I have a tableViewController utilizing an NSFetchedResultsController to display data. The Cell's primarily consist of textView's which resize based on content. The tableView uses automatically sizing cells.
Everything works fine except that when the tableView is first presented, the cells can be seen resizing horizontally into place. Subsequently when the tableView is presented the cells are sized correctly.
All other behavior is normal. When cells are dequeued they are sized normally and do not resize as they appear.
The cell's are subclassed in the normal way and AutoLayout is used. I have set all the priorities for the content of the textView to 751 in storyboard.
The text is added to the cell in cellForRowAtIndexPath with simply cell.textView.text = someText
Just wondering if I need to call tableView.layoutIfNeeded() or any other methods prior to initially displaying the tableViewController.
I am initializing the NSFetchedResultsController in viewDidLoad
After fetching data from your api, you need to call
tableView.layoutIfNeeded()
Related
I have UITableViewController with 1 section and header with UISegmentedControl inside.
If user presses first segment we should display UITableView cells
If user presses second segment we should display custom vertical scrolling collection grid with collection items below that header
possible solutions:
change UITableViewController to UICollectionViewController, and UITableViewCells to UICollectionViewCells. This should work but I'm trying to avoid this solution
UICollectionView embedded in UITableViewCell. Setting UICollectionView scrolling enabled to false, adjusting UITableViewCell's height to fit entire UICollectionView's contentSize.height. In systemLayoutSizeFitting(...) method of container (UITableViewCell) we call layoutIfNeeded on container and on contained UICollectionView and return UICollectionView's contentSize.
problem:
(re)calculation of entire UICollectionView contentSize requires a lot of work if we have hundreds of items (cellForItemAtIndexPath for every item). Want to avoid this somehow. Maybe we can increase container (UITableViewCell) height during scrolling UICollectionView which is embedded inside.
Same as 2 but we have fixed size container UITableViewCell (same height as view without header) with UICollectionView inside. When we scroll UITableView to the very bottom UICollectionView scroll should continue scrolling.
problem:
I don't understand how to deal with 2 instances of UIScrollView with scrollingEnabled = true for both. I think this could be solved with pan gesture recognizer delegates. If it is so I need help here.
I would personally opt for number 1 and completely avoid number 2. For number 3, you could set tableView.scrollingEnabled = false when the second segment is tapped. Set it to true when the first segment is tapped. That way, when it's false, the UICollectionView in your UITableViewCell can still scroll.
This tutorial may help with putting a UICollectionView in a UITableViewCell.
The setup
I have a rather complex view hierarchy which made me do terrible things with tableViews and collectionViews. Right now I'm having a regular grouped TableView with custom TableCells. TableCell itself contains a couple of views and a Collection View. The height of the table cell is calculated based on number of items in the data source. On its creation table cell creates a collection view with a calculated size to fit necessary data.
-- UITableView
---- UITableViewCell
------ UICollectionView
--------- UICollectionViewCell
The problem
I've encountered unusual problem with a custom collectionViewCell. I have a vertical single-column collectionView with dynamic amount of cells. Ideally tapping on the cell should call didSelectItemAt. The cell also has three buttons. Tapping on the button should trigger some action. All of the desired functions work only for a first cell. The rest of the cells are not responsive to any actions.
Things that look strange
By default the scrolling of a collectionView inside of the tableViewCell is disabled because it basically fits all the content based on calculated height and doesn't require scrolling. (Also I don't want it to interfere with tableView scrolling logic).
First
I've tried to hardcode some value for the height of collectionView and enable scrolling. What happened is a mystery for me.
Let's say that calculated height required for the collectionView to show all the content without scrolling is 740. When I manually set it to be 280 (this is enough for exactly 2 cells to fit) and enabled scrolling my first cell were still working, but also when I scrolled collection just a little bit my second cell started to act normally as well. When I scrolled back to the top of the collectionView it was disabled once again.
So it looks like when the scrolling is enabled and will actually occur because of insufficient height to fit the content, cells behave as they should. As soon as I set height of the collectionView to be enough to fit its content, things go wrong.
Second
In some cases I can actually tap on the second cell and it will call the delegate. But the weird thing is it works when I tap in the top area of the cell, like 10pts from the top. The other areas of the cell are unresponsive so are the rest of the cells in the collection.
The working delegates and buttons with enabled scrolling forces to think that this has nothing to do with delayed or canceled touches. The frame for collectionView and height of the table cell are calculated properly as well.
xCode 8.3, iOS9+
As it turned out when I was creating my tableViewCell, I hardcoded the height of the collection to value of 214. The reason for that is very simple. I create a cell programmatically and with tableViewCells created programmatically the height of the cell is always 44. When you override init(style: UITableViewCellStyle, reuseIdentifier: String?)
You need to either hardcore the height, or update it in cellForRowAtIndexPath. Even though I updated collection frame when it was filled with data, the container view of this collection wasn't updated resulting in some sort of clipping area for user interactions.
I'm struggling with wired kind of problem. I have UITableView with one cell. This cell is only holding containerView with childViewController (second tableView). My problem is that, first tableView(parent) must have UITableViewAutomaticDimension row height but it doesn't work (It dosen't know correct size of that cell with second tableView).
How to get correct size of second tableView) ?
Second tableView (inside Cell) have scrollingEnabled turned off (tableView.scrollEnabled = false), first tableView must have correct size of second tableView in order to provide correct scrolling experience.
Since a UITableView inherits from UIScrollView you can use the contentSize property to get this information. This is how the scrollbar works on the side.
I have done a similar thing before (long ago), so the following is somewhat hazy/ irrelevant/ unessecary. There might be some gotchas with unknown/unrendered cell heights in the embedded tableview. I rememeber having to set the tableview height to a large number (forcing all cells to render) fetching the contentSize then resetting the tableview height to the contentSize.height.
Are you shure you really need second table view? If you have just one cell probably you don't need it. I recommend you to calculate table view height as the summ of it's cells heights. If cells of embedded table view have constant height it could be simple. In other case you also could calculate cells height.
I want to show multiple labels in my main UITableViewCell, for which I am trying to use a UITableView within the cell. Now I have setup all the delegates and datasources properly, and the data is coming in right. But the inner UITableView has a dynamic number of cells, and a dynamic height respectively.
What I want is, to have an autolayout constraints setup, which allows my main UITableViewCell to resize as per it's inner UITableView.
Currently what's happening is, the inner tableView loads data perfectly, but does not resize as per the data, due to which the main cell can also not resize.
Any help in this regard would be appreciated.
Autolayout can not calculate the height of uitableview that inside cell because uitableview scroll inside there fore you can calculate the heigth required for your uitableview According to no. Of rows and content and then set this calculated height . in heightForRowAtIndexPath for main cell .
I have a UIScrollView in each UITableViewCell of my table view that lays out UIViews horizontally - kind of like the "Featured" section on Apple's App Store. When I'm setting up the UITableViewCell I call a function within the custom UITableViewCell to layout the scroll view. This loops through data assigned to that tableview cell's index path and then creates the custom views and adds them to the scroll view. However, these get mixed up when scrolling the tableview and when the tableview refreshes.
If I clear the subviews before laying them out, it does work. However, I'd like to keep the scroll position at the same point every time it shows the cells. How is this possible?
I've just added an external array that stores the current offset for each scrollview, and then manually set the offset on each scrollview everytime the tableview gets refreshed.