0.57

Edit

Text

A React component for displaying text.

Text supports nesting, styling, and touch handling.

In the following example, the nested title and body text will inherit the fontFamily from styles.baseText, but the title provides its own additional styles. The title and body will stack on top of each other on account of the literal newlines:

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

export default class TextInANest extends Component {
  constructor(props) {
    super(props);
    this.state = {
      titleText: "Bird's Nest",
      bodyText: 'This is not really a bird nest.'
    };
  }

  render() {
    return (
      <Text style={styles.baseText}>
        <Text style={styles.titleText} onPress={this.onPressTitle}>
          {this.state.titleText}{'\n'}{'\n'}
        </Text>
        <Text numberOfLines={5}>
          {this.state.bodyText}
        </Text>
      </Text>
    );
  }
}

const styles = StyleSheet.create({
  baseText: {
    fontFamily: 'Cochin',
  },
  titleText: {
    fontSize: 20,
    fontWeight: 'bold',
  },
});

// skip this line if using Create React Native App
AppRegistry.registerComponent('TextInANest', () => TextInANest);

Nested text

Both iOS and Android allow you to display formatted text by annotating ranges of a string with specific formatting like bold or colored text (NSAttributedString on iOS, SpannableString on Android). In practice, this is very tedious. For React Native, we decided to use web paradigm for this where you can nest text to achieve the same effect.

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

export default class BoldAndBeautiful extends Component {
  render() {
    return (
      <Text style={{fontWeight: 'bold'}}>
        I am bold
        <Text style={{color: 'red'}}>
          and red
        </Text>
      </Text>
    );
  }
}

// skip this line if using Create React Native App
AppRegistry.registerComponent('AwesomeProject', () => BoldAndBeautiful);

Behind the scenes, React Native converts this to a flat NSAttributedString or SpannableString that contains the following information:

"I am bold and red"
0-9: bold
9-17: bold, red

Nested views (iOS only)

On iOS, you can nest views within your Text component. Here's an example:

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

export default class BlueIsCool extends Component {
  render() {
    return (
      <Text>
        There is a blue square
        <View style={{width: 50, height: 50, backgroundColor: 'steelblue'}} />
        in between my text.
      </Text>
    );
  }
}

// skip this line if using Create React Native App
AppRegistry.registerComponent('AwesomeProject', () => BlueIsCool);

In order to use this feature, you must give the view a width and a height.

Containers

The <Text> element is special relative to layout: everything inside is no longer using the flexbox layout but using text layout. This means that elements inside of a <Text> are no longer rectangles, but wrap when they see the end of the line.

<Text>
  <Text>First part and </Text>
  <Text>second part</Text>
</Text>
// Text container: all the text flows as if it was one
// |First part |
// |and second |
// |part       |

<View>
  <Text>First part and </Text>
  <Text>second part</Text>
</View>
// View container: each text is its own block
// |First part |
// |and        |
// |second part|

Limited Style Inheritance

On the web, the usual way to set a font family and size for the entire document is to take advantage of inherited CSS properties like so:

html {
  font-family: 'lucida grande', tahoma, verdana, arial, sans-serif;
  font-size: 11px;
  color: #141823;
}

All elements in the document will inherit this font unless they or one of their parents specifies a new rule.

In React Native, we are more strict about it: you must wrap all the text nodes inside of a <Text> component. You cannot have a text node directly under a <View>.

// BAD: will raise exception, can't have a text node as child of a <View>
<View>
  Some text
</View>

// GOOD
<View>
  <Text>
    Some text
  </Text>
</View>

You also lose the ability to set up a default font for an entire subtree. The recommended way to use consistent fonts and sizes across your application is to create a component MyAppText that includes them and use this component across your app. You can also use this component to make more specific components like MyAppHeaderText for other kinds of text.

<View>
  <MyAppText>
    Text styled with the default font for the entire application
  </MyAppText>
  <MyAppHeaderText>Text styled as a header</MyAppHeaderText>
</View>

Assuming that MyAppText is a component that simply renders out its children into a Text component with styling, then MyAppHeaderText can be defined as follows:

class MyAppHeaderText extends Component {
  render() {
    return (
      <MyAppText>
        <Text style={{fontSize: 20}}>{this.props.children}</Text>
      </MyAppText>
    );
  }
}

Composing MyAppText in this way ensures that we get the styles from a top-level component, but leaves us the ability to add / override them in specific use cases.

React Native still has the concept of style inheritance, but limited to text subtrees. In this case, the second part will be both bold and red.

<Text style={{fontWeight: 'bold'}}>
  I am bold
  <Text style={{color: 'red'}}>and red</Text>
</Text>

We believe that this more constrained way to style text will yield better apps:

  • (Developer) React components are designed with strong isolation in mind: You should be able to drop a component anywhere in your application, trusting that as long as the props are the same, it will look and behave the same way. Text properties that could inherit from outside of the props would break this isolation.

  • (Implementor) The implementation of React Native is also simplified. We do not need to have a fontFamily field on every single element, and we do not need to potentially traverse the tree up to the root every time we display a text node. The style inheritance is only encoded inside of the native Text component and doesn't leak to other components or the system itself.

Props

Reference

Props

selectable

Lets the user select text, to use the native copy and paste functionality.

TypeRequired
boolNo

accessibilityHint

An accessibility hint helps users understand what will happen when they perform an action on the accessibility element when that result is not obvious from the accessibility label.

