I've created a UITableVIew and it is a subview of a UIView. There are three issues that i'm having and it is only occurring on iOS 4 devices:
1) The table doesn't bounce when the view hits either the top or bottom of the table while scrolling. The vertical bar doesn't shrink either, it feels sticky and it is very much acting like an Android table view. I've tried enabling the bounce property but that doesn't make any difference.
2) The horizontal scroll bar appears when the view is scrolled down to the bottom of the table. This shouldn't appear since the table view's contentSize has been set correctly. It does eventually disappear when the contentSize is set 20 pixels less than what it should be.
3) I can't scroll to the bottom of the footer view, and only half the footer view is visible.
I've added a UITableView as a subview to other views throughout my project and this has never occurred, and so i've copied the way that I create other UITableViews, but still no luck.
Any suggestions would be greatly appreciated.
Thanks,
Ankur
I worked out the problem. The problem is a little strange, although i had a feeling that the way i was coding was a little messy.
I am subclassing a View, and the parent view has a layoutSubview method, which is only calculating and setting the frame for a table view subview. In the subclass, i had to override layoutSubview for the same reason as the values for the table view's frame need to be different. This means that the table view's frame was being laid out twice, once by the parent class and a second time by the subclass. It seems that iOS 4 doesn't like this, and i should only set the frame once per subview per layoutSubview call.
Now i've created a layoutTableView method, which is called from the parents layoutSubview, and i've overridden layoutTableView in the subclass. Therefore the table view's frame is only being set once.
Related
iOS 13 (but seems to hold true in iOS 10.3, also).
I'm having a very hard time getting the final height of a view in a complex view hierarchy before anything is drawn to the screen. I have a UIPageViewControl with a series of custom UIViewController. One of the subviews in that is a table view, and I want to adjust the cell height based on the table view's height so that I have an integral number of cells showing.
Unfortunately, the final height of the table view is not determined, it seems, until after all hooks have been exhausted. I've tried all of the following: viewDidLoad(), viewWill/DidAppear(), viewDidLayoutSubviews(), layoutSubviews() and didMoveToWindow() (on the table view and the root view). I've tried calling layoutIfNeeded() in each of the above.
In the end, well after didMoveToWindow() (which comes after viewDidAppear, annoyingly), layoutSubviews() gets called a couple more times, and it’s only in those last two calls that the view has its final height. At this point it’s not possible to set the cell height and reload the table view without it visibly changing on-screen.
There seems to be no way to accomplish this.
Am I missing something? I guess I can try UICollectionView instead.
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 the following autolayout-driven setup:
Main viewController, with a scrollview inside it. Scrollview pinned to superview edges. This one scrolls up and down.
A few normal, fixed size views at the top of the scrollview
Another scrollview. This one scrolls left and right. The second scrollview contains a couple of tableviews, side by side. The idea is that the user can switch between them. They both contain a handful of cells, all the same width as the screen and 72pts tall.
The problem I'm trying to solve is that the tableview contents are not the same size. The left one has say, 6 cells, and the right one has 3.
My first approach was to dynamically change the second scrollview height to match which ever tableview was currently visible. What ended up happening was that switching between the two tableviews (by doing setContentOffset:animated:) went extremely wrong if animated was set to true - it would adjust the content offset so everything was offscreen. In fact it would set the content offset to and then as I switched, about a dozen times, then it'd reset. It was weird, I gave up.
Now I'm trying to just adjust the content inset of the main scrollview to offset the gap in the content of the current tableview, and it's also being weird. When I set the bottom content inset in viewDidLoad, it works fine. When I set it at the time the tableview becomes current, it does nothing.
What gives? What scenarios would lead to these view interactions not behaving properly?
Use different tableViewController for each table.
Embed them in pageViewController.
Add those few normal, fixed size views at the top of the pageViewControllers view.
Conform scrollViewDelegate in pageViewController.
Pass scrollViewDidScroll from tableViews to pageViewController.
Set tableViews inset to match those fixed size views at top.
