634 lines
25 KiB
JavaScript
634 lines
25 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule ScrollResponder
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* @flow
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*/
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'use strict';
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var Dimensions = require('Dimensions');
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var FrameRateLogger = require('FrameRateLogger');
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var Keyboard = require('Keyboard');
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var ReactNative = require('ReactNative');
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var Subscribable = require('Subscribable');
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var TextInputState = require('TextInputState');
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var UIManager = require('UIManager');
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var invariant = require('fbjs/lib/invariant');
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var nullthrows = require('fbjs/lib/nullthrows');
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/* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an error
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* found when Flow v0.54 was deployed. To see the error delete this comment and
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* run Flow. */
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var performanceNow = require('fbjs/lib/performanceNow');
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/* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an error
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* found when Flow v0.54 was deployed. To see the error delete this comment and
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* run Flow. */
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var warning = require('fbjs/lib/warning');
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var { ScrollViewManager } = require('NativeModules');
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var { getInstanceFromNode } = require('ReactNativeComponentTree');
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/**
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* Mixin that can be integrated in order to handle scrolling that plays well
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* with `ResponderEventPlugin`. Integrate with your platform specific scroll
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* views, or even your custom built (every-frame animating) scroll views so that
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* all of these systems play well with the `ResponderEventPlugin`.
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*
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* iOS scroll event timing nuances:
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* ===============================
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*
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*
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* Scrolling without bouncing, if you touch down:
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* -------------------------------
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*
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* 1. `onMomentumScrollBegin` (when animation begins after letting up)
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* ... physical touch starts ...
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* 2. `onTouchStartCapture` (when you press down to stop the scroll)
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* 3. `onTouchStart` (same, but bubble phase)
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* 4. `onResponderRelease` (when lifting up - you could pause forever before * lifting)
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* 5. `onMomentumScrollEnd`
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*
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*
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* Scrolling with bouncing, if you touch down:
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* -------------------------------
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*
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* 1. `onMomentumScrollBegin` (when animation begins after letting up)
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* ... bounce begins ...
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* ... some time elapses ...
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* ... physical touch during bounce ...
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* 2. `onMomentumScrollEnd` (Makes no sense why this occurs first during bounce)
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* 3. `onTouchStartCapture` (immediately after `onMomentumScrollEnd`)
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* 4. `onTouchStart` (same, but bubble phase)
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* 5. `onTouchEnd` (You could hold the touch start for a long time)
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* 6. `onMomentumScrollBegin` (When releasing the view starts bouncing back)
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*
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* So when we receive an `onTouchStart`, how can we tell if we are touching
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* *during* an animation (which then causes the animation to stop)? The only way
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* to tell is if the `touchStart` occurred immediately after the
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* `onMomentumScrollEnd`.
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*
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* This is abstracted out for you, so you can just call this.scrollResponderIsAnimating() if
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* necessary
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*
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* `ScrollResponder` also includes logic for blurring a currently focused input
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* if one is focused while scrolling. The `ScrollResponder` is a natural place
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* to put this logic since it can support not dismissing the keyboard while
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* scrolling, unless a recognized "tap"-like gesture has occurred.
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*
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* The public lifecycle API includes events for keyboard interaction, responder
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* interaction, and scrolling (among others). The keyboard callbacks
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* `onKeyboardWill/Did/*` are *global* events, but are invoked on scroll
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* responder's props so that you can guarantee that the scroll responder's
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* internal state has been updated accordingly (and deterministically) by
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* the time the props callbacks are invoke. Otherwise, you would always wonder
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* if the scroll responder is currently in a state where it recognizes new
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* keyboard positions etc. If coordinating scrolling with keyboard movement,
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* *always* use these hooks instead of listening to your own global keyboard
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* events.
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*
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* Public keyboard lifecycle API: (props callbacks)
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*
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* Standard Keyboard Appearance Sequence:
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*
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* this.props.onKeyboardWillShow
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* this.props.onKeyboardDidShow
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*
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* `onScrollResponderKeyboardDismissed` will be invoked if an appropriate
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* tap inside the scroll responder's scrollable region was responsible
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* for the dismissal of the keyboard. There are other reasons why the
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* keyboard could be dismissed.
