I'm experiencing a strange behaviour in my UITableView. In my app when the UIViewController that contains the tableView is first shown (ViewDidLoad?) all of its elements (from cells to UISearchBar) are animating their sizes and finally get the right dimensions. After that (ViewWillAppear...), every time i present this view everything looks good. I'm using Autolayout in Storyboard and it's like the constraints are animating to their proper values. I'm using Swift 1.2, Xcode 6.4 and it's a UITabBar based app. Any ideas what i'm doing wrong? Thanks!
EDIT: My UITableView uses self-sizing cells with UITableViewAutomaticDimension height. It also contains a UISearchBar.
|search bar|
|---cell 1---|
|---cell 2---|
...
This usually happens when there is an animation in progress while the cells in the table view are about to load. Try looking into all the animations in your file and see which animation block is adding those animations to your table view cells.
Also if you are animating constraints using UIView animation block, do call [self.view layoutIfNeeded]
before the animation block and inside the block.
Related
so, the setup looks like this:
I want to have one navigationbar and three collectionViews. I want to be able to horizontally scroll through the collectionviews and on vertical scroll the navigationBar large title animation should trigger as well.
What I have tried:
My first try was to create one horizontally.scrolling collectionView with cells having the size of the whole view and in each cell there would be another collectionView that would scroll vertically. Now, that worked great for my purpose but the large title stayed the same size - which, as I understand, is because it does not receive any vertical scroll events since my collectionViews for vertical scrolling are embedded in main collectionView.
It looked like this: https://giphy.com/gifs/50hYRx71XSdYA/html5
Then I tried a different approach. I created pageViewController and two viewControllers both with one vertically-scrolling collectionView. And ... it did not work either. This time if there was pageCurl animation, the navigation title DID animate - but I do not want a pageCurl animation, you can see that here: https://giphy.com/gifs/jFmOpEtUOyxtC/html5
Changing the animation to .scroll just disabled the title animation: https://giphy.com/gifs/l0IsGVhKKb0lzomqc/html5
I can not find a way to do this, do any of you have any idea?
Thanks!
Unfortunately the new self-collapsing navigation bar is using some private Apple-magic in the background to hook into the top-level scroll view of the view controller, therefore you cannot use this mechanism the way you've described.
I seem to be having a very strange problem with my UITableview cells and autolayout. So my tableview is set up as follows:
I have a UITableView within a UIViewController that I created via Interface builder using Autolayout
My tableview is using UITableViewAutomaticDimension so that the cells can resize based on the text within them.
Each cell has 2 subviews within it. A front view and a back view. The back view contains the buttons for my slide-able cells
I am using NSFetchedResults controller to update the tableview
The problem occurs when I tap on a cell and am taken to the next view. Then I create a core data item within that view and save so that it is inserted into my tableview (now behind the current view controller).
What happens is that the newly inserted cell seems to lose all autolayout constraints and all view elements are on top of each other in the top left of the cell. It also looks like they are not even contained within the front view for the cell (or the front view has a width and height of 0).
Example:
It gets even stranger. If I refresh the tableview by pulling down and the cells are reloaded it corrects itself. However, if I refresh the tableview again then the problem appears again but on a different cell. This bug does not happen consistantly which is rather frustrating.
Any help would be appreciated as I only have a few remaining hairs on my head to pull out at this stage.
Thanks in advance!
So I found out what the issue was. The issue was that I was using size classes in Interface builder but I was only using the iPhone Portrait size class and did all my work in there instead of the "any" size class. Disabling size classes and setting the project to iPhone only fixed all these problems.
Weird I know
I'm working on a application where I have a UITableView inside a UIScrollview.
The TableView will display current games players are in, its inside a UIScrollView. I dynamically add cells to the UITableView for each game, but when I scroll the UIScrollView, the tableview inside it snaps back to its size set in the storybuilder.
This is because of autolayout, when I disable it, it doesn't happen anymore. However I do like autolayout for other views in my app. So my question is, how can I fix this problem?
Maybe someone can help me get on the right track.
Thanks
EDIT
I think I must explain my situation more, I will use an image where I can display what is happening
Explanation
Before and after scrolling.
As you can see I use the scrollview because there can be many games, so you'll have to scroll down to see them all. The TableView is just to hold the data, scrolling is disabled on that. After scrolling the TableView that says "JOUW BEURT" snaps back to its size set in the Storybuilder. This is because of auto layout like I said, but I don't know how to fix this.
You shouldn't put a tableview inside a scrollview as a tableview itself contains a scrollview and causes issues just like you are seeing when you have a scrollview inside a scrollview.
Remove the scrollview and this should fix your issue. If you are wanting to put content above the tableview or where you scroll down to view the tableview cells etc, consider adding a tableview header view that is added above the tableview.
Why did you place UITableView inside UIScrollView?
Check below
Check your constraints of UITableView and UIScrollView
Placing UITableView inside UIScrollView is somewhat strange
EDIT
You will just need to remove the scrollview and enable scrolling feature of the tableview. that will fix it
UITableView is already a subclass of
UIScrollView
I upload my demo code here:https://github.com/liuxuan30/Problems
The main problem is, I had a view which have a scroll view inside, and there is a label and collection view inside scroll view.
