react-native/Libraries/Components/View/View.js

538 lines
20 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 View
* @flow
*/
'use strict';
const EdgeInsetsPropType = require('EdgeInsetsPropType');
const NativeMethodsMixin = require('NativeMethodsMixin');
const NativeModules = require('NativeModules');
const React = require('React');
const ReactNativeStyleAttributes = require('ReactNativeStyleAttributes');
const ReactNativeViewAttributes = require('ReactNativeViewAttributes');
const StyleSheetPropType = require('StyleSheetPropType');
const ViewStylePropTypes = require('ViewStylePropTypes');
const requireNativeComponent = require('requireNativeComponent');
const PropTypes = React.PropTypes;
const stylePropType = StyleSheetPropType(ViewStylePropTypes);
const AccessibilityTraits = [
'none',
'button',
'link',
'header',
'search',
'image',
'selected',
'plays',
'key',
'text',
'summary',
'disabled',
'frequentUpdates',
'startsMedia',
'adjustable',
'allowsDirectInteraction',
'pageTurn',
];
const AccessibilityComponentType = [
'none',
'button',
'radiobutton_checked',
'radiobutton_unchecked',
];
const forceTouchAvailable = (NativeModules.IOSConstants &&
NativeModules.IOSConstants.forceTouchAvailable) || false;
const statics = {
AccessibilityTraits,
AccessibilityComponentType,
/**
* Is 3D Touch / Force Touch available (i.e. will touch events include `force`)
* @platform ios
*/
forceTouchAvailable,
};
/**
* The most fundamental component for building a UI, `View` is a container that supports layout with
* [flexbox](/react-native/docs/flexbox.html), [style](/react-native/docs/style.html),
* [some touch handling](/react-native/docs/handling-touches.html), and
* [accessibility](/react-native/docs/accessibility.html) controls. `View` maps directly to the
* native view equivalent on whatever platform React Native is running on, whether that is a
* `UIView`, `<div>`, `android.view`, etc.
*
* `View` is designed to be nested inside other views and can have 0 to many children of any type.
*
* This example creates a `View` that wraps two colored boxes and a text component in a row with
* padding.
*
* ```javascript
* class ViewColoredBoxesWithText extends Component {
* render() {
* return (
* <View style={{flexDirection: 'row', height: 100, padding: 20}}>
* <View style={{backgroundColor: 'blue', flex: 0.3}} />
* <View style={{backgroundColor: 'red', flex: 0.5}} />
* <Text>Hello World!</Text>
* </View>
* );
* }
* }
* ```
*
* > `View`s are designed to be used with [`StyleSheet`](/react-native/docs/style.html) for clarity
* > and performance, although inline styles are also supported.
*
* ### Synthetic Touch Events
*
* For `View` responder props (e.g., `onResponderMove`), the synthetic touch event passed to them
* are of the following form:
*
* - `nativeEvent`
* - `changedTouches` - Array of all touch events that have changed since the last event.
* - `identifier` - The ID of the touch.
* - `locationX` - The X position of the touch, relative to the element.
* - `locationY` - The Y position of the touch, relative to the element.
* - `pageX` - The X position of the touch, relative to the root element.
* - `pageY` - The Y position of the touch, relative to the root element.
* - `target` - The node id of the element receiving the touch event.
* - `timestamp` - A time identifier for the touch, useful for velocity calculation.
* - `touches` - Array of all current touches on the screen.
*/
const View = React.createClass({
// TODO: We should probably expose the mixins, viewConfig, and statics publicly. For example,
// one of the props is of type AccessibilityComponentType. That is defined as a const[] above,
// but it is not rendered by the docs, since `statics` below is not rendered. So its Possible
// values had to be hardcoded.
mixins: [NativeMethodsMixin],
/**
* `NativeMethodsMixin` will look for this when invoking `setNativeProps`. We
* make `this` look like an actual native component class.
*/
viewConfig: {
uiViewClassName: 'RCTView',
validAttributes: ReactNativeViewAttributes.RCTView
},
statics: {
...statics,
},
propTypes: {
/**
* When `true`, indicates that the view is an accessibility element. By default,
* all the touchable elements are accessible.
*/
accessible: PropTypes.bool,
/**
* 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.
