title: fontFamily is not a system font and has not been loaded through Font.loadAsync But with Font.loadAsync
body: <p>I'm learning react native by creating some projects.</p>
  <p>I got stuck and unable to load custom fonts. I've followed <a href="https://docs.expo.io/guides/using-custom-fonts/" rel="nofollow noreferrer">this</a> guide from expo docs. but I'm getting an error</p>
  <blockquote>
  <p>fontFamily &quot;raleway-bold&quot; is not a system font and has not been loaded
  through Font.loadAsync.</p>
  </blockquote>
  <p>Then I have use this <code>Font.loadAsync</code> in my code but I still get the same error.</p>
  <p>Any suggestions?</p>
  <pre><code>import React, { useState } from 'react';
  import Home from './screens/Home';
  import AppLoading from 'expo-app-loading';
  import * as Font from 'expo-font';
  
  const getFonts = () =&gt;
    Font.loadAsync({
      'raleway-regular': require('./assets/fonts/Raleway-Regular.ttf'),
      'raleway-bold': require('./assets/fonts/Raleway-Bold.ttf'),
    });
  
  export default function App() {
    const [fontsLoaded, setFontsLoaded] = useState(false);
  
    if (fontsLoaded) {
      return &lt;Home /&gt;;
    } else {
      return (
        &lt;AppLoading
          startAsync={getFonts}
          onFinish={() =&gt; setFontsLoaded(true)}
          onError={console.warn}
        /&gt;
      );
    }
  }
  </code></pre>