Have looked at other examples and trying to do the same thing but not sure why my code is not working. I have code which loops through some keys and renders a div. I want to conditionally apply some styles based on whether the key is even or odd. Example:
<div className={parseInt(key) % 2 === 0 ? 'label1' : 'label2' }>
<span style={{ marginLeft: "10px" }}>{key}:00</span>
</div>
The styles are accessible in the same file and look something like:
# Material UI
const useStyles = makeStyles((theme) => ({
label1: {
width: "50px",
height: "16px",
top: "458px",
background: "yellow",
fontSize: "12px",
},
label2: {
width: "50px",
height: "16px",
top: "458px",
background: "red",
fontSize: "12px",
},
}));
What am I doing wrong? Currently no style is getting applied to the div
You need to use the classes from the material ui useStyles hook.
const classes = useStyles()
....
<div className={parseInt(key) % 2 === 0 ? classes.label1 : classes.label2 }>
<span style={{ marginLeft: "10px" }}>{key}:00</span>
</div>
Check the useStyles hook api: https://material-ui.com/styles/basics/
If you have a class component and you can use hooks then you can do it with the withStyles higher order component, like this example:
import { withStyles } from "#material-ui/core/styles"
const styles = theme => ({
label1: {
backgroundColor: "red",
},
label2: {
backgroundColor: "red",
},
})
class ClassComponent extends Component {
state = {
searchNodes: "",
}
render() {
const { classes } = this.props
return (
<div className={parseInt(key) % 2 === 0 ? classes.label1 : classes.label2}>
<span style={{ marginLeft: "10px" }}>{key}:00</span>
</div>
)
}
}
export default withStyles(styles, { withTheme: true })(ClassComponent)
I have a scrollbar in multiple lists in the React app.
My global CSS within Material-UI is:
MuiCssBaseline: {
...theme.overrides?.MuiCssBaseline,
'#global': {
'#font-face': fontFace,
'*::-webkit-scrollbar': {
width: '1.3%',
maxWidth: '5px'
},
'*::-webkit-scrollbar-thumb': {
backgroundColor: 'white'
},
'*:focus': {
outline: 'none'
}
}
}
};
I am trying to add global state for hover.
When I hover on the box(!) not on the scroll itself, the scrollbar should be changed to gray.
Let's say I have box like:
<Box className={listStyle.root}>
<AutoSizer>
{({ height, width }) => (
<List dense ......
return (
<ListItem
/>
);
})}
</List>
)}
</AutoSizer>
I tried something like the following and it's not working:
.listStyle:{
'&:hover':{
'*::-webkit-scrollbar-thumb': {
backgroundColor: 'gray'
},
}
}
How can I achieve that?
The primary issue I see is that when nesting a rule (e.g. ::-webkit-scrollbar-thumb pseudo-element within :hover pseudo-class), you need to use & to refer to the parent rule instead of using *. So your listStyle should look like:
.listStyle:{
'&:hover':{
'&::-webkit-scrollbar-thumb': {
backgroundColor: 'gray'
},
}
}
It would also be equivalent to do the following:
.listStyle:{
'&:hover::-webkit-scrollbar-thumb': {
backgroundColor: 'gray'
}
}
If you want to apply this globally, you can do something like the following (I've changed the colors just to make the effects more easily distinguishable from browser defaults):
const theme = createMuiTheme({
overrides: {
MuiCssBaseline: {
"#global": {
"*::-webkit-scrollbar": {
width: "1.3%",
maxWidth: "5px"
},
"*::-webkit-scrollbar-thumb": {
backgroundColor: "purple"
},
"*:hover": {
"&::-webkit-scrollbar-thumb": {
backgroundColor: "green"
}
}
/* Equivalent alternative:
"*:hover::-webkit-scrollbar-thumb": {
backgroundColor: "green"
}
*/
}
}
}
});
Here is a full example showing both the global approach and overriding that using a class name at a lower level:
import React from "react";
import CssBaseline from "#material-ui/core/CssBaseline";
import {
ThemeProvider,
createMuiTheme,
makeStyles
} from "#material-ui/core/styles";
const theme = createMuiTheme({
overrides: {
MuiCssBaseline: {
"#global": {
"*::-webkit-scrollbar": {
width: "1.3%",
maxWidth: "5px"
},
"*::-webkit-scrollbar-thumb": {
backgroundColor: "purple"
},
"*:hover": {
"&::-webkit-scrollbar-thumb": {
backgroundColor: "green"
}
}
/* Equivalent alternative:
"*:hover::-webkit-scrollbar-thumb": {
backgroundColor: "green"
}
*/
}
}
}
});
const useStyles = makeStyles({
divStyle: {
"&:hover::-webkit-scrollbar-thumb": {
backgroundColor: "red"
}
}
});
export default function App() {
const classes = useStyles();
return (
<ThemeProvider theme={theme}>
<CssBaseline />
<div style={{ height: "200px", overflowY: "scroll" }}>
<h1>
Div with enough content to scroll. Globally controlled scrollbar hover
color
</h1>
<h2>1</h2>
<h2>2</h2>
<h2>3</h2>
<h2>4</h2>
<h2>5</h2>
<h2>6</h2>
</div>
<div
style={{ height: "200px", overflowY: "scroll" }}
className={classes.divStyle}
>
<h1>
Div with enough content to scroll. Scrollbar hover color controlled by
classes.divStyle.