*/
accessibilityLabel: PropTypes.node,
/**
* Indicates to accessibility services to treat UI component like a
* native one. Works for Android only.
*
* Possible values are one of:
*
* - `'none'`
* - `'button'`
* - `'radiobutton_checked'`
* - `'radiobutton_unchecked'`
*
* @platform android
*/
accessibilityComponentType: PropTypes.oneOf(AccessibilityComponentType),
/**
* Indicates to accessibility services whether the user should be notified
* when this view changes. Works for Android API >= 19 only.
* Possible values:
*
* - `'none'` - Accessibility services should not announce changes to this view.
* - `'polite'`- Accessibility services should announce changes to this view.
* - `'assertive'` - Accessibility services should interrupt ongoing speech to immediately announce changes to this view.
*
* See the [Android `View` docs](http://developer.android.com/reference/android/view/View.html#attr_android:accessibilityLiveRegion)
* for reference.
*
* @platform android
*/
accessibilityLiveRegion: PropTypes.oneOf([
'none',
'polite',
'assertive',
]),
/**
* Controls how view is important for accessibility which is if it
* fires accessibility events and if it is reported to accessibility services
* that query the screen. Works for Android only.
*
* Possible values:
*
* - `'auto'` - The system determines whether the view is important for accessibility -
* default (recommended).
* - `'yes'` - The view is important for accessibility.
* - `'no'` - The view is not important for accessibility.
* - `'no-hide-descendants'` - The view is not important for accessibility,
* nor are any of its descendant views.
*
* See the [Android `importantForAccessibility` docs](http://developer.android.com/reference/android/R.attr.html#importantForAccessibility)
* for reference.
*
* @platform android
*/
importantForAccessibility: PropTypes.oneOf([
'auto',
'yes',
'no',
'no-hide-descendants',
]),
/**
* Provides additional traits to screen reader. By default no traits are
* provided unless specified otherwise in element.
*
* You can provide one trait or an array of many traits.
*
* Possible values for `AccessibilityTraits` are:
*
* - `'none'` - The element has no traits.
* - `'button'` - The element should be treated as a button.
* - `'link'` - The element should be treated as a link.
* - `'header'` - The element is a header that divides content into sections.
* - `'search'` - The element should be treated as a search field.
* - `'image'` - The element should be treated as an image.
* - `'selected'` - The element is selected.
* - `'plays'` - The element plays sound.
* - `'key'` - The element should be treated like a keyboard key.
* - `'text'` - The element should be treated as text.
* - `'summary'` - The element provides app summary information.
* - `'disabled'` - The element is disabled.
* - `'frequentUpdates'` - The element frequently changes its value.
* - `'startsMedia'` - The element starts a media session.
* - `'adjustable'` - The element allows adjustment over a range of values.
* - `'allowsDirectInteraction'` - The element allows direct touch interaction for VoiceOver users.
* - `'pageTurn'` - Informs VoiceOver that it should scroll to the next page when it finishes reading the contents of the element.
*
* See the [Accessibility guide](/react-native/docs/accessibility.html#accessibilitytraits-ios)
* for more information.
*
* @platform ios
*/
accessibilityTraits: PropTypes.oneOfType([
PropTypes.oneOf(AccessibilityTraits),
PropTypes.arrayOf(PropTypes.oneOf(AccessibilityTraits)),
]),
/**
* When `accessible` is true, the system will try to invoke this function
* when the user performs accessibility tap gesture.
*/
onAccessibilityTap: PropTypes.func,
/**
* When `accessible` is `true`, the system will invoke this function when the
* user performs the magic tap gesture.
*/
onMagicTap: PropTypes.func,
/**
* Used to locate this view in end-to-end tests.
*
* > This disables the 'layout-only view removal' optimization for this view!
*/
testID: PropTypes.string,
/**
* For most touch interactions, you'll simply want to wrap your component in
* `TouchableHighlight` or `TouchableOpacity`. Check out `Touchable.js`,
* `ScrollResponder.js` and `ResponderEventPlugin.js` for more discussion.
*/
/**
* The View is now responding for touch events. This is the time to highlight and show the user
* what is happening.
