blob: a1a72ae75dec280dfecb38b3e31cb3abe0f42bf8 [file] [log] [blame]
// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#import "ios/chrome/browser/ui/main_content/main_content_ui_state.h"
#include "base/logging.h"
#include "ios/chrome/browser/ui/ui_util.h"
#if !defined(__has_feature) || !__has_feature(objc_arc)
#error "This file requires ARC support."
#endif
@interface MainContentUIState ()
// Redefine broadcast properties as readwrite.
@property(nonatomic, assign) CGSize scrollViewSize;
@property(nonatomic, assign) CGSize contentSize;
@property(nonatomic, assign) UIEdgeInsets contentInset;
@property(nonatomic, assign) CGFloat yContentOffset;
@property(nonatomic, assign, getter=isScrolling) BOOL scrolling;
@property(nonatomic, assign, getter=isZooming) BOOL zooming;
@property(nonatomic, assign, getter=isDragging) BOOL dragging;
// Whether the scroll view is decelerating.
@property(nonatomic, assign, getter=isDecelerating) BOOL decelerating;
// Updates |scrolling| based |dragging| and |decelerating|.
- (void)updateIsScrolling;
@end
@implementation MainContentUIState
@synthesize scrollViewSize = _scrollViewSize;
@synthesize contentSize = _contentSize;
@synthesize contentInset = _contentInset;
@synthesize yContentOffset = _yContentOffset;
@synthesize scrolling = _scrolling;
@synthesize zooming = _zooming;
@synthesize dragging = _dragging;
@synthesize decelerating = _decelerating;
- (void)setDragging:(BOOL)dragging {
if (_dragging == dragging)
return;
_dragging = dragging;
// When a scroll view is being dragged, its contents are tracking the pan
// gesture, and previous deceleration is cancelled.
if (_dragging)
_decelerating = NO;
[self updateIsScrolling];
}
- (void)setDecelerating:(BOOL)decelerating {
if (_decelerating == decelerating)
return;
// If the scroll view is starting to decelerate after a drag, it is expected
// that this property is set before |dragging| is reset to NO. This ensures
// that the broadcasted |scrolling| property does not quickly flip to NO when
// drag events finish.
DCHECK(!decelerating || self.dragging);
_decelerating = decelerating;
[self updateIsScrolling];
}
#pragma mark Private
- (void)updateIsScrolling {
self.scrolling = self.dragging || self.decelerating;
}
@end
@interface MainContentUIStateUpdater ()
// The pan gesture driving the current scroll event.
// TODO(crbug.com/785508): Use this gesture recognizer to broadcast the scroll
// touch location.
@property(nonatomic, weak) UIPanGestureRecognizer* panGesture;
@end
@implementation MainContentUIStateUpdater
@synthesize state = _state;
@synthesize panGesture = _panGesture;
- (instancetype)initWithState:(MainContentUIState*)state {
if (self = [super init]) {
_state = state;
DCHECK(_state);
}
return self;
}
#pragma mark Public
- (void)scrollViewSizeDidChange:(CGSize)scrollViewSize {
self.state.scrollViewSize = scrollViewSize;
}
- (void)scrollViewDidResetContentSize:(CGSize)contentSize {
self.state.contentSize = contentSize;
}
- (void)scrollViewDidResetContentInset:(UIEdgeInsets)contentInset {
self.state.contentInset = contentInset;
}
- (void)scrollViewDidScrollToOffset:(CGPoint)offset {
self.state.yContentOffset = offset.y;
}
- (void)scrollViewWillBeginDraggingWithGesture:
(UIPanGestureRecognizer*)panGesture {
self.state.dragging = YES;
self.panGesture = panGesture;
}
- (void)scrollViewDidEndDraggingWithGesture:(UIPanGestureRecognizer*)panGesture
residualVelocity:(CGPoint)velocity {
// It's possible during the side-swipe gesture for a drag to end on the scroll
// view without a corresponding begin dragging call. Early return if there
// is no pan gesture from the begin call.
if (!self.panGesture)
return;
DCHECK_EQ(panGesture, self.panGesture);
if (!AreCGFloatsEqual(velocity.y, 0.0))
self.state.decelerating = YES;
self.state.dragging = NO;
self.panGesture = nil;
}
- (void)scrollViewDidEndDecelerating {
self.state.decelerating = NO;
}
- (void)scrollViewDidStartZooming {
self.state.zooming = YES;
}
- (void)scrollViewDidEndZooming {
self.state.zooming = NO;
}
- (void)scrollWasInterrupted {
self.state.scrolling = NO;
self.state.dragging = NO;
self.state.decelerating = NO;
self.state.zooming = NO;
}
@end