There will be a unread message button generated by code, when there is unread messages, the button will pop out, and I expect the animation: label and collection view will down-shift by the button's height.
When I test the animation without adding the button in subviews, animate as expected.
When I add the button in, it seems like the label and collection view's origin.Y up-shifted, and start the animation. Turning off auto layout will solve it, but I have to have auto layout. I tried to add constraints for all views, but the animation still not work out.
You can try comment out
[self.HomeScrollView addSubview:AlertView]; and self.UnreadAlertView.alpha = 1.0f; inside the code to see the animation.
Hope someone could figure out where i did wrong.
UICollectionView is already a subclass of UIScrollView. Embedding your collection view inside a scroll view may be what is causing problems with your animation.
Try removing your scroll view and just put your UIButton, UILabel, and UICollectionView inside your overarching view.
My UITableView has a bunch of reusable cells, and when I tap on one of them, it takes me to another view controller (via push segue) showing the details of that cell (let's say it's an item, so it would show details about an item - name, price, image, etc...). When I pop that view controller (by tapping on the back button), the UITableView has a strange behavior:
a) if it's scrolled all the way to the bottom, it will scroll automatically tad up (around 50 points), leaving the last cell barely visible, so I have to scroll back down again. My cell all have 60 points for height.
b) the scrollbar always shows and then disappears, indicating that something is moving that UITableView (although if not scrolled to the bottom, the content will not move automatically).
This happens in multiple UITableView's I have in my app. I am not forcing a reload of the table view in viewWillAppear, so I don't understand what is happening. My content is static after loading from the server (unless the user changes it, and then the reload is executed). But simply showing details of an item and popping that VC doesn't change anything in the table view.
Edit: Okay, I've figured what the problem is: I'm hiding a UIToolbar when pushing that segue. If I keep it always visible (which I don't want), it still shows the scrollbars animating when popping in my table view but doesn't scroll the table view if on the last few rows.
Add the following to viewDidLoad.
self.automaticallyAdjustsScrollViewInsets = NO;
This solved my problem of table view moving down after navigating back to view controller.
I managed to fix the first issue. It seems like the tableview is not taking into account the 44 points of the UIToolbar.
Save the tableview offset in prepareForSegue: (save it in a CGPoint property)
self.tableViewScrollOffset = self.tableView.contentOffset;
Then, in viewWillAppear:, check if it has been modified. If so, restore it.
if(self.tableView.contentOffset.y != self.tableViewScrollOffset.y) {
[self.tableView setContentOffset:self.tableViewScrollOffset];
self.tableViewScrollOffset = CGPointZero;
}
This behavior is indeed a bug in iOS 8.x.
All answers given so far can not really solve the issue. The issue is, that iOS forgets (or doesn't) consider the previously calculated cell sizes, when a table is being redrawn for instance when the view is being pushed.
One approach to solve this can be found here: UITableView layout messing up on push segue and return. (iOS 8, Xcode beta 5, Swift) (so this question is even a duplicate to this one).
However, the solution provided there is overkill and there are certain situations why this caching will fail (for instance a UIContentSizeCategoryDidChangeNotification is not regarded)
But there is a quite simpler solution even though it is odd:
If you are using a manual performSequeWithIdentifier in didSelectRowAtIndexPath, just add a [self.tableView reloadData] just before.
If you are using a IB seque from the cell, just add [self.tableView reloadData] in your prepareForSeque code.
The reason, why this solves the issue is, that this will force iOS to re-estimate the visible cells and so it no longer scrolls the content to another location. Fortunately, tableView reloadData doesn't cost too much overhead here as only the visible cells will be re-estimated.
Just a hunch, have you got a rogue scrollToRowAtIndexPath:atScrollPosition:animated hanging around?
I was also facing this issue. I managed to find it out. The reason in my case is tableview header height was calculating based text and text height was negative due to which tableview was shifting down even though the contentinset and scrollinset are zero.
This was only occurring for first time. Next time it is calculating correct. One weired thing i found is that when Class A (having tableview) have pushed another Class B from init. When keyboard from Class B is opened viewDidLoad of Class A is called. and before Class B is unloaded from navigation controller. Tableview is reloaded for Class A.
Setting the automaticallyAdjustsScrollViewInsets as suggested above did not work neither did caching and setting the tableViewScrollOffset work.
Hence came up with an workaround which worked like a charm for me.
The workaround was to add an Dummy UIView which has height of 1px and width of 320px and place it between the "Top Layout Guide" and the UITableView. This view's background could be set to clear so that it is invisible.
Now using Autolayouts, fix the Dummy View's top to the Top. Now set the tableview's top constraint with respect to Dummy View. Found that this resolved the issue of the tableview's misplacement.
Screenshot of the Dummy View along with the autolayout constraints have been provided for easy reference. The Dummy View has been set to a larger height and red background colour for illustration purpose only.