*
* `View.props.onResponderGrant: (event) => {}`, where `event` is a synthetic touch event as
* described above.
*/
onResponderGrant: PropTypes.func,
/**
* The user is moving their finger.
*
* `View.props.onResponderMove: (event) => {}`, where `event` is a synthetic touch event as
* described above.
*/
onResponderMove: PropTypes.func,
/**
* Another responder is already active and will not release it to that `View` asking to be
* the responder.
*
* `View.props.onResponderReject: (event) => {}`, where `event` is a synthetic touch event as
* described above.
*/
onResponderReject: PropTypes.func,
/**
* Fired at the end of the touch.
*
* `View.props.onResponderRelease: (event) => {}`, where `event` is a synthetic touch event as
* described above.
*/
onResponderRelease: PropTypes.func,
/**
* The responder has been taken from the `View`. Might be taken by other views after a call to
* `onResponderTerminationRequest`, or might be taken by the OS without asking (e.g., happens
* with control center/ notification center on iOS)
*
* `View.props.onResponderTerminate: (event) => {}`, where `event` is a synthetic touch event as
* described above.
*/
onResponderTerminate: PropTypes.func,
/**
* Some other `View` wants to become responder and is asking this `View` to release its
* responder. Returning `true` allows its release.
*
* `View.props.onResponderTerminationRequest: (event) => {}`, where `event` is a synthetic touch
* event as described above.
*/
onResponderTerminationRequest: PropTypes.func,
/**
* Does this view want to become responder on the start of a touch?
*
* `View.props.onStartShouldSetResponder: (event) => [true | false]`, where `event` is a
* synthetic touch event as described above.
*/
onStartShouldSetResponder: PropTypes.func,
/**
* If a parent `View` wants to prevent a child `View` from becoming responder on a touch start,
* it should have this handler which returns `true`.
*
* `View.props.onStartShouldSetResponderCapture: (event) => [true | false]`, where `event` is a
* synthetic touch event as described above.
*/
onStartShouldSetResponderCapture: PropTypes.func,
/**
* Does this view want to "claim" touch responsiveness? This is called for every touch move on
* the `View` when it is not the responder.
*
* `View.props.onMoveShouldSetResponder: (event) => [true | false]`, where `event` is a
* synthetic touch event as described above.
*/
onMoveShouldSetResponder: PropTypes.func,
/**
* If a parent `View` wants to prevent a child `View` from becoming responder on a move,
* it should have this handler which returns `true`.
*
* `View.props.onMoveShouldSetResponderCapture: (event) => [true | false]`, where `event` is a
* synthetic touch event as described above.
*/
onMoveShouldSetResponderCapture: PropTypes.func,
/**
* This defines how far a touch event can start away from the view.
* Typical interface guidelines recommend touch targets that are at least
* 30 - 40 points/density-independent pixels.
*
* For example, if a touchable view has a height of 20 the touchable height can be extended to
* 40 with `hitSlop={{top: 10, bottom: 10, left: 0, right: 0}}`
*
* > The touch area never extends past the parent view bounds and the Z-index
* > of sibling views always takes precedence if a touch hits two overlapping
* > views.
*/
hitSlop: EdgeInsetsPropType,
/**
* Invoked on mount and layout changes with:
*
* `{nativeEvent: { layout: {x, y, width, height}}}`
*
* This event is fired immediately once the layout has been calculated, but
* the new layout may not yet be reflected on the screen at the time the
* event is received, especially if a layout animation is in progress.
*/
onLayout: PropTypes.func,
/**
* Controls whether the `View` can be the target of touch events.
*
* - `'auto'`: The View can be the target of touch events.
* - `'none'`: The View is never the target of touch events.
* - `'box-none'`: The View is never the target of touch events but it's
* subviews can be. It behaves like if the view had the following classes
* in CSS:
* ```
* .box-none {
* pointer-events: none;
* }
* .box-none * {
* pointer-events: all;
* }
* ```
* - `'box-only'`: The view can be the target of touch events but it's
* subviews cannot be. It behaves like if the view had the following classes
* in CSS:
* ```
* .box-only {
* pointer-events: all;
* }
* .box-only * {
* pointer-events: none;
* }
* ```
* > Since `pointerEvents` does not affect layout/appearance, and we are
* > already deviating from the spec by adding additional modes, we opt to not
* > include `pointerEvents` on `style`. On some platforms, we would need to
* > implement it as a `className` anyways. Using `style` or not is an
* > implementation detail of the platform.
