This issue is driving me crazy.
I have a UIScrollView with a content view that doubles its size. Scroll is enabled and contentSize is set. The content view has a pair of UICollectionView side by side so you can scroll the view between both of them (scroll paging is enabled too). Everything works ok until I select a cell. The app presents a modal with some info and, when I dismiss the modalview, the scrollView becomes unresponsive and doesn't scroll (but I still can select the collectionView cells!). It even change the contentOffset with animation to the proper "page" but doesn't scroll at all when dragging.
It sounds like the good old contenSize error but when I log the sizes in viewDidAppear, it has the right size.
FYI: I'm targeting iOS7 and I set the scrollview layout using storyboard with AutoLayout.
Any help will be appreciated
Solved. It seems that the constraints I set in storyboard weren't recreated when the modal was dismissed (I don't know why). Creating the layout by code did the trick.
Related
I want my app to have a view that can scroll even when there isn't always content to scroll to. For instance, the Wifi tab in settings is always scrollable. Is this a UIScrollView?
I'm using Storyboard, not SwiftUI by the way.
Thanks in advance for any suggestions!
I've tried using a UIScrollView but I think what I'm trying to achieve is different.
I think you're looking for the UIScrollView's alwaysBounceVertical property:
If the value of this property is true and bounces is true, the scroll view allows vertical dragging even if the content is smaller than the bounds of the scroll view. The default value is false.
The Settings app is using UITableView in "group" mode for most screens. The little bit of scrolling you can do even when there is little content is referred to as "bounce".
UIScrollView can also be used (UITableView extends UIScrollView). The bounce actually comes from the scroll view. You can enable the bounces property.
I have an unusual and challenging problem. I have researched deeply on StackOverflow and have been unable to find any solutions. Please do not ask about my design style- it must be this way.
I have a UIPageViewController that contains a UIScrollView which contains 4 UICollectionViews. Each of these collection views should be horizontally scrollable but not vertically scrollable. The scroll view is necessary because the screen is not large enough to display all 4 collection views. Upon loading the screen, the 4th collection view is not immediately visible. After scrolling down, the 4th collection view then becomes visible.
The problem I am having is the 4th collection view does not respond to touches. Specifically, it does not respond to taps or attempts to scroll. The other 3 work perfectly fine. What makes this puzzling and odd is that the 4th one is exactly the same as the other 3, the delegate and data source are set properly and user interaction is enabled. The only real difference between the problematic collection view and the others is that it is not immediately visible when the screen loads.
When I attempt to scroll it behaves as if I am trying to change the page, so the UIPageView changes the page. So the CollectionView isn't registering any touches at all. I have a hunch that it either has to do with the GestureRecognizer from the PageView or something to do with how it isn't visible on the screen upon the initial load.
Any thoughts?
Not 100% sure without seeing the initialization of code or storyboard, but the best thing is that maybe there is a view overlapping. You can run your program and click on the 2 overlapping rectangles. This is the Debug View Hierarchy. It shows you your current frame on your phone and you can see the view laid out in hierarchal status.
Solved my own problem thanks to impression7vx's mention of the Debug View Hierarchy. Had no clue this existed but it let me discover the flaw. I am just writing this to help people who stumble upon this in the future.
I had a content view inside the ScrollView that had a problematic constraint. I set it to have "Equal Heights" with the ScrollView but upon loading the screen the height was static. Only half of the scroll view showed and that half would be registered as the height for the UIView. Since it was static the view would not become larger when I'd scroll, and the 4th collection view would not be inside that container view anymore. For some reason, since the collection view wasn't in the container view it wouldn't register touches.
Solved by manually making the height the same value of the scroll view! This allowed the content view to contain all of the collection views which made them behave normally again.
Just take NSLayoutConstraint of height of the UIView inside the UIScrollView
#IBOutlet weak var scrollContentViewHeight: NSLayoutConstraint!
Set height of this scrollContentViewHeight equal to height of dynamic size of the UIScrollView
if scrollableView.contentSize.height = 840.0
then
scrollContentViewHeight.constant = 840.0
set it on viewDidLayoutSubviews
override func viewDidLayoutSubviews() {
scrollableView.contentSize.height = 840.0
scrollContentViewHeight.constant = 840.0
}
I have successfully set up a scroll view into my Main View Controller so it only scrolls vertically. I then proceeded the same way to set another scroll view in my Wallet View Controller but it keeps scrolling horizontally too! I tried every programmatical solution but I could not fix it. The constrains are absolutely the same in both situations which drives me nuts.
Here are a few screenshots of what is going on:
What is the problem?
I have a scroll view which works fine. Almost. I'm building in Any/Any. The problem is that the scroll view won't scroll past the view controller. I have a switch that is mostly in the view controller window, but the rest is off the box (not really sure how to describe it; it's in the view in the scroll view, but the view is longer than the view controller so part of it is hidden).
The scroll view will scroll down until it hits the part where the view controller would end if you were looking at it in Xcode. There is some more stuff under the switch (labels and another switch). To view these you have to forcefully scroll down. Xcode shows no constraint errors (little red circle with white arrow).
Hopefully this makes sense
A ScrollView needs to know the height and width of the content it is holding in order to know how much to scroll and which direction. Here is a quick read on how ScrollViews work in iOS: https://www.objc.io/issues/3-views/scroll-view/
You can set this programmatically using the contentSize property, but this requires you to know and or calculate the contentSize, which is pretty tedious in most cases.
The correct way of defining the contentSize in iOS is to define AutoLayout constraints in your View. Here is an excellent tutorial on doing just that:
https://www.natashatherobot.com/ios-autolayout-scrollview/
I have the following layout
So it's basically a scroll view that occupies whole screen. Content size is set to triple-width and same height. Inside the scroll view - there is container view and three table views - one per page. Only middle table view is visible initially.
This allows me to use scroll view horizontal scrolling to navigate between the tables and vertical scrolling inside the middle table.
I know that Apple doesn't really recommend putting UITableView inside UIScrollView, but in this particular case I don't know how to implement it differently, and until iOS8 everything was working fine.
UIScrollView would not recognize any vertical scrolling (since content height was equal to scroll view height) and these gestures were passed directly to UITableView.
But starting in iOS8 - this getting broken. UIScrollView would allow some vertical scrolling and basically intercept scrolling gestures sent to UITableView.
I created a simple project that works fine in iOS7 but is broken in iOS8. Anybody has any idea how to fix this problem?
Link to the project: https://dl.dropboxusercontent.com/u/6402890/TablePaging.zip
I haven't been able to solve this and as I mentioned in comments had to re-write logic using built-in UIPageViewController class.
If I change the Class of your ScrollView in Interface Builder to UIScrollView, it fixes part of the problem. Now just the UITableView goes up and down, and I go left-and-right, but haven't gotten rid of the space at the top.