Can I make dynamic styles in React Native?

Question

Say I have a component with a render like this:

Where jewelStyle =

  {
    bo         


        

Answer 1

I know this is extremely late, but for anyone still wondering here's an easy solution.

You could just make an array for the styles :

this.state ={
   color: "#fff"
}

style={[
  styles.jewelstyle, {
  backgroundColor: this.state.BGcolor
}

The second will override any original background color as stated in the stylesheet. Then have a function that changes the color:

generateNewColor(){
  var randomColor = '#'+Math.floor(Math.random()*16777215).toString(16);
  this.setState({BGcolor: randomColor})
}

This will generate a random hex color. Then just call that function whenever and bam, new background color.

Answer 2

You'll want something like this:

var RandomBgApp = React.createClass({
    render: function() {

        var getRandomColor = function() {
            var letters = '0123456789ABCDEF'.split('');
            var color = '#';
            for (var i = 0; i < 6; i++ ) {
                color += letters[Math.floor(Math.random() * 16)];
            }
            return color;
        };

        var rows = [
            { name: 'row 1'},
            { name: 'row 2'},
            { name: 'row 3'}
        ];

        var rowNodes = rows.map(function(row) {
            return <Text style={{backgroundColor:getRandomColor()}}>{row.name}</Text>
        });

        return (
            <View>
                {rowNodes}
            </View>
        );

    }
});

In this example I take the rows array, containing the data for the rows in the component, and map it into an array of Text components. I use inline styles to call the getRandomColor function every time I create a new Text component.

The issue with your code is that you define the style once and therefore getRandomColor only gets called once - when you define the style.

Answer 3

I know there are several answers, but i think the best and most simple is using a state "To change" is the state purpose.

export default class App extends Component {
    constructor(props) {
      super(props);
      this.state = {
          style: {
              backgroundColor: "white"
          }
      };
    }
    onPress = function() {
      this.setState({style: {backgroundColor: "red"}});
    }
    render() {
       return (
          ...
          <View style={this.state.style}></View>
          ...
       )
    }

}

Answer 4

Yes you can and actually, you should use StyleSheet.create to create your styles.

import React, { Component } from 'react';
import {
    StyleSheet,
    Text,
    View
} from 'react-native';    

class Header extends Component {
    constructor(props){
        super(props);
    }    

    render() {
        const { title, style } = this.props;
        const { header, text } = defaultStyle;
        const combineStyles = StyleSheet.flatten([header, style]);    

        return (
            <View style={ combineStyles }>
                <Text style={ text }>
                    { title }
                </Text>
            </View>
        );
    }
}    

const defaultStyle = StyleSheet.create({
    header: {
        justifyContent: 'center',
        alignItems: 'center',
        backgroundColor: '#fff',
        height: 60,
        paddingTop: 15,
        shadowColor: '#000',
        shadowOffset: { width: 0, height: 3 },
        shadowOpacity: 0.4,
        elevation: 2,
        position: 'relative'
    },
    text: {
        color: '#0d4220',
        fontSize: 16
    }
});    

export default Header;

And then:

<Header title="HOME" style={ {backgroundColor: '#10f1f0'} } />

Answer 5

The easiest is mine:

<TextInput
  style={[
    styles.default,
    this.props.singleSourceOfTruth ?
    { backgroundColor: 'black' } 
    : { backgroundColor: 'white' }
]}/>

Answer 6

Using object spread operator "..." worked for me:

<View style={{...jewelStyle, ...{'backgroundColor': getRandomColor()}}}></View>