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*
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* this.props.onScrollResponderKeyboardDismissed
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*
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* Standard Keyboard Hide Sequence:
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*
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* this.props.onKeyboardWillHide
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* this.props.onKeyboardDidHide
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*/
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var IS_ANIMATING_TOUCH_START_THRESHOLD_MS = 16;
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type State = {
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isTouching: boolean,
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lastMomentumScrollBeginTime: number,
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lastMomentumScrollEndTime: number,
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observedScrollSinceBecomingResponder: boolean,
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becameResponderWhileAnimating: boolean,
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};
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type Event = Object;
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function isTagInstanceOfTextInput(tag) {
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var instance = getInstanceFromNode(tag);
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return instance && instance.viewConfig && (
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instance.viewConfig.uiViewClassName === 'AndroidTextInput' ||
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instance.viewConfig.uiViewClassName === 'RCTTextView' ||
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instance.viewConfig.uiViewClassName === 'RCTTextField'
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);
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}
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var ScrollResponderMixin = {
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mixins: [Subscribable.Mixin],
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scrollResponderMixinGetInitialState: function(): State {
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return {
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isTouching: false,
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lastMomentumScrollBeginTime: 0,
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lastMomentumScrollEndTime: 0,
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// Reset to false every time becomes responder. This is used to:
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// - Determine if the scroll view has been scrolled and therefore should
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// refuse to give up its responder lock.
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// - Determine if releasing should dismiss the keyboard when we are in
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// tap-to-dismiss mode (this.props.keyboardShouldPersistTaps !== 'always').
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observedScrollSinceBecomingResponder: false,
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becameResponderWhileAnimating: false,
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};
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},
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/**
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* Invoke this from an `onScroll` event.
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*/
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scrollResponderHandleScrollShouldSetResponder: function(): boolean {
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return this.state.isTouching;
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},
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/**
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* Merely touch starting is not sufficient for a scroll view to become the
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* responder. Being the "responder" means that the very next touch move/end
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* event will result in an action/movement.
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*
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* Invoke this from an `onStartShouldSetResponder` event.
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*
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* `onStartShouldSetResponder` is used when the next move/end will trigger
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* some UI movement/action, but when you want to yield priority to views
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* nested inside of the view.
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*
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* There may be some cases where scroll views actually should return `true`
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* from `onStartShouldSetResponder`: Any time we are detecting a standard tap
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* that gives priority to nested views.
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*
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* - If a single tap on the scroll view triggers an action such as
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* recentering a map style view yet wants to give priority to interaction
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* views inside (such as dropped pins or labels), then we would return true
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* from this method when there is a single touch.
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*
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* - Similar to the previous case, if a two finger "tap" should trigger a
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* zoom, we would check the `touches` count, and if `>= 2`, we would return
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* true.
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*
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*/
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scrollResponderHandleStartShouldSetResponder: function(e: Event): boolean {
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var currentlyFocusedTextInput = TextInputState.currentlyFocusedField();
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if (this.props.keyboardShouldPersistTaps === 'handled' &&
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currentlyFocusedTextInput != null &&
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e.target !== currentlyFocusedTextInput) {
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return true;
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}
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return false;
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},
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/**
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* There are times when the scroll view wants to become the responder
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* (meaning respond to the next immediate `touchStart/touchEnd`), in a way
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* that *doesn't* give priority to nested views (hence the capture phase):
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*
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* - Currently animating.
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* - Tapping anywhere that is not a text input, while the keyboard is
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* up (which should dismiss the keyboard).
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*
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* Invoke this from an `onStartShouldSetResponderCapture` event.
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*/
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scrollResponderHandleStartShouldSetResponderCapture: function(e: Event): boolean {
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// First see if we want to eat taps while the keyboard is up
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var currentlyFocusedTextInput = TextInputState.currentlyFocusedField();
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var {keyboardShouldPersistTaps} = this.props;
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var keyboardNeverPersistTaps = !keyboardShouldPersistTaps ||
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keyboardShouldPersistTaps === 'never';
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if (keyboardNeverPersistTaps &&
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currentlyFocusedTextInput != null &&
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!isTagInstanceOfTextInput(e.target)) {
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return true;
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}
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return this.scrollResponderIsAnimating();
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},
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/**
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* Invoke this from an `onResponderReject` event.
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*
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* Some other element is not yielding its role as responder. Normally, we'd
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* just disable the `UIScrollView`, but a touch has already began on it, the
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* `UIScrollView` will not accept being disabled after that. The easiest
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* solution for now is to accept the limitation of disallowing this
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* altogether. To improve this, find a way to disable the `UIScrollView` after
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* a touch has already started.
