Created
October 29, 2015 19:19
-
-
Save fpillet/04b46aa22edb516c7ee3 to your computer and use it in GitHub Desktop.
Example of encapsulating a gesture recognizer's behavior within a signal's callbacks
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
- (void)setupDraggableHeaderGestureRecognizer { | |
// setup a gesture recognizer so we can drag the "I need some daytime hours" header up and down | |
@weakify(self); | |
UIPanGestureRecognizer *recognizer = [[UIPanGestureRecognizer alloc] init]; | |
_draggableHeaderView.userInteractionEnabled = YES; | |
[_draggableHeaderView addGestureRecognizer:recognizer]; | |
RACDisposable *disposable = [[[recognizer | |
rac_gestureSignal] | |
scanWithStart:RACTuplePack(@(_mapViewHeightConstraint.constant), @0) | |
reduce:^(RACTuple *translations, UIPanGestureRecognizer *gestureRecognizer) { | |
@strongify(self); | |
switch (gestureRecognizer.state) { | |
case UIGestureRecognizerStateBegan: | |
return RACTuplePack(@(self.mapViewHeightConstraint.constant), @0); | |
case UIGestureRecognizerStateChanged: { | |
CGFloat verticalTranslation = floorf([gestureRecognizer translationInView:self.mapView.superview].y); | |
CGFloat initialConstant = ((NSNumber *) translations.first).floatValue; | |
CGFloat constant = initialConstant + verticalTranslation; | |
if (constant < [self minimumMapHeight]) | |
constant = [self minimumMapHeight]; | |
else if ((CGRectGetMinY(self.mapView.frame)+constant) > (CGRectGetMinY(self.searchButton.frame) - CGRectGetHeight(self.draggableHeaderView.frame))) { | |
constant = CGRectGetMinY(self.searchButton.frame) - CGRectGetHeight(self.draggableHeaderView.frame) - CGRectGetMinY(self.mapView.frame); | |
} | |
return RACTuplePack(translations.first, @(constant - initialConstant)); | |
} | |
case UIGestureRecognizerStateCancelled: | |
return RACTuplePack(translations.first, translations.first); | |
default: | |
return translations; | |
} | |
}] | |
subscribeNext:^(RACTuple *tuple) { | |
@strongify(self); | |
self.mapViewHeightConstraint.constant = ((NSNumber *) tuple.first).floatValue + ((NSNumber *) tuple.second).floatValue; | |
}]; | |
_draggableHeaderDisposable = [RACDisposable disposableWithBlock:^{ | |
[_draggableHeaderView removeGestureRecognizer:recognizer]; | |
[disposable dispose]; | |
}].asScopedDisposable; | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment