CODEWITHSUNDEEP
iosswiftuicollectionviewuikituitouch
Adrien Zier
Adrien Zier

Reputation: 816

UIKit collection view, strange behavior (accessing/scrolling cells)

So I recently implemented a collection view in my app, and I got a bug that I can't seem to solve, searched it and saw no threads about it.

If I have my cursor/finger over the cells i can't scroll through my collection view i need select a "empty" area to scroll.

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Second strange Behavior I came across is that I can't directly touch a cell. I need some sort of swipe gesture over it to trigger the code when a cell is selected.

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If I go to my collection view on my storyboard and select Delays Content Touches and Cancellable Content Touches in the scrollview section, the collection view scrolls just fine but if I put my finger/cursor over a cell with these option enabled I can't access any cells anymore.

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This completely confuses me.

and thank you for reading/considering this thread.

Upvotes: 4

Views: 706

Answers (2)

Dory Daniel
Dory Daniel

Reputation: 826

i had the same problem when touching a cell, the problem was that I'm using more than one UIGesture without adding ".cancelsTouchesInView = false" for each one

so if you're using a UIGesture just add Your_Gesture.cancelsTouchesInView = false

and you should be able to access your cells

Upvotes: 1

jasamer
jasamer

Reputation: 46

Let's see what your two properties do.

delaysContentTouches: If the value of this property is true, the scroll view delays handling the touch-down gesture until it can determine if scrolling is the intent. If the value is false , the scroll view immediately calls touchesShouldBegin(_:with:in:). The default value is true.

canCancelContentTouches: If the value of this property is true and a view in the content has begun tracking a finger touching it, and if the user drags the finger enough to initiate a scroll, the view receives a touchesCancelled(_:with:) message and the scroll view handles the touch as a scroll. If the value of this property is false, the scroll view does not scroll regardless of finger movement once the content view starts tracking.

First, you set delaysContentTouches to false. So the scrollview immediately calls the content view's touch handling methods, allowing it to handle the touch. Obviously, the scroll view won't start scrolling right away because of this, even if you drag.

Second, you also set canCancelContentTouches to false. But if the scroll view isn't allowed to "take over" touches that the content already handles (by cancelling them), it is never able to start scrolling later on either. So if your touch hits a content view, there is no possible way for the scroll view to start scrolling: it isn't allowed to scroll right away because it isn't allowed to delay the content touches, and it can't start scrolling later because it can't cancel the content touches.

I don't know what happens within your cells, not sure what code you put in there. However, you should probably allow your tableview to both delay touches (that means that your cell won't handle swipes that are cancelled immediately anyway because they were intended to be scroll gestures), and to cancel content touches (that means that when you touch down and don't release, you can still start a scroll gesture after a cell became highlighted).

Upvotes: 3

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