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*/
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scrollResponderHandleResponderReject: function() {
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},
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/**
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* We will allow the scroll view to give up its lock iff it acquired the lock
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* during an animation. This is a very useful default that happens to satisfy
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* many common user experiences.
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*
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* - Stop a scroll on the left edge, then turn that into an outer view's
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* backswipe.
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* - Stop a scroll mid-bounce at the top, continue pulling to have the outer
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* view dismiss.
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* - However, without catching the scroll view mid-bounce (while it is
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* motionless), if you drag far enough for the scroll view to become
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* responder (and therefore drag the scroll view a bit), any backswipe
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* navigation of a swipe gesture higher in the view hierarchy, should be
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* rejected.
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*/
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scrollResponderHandleTerminationRequest: function(): boolean {
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return !this.state.observedScrollSinceBecomingResponder;
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},
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/**
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* Invoke this from an `onTouchEnd` event.
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*
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* @param {SyntheticEvent} e Event.
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*/
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scrollResponderHandleTouchEnd: function(e: Event) {
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var nativeEvent = e.nativeEvent;
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this.state.isTouching = nativeEvent.touches.length !== 0;
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this.props.onTouchEnd && this.props.onTouchEnd(e);
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},
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/**
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* Invoke this from an `onTouchCancel` event.
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*
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* @param {SyntheticEvent} e Event.
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*/
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scrollResponderHandleTouchCancel: function(e: Event) {
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this.state.isTouching = false;
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this.props.onTouchCancel && this.props.onTouchCancel(e);
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},
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/**
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* Invoke this from an `onResponderRelease` event.
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*/
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scrollResponderHandleResponderRelease: function(e: Event) {
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this.props.onResponderRelease && this.props.onResponderRelease(e);
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// By default scroll views will unfocus a textField
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// if another touch occurs outside of it
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var currentlyFocusedTextInput = TextInputState.currentlyFocusedField();
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if (this.props.keyboardShouldPersistTaps !== true &&
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this.props.keyboardShouldPersistTaps !== 'always' &&
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currentlyFocusedTextInput != null &&
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e.target !== currentlyFocusedTextInput &&
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!this.state.observedScrollSinceBecomingResponder &&
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!this.state.becameResponderWhileAnimating) {
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this.props.onScrollResponderKeyboardDismissed &&
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this.props.onScrollResponderKeyboardDismissed(e);
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TextInputState.blurTextInput(currentlyFocusedTextInput);
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}
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},
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scrollResponderHandleScroll: function(e: Event) {
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this.state.observedScrollSinceBecomingResponder = true;
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this.props.onScroll && this.props.onScroll(e);
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},
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/**
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* Invoke this from an `onResponderGrant` event.
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*/
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scrollResponderHandleResponderGrant: function(e: Event) {
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this.state.observedScrollSinceBecomingResponder = false;
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this.props.onResponderGrant && this.props.onResponderGrant(e);
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this.state.becameResponderWhileAnimating = this.scrollResponderIsAnimating();
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},
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/**
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* Unfortunately, `onScrollBeginDrag` also fires when *stopping* the scroll
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* animation, and there's not an easy way to distinguish a drag vs. stopping
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* momentum.
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*
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* Invoke this from an `onScrollBeginDrag` event.
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*/
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scrollResponderHandleScrollBeginDrag: function(e: Event) {
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FrameRateLogger.beginScroll(); // TODO: track all scrolls after implementing onScrollEndAnimation
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this.props.onScrollBeginDrag && this.props.onScrollBeginDrag(e);
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},
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/**
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* Invoke this from an `onScrollEndDrag` event.
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*/
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scrollResponderHandleScrollEndDrag: function(e: Event) {
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const {velocity} = e.nativeEvent;
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// - If we are animating, then this is a "drag" that is stopping the scrollview and momentum end
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// will fire.
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// - If velocity is non-zero, then the interaction will stop when momentum scroll ends or
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// another drag starts and ends.
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// - If we don't get velocity, better to stop the interaction twice than not stop it.
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if (!this.scrollResponderIsAnimating() &&
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(!velocity || velocity.x === 0 && velocity.y === 0)) {
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FrameRateLogger.endScroll();
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}
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this.props.onScrollEndDrag && this.props.onScrollEndDrag(e);
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},
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/**
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* Invoke this from an `onMomentumScrollBegin` event.
