285 lines
12 KiB
JavaScript
285 lines
12 KiB
JavaScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow
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* @format
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*/
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import type {EdgeInsetsProp} from '../../StyleSheet/EdgeInsetsPropType';
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import type {ColorValue} from '../../StyleSheet/StyleSheet';
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import type {PressEvent} from '../../Types/CoreEventTypes';
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import * as React from 'react';
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/**
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* `Touchable`: Taps done right.
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*
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* You hook your `ResponderEventPlugin` events into `Touchable`. `Touchable`
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* will measure time/geometry and tells you when to give feedback to the user.
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*
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* ====================== Touchable Tutorial ===============================
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* The `Touchable` mixin helps you handle the "press" interaction. It analyzes
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* the geometry of elements, and observes when another responder (scroll view
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* etc) has stolen the touch lock. It notifies your component when it should
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* give feedback to the user. (bouncing/highlighting/unhighlighting).
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*
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* - When a touch was activated (typically you highlight)
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* - When a touch was deactivated (typically you unhighlight)
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* - When a touch was "pressed" - a touch ended while still within the geometry
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* of the element, and no other element (like scroller) has "stolen" touch
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* lock ("responder") (Typically you bounce the element).
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*
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* A good tap interaction isn't as simple as you might think. There should be a
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* slight delay before showing a highlight when starting a touch. If a
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* subsequent touch move exceeds the boundary of the element, it should
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* unhighlight, but if that same touch is brought back within the boundary, it
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* should rehighlight again. A touch can move in and out of that boundary
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* several times, each time toggling highlighting, but a "press" is only
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* triggered if that touch ends while within the element's boundary and no
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* scroller (or anything else) has stolen the lock on touches.
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*
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* To create a new type of component that handles interaction using the
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* `Touchable` mixin, do the following:
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*
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* - Initialize the `Touchable` state.
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*
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* getInitialState: function() {
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* return merge(this.touchableGetInitialState(), yourComponentState);
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* }
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*
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* - Choose the rendered component who's touches should start the interactive
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* sequence. On that rendered node, forward all `Touchable` responder
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* handlers. You can choose any rendered node you like. Choose a node whose
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* hit target you'd like to instigate the interaction sequence:
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*
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* // In render function:
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* return (
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* <View
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* onStartShouldSetResponder={this.touchableHandleStartShouldSetResponder}
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* onResponderTerminationRequest={this.touchableHandleResponderTerminationRequest}
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* onResponderGrant={this.touchableHandleResponderGrant}
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* onResponderMove={this.touchableHandleResponderMove}
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* onResponderRelease={this.touchableHandleResponderRelease}
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* onResponderTerminate={this.touchableHandleResponderTerminate}>
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* <View>
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* Even though the hit detection/interactions are triggered by the
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* wrapping (typically larger) node, we usually end up implementing
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* custom logic that highlights this inner one.
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* </View>
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* </View>
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* );
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*
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* - You may set up your own handlers for each of these events, so long as you
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* also invoke the `touchable*` handlers inside of your custom handler.
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*
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* - Implement the handlers on your component class in order to provide
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* feedback to the user. See documentation for each of these class methods
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* that you should implement.
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*
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* touchableHandlePress: function() {
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* this.performBounceAnimation(); // or whatever you want to do.
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* },
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* touchableHandleActivePressIn: function() {
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* this.beginHighlighting(...); // Whatever you like to convey activation
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* },
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* touchableHandleActivePressOut: function() {
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* this.endHighlighting(...); // Whatever you like to convey deactivation
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* },
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*
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* - There are more advanced methods you can implement (see documentation below):
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* touchableGetHighlightDelayMS: function() {
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* return 20;
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* }
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* // In practice, *always* use a predeclared constant (conserve memory).
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* touchableGetPressRectOffset: function() {
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* return {top: 20, left: 20, right: 20, bottom: 100};
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* }
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*/
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/**
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* Touchable states.
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*/
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const States = {
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NOT_RESPONDER: 'NOT_RESPONDER', // Not the responder
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RESPONDER_INACTIVE_PRESS_IN: 'RESPONDER_INACTIVE_PRESS_IN', // Responder, inactive, in the `PressRect`
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RESPONDER_INACTIVE_PRESS_OUT: 'RESPONDER_INACTIVE_PRESS_OUT', // Responder, inactive, out of `PressRect`
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RESPONDER_ACTIVE_PRESS_IN: 'RESPONDER_ACTIVE_PRESS_IN', // Responder, active, in the `PressRect`
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RESPONDER_ACTIVE_PRESS_OUT: 'RESPONDER_ACTIVE_PRESS_OUT', // Responder, active, out of `PressRect`
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RESPONDER_ACTIVE_LONG_PRESS_IN: 'RESPONDER_ACTIVE_LONG_PRESS_IN', // Responder, active, in the `PressRect`, after long press threshold
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RESPONDER_ACTIVE_LONG_PRESS_OUT: 'RESPONDER_ACTIVE_LONG_PRESS_OUT', // Responder, active, out of `PressRect`, after long press threshold
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ERROR: 'ERROR',
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};
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type State =
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| typeof States.NOT_RESPONDER
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| typeof States.RESPONDER_INACTIVE_PRESS_IN
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| typeof States.RESPONDER_INACTIVE_PRESS_OUT
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| typeof States.RESPONDER_ACTIVE_PRESS_IN
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| typeof States.RESPONDER_ACTIVE_PRESS_OUT
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| typeof States.RESPONDER_ACTIVE_LONG_PRESS_IN
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| typeof States.RESPONDER_ACTIVE_LONG_PRESS_OUT
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| typeof States.ERROR;
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/**
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* By convention, methods prefixed with underscores are meant to be @private,
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* and not @protected. Mixers shouldn't access them - not even to provide them
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* as callback handlers.
