In my app I have a UIScrollView and I need to swipe left and right from one picture to the next, but I also need to recognize a scroll.
How do I differentiate between a scroll and a swipe with UIScrollView?
I believe you're actually looking for is an implementation of UIScrollView with Paging, as you do not need to handle the touch events yourself, or determine if they are scrolls or swipes.
The Apple Documentation on Scroll Views and Paging Mode should help you get started
Look into the UIScrollView Delegate Methods. ScrollView can detect different types of actions drag etc or add swipeGesture directly to the scroll view
StackOverflow has questions already on this
iOS: UIScrollView detecting Swipe Gesture
Setting up UIScrollView to swipe between 3 view controllers
How to recognize swipe gesture in UIScrollView
Related
In one of my app, I am having multiple table views inside a horizontal scroll view. So, user can horizontally swipe between table views. I am not using UIPageViewController for some reason.
The problem that I am facing is that I have swipe to delete feature on my UITableView but does not work when I have multiple pages in the horizontal scroll view.
Is there an elegant way to provide both the features at the same time?
You can subclass UIScrollView and implement UIGestureRecognizerDelegate. Then return true in gestureRecognizer(_:,shouldRecognizeSimultaneouslyWith) for the appropriate recognizers.
I have UIScrollView with other UIView elements inside. My other UIView elements are mostly segmented controls. If I click on a UISegmentedControl and hold for a second and then try to scroll, then no scrolling happens. I can only scroll when my finger touches and swipes immediately. I checked other iOS applications such as mail. The behavior was that you touch and hold on a mail, then it's highlighted, but as soon as finger moves away, the scrolling happens and highlighting is undone. How can I implement this behavior?
The issue was the property of UIScrollView. The property canCancelContentTouches was set to NO. Because of that, touch events were handled by subviews of scroll view and swiping didn't cause scrolling.
You can follow one of these steps:
If you are using UISegmentedControl over you UIScrollView, instead of that, add the UISegmentedControl over your controller's view.
If you want to use UISegmentedControl over your scrollView, then you have to create a custom scrollView by creating a subclass of UIScrollView and use an image view instead of UISegmentedControl adding the labels which can act as the segments. This is because your UISegmentControl itself is a touch handler and it breaks the UIResponder chain. So, the scrolling might face issues during the touch events.
Please let me know if any of these works. Thanks :)
I'm building an iOS layout which consists of a UITableView and a UIScrollView. The UIScrollView is inside a table cell of the UITableView and can be scrolled both horizontally and vertically. The diagram below shows this situation. If the user begins scrolling down/up on the UIScrollView the scrolling event should trigger setContentOffset of the table view, and not setContentOffset for the scroll view while the top of the scroll view will be on the dotted line (it's constant height). Then a scrolling touch event should trigger setContentOffset for the scroll view, not for the table view.
In another case: When the user starts scrolling on the table view, it should trigger setContentOffset for the table view, until the scroll view reaches the dotted line. Then the scroll view should handle setContentOffset.
My problem is how to transfer touch events between the table view and the scroll view during one sliding action.
This sounds like one of those cases where you want something quite specific and custom. So trying to do something clever with the gesture recognizers won't be enough.
The main problem is that the ways you can control gesture recognizers such as with gestureRecognizer:shouldReceiveTouch: and gestureRecognizerShouldBegin: only affect the start of the gesture (or for new touches, not ongoing ones), but you want a single ongoing gesture to transition between controlling each view. So for this reason I think you will need to place a large transparent view over your entire screen with a pan gesture recognizer on it and in your handlePan method decide which view you want to adjust and then call setContentOffset directly on that view. You can use the translation of the pan recognizer and the existing content offset to calculate the new one. I know this isn't very elegant, but I can't think of another way to achieve the effect you want.
I'm not sure if this is going to work, but you could try doing something like this:
Option
self.scrollView.panGestureRecognizer = self.tableView.panGestureRecognizer;
Option
[self.scrollView addGestureRecognizer:self.tableView.panGestureRecognizer];
Option
[self.tableView.panGestureRecognizer requireGestureRecognizerToFail:self.scrollView.panGestureRecognizer];
I have a UIScrollView that contains several UIButtons. Each button is wired up to take an action when the user inputs a touch up event, so they are able to place their finger on the button and it will not be selected until it is raised. Currently, if I made a swipe gesture to scroll the UIScrollView quickly, then the scroll view moves as expected even if the gesture happens directly over a UIButton. HOWEVER, if I hold my finger down too long on a UIButton (about 1 second), the UIScrollView will no longer recognize the gesture and will not be able to scroll until the finger is lifted up.
I am wondering if their is a way to always have the UIScrollView recognize the scroll gesture? Note that this is not an issue if I touch the UiScrollView in a location without a UIButton - it then scrolls as expected.
It may worth a try to let your UIButton respond to UIControlEventTouchDown (maybe with an empty action). I'm not sure if this will work, but conceptually I think it should let the UIButton capture the touch immediately.
(Also make sure you don't enable delaysContentTouches on your scrollview.)
I found the answer to this here: UIScrollview with UIButtons - how to recreate springboard?
Essentially, I had to extend UIScrollView and override touchesShouldCancelInContentView, having it always return YES.
I have a UIScrollView with zooming enabled, and a swipe gesture recognizer setup. When the user is not zoomed, the swipes come through great, but as soon as the user zooms in, the swipe won't come through.
My swipe recognizer is applied to the imageview, and I have tried to apply it to the scroller also. When zoomed, no go.
Is there a secret to getting the swipe while zoomed?
Thanks in advance!
Rob
Where is your swipe gesture recognizer?
Have you tried setting scrollView setCanCancelContentTouches:NO?
Is there a secret to getting the swipe
while zoomed?
Yes, there is. Each UIImageView should be inside its own UIScrollView which in turn are inside of main UIScrollView. No gesture recognizers are needed, just set UIScrollViews options like zoom scales etc and implement UIScrollViewDelegate methods for master UIScrollView.