</h1>
<h2>1</h2>
<h2>2</h2>
<h2>3</h2>
<h2>4</h2>
<h2>5</h2>
<h2>6</h2>
</div>
</ThemeProvider>
);
}
Say I have a component with a render like this:
<View style={jewelStyle}></View>
Where jewelStyle =
{
borderRadius: 10,
backgroundColor: '#FFEFCC',
width: 20,
height: 20,
},
How could I make the background colour dynamic and randomly assigned? I've tried
{
borderRadius: 10,
backgroundColor: getRandomColor(),
width: 20,
height: 20,
},
But this makes all instances of View have the same colour, I want each one to be unique.
Any tips?
I usually do something along the lines of:
<View style={this.jewelStyle()} />
...
jewelStyle = function(options) {
return {
borderRadius: 12,
background: randomColor(),
}
}
Every time View is rendered, a new style object will be instantiated with a random color associated with it. Of course, this means that the colors will change every time the component is re-rendered, which is perhaps not what you want. Instead, you could do something like this:
var myColor = randomColor()
<View style={jewelStyle(myColor)} />
...
jewelStyle = function(myColor) {
return {
borderRadius: 10,
background: myColor,
}
}
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'} } />
If you still want to take advantage of StyleSheet.create and also have dynamic styles, try this out:
const Circle = ({initial}) => {
const initial = user.pending ? user.email[0] : user.firstName[0];
const colorStyles = {
backgroundColor: randomColor()
};
return (
<View style={[styles.circle, colorStyles]}>
<Text style={styles.text}>{initial.toUpperCase()}</Text>
</View>
);
};
const styles = StyleSheet.create({
circle: {
height: 40,
width: 40,
borderRadius: 30,
overflow: 'hidden'
},
text: {
fontSize: 12,
lineHeight: 40,
color: '#fff',
textAlign: 'center'
}
});
Notice how the style property of the View is set as an array that combines your stylesheet with your dynamic styles.
The easiest is mine:
<TextInput
style={[
styles.default,
this.props.singleSourceOfTruth ?
{ backgroundColor: 'black' }
: { backgroundColor: 'white' }
]}/>
Had some issue syntactically.
This worked for me
<Text style={[styles.textStyle,{color: 'red'}]}> Hello </Text>
const styles = StyleSheet.create({
textStyle :{
textAlign: 'center',
fontFamily: 'Arial',
fontSize: 16
}
});
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.
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.
Actually, you can write your StyleSheet.create object as a key with function value, it works properly but it has a type issue in TypeScript:
import React from 'react';
import { View, Text, StyleSheet } from 'react-native';
const SomeComponent = ({ bgColor }) => (
<View style={styles.wrapper(bgColor)}>
<Text style={styles.text}>3333</Text>
</View>
);
const styles = StyleSheet.create({
wrapper: color => ({
flex: 1,
backgroundColor: color,
}),
text: {
color: 'red',
},
});
import React, { useContext, useMemo } from 'react';
import { Text, StyleSheet, View } from 'react-native';
import colors from '../utils/colors';
import ThemeContext from './../contexts/ThemeContext';
export default (props) => {
const { theme } = useContext(ThemeContext);
// Constructing styles for current theme
const styles = useMemo(() => createStyles(theme), [theme]);
return (
<View style={styles.container}>
<Text style={styles.label}>{label}</Text>
</View>
);
};
const createStyles = (theme: AppTheme) =>
StyleSheet.create({
container: { width: '100%', position: 'relative', backgroundColor: colors[theme].background },
label: {
fontSize: 13,
fontWeight: 'bold',
},
});
colors.ts
export type AppTheme = 'dark' | 'light';
const light: Colors = {
background: '#FFFFFF',
onBackground: '#333333',
gray: '#999999',
grayLight: '#DDDDDD',
red: 'red',
};
const dark: Colors = {
background: '#333333',
onBackground: '#EEEEEE',
gray: '#999999',
grayLight: '#DDDDDD',
red: 'red',
};
const colors = {
dark,
light,
primary: '#2E9767',
secondary: '#F6D130',
};
export default colors;
Using object spread operator "..." worked for me:
<View style={{...jewelStyle, ...{'backgroundColor': getRandomColor()}}}></View>
Yes, you can make dynamic styles. You can pass values from Components.