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*
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*
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* ========== Geometry =========
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* `Touchable` only assumes that there exists a `HitRect` node. The `PressRect`
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* is an abstract box that is extended beyond the `HitRect`.
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*
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* +--------------------------+
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* | | - "Start" events in `HitRect` cause `HitRect`
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* | +--------------------+ | to become the responder.
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* | | +--------------+ | | - `HitRect` is typically expanded around
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* | | | | | | the `VisualRect`, but shifted downward.
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* | | | VisualRect | | | - After pressing down, after some delay,
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* | | | | | | and before letting up, the Visual React
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* | | +--------------+ | | will become "active". This makes it eligible
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* | | HitRect | | for being highlighted (so long as the
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* | +--------------------+ | press remains in the `PressRect`).
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* | PressRect o |
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* +----------------------|---+
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* Out Region |
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* +-----+ This gap between the `HitRect` and
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* `PressRect` allows a touch to move far away
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* from the original hit rect, and remain
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* highlighted, and eligible for a "Press".
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* Customize this via
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* `touchableGetPressRectOffset()`.
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*
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*
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*
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* ======= State Machine =======
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*
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* +-------------+ <---+ RESPONDER_RELEASE
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* |NOT_RESPONDER|
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* +-------------+ <---+ RESPONDER_TERMINATED
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* +
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* | RESPONDER_GRANT (HitRect)
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* v
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* +---------------------------+ DELAY +-------------------------+ T + DELAY +------------------------------+
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* |RESPONDER_INACTIVE_PRESS_IN|+-------->|RESPONDER_ACTIVE_PRESS_IN| +------------> |RESPONDER_ACTIVE_LONG_PRESS_IN|
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* +---------------------------+ +-------------------------+ +------------------------------+
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* + ^ + ^ + ^
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* |LEAVE_ |ENTER_ |LEAVE_ |ENTER_ |LEAVE_ |ENTER_
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* |PRESS_RECT |PRESS_RECT |PRESS_RECT |PRESS_RECT |PRESS_RECT |PRESS_RECT
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* | | | | | |
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* v + v + v +
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* +----------------------------+ DELAY +--------------------------+ +-------------------------------+
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* |RESPONDER_INACTIVE_PRESS_OUT|+------->|RESPONDER_ACTIVE_PRESS_OUT| |RESPONDER_ACTIVE_LONG_PRESS_OUT|
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* +----------------------------+ +--------------------------+ +-------------------------------+
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*
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* T + DELAY => LONG_PRESS_DELAY_MS + DELAY
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*
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* Not drawn are the side effects of each transition. The most important side
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* effect is the `touchableHandlePress` abstract method invocation that occurs
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* when a responder is released while in either of the "Press" states.
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*
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* The other important side effects are the highlight abstract method
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* invocations (internal callbacks) to be implemented by the mixer.
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*
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*
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* @lends Touchable.prototype
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*/
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interface TouchableMixinType {
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/**
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* Invoked when the item receives focus. Mixers might override this to
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* visually distinguish the `VisualRect` so that the user knows that it
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* currently has the focus. Most platforms only support a single element being
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* focused at a time, in which case there may have been a previously focused
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* element that was blurred just prior to this. This can be overridden when
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* using `Touchable.Mixin.withoutDefaultFocusAndBlur`.
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*/
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touchableHandleFocus: (e: Event) => void;
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/**
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* Invoked when the item loses focus. Mixers might override this to
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* visually distinguish the `VisualRect` so that the user knows that it
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* no longer has focus. Most platforms only support a single element being
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* focused at a time, in which case the focus may have moved to another.
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* This can be overridden when using
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* `Touchable.Mixin.withoutDefaultFocusAndBlur`.
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*/
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touchableHandleBlur: (e: Event) => void;
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componentDidMount: () => void;
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/**
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* Clear all timeouts on unmount
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*/
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componentWillUnmount: () => void;
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/**
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* It's prefer that mixins determine state in this way, having the class
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* explicitly mix the state in the one and only `getInitialState` method.
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*
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* @return {object} State object to be placed inside of
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* `this.state.touchable`.
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*/
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touchableGetInitialState: () => {
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touchable: {
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touchState: ?State,
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responderID: ?PressEvent['currentTarget'],
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},
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};
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// ==== Hooks to Gesture Responder system ====
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/**
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* Must return true if embedded in a native platform scroll view.
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*/
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touchableHandleResponderTerminationRequest: () => any;
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/**
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* Must return true to start the process of `Touchable`.
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*/
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touchableHandleStartShouldSetResponder: () => any;
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/**
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* Return true to cancel press on long press.
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*/
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touchableLongPressCancelsPress: () => boolean;
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/**
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* Place as callback for a DOM element's `onResponderGrant` event.
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* @param {SyntheticEvent} e Synthetic event from event system.
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*
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*/
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touchableHandleResponderGrant: (e: PressEvent) => void;
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/**
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* Place as callback for a DOM element's `onResponderRelease` event.
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*/
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touchableHandleResponderRelease: (e: PressEvent) => void;
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/**
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* Place as callback for a DOM element's `onResponderTerminate` event.
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*/
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touchableHandleResponderTerminate: (e: PressEvent) => void;
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/**
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* Place as callback for a DOM element's `onResponderMove` event.
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*/
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touchableHandleResponderMove: (e: PressEvent) => void;
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withoutDefaultFocusAndBlur: {...};
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}
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export type TouchableType = {
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Mixin: TouchableMixinType,
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/**
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* Renders a debugging overlay to visualize touch target with hitSlop (might not work on Android).
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*/
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renderDebugView: ({
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color: ColorValue,
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hitSlop: EdgeInsetsProp,
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...
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}) => null | React.Node,
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};
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