react-native/Libraries/Text/Text.js

586 lines
19 KiB
JavaScript

/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* @providesModule Text
* @flow
*/
'use strict';
const ColorPropType = require('ColorPropType');
const EdgeInsetsPropType = require('EdgeInsetsPropType');
const NativeMethodsMixin = require('NativeMethodsMixin');
const Platform = require('Platform');
const React = require('React');
const PropTypes = require('prop-types');
const ReactNativeViewAttributes = require('ReactNativeViewAttributes');
const StyleSheetPropType = require('StyleSheetPropType');
const TextStylePropTypes = require('TextStylePropTypes');
const Touchable = require('Touchable');
const createReactClass = require('create-react-class');
const createReactNativeComponentClass = require('createReactNativeComponentClass');
const mergeFast = require('mergeFast');
const processColor = require('processColor');
const stylePropType = StyleSheetPropType(TextStylePropTypes);
const viewConfig = {
validAttributes: mergeFast(ReactNativeViewAttributes.UIView, {
isHighlighted: true,
numberOfLines: true,
ellipsizeMode: true,
allowFontScaling: true,
disabled: true,
selectable: true,
selectionColor: true,
adjustsFontSizeToFit: true,
minimumFontScale: true,
textBreakStrategy: true,
}),
uiViewClassName: 'RCTText',
};
/**
* 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 willstack on top of each other on
* account of the literal newlines:
*
* ```ReactNativeWebPlayer
* 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.
*
*
* ```ReactNativeWebPlayer
* 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:
*
* ```javascript
* "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:
*
* ```ReactNativeWebPlayer
* 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.
*
* ```javascript
* <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:
*
* ```css
* 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>`.
*
*
* ```javascript
* // 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.
*
* ```javascript
* <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:
*
* ```javascript
* class MyAppHeaderText extends Component {
* render() {
* <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.
*
* ```javascript
* <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.
*
*/
// $FlowFixMe(>=0.41.0)
const Text = createReactClass({
displayName: 'Text',
propTypes: {
/**
* 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`.
*
* > `clip` is working only for iOS
*/
ellipsizeMode: PropTypes.oneOf(['head', 'middle', 'tail', 'clip']),
/**
* 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`.
*/
numberOfLines: PropTypes.number,
/**
* Set text break strategy on Android API Level 23+, possible values are `simple`, `highQuality`, `balanced`
* The default value is `highQuality`.
* @platform android
*/
textBreakStrategy: PropTypes.oneOf(['simple', 'highQuality', 'balanced']),
/**
* Invoked on mount and layout changes with
*
* `{nativeEvent: {layout: {x, y, width, height}}}`
*/
onLayout: PropTypes.func,
/**
* This function is called on press.
*
* e.g., `onPress={() => console.log('1st')}`
*/
onPress: PropTypes.func,
/**
* This function is called on long press.
*
* e.g., `onLongPress={this.increaseSize}>`
*/
onLongPress: PropTypes.func,
/**
* 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.
*/
pressRetentionOffset: EdgeInsetsPropType,
/**
* Lets the user select text, to use the native copy and paste functionality.
*/
selectable: PropTypes.bool,
/**
* The highlight color of the text.
* @platform android
*/
selectionColor: ColorPropType,
/**
* When `true`, no visual change is made when text is pressed down. By
* default, a gray oval highlights the text on press down.
* @platform ios
*/
suppressHighlighting: PropTypes.bool,
style: stylePropType,
/**
* Used to locate this view in end-to-end tests.
*/
testID: PropTypes.string,
/**
* Used to locate this view from native code.
*/
nativeID: PropTypes.string,
/**
* Specifies whether fonts should scale to respect Text Size accessibility settings. The
* default is `true`.
*/
allowFontScaling: PropTypes.bool,
/**
* 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](docs/accessibility.html#accessible-ios-android)
* for more information.
*/
accessible: PropTypes.bool,
/**
* Specifies whether font should be scaled down automatically to fit given style constraints.
* @platform ios
*/
adjustsFontSizeToFit: PropTypes.bool,
/**
* Specifies smallest possible scale a font can reach when adjustsFontSizeToFit is enabled. (values 0.01-1.0).
* @platform ios
*/
minimumFontScale: PropTypes.number,
/**
* Specifies the disabled state of the text view for testing purposes
* @platform android
*/
disabled: PropTypes.bool,
},
getDefaultProps(): Object {
return {
accessible: true,
allowFontScaling: true,
ellipsizeMode: 'tail',
disabled: false,
};
},
getInitialState: function(): Object {
return mergeFast(Touchable.Mixin.touchableGetInitialState(), {
isHighlighted: false,
});
},
mixins: [NativeMethodsMixin],
viewConfig: viewConfig,
getChildContext(): Object {
return {isInAParentText: true};
},
childContextTypes: {
isInAParentText: PropTypes.bool
},
contextTypes: {
isInAParentText: PropTypes.bool
},
/**
* Only assigned if touch is needed.
