title: React Native Android TextInput placeholder style not completely updating
body: <p>I am trying to update the placeholder style of the TextInput component but on android its not completely updating the style. </p>
  
  <p>It starts off with the correct style but once the text field is updated then cleared certain styles are not being applied. Like, fontWeight or fontFamily. However, fontSize is changing ?!</p>
  
  <p>Here is my snak example: <a href="https://snack.expo.io/By2ijBW5X" rel="nofollow noreferrer">https://snack.expo.io/By2ijBW5X</a></p>
  
  <pre><code>export default class App extends Component {
    constructor(props) {
      super(props);
      this.state = {textStyle: styles.textPlaceholder };
    }
  
    onChangeHandle = (txt) =&gt; {
      this.setState({ textStyle: txt.length &gt; 0 ? styles.text : styles.textPlaceholder });
    }
  
    render() {
      return (
        &lt;View style={styles.container}&gt;
        &lt;Text style={this.state.textStyle}&gt;Text Input&lt;/Text&gt;
          &lt;TextInput 
            onChangeText={this.onChangeHandle}
            placeholder='Enter Input Here'
            style={[{ height: 50, width: 200 }, this.state.textStyle]}
            /&gt;
        &lt;/View&gt;
      );
    }
  }
  
  const styles = StyleSheet.create({
   container: {
      flex: 1,
      alignItems: 'center',
      paddingTop: 100,
      backgroundColor: '#ecf0f1',
    },
  
    text: {
      fontWeight: '900',
      fontSize: 20,
    },
  
    textPlaceholder: {
      fontWeight: '100',
      fontSize: 19,
   }
  });
  </code></pre>
  
  <p>Does anyone know why this is happening? or know of a workaround? </p>
  
  <p>Note: iOS is working correctly.</p>