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*/
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scrollResponderHandleMomentumScrollBegin: function(e: Event) {
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this.state.lastMomentumScrollBeginTime = performanceNow();
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this.props.onMomentumScrollBegin && this.props.onMomentumScrollBegin(e);
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},
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/**
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* Invoke this from an `onMomentumScrollEnd` event.
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*/
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scrollResponderHandleMomentumScrollEnd: function(e: Event) {
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FrameRateLogger.endScroll();
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this.state.lastMomentumScrollEndTime = performanceNow();
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this.props.onMomentumScrollEnd && this.props.onMomentumScrollEnd(e);
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},
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/**
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* Invoke this from an `onTouchStart` event.
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*
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* Since we know that the `SimpleEventPlugin` occurs later in the plugin
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* order, after `ResponderEventPlugin`, we can detect that we were *not*
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* permitted to be the responder (presumably because a contained view became
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* responder). The `onResponderReject` won't fire in that case - it only
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* fires when a *current* responder rejects our request.
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*
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* @param {SyntheticEvent} e Touch Start event.
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*/
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scrollResponderHandleTouchStart: function(e: Event) {
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this.state.isTouching = true;
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this.props.onTouchStart && this.props.onTouchStart(e);
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},
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/**
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* Invoke this from an `onTouchMove` event.
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*
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* Since we know that the `SimpleEventPlugin` occurs later in the plugin
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* order, after `ResponderEventPlugin`, we can detect that we were *not*
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* permitted to be the responder (presumably because a contained view became
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* responder). The `onResponderReject` won't fire in that case - it only
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* fires when a *current* responder rejects our request.
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*
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* @param {SyntheticEvent} e Touch Start event.
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*/
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scrollResponderHandleTouchMove: function(e: Event) {
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this.props.onTouchMove && this.props.onTouchMove(e);
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},
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/**
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* A helper function for this class that lets us quickly determine if the
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* view is currently animating. This is particularly useful to know when
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* a touch has just started or ended.
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*/
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scrollResponderIsAnimating: function(): boolean {
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var now = performanceNow();
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var timeSinceLastMomentumScrollEnd = now - this.state.lastMomentumScrollEndTime;
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var isAnimating = timeSinceLastMomentumScrollEnd < IS_ANIMATING_TOUCH_START_THRESHOLD_MS ||
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this.state.lastMomentumScrollEndTime < this.state.lastMomentumScrollBeginTime;
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return isAnimating;
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},
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/**
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* Returns the node that represents native view that can be scrolled.
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* Components can pass what node to use by defining a `getScrollableNode`
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* function otherwise `this` is used.
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*/
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scrollResponderGetScrollableNode: function(): any {
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return this.getScrollableNode ?
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this.getScrollableNode() :
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ReactNative.findNodeHandle(this);
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},
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/**
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* A helper function to scroll to a specific point in the ScrollView.
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* This is currently used to help focus child TextViews, but can also
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* be used to quickly scroll to any element we want to focus. Syntax:
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*
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* `scrollResponderScrollTo(options: {x: number = 0; y: number = 0; animated: boolean = true})`
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*
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* Note: The weird argument signature is due to the fact that, for historical reasons,
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* the function also accepts separate arguments as as alternative to the options object.
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* This is deprecated due to ambiguity (y before x), and SHOULD NOT BE USED.
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*/
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scrollResponderScrollTo: function(
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x?: number | { x?: number, y?: number, animated?: boolean },
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y?: number,
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animated?: boolean
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) {
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if (typeof x === 'number') {
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console.warn('`scrollResponderScrollTo(x, y, animated)` is deprecated. Use `scrollResponderScrollTo({x: 5, y: 5, animated: true})` instead.');
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} else {
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({x, y, animated} = x || {});
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}
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UIManager.dispatchViewManagerCommand(
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nullthrows(this.scrollResponderGetScrollableNode()),
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UIManager.RCTScrollView.Commands.scrollTo,
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[x || 0, y || 0, animated !== false],
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);
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},
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/**
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* Scrolls to the end of the ScrollView, either immediately or with a smooth
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* animation.
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*
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* Example:
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*
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* `scrollResponderScrollToEnd({animated: true})`
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*/
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scrollResponderScrollToEnd: function(
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options?: { animated?: boolean },
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) {
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// Default to true
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const animated = (options && options.animated) !== false;
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UIManager.dispatchViewManagerCommand(
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this.scrollResponderGetScrollableNode(),
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UIManager.RCTScrollView.Commands.scrollToEnd,
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[animated],
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);
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},
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/**
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* Deprecated, do not use.