Change height according to the scroll.
This is the way you can achieve the functionality you want.
I hope it helps.
I've been trying to replicate this effect for a couple days which was inspired by Tumblr.
I've previously asked questions on here with different approaches of the same problem but to no avail. I'm just curious as to how the engineers at Tumblr created a horizontal collection view, with two vertical collection views, and is able to scroll down without affecting the view above (without resetting the position of the view when you scroll vertically in a different tab).
Header Views
I tried this, but the header view was isolated and I had to scroll to the right to see the collectionView cells. This did not work.
Changing the topLayoutConstraint constant of my UIView (not cv header) with respect to the contentOffSet of the vertical collectionView.
This almost got the effect I wanted, except that when I scrolled horizontally, there was a huge gap between my collection view and if I scrolled in that new tab, the UIView would appear again because, again, topLayoutConstraint gets scrolled up depending on the contentOffSet of my vertical collectionView contentOffset.
Changing the position of the UICollectionView frame, and scrolling the super view up simultaneously with NSNotificationCenter.
Alas, this method did the same as method #2, except that the vertical collection view cells scrolled faster than the super view.
I ran out of options to make this work so I will show you in detail what's attempted to be replicated (also note the scroll bar on the right):
Note when I scroll down the first tab. I switch, and then scroll down further. Originally, as I've said, there would be a gap between the second main CV, and when I scrolled, the view would reposition as if were scrolling up again. On here, the view on top keeps going up. So I'm curious as to what method Tumblr engineers used to do this. UICollectionView inside UIScrollView? Other suggestions?
I believe there is no UICollectionView involved. It looks like UIPageViewController and each its page is a UITableView.
Perhaps the UIPageViewController sits in a UITableView as well - the header also moves up when you scroll. This main table has only one cell (and a header) which is occupied by the UIPageViewController.
Hope it helps.
I have a tableview which will not budge when touched. It is very confusing to me. It is the most recently added subview (I checked - it is the last entry in my view's subviews array) and for some reason it just won't scroll up or down. If I tap multiple fingers wildly on the tableview it will one in a while highlight the cell under one of my fingers, but it will not scroll even a little. I have set the number of rows to 100 (many more than are visible on screen) and I have set the 'bounces', 'scrollEnabled', and 'userInteractionEnabled' properties to YES.
I know that I have not provided much to go on here, but if anyone could at least give some tips on how to go about debugging this I would be very grateful. Can I log from within the tableView gestureRecognizer handling method? Can I test where my touches are going?
Please help!
Thanks.
A TableView is basically a specialized ScrollView. If it's not scrolling, it seems to me it could be one of two things. Either something is on top of the TableView and is capturing the gesture events before the TableView can get them, or You have set the bounds and contentSize incorrectly. For a TableView or ScrollView, the bounds of the view should be the visible area, and the contentSize (should be handled by the TableView without you needing to do anything) is the size of all the cells in the Table.
So I would check the bounds of the table view and make sure you are setting that to the contentSize, since that would cause it nor to scroll.
Just to make sure it's on the top, try calling
[view bringSubviewToFront:tableView];
In my case tableview "User Interaction" was disabled. I just enabled it & works.
In my case, tableView "canCancelContentTouches" was not enabled. I set it to true in the storyboard.
Can you check the frame of the parent on which the tableview is added? Make sure the parent view have correct frame to include the table view. I have faced this issue sometime back my table view was not responding to touches and there was some problem with frame size. Also do check the bounds and frames of your tableview
-anoop
Please check tableview scroll is enabled.
I just hate XIB and Storyboard. After 30 mins of debugging it come to know that scroll was not enable in XIB.
Thanks
Basically, Table view is just a kind of scrollview. So in case it is not scrolling You should be sure that if the frame size of your table view is less than the contentSize of your table view. For this just log the frame and content size of tableView's scroll view. If you found that frame size is greater or equal to your content size, just correct your layout constrain of your view. And I hope it will work.