First create StyleSheetFactory.js
import { StyleSheet } from "react-native";
export default class StyleSheetFactory {
static getSheet(backColor) {
return StyleSheet.create({
jewelStyle: {
borderRadius: 10,
backgroundColor: backColor,
width: 20,
height: 20,
}
})
}
}
then use it in your component following way
import React from "react";
import { View } from "react-native";
import StyleSheetFactory from './StyleSheetFactory'
class Main extends React.Component {
getRandomColor = () => {
var letters = "0123456789ABCDEF";
var color = "#";
for (var i = 0; i < 6; i++) {
color += letters[Math.floor(Math.random() * 16)];
}
return color;
};
render() {
return (
<View>
<View
style={StyleSheetFactory.getSheet(this.getRandomColor()).jewelStyle}
/>
<View
style={StyleSheetFactory.getSheet(this.getRandomColor()).jewelStyle}
/>
<View
style={StyleSheetFactory.getSheet(this.getRandomColor()).jewelStyle}
/>
</View>
);
}
}
<View
style={[styles.categoryItem,{marginTop: index <= numOfColumns-1 ? 10 : 0 }]}
>
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>
...
)
}
}
You can bind state value directly to style object. Here is an example:
class Timer extends Component{
constructor(props){
super(props);
this.state = {timer: 0, color: '#FF0000'};
setInterval(() => {
this.setState({timer: this.state.timer + 1, color: this.state.timer % 2 == 0 ? '#FF0000' : '#0000FF'});
}, 1000);
}
render(){
return (
<View>
<Text>Timer:</Text>
<Text style={{backgroundColor: this.state.color}}>{this.state.timer}</Text>
</View>
);
}
}
If you are using a screen with filters for example, and you want to set the background of the filter regarding if it was selected or not, you can do:
<TouchableOpacity style={this.props.venueFilters.includes('Bar')?styles.filterBtnActive:styles.filterBtn} onPress={()=>this.setFilter('Bar')}>
<Text numberOfLines={1}>
Bar
</Text>
</TouchableOpacity>
On which set filter is:
setVenueFilter(filter){
var filters = this.props.venueFilters;
filters.push(filter);
console.log(filters.includes('Bar'), "Inclui Bar");
this.setState(previousState => {
return { updateFilter: !previousState.updateFilter };
});
this.props.setVenueFilter(filters);
}
PS: the function this.props.setVenueFilter(filters) is a redux action, and this.props.venueFilters is a redux state.
You can do something like this.
In your component:
const getRandomColor = () => {
// you can use your component props here.
}
<View style={[styles.jewelStyle, {backgroundColor: getRandomColor()}]} />
Create your style using stylesheet:
const styles = StyleSheet.create({
jewelStyle: {
backgroundColor: 'red',
},
});
If you are following the functional approach of React-Native, you can use a package called dynamic-styles that tries to solve exactly your problem.
// -- theme.js ------------------------------------------------------
// Initialization of a StyleSheet instance called 'styleSheet'
export const styleSheet = createStyleSheet({
theme: /* optional theme */
});
// -- MyComponent.js -----------------------------------------------
// Create dynamic stylesheet that has access
// to the previously specified theme and parameters
const useStyles = styleSheet.create(({theme, params}) => ({
root: /* Dynamic Styles */,
button: /* Dynamic Styles */,
text: /* Dynamic Styles */,
}));
const MyComponent = (props) => {
// Access dynamic styles using the created 'useStyles()' hook
// and specify the corresponding parameters
const { styles } = useStyles({ color: props.color, fontSize: 10 });
return (
<div className={styles.root}>
{/* */}
</div>
);
}
It basically allows you to create dynamic stylesheets
and link them to functional Components using the React hook pattern.
-> Codesandbox
In case someone needs to apply conditions
selectedMenuUI = function(value) {
if(value==this.state.selectedMenu){
return {
flexDirection: 'row',
alignItems: 'center',
paddingHorizontal: 20,
paddingVertical: 10,
backgroundColor: 'rgba(255,255,255,0.3)',
borderRadius: 5
}
}
return {
flexDirection: 'row',
alignItems: 'center',
paddingHorizontal: 20,
paddingVertical: 10
}
}
Here is what worked for me:
render() {
const { styleValue } = this.props;
const dynamicStyleUpdatedFromProps = {
height: styleValue,
width: styleValue,
borderRadius: styleValue,
}
return (
<View style={{ ...styles.staticStyleCreatedFromStyleSheet, ...dynamicStyleUpdatedFromProps }} />
);
}
For some reason, this was the only way that mine would update properly.
you can use styled-components for react native it will provide you dynamic styling just like emotion or styled-components for web.
For something relatively simple, you can use this approach:
StyleSheet.create({
item: props.selectedId === item.id ? {
backgroundColor: 'red',
}: null
});