javascript - Focus style for TextInput in react-native

Question

In React Native, how do you change the style of a textInput when it gets focus? Say I have something like

class MyInput extends Component {
    render () {
        return <TextInput style={styles.textInput} />;
    }
};

const stylesObj = {
    textInput: {
        height: 50,
        fontSize: 15,
        backgroundColor: 'yellow',
        color: 'black',
    }
};
const styles = StyleSheet.create(stylesObj);

And I want to change the background color on focus to green.

This documentation leads me to believe that the solution is something like

class MyInput extends Component {
    constructor (props) {
        super(props);
        this.state = {hasFocus: false};
    }

    render () {
        return (<TextInput
            style={this.state.hasFocus ? styles.focusedTextInput : styles.textInput}
            onFocus={this.setFocus.bind(this, true)}
            onBlur={this.setFocus.bind(this, false)}
        />);
    }

    setFocus (hasFocus) {
        this.setState({hasFocus});
    }
};

const stylesObj = {
    textInput: {
        height: 50,
        fontSize: 15,
        backgroundColor: 'yellow',
        color: 'black',
    }
};
const styles = StyleSheet.create({
    ...stylesObj,
    focusedTextInput: {
        ...stylesObj,
        backgroundColor: 'green',
    }
});

Ignoring potential mistakes in the styles structuring, would this be considered correct way to handle it? It seems very verbose to me.

Answer 1

You can achieve this by passing in the onFocus and onBlur events to set and unset styles when focused and blurred:

  onFocus() {
    this.setState({
        backgroundColor: 'green'
    })
  },

  onBlur() {
    this.setState({
      backgroundColor: '#ededed'
    })
  },

And then, in the TextInput do this:

<TextInput 
    onBlur={ () => this.onBlur() }
    onFocus={ () => this.onFocus() }
    style={{ height:60, backgroundColor: this.state.backgroundColor, color: this.state.color }}  />

I've set up a full working project here. I hope this helps!

https://rnplay.org/apps/hYrKmQ

'use strict';

var React = require('react-native');
var {
  AppRegistry,
  StyleSheet,
  Text,
  View,
  TextInput
} = React;

var SampleApp = React.createClass({

  getInitialState() {
    return {
        backgroundColor: '#ededed',
      color: 'white'
    }
  },

  onFocus() {
        this.setState({
        backgroundColor: 'green'
    })
  },

  onBlur() {
    this.setState({
      backgroundColor: '#ededed'
    })
  },

  render: function() {
    return (
      <View style={styles.container}>
       <TextInput 
        onBlur={ () => this.onBlur() }
        onFocus={ () => this.onFocus() }
        style={{ height:60, backgroundColor: this.state.backgroundColor, color: this.state.color }}  />
      </View>
    );
  }
});

var styles = StyleSheet.create({
  container: {
    flex: 1,
    marginTop:60
  }
});

AppRegistry.registerComponent('SampleApp', () => SampleApp);