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*/
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scrollResponderScrollWithoutAnimationTo: function(offsetX: number, offsetY: number) {
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console.warn('`scrollResponderScrollWithoutAnimationTo` is deprecated. Use `scrollResponderScrollTo` instead');
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this.scrollResponderScrollTo({x: offsetX, y: offsetY, animated: false});
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},
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/**
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* A helper function to zoom to a specific rect in the scrollview. The argument has the shape
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* {x: number; y: number; width: number; height: number; animated: boolean = true}
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*
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* @platform ios
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*/
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scrollResponderZoomTo: function(
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rect: { x: number, y: number, width: number, height: number, animated?: boolean },
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animated?: boolean // deprecated, put this inside the rect argument instead
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) {
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invariant(ScrollViewManager && ScrollViewManager.zoomToRect, 'zoomToRect is not implemented');
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if ('animated' in rect) {
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|
/* $FlowFixMe(>=0.60.0 site=react_native_fb) This comment suppresses an
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* error found when Flow v0.60 was deployed. To see the error delete this
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* comment and run Flow. */
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var { animated, ...rect } = rect;
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} else if (typeof animated !== 'undefined') {
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console.warn('`scrollResponderZoomTo` `animated` argument is deprecated. Use `options.animated` instead');
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}
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ScrollViewManager.zoomToRect(this.scrollResponderGetScrollableNode(), rect, animated !== false);
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},
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|
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|
/**
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* Displays the scroll indicators momentarily.
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|
*/
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|
scrollResponderFlashScrollIndicators: function() {
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|
UIManager.dispatchViewManagerCommand(
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|
this.scrollResponderGetScrollableNode(),
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|
UIManager.RCTScrollView.Commands.flashScrollIndicators,
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|
[]
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|
);
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|
},
|
|
|
|
/**
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|
* This method should be used as the callback to onFocus in a TextInputs'
|
|
* parent view. Note that any module using this mixin needs to return
|
|
* the parent view's ref in getScrollViewRef() in order to use this method.
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|
* @param {any} nodeHandle The TextInput node handle
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|
* @param {number} additionalOffset The scroll view's bottom "contentInset".
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|
* Default is 0.
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|
* @param {bool} preventNegativeScrolling Whether to allow pulling the content
|
|
* down to make it meet the keyboard's top. Default is false.
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|
*/
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|
scrollResponderScrollNativeHandleToKeyboard: function(nodeHandle: any, additionalOffset?: number, preventNegativeScrollOffset?: bool) {
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|
this.additionalScrollOffset = additionalOffset || 0;
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|
this.preventNegativeScrollOffset = !!preventNegativeScrollOffset;
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|
UIManager.measureLayout(
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|
nodeHandle,
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|
ReactNative.findNodeHandle(this.getInnerViewNode()),
|
|
this.scrollResponderTextInputFocusError,
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|
this.scrollResponderInputMeasureAndScrollToKeyboard
|
|
);
|
|
},
|
|
|
|
/**
|
|
* The calculations performed here assume the scroll view takes up the entire
|
|
* screen - even if has some content inset. We then measure the offsets of the
|
|
* keyboard, and compensate both for the scroll view's "contentInset".
|
|
*
|
|
* @param {number} left Position of input w.r.t. table view.
|
|
* @param {number} top Position of input w.r.t. table view.
|
|
* @param {number} width Width of the text input.
|
|
* @param {number} height Height of the text input.
|
|
*/
|
|
scrollResponderInputMeasureAndScrollToKeyboard: function(left: number, top: number, width: number, height: number) {
|
|
var keyboardScreenY = Dimensions.get('window').height;
|
|
if (this.keyboardWillOpenTo) {
|
|
keyboardScreenY = this.keyboardWillOpenTo.endCoordinates.screenY;
|
|
}
|
|
var scrollOffsetY = top - keyboardScreenY + height + this.additionalScrollOffset;
|
|
|
|
// By default, this can scroll with negative offset, pulling the content
|
|
// down so that the target component's bottom meets the keyboard's top.
|
|
// If requested otherwise, cap the offset at 0 minimum to avoid content
|
|
// shifting down.
