120 lines
4.2 KiB
Markdown
120 lines
4.2 KiB
Markdown
---
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title: Styling
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---
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## React Native - Styling
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React Native provides an API for creating stylesheets and styling your components: [Documentation on Stylesheets](https://facebook.github.io/react-native/docs/stylesheet).
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```jsx
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import React, { Component } from 'react';
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import { StyleSheet, View, Text } from 'react-native';
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export default class App extends Component {
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render() {
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return (
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<View>
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<Text style={styles.header}>I am a header!</Text>
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<Text style={styles.text}>I am some blue text.</Text>
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</View>
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);
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}
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}
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const styles = StyleSheet.create({
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header: {
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fontSize: 20,
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},
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text: {
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color: 'blue',
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},
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});
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```
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While regular CSS stylesheets aren't valid, React Native's superset of CSS is very similar to traditional CSS. Many CSS properties (e.g. `color`, `height`, `top`, `right`, `bottom`, `left`) are the same in StyleSheet. Any CSS properties that have hyphens (e.g. `font-size`, `background-color`) must be changed to camelCase (e.g. `fontSize`, `backgroundColor`).
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Not all CSS properties exist in StyleSheet. Since there is no true concept of hovering on mobile devices, CSS hover properties don't exist in React Native. Instead, React Native provides [Touchable components](https://facebook.github.io/react-native/docs/handling-touches#touchables) that respond to touch events.
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Styles are also not inherited, as they are in traditional CSS. In most cases, you must declare the style of each component.
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### Flexbox Layouts
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React Native uses an implementation of [flexbox](https://facebook.github.io/react-native/docs/flexbox), similar to the web standard. By default, items in the view will be set to `display: flex`.
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> If you do not want to use flexbox, you can also arrange React Native components via `relative` or `absolute` positioning.
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Flexbox in React Native defaults to `flexDirection: column`, instead of `flex-direction: row` (web standard). The `column` value displays flexible items vertically, which accommodates mobile devices in portrait orientation.
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To learn more about flexbox, visit [this detailed guide on CSS-Tricks](https://css-tricks.com/snippets/css/a-guide-to-flexbox/) and a gamified learning approach with [Flexbox Froggy](http://flexboxfroggy.com/).
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### Styled Components
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Including lots of styles in a file with a component isn't always easy to maintain. Styled components can solve this issue.
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For example, a Button component may be used in multiple places across an application. Copying and pasting the style object with each Button instance would be inefficient. Instead, create a reusable, styled Button component:
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```jsx
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import React from 'react';
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import { Text, TouchableOpacity } from 'react-native';
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const Button = ({ onPress, children }) => {
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const { buttonStyle, textStyle } = styles;
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return (
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<TouchableOpacity onPress={onPress} style={buttonStyle}>
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<Text style={textStyle}>{children}</Text>
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</TouchableOpacity>
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);
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};
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export default Button;
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const styles = {
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textStyle: {
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alignSelf: 'center',
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color: '#336633',
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fontSize: 16,
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fontWeight: '600',
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paddingTop: 10,
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paddingBottom: 10,
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},
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buttonStyle: {
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backgroundColor: '#fff',
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borderWidth: 1,
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borderColor: '#336633',
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paddingTop: 4,
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paddingBottom: 4,
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paddingRight: 25,
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paddingLeft: 25,
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marginTop: 10,
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width: 300,
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},
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};
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```
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The styled Button component can be easily imported and used across the application without repeatedly declaring the style object:
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```jsx
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import React, { Component } from 'react';
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import { TextInput, View } from 'react-native';
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import Button from './styling/Button';
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export default class Login extends Component {
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render() {
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return (
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<View>
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<TextInput placeholder="Username or Email" />
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<TextInput placeholder="Password" />
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<Button>Log In</Button>
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</View>
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);
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}
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}
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```
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### Libraries for Styling
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There are a few popular libraries for styling React Native. Some of them provide features similar to [Bootstrap](../../bootstrap/index.md); including default forms, button styles, and page layout options.
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One of the most popular libraries is [styled-components](https://github.com/styled-components/styled-components). There are many others you can find on npm and GitHub to try for yourself.
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