TypeRequired
stringNo

accessibilityLabel

Overrides the text that's read by the screen reader when the user interacts with the element. By default, the label is constructed by traversing all the children and accumulating all the Text nodes separated by space.

TypeRequired
nodeNo

accessible

When set to true, indicates that the view is an accessibility element. The default value for a Text element is true.

See the Accessibility guide for more information.

TypeRequired
boolNo

ellipsizeMode

When numberOfLines is set, this prop defines how text will be truncated. numberOfLines must be set in conjunction with this prop.

This can be one of the following values:

  • head - The line is displayed so that the end fits in the container and the missing text at the beginning of the line is indicated by an ellipsis glyph. e.g., "...wxyz"
  • middle - The line is displayed so that the beginning and end fit in the container and the missing text in the middle is indicated by an ellipsis glyph. "ab...yz"
  • tail - The line is displayed so that the beginning fits in the container and the missing text at the end of the line is indicated by an ellipsis glyph. e.g., "abcd..."
  • clip - Lines are not drawn past the edge of the text container.

The default is tail.

TypeRequired
enum('head', 'middle', 'tail', 'clip')No

nativeID

Used to locate this view from native code.

TypeRequired
stringNo

numberOfLines

Used to truncate the text with an ellipsis after computing the text layout, including line wrapping, such that the total number of lines does not exceed this number.

This prop is commonly used with ellipsizeMode.

TypeRequired
numberNo

onLayout

Invoked on mount and layout changes with

{nativeEvent: {layout: {x, y, width, height}}}

TypeRequired
functionNo

onLongPress

This function is called on long press.

e.g., onLongPress={this.increaseSize}>

TypeRequired
functionNo

onPress

This function is called on press.

e.g., onPress={() => console.log('1st')}

TypeRequired
functionNo

pressRetentionOffset

When the scroll view is disabled, this defines how far your touch may move off of the button, before deactivating the button. Once deactivated, try moving it back and you'll see that the button is once again reactivated! Move it back and forth several times while the scroll view is disabled. Ensure you pass in a constant to reduce memory allocations.

TypeRequired
object: {top: number, left: number, bottom: number, right: number}No

allowFontScaling

Specifies whether fonts should scale to respect Text Size accessibility settings. The default is true.

TypeRequired
boolNo

style

TypeRequired
styleNo

  • View Style Props...

  • textShadowOffset: object: {width: number,height: number}

  • color: color

  • fontSize: number

  • fontStyle: enum('normal', 'italic')

  • fontWeight: enum('normal', 'bold', '100', '200', '300', '400', '500', '600', '700', '800', '900')

    Specifies font weight. The values 'normal' and 'bold' are supported for most fonts. Not all fonts have a variant for each of the numeric values, in that case the closest one is chosen.

  • lineHeight: number

  • textAlign: enum('auto', 'left', 'right', 'center', 'justify')

    Specifies text alignment. The value 'justify' is only supported on iOS and fallbacks to left on Android.

  • textDecorationLine: enum('none', 'underline', 'line-through', 'underline line-through')

  • textShadowColor: color

  • fontFamily: string

  • textShadowRadius: number

  • includeFontPadding: bool (Android)

    Set to false to remove extra font padding intended to make space for certain ascenders / descenders. With some fonts, this padding can make text look slightly misaligned when centered vertically. For best results also set textAlignVertical to center. Default is true.

  • textAlignVertical: enum('auto', 'top', 'bottom', 'center') (Android)

  • fontVariant: array of enum('small-caps', 'oldstyle-nums', 'lining-nums', 'tabular-nums', 'proportional-nums') (iOS)

  • letterSpacing: number

    Increase or decrease the spacing between characters. The default is 0, for no extra letter spacing.

    iOS: The additional space will be rendered after each glyph.

    Android: Only supported since Android 5.0 - older versions will ignore this attribute. Please note that additional space will be added around the glyphs (half on each side), which differs from the iOS rendering. It is possible to emulate the iOS rendering by using layout attributes, e.g. negative margins, as appropriate for your situation.

  • textDecorationColor: color (iOS)

  • textDecorationStyle: enum('solid', 'double', 'dotted', 'dashed') (iOS)

  • textTransform: enum('none', 'uppercase', 'lowercase', 'capitalize')

  • writingDirection: enum('auto', 'ltr', 'rtl') (iOS)

testID

Used to locate this view in end-to-end tests.

TypeRequired
stringNo

disabled

Specifies the disabled state of the text view for testing purposes

TypeRequiredPlatform
boolNoAndroid

selectionColor

The highlight color of the text.

TypeRequiredPlatform
colorNoAndroid

textBreakStrategy

Set text break strategy on Android API Level 23+, possible values are simple, highQuality, balanced The default value is highQuality.

TypeRequiredPlatform
enum('simple', 'highQuality', 'balanced')NoAndroid

adjustsFontSizeToFit

Specifies whether font should be scaled down automatically to fit given style constraints.

TypeRequiredPlatform
boolNoiOS

minimumFontScale

Specifies smallest possible scale a font can reach when adjustsFontSizeToFit is enabled. (values 0.01-1.0).

TypeRequiredPlatform
numberNoiOS

suppressHighlighting

When true, no visual change is made when text is pressed down. By default, a gray oval highlights the text on press down.

TypeRequiredPlatform
boolNoiOS
← TabBarIOS.ItemTextInput →