*/
pointerEvents: PropTypes.oneOf([
'box-none',
'none',
'box-only',
'auto',
]),
style: stylePropType,
/**
* This is a special performance property exposed by `RCTView` and is useful
* for scrolling content when there are many subviews, most of which are
* offscreen. For this property to be effective, it must be applied to a
* view that contains many subviews that extend outside its bound. The
* subviews must also have `overflow: hidden`, as should the containing view
* (or one of its superviews).
*/
removeClippedSubviews: PropTypes.bool,
/**
* Whether this `View` should render itself (and all of its children) into a
* single hardware texture on the GPU.
*
* On Android, this is useful for animations and interactions that only
* modify opacity, rotation, translation, and/or scale: in those cases, the
* view doesn't have to be redrawn and display lists don't need to be
* re-executed. The texture can just be re-used and re-composited with
* different parameters. The downside is that this can use up limited video
* memory, so this prop should be set back to false at the end of the
* interaction/animation.
*
* @platform android
*/
renderToHardwareTextureAndroid: PropTypes.bool,
/**
* Whether this `View` should be rendered as a bitmap before compositing.
*
* On iOS, this is useful for animations and interactions that do not
* modify this component's dimensions nor its children; for example, when
* translating the position of a static view, rasterization allows the
* renderer to reuse a cached bitmap of a static view and quickly composite
* it during each frame.
*
* Rasterization incurs an off-screen drawing pass and the bitmap consumes
* memory. Test and measure when using this property.
*
* @platform ios
*/
shouldRasterizeIOS: PropTypes.bool,
/**
* Views that are only used to layout their children or otherwise don't draw
* anything may be automatically removed from the native hierarchy as an
* optimization. Set this property to `false` to disable this optimization and
* ensure that this `View` exists in the native view hierarchy.
*
* @platform android
*/
collapsable: PropTypes.bool,
/**
* Whether this `View` needs to rendered offscreen and composited with an alpha
* in order to preserve 100% correct colors and blending behavior. The default
* (`false`) falls back to drawing the component and its children with an alpha
* applied to the paint used to draw each element instead of rendering the full
* component offscreen and compositing it back with an alpha value. This default
* may be noticeable and undesired in the case where the `View` you are setting
* an opacity on has multiple overlapping elements (e.g. multiple overlapping
* `View`s, or text and a background).
*
* Rendering offscreen to preserve correct alpha behavior is extremely
* expensive and hard to debug for non-native developers, which is why it is
* not turned on by default. If you do need to enable this property for an
* animation, consider combining it with renderToHardwareTextureAndroid if the
* view **contents** are static (i.e. it doesn't need to be redrawn each frame).
* If that property is enabled, this View will be rendered off-screen once,
* saved in a hardware texture, and then composited onto the screen with an alpha
* each frame without having to switch rendering targets on the GPU.
*
* @platform android
*/
needsOffscreenAlphaCompositing: PropTypes.bool,
},
render: function() {
// WARNING: This method will not be used in production mode as in that mode we
// replace wrapper component View with generated native wrapper RCTView. Avoid
// adding functionality this component that you'd want to be available in both
// dev and prod modes.
return <RCTView {...this.props} />;
},
});
const RCTView = requireNativeComponent('RCTView', View, {
nativeOnly: {
nativeBackgroundAndroid: true,
nativeForegroundAndroid: true,
}
});
if (__DEV__) {
const UIManager = require('UIManager');
const viewConfig = UIManager.viewConfigs && UIManager.viewConfigs.RCTView || {};
for (const prop in viewConfig.nativeProps) {
const viewAny: any = View; // Appease flow
if (!viewAny.propTypes[prop] && !ReactNativeStyleAttributes[prop]) {
throw new Error(
'View is missing propType for native prop `' + prop + '`'
);
}
}
}
let ViewToExport = RCTView;
if (__DEV__) {
ViewToExport = View;
} else {
Object.assign(RCTView, statics);
}
module.exports = ViewToExport;