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How to use ReactiveCocoa with gesture recognizers

I am creating an application using ReactiveCocoa. Top view is a menu that you can pull out and then click again. I have to use two different gesture recognizers - one for lowering and one for pushing back. Only one can be turned on at a time - and there is my problem. Condition.

I use the BlocksKit extension to configure gesture recognizer.

self.panHeaderDownGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithHandler:^(UIGestureRecognizer *sender, UIGestureRecognizerState state, CGPoint location) {
    UIPanGestureRecognizer *recognizer = (UIPanGestureRecognizer *)sender;

    CGPoint translation = [recognizer translationInView:self.view];

    if (state == UIGestureRecognizerStateChanged)
    {
        [self.downwardHeaderPanSubject sendNext:@(translation.y)];
    }
    else if (state == UIGestureRecognizerStateEnded)
    {
        // Determine the direction the finger is moving and ensure if it was moving down, that it exceeds the minimum threshold for opening the menu.
        BOOL movingDown = ([recognizer velocityInView:self.view].y > 0 && translation.y > kMoveDownThreshold);

        // Animate the change
        [UIView animateWithDuration:0.25f animations:^{
            if (movingDown)
            {
                [self.downwardHeaderPanSubject sendNext:@(kMaximumHeaderTranslationThreshold)];
            }
            else
            {
                [self.downwardHeaderPanSubject sendNext:@(0)];
            }
        } completion:^(BOOL finished) {
            [self.menuFinishedTransitionSubject sendNext:@(movingDown)];
        }];
    }
}];

In my method, initWithNibName:bundle:I configure the following RACSubjects.

self.headerMovementSubject = [RACSubject subject];
[self.headerMovementSubject subscribeNext:^(id x) {
    @strongify(self);

    // This is the ratio of the movement. 0 is closed and 1 is open.
    // Values less than zero are treated as zero.
    // Values greater than one are valid and will be extrapolated beyond the fully open menu.
    CGFloat ratio = [x floatValue];

    CGRect headerFrame = CGRectMake(0, 0, CGRectGetWidth(self.view.bounds), kHeaderHeight + ratio * kMaximumHeaderTranslationThreshold);

    if (ratio < 0)
    {            
        headerFrame = CGRectMake(0, 0, CGRectGetWidth(self.view.bounds), kHeaderHeight);
    }

    self.headerViewController.view.frame = headerFrame;
}];

// This subject is responsible for receiving translations from a gesture recognizers and turning
// thos values into ratios. These ratios are fead into other signals.
self.downwardHeaderPanSubject = [RACSubject subject];
[self.downwardHeaderPanSubject subscribeNext:^(NSNumber *translation) {
    @strongify(self);
    CGFloat verticalTranslation = [translation floatValue];

    CGFloat effectiveRatio = 0.0f;

    if (verticalTranslation <= 0)
    {
        effectiveRatio = 0.0f;
    }
    else if (verticalTranslation <= kMaximumHeaderTranslationThreshold)
    {
        effectiveRatio = fabsf(verticalTranslation / kMaximumHeaderTranslationThreshold);
    }
    else
    {
        CGFloat overshoot = verticalTranslation - kMaximumHeaderTranslationThreshold;
        CGFloat y = 2 * sqrtf(overshoot + 1) - 2;
        effectiveRatio = 1.0f + (y / kMaximumHeaderTranslationThreshold);
    }

    [self.headerMovementSubject sendNext:@(effectiveRatio)];
}];

// This subject is responsible for mapping this value to other signals and state (ugh). 
self.menuFinishedTransitionSubject = [RACReplaySubject subject];
[self.menuFinishedTransitionSubject subscribeNext:^(NSNumber *menuIsOpenNumber) {
    @strongify(self);

    BOOL menuIsOpen = menuIsOpenNumber.boolValue;

    self.panHeaderDownGestureRecognizer.enabled = !menuIsOpen;
    self.panHeaderUpGestureRecognizer.enabled = menuIsOpen;
    self.otherViewController.view.userInteractionEnabled = !menuIsOpen;

    if (menuIsOpen)
    {
        [self.headerViewController flashScrollBars];
    }
}];

A lot is going on here. The problem is compounded by the fact that I have almost twice as many items that I have listed here (for a chewing ad recognizer), plus another set of recognizers for similar interaction with the footer. This is a lot of items.

My question has two parts:

  • , ? , . RACSubjects, .
  • menuFinishedTransitionSubject . enabled . ?
+5
1

, .

, , headerMovementSubject downwardHeaderPanSubject ( ). :

RACSignal *headerFrameSignal = [[self.downwardHeaderPanSubject
    map:^(NSNumber *translation) {
        CGFloat verticalTranslation = [translation floatValue];
        CGFloat effectiveRatio = 0.0f;

        // Calculate effectiveRatio.

        return @(effectiveRatio);
    }]
    map:^(NSNumber *effectiveRatio) {
        // Calculate headerFrame.

        return @(headerFrame);
    }];

self.headerViewController.view.frame :

RAC(self.headerViewController.view.frame) = headerFrameSignal;

menuFinishedTransitionSubject:

RAC(self.panHeaderDownGestureRecognizer.enabled) = [self.menuFinishedTransitionSubject not];
RAC(self.panHeaderUpGestureRecognizer.enabled) = self.menuFinishedTransitionSubject;
RAC(self.otherViewController.view.userInteractionEnabled) = [self.menuFinishedTransitionSubject not];

, -flashScrollBars , :

[[self.menuFinishedTransitionSubject
    filter:^(NSNumber *menuIsOpen) {
        return menuIsOpen.boolValue;
    }]
    subscribeNext:^(id _) {
        @strongify(self);

        [self.headerViewController flashScrollBars];
    }];

- , , ReactiveCocoaLayout, .

+5

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