
                   &lt;/View&gt;
               );
      }
  }
  export default createBottomTabNavigator({
  'test':{screen:test,
  navigationOption:{
  tabBarLabel:'test',
  tabBarIcon:({tintColor})=&gt;(
  &lt;Icon name="rocket" color={tintColor} size={40}/&gt;
   )}},
   'Profile': { screen:profile,
      navigationOption:{
          tabBarLabel:'profile',
          tabBarIcon:({tintColor})=&gt;(
              &lt;Icon name="rocket" color={tintColor} size={40}/&gt;
  ) } }     
  },{
  
      navigationOption:{
          tabBarVisible:true
      },   
      tabBarOptions:{
          activeTintColor:'red',
          inactiveTintColor:'grey'
      }
  });
  
  const styles= StyleSheet.create({
      container:{
                   flexGrow:1,
  
                    backgroundColor:'#1c313a',
                  justifyContent:'center',
                  alignItems:'center'
                },
                  text:{
                  fontSize:25,
                  fontWeight:'500',
                  color :'#fff',
                  paddingHorizontal:16 ,
                  textAlign:'center'
                 }
  });
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/z3YHt.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/z3YHt.png" alt="enter image description here"></a></p>