1#import "RNFlingHandler.h"
2
3@interface RNBetterSwipeGestureRecognizer : UISwipeGestureRecognizer
4
5- (id)initWithGestureHandler:(RNGestureHandler *)gestureHandler;
6
7@end
8
9@implementation RNBetterSwipeGestureRecognizer {
10  __weak RNGestureHandler *_gestureHandler;
11  CGPoint _lastPoint; // location of the most recently updated touch, relative to the view
12  bool _hasBegan; // whether the `BEGAN` event has been sent
13}
14
15- (id)initWithGestureHandler:(RNGestureHandler *)gestureHandler
16{
17  if ((self = [super initWithTarget:gestureHandler action:@selector(handleGesture:)])) {
18    _gestureHandler = gestureHandler;
19    _lastPoint = CGPointZero;
20    _hasBegan = NO;
21  }
22  return self;
23}
24
25- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
26{
27  _lastPoint = [[[touches allObjects] objectAtIndex:0] locationInView:_gestureHandler.recognizer.view];
28  [_gestureHandler reset];
29  [super touchesBegan:touches withEvent:event];
30  [_gestureHandler.pointerTracker touchesBegan:touches withEvent:event];
31
32  // self.numberOfTouches doesn't work for this because in case than one finger is required,
33  // when holding one finger on the screen and tapping with the second one, numberOfTouches is equal
34  // to 2 only for the first tap but 1 for all the following ones
35  if (!_hasBegan) {
36    [self triggerAction];
37    _hasBegan = YES;
38  }
39}
40
41- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
42{
43  _lastPoint = [[[touches allObjects] objectAtIndex:0] locationInView:_gestureHandler.recognizer.view];
44  [super touchesMoved:touches withEvent:event];
45  [_gestureHandler.pointerTracker touchesMoved:touches withEvent:event];
46}
47
48- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
49{
50  _lastPoint = [[[touches allObjects] objectAtIndex:0] locationInView:_gestureHandler.recognizer.view];
51  [super touchesEnded:touches withEvent:event];
52  [_gestureHandler.pointerTracker touchesEnded:touches withEvent:event];
53}
54
55- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
56{
57  _lastPoint = [[[touches allObjects] objectAtIndex:0] locationInView:_gestureHandler.recognizer.view];
58  [super touchesCancelled:touches withEvent:event];
59  [_gestureHandler.pointerTracker touchesCancelled:touches withEvent:event];
60}
61
62- (void)triggerAction
63{
64  [_gestureHandler handleGesture:self];
65}
66
67- (void)reset
68{
69  [self triggerAction];
70  [_gestureHandler.pointerTracker reset];
71  _hasBegan = NO;
72  [super reset];
73}
74
75- (CGPoint)getLastLocation
76{
77  // I think keeping the location of only one touch is enough since it would be used to determine the direction
78  // of the movement, and if it's wrong the recognizer fails anyway.
79  // In case the location of all touches is required, touch events are the way to go
80  return _lastPoint;
81}
82
83@end
84
85@implementation RNFlingGestureHandler
86
87- (instancetype)initWithTag:(NSNumber *)tag
88{
89  if ((self = [super initWithTag:tag])) {
90    _recognizer = [[RNBetterSwipeGestureRecognizer alloc] initWithGestureHandler:self];
91  }
92  return self;
93}
94- (void)resetConfig
95{
96  [super resetConfig];
97  UISwipeGestureRecognizer *recognizer = (UISwipeGestureRecognizer *)_recognizer;
98  recognizer.direction = UISwipeGestureRecognizerDirectionRight;
99#if !TARGET_OS_TV
100  recognizer.numberOfTouchesRequired = 1;
101#endif
102}
103
104- (void)configure:(NSDictionary *)config
105{
106  [super configure:config];
107  UISwipeGestureRecognizer *recognizer = (UISwipeGestureRecognizer *)_recognizer;
108
109  id prop = config[@"direction"];
110  if (prop != nil) {
111    recognizer.direction = [RCTConvert NSInteger:prop];
112  }
113
114#if !TARGET_OS_TV
115  prop = config[@"numberOfPointers"];
116  if (prop != nil) {
117    recognizer.numberOfTouchesRequired = [RCTConvert NSInteger:prop];
118  }
119#endif
120}
121
122- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
123{
124  RNGestureHandlerState savedState = _lastState;
125  BOOL shouldBegin = [super gestureRecognizerShouldBegin:gestureRecognizer];
126  _lastState = savedState;
127
128  return shouldBegin;
129}
130
131- (RNGestureHandlerEventExtraData *)eventExtraData:(id)_recognizer
132{
133  // For some weird reason [recognizer locationInView:recognizer.view.window] returns (0, 0).
134  // To calculate the correct absolute position, first calculate the absolute position of the
135  // view inside the root view controller (https://stackoverflow.com/a/7448573) and then
136  // add the relative touch position to it.
137
138  RNBetterSwipeGestureRecognizer *recognizer = (RNBetterSwipeGestureRecognizer *)_recognizer;
139
140  CGPoint viewAbsolutePosition =
141      [recognizer.view convertPoint:recognizer.view.bounds.origin
142                             toView:[UIApplication sharedApplication].keyWindow.rootViewController.view];
143  CGPoint locationInView = [recognizer getLastLocation];
144
145  return [RNGestureHandlerEventExtraData
146               forPosition:locationInView
147      withAbsolutePosition:CGPointMake(
148                               viewAbsolutePosition.x + locationInView.x, viewAbsolutePosition.y + locationInView.y)
149       withNumberOfTouches:recognizer.numberOfTouches];
150}
151
152@end
153