mirror of
https://github.com/facebook/react-native.git
synced 2025-11-01 09:14:26 +00:00
Valentin SherginandFacebook GitHub Bot
9a72702b44
Summary: This is the first implementation stage of on-demand child views mounting for <ScrollView> feature. It works this way. When mounting layer requests mounting of a subview of <ScrollView>, the component does not mount it immediately. Instead, it stores it in an internal collection, and then after the transaction finishes use that to mount views that are in a visible area. Then we re-evaluate which child views are should be mounted and unmounted on every significant onScroll event. We use some leeway to do it not so often to save CPU cycles on scrolling. This feature already works fine but to make it shippable we need to integrate it with an `overflow inset` feature to make it 100% reliable in complex cases when some views have overflow content. Changelog: [Internal] Fabric-specific internal change. Reviewed By: sammy-SC Differential Revision: D22304012 fbshipit-source-id: be4ae21378d9d1c457cad2826da7d8c8d6395be5
69 lines
2.5 KiB
Objective-C
69 lines
2.5 KiB
Objective-C
/*
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* Copyright (c) Facebook, Inc. and its 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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#import <UIKit/UIKit.h>
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#import <React/RCTDefines.h>
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#import <React/RCTGenericDelegateSplitter.h>
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#import <React/RCTMountingTransactionObserving.h>
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#import <React/RCTScrollableProtocol.h>
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#import <React/RCTViewComponentView.h>
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/*
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* Allows to enable or disable on-demand view mounting feature of ScrollView.
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* It's an experimental feature that improves performance and memory footprint of huge lists inside ScrollView.
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*/
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RCT_EXTERN void RCTSetEnableOnDemandViewMounting(BOOL value);
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NS_ASSUME_NONNULL_BEGIN
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/*
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* UIView class for <ScrollView> component.
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*
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* By design, the class does not implement any logic that contradicts to the normal behavior of UIScrollView and does
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* not contain any special/custom support for things like floating headers, pull-to-refresh components,
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* keyboard-avoiding functionality and so on. All that complexity must be implemented inside those components in order
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* to keep the complexity of this component manageable.
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*/
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@interface RCTScrollViewComponentView : RCTViewComponentView <RCTMountingTransactionObserving>
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/*
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* Finds and returns the closet RCTScrollViewComponentView component to the given view
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*/
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+ (RCTScrollViewComponentView *_Nullable)findScrollViewComponentViewForView:(UIView *)view;
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/*
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* Returns an actual UIScrollView that this component uses under the hood.
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*/
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@property (nonatomic, strong, readonly) UIScrollView *scrollView;
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/*
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* Returns the subview of the scroll view that the component uses to mount all subcomponents into. That's useful to
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* separate component views from auxiliary views to be able to reliably implement pull-to-refresh- and RTL-related
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* functionality.
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*/
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@property (nonatomic, strong, readonly) UIView *containerView;
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/*
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* Returns a delegate splitter that can be used to subscribe for UIScrollView delegate.
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*/
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@property (nonatomic, strong, readonly)
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RCTGenericDelegateSplitter<id<UIScrollViewDelegate>> *scrollViewDelegateSplitter;
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@end
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/*
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* RCTScrollableProtocol is a protocol which RCTScrollViewManager uses to communicate with all kinds of `UIScrollView`s.
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* Until Fabric has own command-execution pipeline we have to support that to some extent. The implementation shouldn't
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* be perfect though because very soon we will migrate that to the new commands infra and get rid of this.
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*/
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@interface RCTScrollViewComponentView (ScrollableProtocol) <RCTScrollableProtocol>
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@end
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NS_ASSUME_NONNULL_END
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