*/
_handlers: (null: ?Object),
_hasPressHandler(): boolean {
return !!this.props.onPress || !!this.props.onLongPress;
},
/**
* These are assigned lazily the first time the responder is set to make plain
* text nodes as cheap as possible.
*/
touchableHandleActivePressIn: (null: ?Function),
touchableHandleActivePressOut: (null: ?Function),
touchableHandlePress: (null: ?Function),
touchableHandleLongPress: (null: ?Function),
touchableGetPressRectOffset: (null: ?Function),
render(): React.Element<any> {
let newProps = this.props;
if (this.props.onStartShouldSetResponder || this._hasPressHandler()) {
if (!this._handlers) {
this._handlers = {
onStartShouldSetResponder: (): bool => {
const shouldSetFromProps = this.props.onStartShouldSetResponder &&
// $FlowFixMe(>=0.41.0)
this.props.onStartShouldSetResponder();
const setResponder = shouldSetFromProps || this._hasPressHandler();
if (setResponder && !this.touchableHandleActivePressIn) {
// Attach and bind all the other handlers only the first time a touch
// actually happens.
for (const key in Touchable.Mixin) {
if (typeof Touchable.Mixin[key] === 'function') {
(this: any)[key] = Touchable.Mixin[key].bind(this);
}
}
this.touchableHandleActivePressIn = () => {
if (this.props.suppressHighlighting || !this._hasPressHandler()) {
return;
}
this.setState({
isHighlighted: true,
});
};
this.touchableHandleActivePressOut = () => {
if (this.props.suppressHighlighting || !this._hasPressHandler()) {
return;
}
this.setState({
isHighlighted: false,
});
};
this.touchableHandlePress = (e: SyntheticEvent<>) => {
this.props.onPress && this.props.onPress(e);
};
this.touchableHandleLongPress = (e: SyntheticEvent<>) => {
this.props.onLongPress && this.props.onLongPress(e);
};
this.touchableGetPressRectOffset = function(): RectOffset {
return this.props.pressRetentionOffset || PRESS_RECT_OFFSET;
};
}
// $FlowFixMe(>=0.41.0)
return setResponder;
},
onResponderGrant: function(e: SyntheticEvent<>, dispatchID: string) {
// $FlowFixMe(>=0.41.0)
this.touchableHandleResponderGrant(e, dispatchID);
this.props.onResponderGrant &&
// $FlowFixMe(>=0.41.0)
this.props.onResponderGrant.apply(this, arguments);
}.bind(this),
onResponderMove: function(e: SyntheticEvent<>) {
// $FlowFixMe(>=0.41.0)
this.touchableHandleResponderMove(e);
this.props.onResponderMove &&
// $FlowFixMe(>=0.41.0)
this.props.onResponderMove.apply(this, arguments);
}.bind(this),
onResponderRelease: function(e: SyntheticEvent<>) {
// $FlowFixMe(>=0.41.0)
this.touchableHandleResponderRelease(e);
this.props.onResponderRelease &&
// $FlowFixMe(>=0.41.0)
this.props.onResponderRelease.apply(this, arguments);
}.bind(this),
onResponderTerminate: function(e: SyntheticEvent<>) {
// $FlowFixMe(>=0.41.0)
this.touchableHandleResponderTerminate(e);
this.props.onResponderTerminate &&
// $FlowFixMe(>=0.41.0)
this.props.onResponderTerminate.apply(this, arguments);
}.bind(this),
onResponderTerminationRequest: function(): bool {
// Allow touchable or props.onResponderTerminationRequest to deny
// the request
// $FlowFixMe(>=0.41.0)
var allowTermination = this.touchableHandleResponderTerminationRequest();
if (allowTermination && this.props.onResponderTerminationRequest) {
// $FlowFixMe(>=0.41.0)
allowTermination = this.props.onResponderTerminationRequest.apply(this, arguments);
}
return allowTermination;
}.bind(this),
};
}
newProps = {
...this.props,
...this._handlers,
isHighlighted: this.state.isHighlighted,
};
}
if (newProps.selectionColor != null) {
newProps = {
...newProps,
selectionColor: processColor(newProps.selectionColor)
};
}
if (Touchable.TOUCH_TARGET_DEBUG && newProps.onPress) {
newProps = {
...newProps,
style: [this.props.style, {color: 'magenta'}],
};
}
if (this.context.isInAParentText) {
return <RCTVirtualText {...newProps} />;
} else {
return <RCTText {...newProps} />;
}
},
});
type RectOffset = {
top: number,
left: number,
right: number,
bottom: number,
}
var PRESS_RECT_OFFSET = {top: 20, left: 20, right: 20, bottom: 30};
var RCTText = createReactNativeComponentClass(viewConfig);
var RCTVirtualText = RCTText;
if (Platform.OS === 'android') {
RCTVirtualText = createReactNativeComponentClass({
validAttributes: mergeFast(ReactNativeViewAttributes.UIView, {
isHighlighted: true,
}),
uiViewClassName: 'RCTVirtualText',
});
}
module.exports = Text;