mirror of
https://github.com/status-im/react-native.git
synced 2025-02-24 15:18:10 +00:00
9733b92f3d
Summary: This PR exposes the `onScrollToTop` event on iOS using the same event-forwarding infrastructure as other ScrollView events. (As such, its `nativeEvent` object reflects the same fields as other ScrollView events.) Motivation: ---------- If your app is only interested in knowing the position of a ScrollView after a scroll has completed, it can use `onScrollEndDrag` and `onMomentumScrollEnd` to inspect the `contentOffset` after a drag-initiated scroll has finished. (This is much less expensive than observing the `onScroll` event if you only want to know the end position.) However, neither of these `End` events fire if the ScrollView is scrolled to the top by tapping the status bar. By exposing `onScrollToTop`, it is now possible for an app to cheaply know when such a scroll has completed. Pull Request resolved: https://github.com/facebook/react-native/pull/21204 Differential Revision: D9943618 Pulled By: hramos fbshipit-source-id: ac5ee42b7f12d94655ffda617f8f811138da7f6f
79 lines
2.8 KiB
Objective-C
79 lines
2.8 KiB
Objective-C
/**
|
|
* Copyright (c) Facebook, Inc. and its affiliates.
|
|
*
|
|
* This source code is licensed under the MIT license found in the
|
|
* LICENSE file in the root directory of this source tree.
|
|
*/
|
|
|
|
#import <UIKit/UIScrollView.h>
|
|
|
|
#import <React/RCTAutoInsetsProtocol.h>
|
|
#import <React/RCTEventDispatcher.h>
|
|
#import <React/RCTScrollableProtocol.h>
|
|
#import <React/RCTView.h>
|
|
|
|
@protocol UIScrollViewDelegate;
|
|
|
|
@interface RCTScrollView : RCTView <UIScrollViewDelegate, RCTScrollableProtocol, RCTAutoInsetsProtocol>
|
|
|
|
- (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher NS_DESIGNATED_INITIALIZER;
|
|
|
|
/**
|
|
* The `RCTScrollView` may have at most one single subview. This will ensure
|
|
* that the scroll view's `contentSize` will be efficiently set to the size of
|
|
* the single subview's frame. That frame size will be determined somewhat
|
|
* efficiently since it will have already been computed by the off-main-thread
|
|
* layout system.
|
|
*/
|
|
@property (nonatomic, readonly) UIView *contentView;
|
|
|
|
/**
|
|
* If the `contentSize` is not specified (or is specified as {0, 0}, then the
|
|
* `contentSize` will automatically be determined by the size of the subview.
|
|
*/
|
|
@property (nonatomic, assign) CGSize contentSize;
|
|
|
|
/**
|
|
* The underlying scrollView (TODO: can we remove this?)
|
|
*/
|
|
@property (nonatomic, readonly) UIScrollView *scrollView;
|
|
|
|
@property (nonatomic, assign) UIEdgeInsets contentInset;
|
|
@property (nonatomic, assign) BOOL automaticallyAdjustContentInsets;
|
|
@property (nonatomic, assign) BOOL DEPRECATED_sendUpdatedChildFrames;
|
|
@property (nonatomic, assign) NSTimeInterval scrollEventThrottle;
|
|
@property (nonatomic, assign) BOOL centerContent;
|
|
@property (nonatomic, copy) NSDictionary *maintainVisibleContentPosition;
|
|
@property (nonatomic, assign) int snapToInterval;
|
|
@property (nonatomic, copy) NSArray<NSNumber *> *snapToOffsets;
|
|
@property (nonatomic, assign) BOOL snapToStart;
|
|
@property (nonatomic, assign) BOOL snapToEnd;
|
|
@property (nonatomic, copy) NSString *snapToAlignment;
|
|
|
|
// NOTE: currently these event props are only declared so we can export the
|
|
// event names to JS - we don't call the blocks directly because scroll events
|
|
// need to be coalesced before sending, for performance reasons.
|
|
@property (nonatomic, copy) RCTDirectEventBlock onScrollBeginDrag;
|
|
@property (nonatomic, copy) RCTDirectEventBlock onScroll;
|
|
@property (nonatomic, copy) RCTDirectEventBlock onScrollToTop;
|
|
@property (nonatomic, copy) RCTDirectEventBlock onScrollEndDrag;
|
|
@property (nonatomic, copy) RCTDirectEventBlock onMomentumScrollBegin;
|
|
@property (nonatomic, copy) RCTDirectEventBlock onMomentumScrollEnd;
|
|
|
|
@end
|
|
|
|
@interface RCTScrollView (Internal)
|
|
|
|
- (void)updateContentOffsetIfNeeded;
|
|
|
|
@end
|
|
|
|
@interface RCTEventDispatcher (RCTScrollView)
|
|
|
|
/**
|
|
* Send a fake scroll event.
|
|
*/
|
|
- (void)sendFakeScrollEvent:(NSNumber *)reactTag;
|
|
|
|
@end
|