I am trying to build a UICollectionView that consists of cells that are of fixed height and varying widths. The cells can either be 100%, 50%, or 25% in width.
I am creating these cells from a custom subclass, and then I am adjusting the size in sizeForIndexPath. My problem is that when reordering cells, I get a lot of weird visual glitches as the cells have their sizes adjusted rapidly as the index path changes.
Basically, I want the size of the cell to depend on the type of cell (or the content in the cell), not the index path of the cell.
What is the best way to handle this? I thought about using multiple classes for the different types of cells, but I can't set the width of the cell with a frame when initializing it. Any ideas?
Update: Here's a link to a video showing the bug I am trying to solve
http://d.pr/v/FTM8+
Try this tutorial. It for a table view but in the conclusion some recomendations for a collection view. I cannot try this tutorial now and garaunted it works for collection view but tomorrow I will do it.
Cheers.
Related
Is it possible to reduce the padding surrounding each table view cell in a table view? I understand I could do this through a custom solution but I would like to have the default auto-resizing behavior of a standard table view cells but just reduce the padding between cells.
I'm not sure if I completely understand your question, but when working with table view cells, I generally
Get rid of the line operator
Set the background color of the cell and the table view to be the same
Create a subview that is essential all the design of the cell
By doing this I can make the subview a different color and increase or decrease its size, and in a way, it acts as padding between cells.
Again I'm not totally sure if that helped, but if it and you would like the code for that just respond to my answer.
I've done some research on self adjusting static cells but they seem to apply to the entire table view as a whole.
what if I'm only interested in targeting a specific cell like the picture below? How do I go about doing it?
edit: What I intend is for the tableview cell to expand when the collectionview gets populated with more cells. Thus allowing the entire page to scroll accordingly.
Are the images in the collection view always the same height ? If the images in the view are a static size, you could just divide the number of images, by the number that will fit on a line. Then multiply that by the height of the lines to set the tableview cell height.
This might be helpful:
Dynamic Sized Tableview Cells
I have a slightly complicated system that I am having some reuse issues with, wanted to get some feedback. Basically it is a vertical tableview, and each cell contains another tableview that is rotated 90 degrees, so that each cell scrolls horizontally. Each horizontal cell is also set up to scroll infinitely with paginated responses from an API. I am having issues where cells are copying on top of each other when the vertical table is scrolled down. I have reuse identifiers set up correctly and in each of the horizontal tableviews I am running the following:
- (void)prepareForReuse
{
[_horizontalTableView reloadData];
}
If I turn off reusing cells the issue doesn't happen, but the vertical scrolling performance suffers. I am wondering if its possible that reusing cells in this type of a set up just isnt possible? Any experience with this is helpful. Thanks.
This is not a direct way to solve your issue, but I believe if you use a horizontal scroll view inside each vertical cell, you will have this done faster and with less weird behaviours. I also believe this is not a standard way, so weird stuff will happen.
All you do is set or extend the content size of the scroll off screen continuously to create an infinite scrolling behaviour. Create views within the scroll view pragmatically to simulate each cell. Hope this helps.
Context:
Building an app that populates a table that takes in data from a asyc json dump.
The cells are of a custom class (I defined). The main label in the cell can be very long.
It is "placed" in storyboard within a prototype cell but customized via code (pretty standard stuff).
Labels are resized in cellForRowAtIndexPath and rows are resized via heightForRowAtIndexPath -- rows are resized by forcing a call to cellForRowAtIndex like Massimo's answer here
So per the question at hand - I've noticed some interesting (bad) things that happen.
First issue: When the table loads, the rows and labels are dynamically resized correctly! Great! However, when I scroll down and then scroll back up, the label heights will be incorrect -- (for example) the first row was correct at loading. Then when I scroll down and then scroll back up to see it again, it will be truncated. Specifically, the row size will be fine but the label height will change and become truncated to 2 lines only. Wondering if this is because I did both storyboard and coding to customize the cell. Anybody see this before?
Second issue: When I scroll down, while the rows are sized correctly (large), the labels are short (truncated.) Wondering if it's some reverse of the above "potential answer".
"potential answer" is that the rows are all calculated and stored "up front" so that scrolling down/then back up doesn't affect it. However, when cells go "out of view" and are dequeued then when they re-viewed (scroll down/then back up) it will rely on the storyboard.(inappropriately?)
All three of your issues are symptomatic of returning the wrong height in heightForRowAtIndexPath. In my data model classes I have a calculateHeight method that I call in heightForRowAtIndexPath. The model also caches the answer so it doesn't have to recalculate it after the first call. The cell class uses the model's calculated height to layout its subviews.
"ANSWERED" by deleting the prototype cell from the storyboard and making them fully in code, the issue went away. The fundamental workings are still not understood (ie. the interactions between storyboard vs. code when cells are put queued and then viewed again)
I am trying to configure my CollectionView to have one section be differently sized than the others. I have two sections. Lower part should show a number of cells simultaneously and the upper section should only show one cell at a time but be scrollable to reveal more cells one by one.
I tried to play with the .frame property of the CollectionView but obviously it is not the right approach as it changes the appearance of the whole view.
I also tried to retrieve the FlowLayout object and see if I can get it from there. Did not find a way.
Neither the section Insets are the answer so far ...
It is simple to use two uicollectionviews for upper and lower section, instead of using only one.