CODEWITHSUNDEEP
iosobjective-cuiscrollviewuipangesturerecognizer
user2397282
user2397282

Reputation: 3818

UIPanGestureRecognizer interfering with scroll

I have a scroll view with 3 view controllers that I want to swipe between. However, one of my view controllers has a UIPanGestureRecognizer and this stops the scrollview from working. This is the code for the pan:

- (void)pan:(UIPanGestureRecognizer *)aPan; // When pan guesture is recognised
{
CGPoint location = [aPan locationInView:self.view]; // Location of finger on screen
CGRect secondRect = CGRectMake(210.0, 45.0, 70.0, 325.0); // Rectangles of maximimum bar area
CGRect minuteRect = CGRectMake(125.0, 45.0, 70.0, 325.0);
CGRect hourRect = CGRectMake(41.0, 45.0, 70.0, 325.0);

if (CGRectContainsPoint(secondRect, location)) { // If finger is inside the 'second' rectangle

    CGPoint currentPoint = [aPan locationInView:self.view];

    currentPoint.y -= 80;  // Make sure animation doesn't go outside the bars' rectangle

    if (currentPoint.y < 0) {
    currentPoint.y = 0;
    }
    else if (currentPoint.y > 239) {
    currentPoint.y = 239;
    }

    currentPoint.y = 239.0 - currentPoint.y;

    CGFloat pointy = currentPoint.y - fmod(currentPoint.y, 4.0);

    [UIView animateWithDuration:0.01f  // Animate the bars to rise as the finger moves up and down
                     animations:^{
                         CGRect oldFrame = secondBar.frame;
                         secondBar.frame = CGRectMake(oldFrame.origin.x, (oldFrame.origin.y - (pointy - secondBar.frame.size.height)), oldFrame.size.width, (pointy));
                     }];

    CGFloat result = secondBar.frame.size.height - fmod(secondBar.frame.size.height, 4.0);

    secondInt = (result / 4.0); // Update labels with new time

    self->secondLabel.text = [NSString stringWithFormat:@"%02d", secondInt];
}
}

Basically, this code allows the user to drag their finger up and down the screen, and change the height of a uiview. Therefore, I only need the up/down pan gesture for this and only the left/right pan gestures for the scroll view.

Does anyone have any idea how I can do this?

Upvotes: 1

Views: 1529

Answers (2)

TotoroTotoro
TotoroTotoro

Reputation: 17622

Your scrollview has a property called panGestureRecognizer. You can create a delegate for your own UIPanGestureRecognizer, and implement this method:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {

    if(otherGestureRecognizer == myScrollView.panGestureRecognizer) {
         return YES;
    } else {
         return NO;
    }
}

Upvotes: 3

jakenberg
jakenberg

Reputation: 2113

UIPanGestureRecognizer contains a delegate method - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch that you can return YES or NO to let/prevent the pan gesture from receiving the touch.

Within that method, you could write something like:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
    CGPoint velocity = [gestureRecognizer velocityInView:yourView];

    if(velocity.x > 0)
    {
        NSLog(@"gesture went right"); // return NO
    }
    else if (velocity.x < 0)
    {
        NSLog(@"gesture went left"); // return NO
    }

    if (velocity.y > 0)
    {
        NSLog(@"gesture went down"); // return YES
    }
    else if (velocity.y < 0)
    {
        NSLog(@"gesture went up"); // return YES
    }
}

Admittedly, that probably isn't the cleanest implementation. You're leaving an open door for mixed gestures. So just make sure to watch for that.

Upvotes: -2

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