scrolling custom UITableView slow - ios

I am facing the following problem :
I have a custom UITableView with each cell having an image with some text. When, I scroll the UITable, for each section, the respective image will be shown on top of the UITable.
The scrolling is little slow and seems to be sticky.
Can anyone give me any idea how to improve this ? Thanks

There is a sample code from apple on lazy image loading: http://developer.apple.com/library/ios/#samplecode/LazyTableImages/Introduction/Intro.html
I think that will help you a lot... You also need to watch for reusing cells properly..

if U have too many subviews in cell,it must be slow when scrolling,apple says it。

Related

Stretchy header view for UICollectionview and minimize UIImageView while scrolling up

I am trying to achieve a certain layout that looks like twitter and many other apps. Some people do it in UIVIewLayouts but I want to achieve it using this way (if possible ). As you see in the attached image. I have Header, and cells in the collectionview.
While scrolling up I want to minimize the imagview avatar inside the headerview. -> ( ViewForSupplementaryEelementHeader )
while scrolling down, I want to make the top UIImageview to be fixed to the top and stretchy
Thank you all in advance
*ps I am doing all of this in code nothing with storyboard and I dont want to use it at all.
Please advise me how to access these imageview while scrolling up and down.
I think this is the example you are looking for
https://github.com/sunlubo/StretchyHeaderView
This will add only tableview in storyboard...other all the work is done through coding

UITableView height for dynamic cells

In my current project i'm trying to display data in a table View, however the former view does not take up the whole screen just a part of it. It's number of cells depends on an external json and the height of the cell is dynamic. Sadly there is no inbuilt way to use auto-layout(at least i think there's not) to expand the tableView depending on it's cells.
In the following picture there's an example of how one of these table views should look like:
And here's an example how the table view looks like using the autolayout:
Is there a way to expand the tableView to it's full size?
I've tried to follow various other questions but none have fully helped me, for exampled i've tried to this solution which sadly did not help me :[, creating a subclass of uitableview and overriding its intrinsicContentSize did not do the trick either.
Any help is much appreciated.
-Jorge :]

How to enable scroll in UICollectionView?

I’m still learning to develop in iOS and Swift so I apologize beforehand if my question is too simple.
I have created an UICollectionViewController to show a matrix of elements. My issue is that the width of the screen is not wide enough to fit all the columns in a single row, so the excess of them are shown in another row below. Instead of this, I’d like to enable the horizontal scroll so the user can scroll to see all the columns in one single row.
I know UICollectionViewController already contains UIScrollView so I guess this should be as simple as to change a setting in the .storyboard but I couldn’t find it after many trial-errors :(
I guess it is related to the "Flow" layouts setting and that I need to handle a custom one, but don't know how exactly.
Would anyone be so kind to please help me? I haven’t attached any code because I’m using a pretty standard/out-of-the-box implementation of UICollectionViewController but if you want me to add anything, just let me know, please.
Many thanks in advance for any help!
I found the answer to my issue perfectly covered on this post:
https://www.credera.com/blog/mobile-applications-and-web/building-a-multi-directional-uicollectionview-in-swift/
It's definitely to do with your UICollectionViewLayout — that tells the collection view where everything should go. The collection view simply picks its scroll behaviour appropriately.
A UICollectionViewFlowLayout is a specific type of layout that fills one row column to the size of the enclosing view, then moves on to the next. So it does one-dimensional scrolling. Does that fit your use case?
If so then you should just be able to set the scroll direction on the flow layout.
If not then you'll need to write a custom subclass of UICollectionViewLayout that implements the layout behaviour you want.

UICollectionView resizes cells incorrectly after reloadData

I have a UICollectionView that renders some autosizing cells. When I load the data into the collection view initially, the data is perfectly sized the way it should be.
I have a weird issue where, when I trigger reloadData with a new data set, the auto sizing goes wrong and I end up with incorrectly sized cells.
Images attached.
I have tried invalidating the collectionViewLayout before I call reloadData.
Oddly enough, if I remove data, and trigger a reloadData the cells resize to their correct layout. So I am wondering if this is a view recycling issue?
Thanks in advance.
Below is the layout after the screen was initially loaded for the first time.
Below is the layout after the + opens a modal to add a new post, closes, and refreshes the data - see incorrect sizing of cell "Thanks for all your hard work".
Below is the screen after the screen was reloaded from scratch again.
My answer might be a bit late, but getting the similar behaviour I did manage to solve it.
In my case, the problem was with multiline labels — so changing them to single-line solved the case.
As I didn't need to have multilines — I had no further research on them.
I hope, this answer could be a good starting point to find a fix.

Why UITableView is only accepting touches on first row?

I'm using a custom UITableViewCell with an UIControl and a few UILabels in my UITableView and everything works fine only if the UITableView takes up the whole screen. I'm using a xib file for this.
The problem is that I need to resize the UITableView to take only the bottom half of the screen, and like this only the first row accepts touches. Also if I try to scroll by pushing up from lower cells it won't do it, but will only scroll if I hold the first row.
It happens on both iPad and iPhone, but it's particularly bad on the iPhone. It seems that only on the bottom half of the screen the scrolling doesn't work.
I've already checked all views, and there is none above the UITableView, I've checked all sizes, I've googled and searched on Stackoverflow, but I couldn't find anything similar to my problem.
What else do I need to be checking? Any thoughts on this?
The problem was that I had a custom Marquee UILabel, allocated and initialized via code and not via xib file, at the bottom of the screen and I was using the iPad frame instead of the iPhone one, so it was huge, being placed above the UITableView, consequently blocking it and preventing touch events.
As I was so focused on the xib file I totally forgot that I had setup this custom Marquee UILabel via code.
I thank Ethan Holshouser and Helium3 for all helpful comments above and the Reveal App suggested by Helium3 helped me greatly visualizing the views hierarchy to solve the problem.

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