|
|
if (this.preventNegativeScrollOffset) {
|
|
scrollOffsetY = Math.max(0, scrollOffsetY);
|
|
}
|
|
this.scrollResponderScrollTo({x: 0, y: scrollOffsetY, animated: true});
|
|
|
|
this.additionalOffset = 0;
|
|
this.preventNegativeScrollOffset = false;
|
|
},
|
|
|
|
scrollResponderTextInputFocusError: function(e: Event) {
|
|
console.error('Error measuring text field: ', e);
|
|
},
|
|
|
|
/**
|
|
* `componentWillMount` is the closest thing to a standard "constructor" for
|
|
* React components.
|
|
*
|
|
* The `keyboardWillShow` is called before input focus.
|
|
*/
|
|
componentWillMount: function() {
|
|
var {keyboardShouldPersistTaps} = this.props;
|
|
warning(
|
|
typeof keyboardShouldPersistTaps !== 'boolean',
|
|
`'keyboardShouldPersistTaps={${keyboardShouldPersistTaps}}' is deprecated. `
|
|
+ `Use 'keyboardShouldPersistTaps="${keyboardShouldPersistTaps ? 'always' : 'never'}"' instead`
|
|
);
|
|
|
|
this.keyboardWillOpenTo = null;
|
|
this.additionalScrollOffset = 0;
|
|
this.addListenerOn(Keyboard, 'keyboardWillShow', this.scrollResponderKeyboardWillShow);
|
|
this.addListenerOn(Keyboard, 'keyboardWillHide', this.scrollResponderKeyboardWillHide);
|
|
this.addListenerOn(Keyboard, 'keyboardDidShow', this.scrollResponderKeyboardDidShow);
|
|
this.addListenerOn(Keyboard, 'keyboardDidHide', this.scrollResponderKeyboardDidHide);
|
|
},
|
|
|
|
/**
|
|
* Warning, this may be called several times for a single keyboard opening.
|
|
* It's best to store the information in this method and then take any action
|
|
* at a later point (either in `keyboardDidShow` or other).
|
|
*
|
|
* Here's the order that events occur in:
|
|
* - focus
|
|
* - willShow {startCoordinates, endCoordinates} several times
|
|
* - didShow several times
|
|
* - blur
|
|
* - willHide {startCoordinates, endCoordinates} several times
|
|
* - didHide several times
|
|
*
|
|
* The `ScrollResponder` providesModule callbacks for each of these events.
|
|
* Even though any user could have easily listened to keyboard events
|
|
* themselves, using these `props` callbacks ensures that ordering of events
|
|
* is consistent - and not dependent on the order that the keyboard events are
|
|
* subscribed to. This matters when telling the scroll view to scroll to where
|
|
* the keyboard is headed - the scroll responder better have been notified of
|
|
* the keyboard destination before being instructed to scroll to where the
|
|
* keyboard will be. Stick to the `ScrollResponder` callbacks, and everything
|
|
* will work.
|
|
*
|
|
* WARNING: These callbacks will fire even if a keyboard is displayed in a
|
|
* different navigation pane. Filter out the events to determine if they are
|
|
* relevant to you. (For example, only if you receive these callbacks after
|
|
* you had explicitly focused a node etc).
|
|
*/
|
|
scrollResponderKeyboardWillShow: function(e: Event) {
|
|
this.keyboardWillOpenTo = e;
|
|
this.props.onKeyboardWillShow && this.props.onKeyboardWillShow(e);
|
|
},
|
|
|
|
scrollResponderKeyboardWillHide: function(e: Event) {
|
|
this.keyboardWillOpenTo = null;
|
|
this.props.onKeyboardWillHide && this.props.onKeyboardWillHide(e);
|
|
},
|
|
|
|
scrollResponderKeyboardDidShow: function(e: Event) {
|
|
// TODO(7693961): The event for DidShow is not available on iOS yet.
|
|
// Use the one from WillShow and do not assign.
|
|
if (e) {
|
|
this.keyboardWillOpenTo = e;
|
|
}
|
|
this.props.onKeyboardDidShow && this.props.onKeyboardDidShow(e);
|
|
},
|
|
|
|
scrollResponderKeyboardDidHide: function(e: Event) {
|
|
this.keyboardWillOpenTo = null;
|
|
this.props.onKeyboardDidHide && this.props.onKeyboardDidHide(e);
|
|
}
|
|
|
|
};
|
|
|
|
var ScrollResponder = {
|
|
Mixin: ScrollResponderMixin,
|
|
};
|
|
|
|
module.exports = ScrollResponder;
|