I want to display two table views inside a uiscrollview and make the table views resize dynamically to fit their content. The table views should not be scrollable, hence the embedding in a scroll view. I have managed to resize the scroll view appropriately. The setup is as follows:
UILabel1
TableView1
..some extra space..
UILabel2
TableView2
I suspect that this should be possible with auto layout, but I need help to get started (I'm new to auto layout). Furthermore, I know that the labels could be added to the headers of the table views, but for now this will do. The data is fetched asynch over a network connection, so the table views need to be updated when the data is in.
Optionally, a couple of spinner could occupy the table view space until the data is ready to be displayed.
Related
I have two collection views with data loaded from an API. the data varies that means that the heights of each of the collection views should be varying. I have tried putting all of them ( 2 collection views and a label between them ) inside a scroll view but that doesn't work because I cannot tell the size of the contents before the data is loaded. How can I do this?
For many reasons, this is should not be the layout of choice for you in this situation. First, the collection views cannot determine their own size based on the size of their content, because they are in fact scroll views – and it would be weird for a scroll view to always scale to the size of its content, it would never scroll at all if it did. Second, as each of the collection views is a scroll view, you would have a hierarchy of scroll views which is hard to handle for the user, let alone the developer.
What I suggest instead is to use a single UICollectionView with multiple sections. You can also implement your own UICollectionViewLayout to suit your needs.
I'm having a hard time finding the best way to structure this design.
The top view has a minimum height and becomes sticky when it reaches this height. The bottom view hosts a paging controller with three views within. Each of these views hosts either a collection view or table view with vertical scrolling.
I'm really at a loss on how to approach this. Is the entire view scrollable and I should prevent scrolling on the second view until the top view has reached it's sticky height? Or are each of these views separate uitableviews and the pagingcontroller is just one cell? Should I even be using a pagingcontroller or should I use a scrollview with paging enabled? (the latter was a little rough interaction-wise)
Thank you!
Take a look at the Advanced User Interfaces using Collection View from WWDC this year. This view is very very very similar to the iTunes Connect app interface. The entire session video explains how they created that interface.
I used a similar method to this to create the keyboard in the Emojicate app.
I think what I'd do is actually fake the sticky header. So something like this...
Use only one collection view.
Create a "segmented data source" that contains three data sources. (See the video from WWDC about this)
When the segmented control is changed then update the collection view by changing its layout and (if you want) dataSource.
Make the entire top section a header on the collection view.
When the collection view scrolls past a certain point (when you want to sticky the header) then have a second view that is the compressed header and make it visible at the top of the screen. This is not attached to the collection view at all.
When the segmented control changes you can update the collection view by changing the "selected datasource". The datasource can also contain a UICollectionViewLayout that will update it.
Essentially, the tableview you are talking about is just a collection view where the cell width is equal to the screen width. i.e. fake a table view.
The sticky header isn't sticky at all. Just when it starts to go off screen you can put a fake header there instead.
It will require a duplicate (ish) view and some thinking about how to structure the data but I think this will be easier and less resource hungry than having multiple collection views and page controller and stuff.
If you want me to go through it in more detail let me know but it's a complex subject. Watch the video first.
I would make this part a navigation bar. Should be relatively easy. Just have to customize the back button with a barButtonItem and do a couple of labels in the titleView.
I would make the next part a Table View.
The tableView has 2 sections. The first section doesn't have a section header and the second section doesn't have any cells but just a section header.
First and only cell in this section:
And the rest would be the second section header's view:
This gives you the stickiness that you want because the section header will remain there even if you scroll past it and since the collection has only 2 sections the controls will always remain on top.
I think the collection/table paging part is the hardest part and I don't know clearly how it can be done. But I was thinking it could perhaps be a ContainerView. Each view of the container view would be either a tableview or a collectionview. You would have to add some code to handle the movement of the containerview relative to the second section header (possibly an autolayout constraint that attaches the containerview to the buttom of the first tableview that you implemented above).
I don't think having your tables/collections in a scrollview would be a good implementation. I think I have even read in documentation that developers should stay away from that (but I might be remembering it incorrectly).
I would have:
A "header view" with three subviews:
Fixed height top and bottom views (they stay visible at any size).
A middle view that appears/disappears as the superview grows/shrinks.
A scroll view (table or collection view are subclasses) on that partially covers the header view with a top inset set enough to reveal the underlying header view (the same way pull to refresh views are revealed).
The paging buttons could be set as table/collection view section header views.
Finally track the scroll view's scroll position to keep manually adjusting the header view height.
Another way to see this solution.
Two completely separated parts, a header view and a table view.
A simple header view (blue) that adjusts its subviews as its height changes. More precisely hides its middle subview (light blue) when it shrinks.
A table view that a) partially covers the header view in Interface builder but b) has a top inset as to avoid hiding the header view in the actual device (tableView.contentInset = UIEdgeInsetsMake(60.0f, 0.0f, 0.0f, 0.0f);).
The two parts are only "connected" by resizing the header view height as the table view scrolls up/down.
I have one simple UIView and three tables nested in the UIScrollView. The first two tables have table headers included. The third (orange) table has no header view and it is resized correctly according the data it uses. The picture displays the closed state of the scroll view. UITableView_A and UITableView_B are closed, UITableView_C opened. The data are ready for use in all tables, and also the cells are being created.
Also in xib I have connected the layout constraints to the properties from the subclass of UIScrollView. The constants are specific sizes as UIScrollView demands it for its nested views.
The issue:
The views are being resized correctly but when I update the constants for heights of the tables without the header views (the first two tables, green and pink) I manipulate only with the header views. Which is odd. The auto layout constraints for the green and the pink table are setup correctly in the xib file. I was checking the resized tables in the simulator using introspection tool and I realized the first two resized tables are not tables BUT only the header views.
The height of cells is 44 and headers also 44. The tables are not scrollable.
Closed state:
Opened state
When I update the auto layout constants related to any table I call this line afterward
[self layoutIfNeeded]; //(scroll view)
UPDATE 1:
When I remove the header views from the tables, then the resizing works perfectly for the tables. I am really curious why I manipulate just with the header views instead of the whole table when the constraints is defined on the table view NOT on the table header view.
I replaced the table header views with the section header views and the resizing works smoothly. I'd be glad to know the explanation for the previous problem.
I want an embedded table view within a view. Depending on the user this table has 1-n rows. So the size varies. If I build it right now the table view has to be scrolled if n is too big. I however don't want the tableview scrollable, but I want to make it grow automatically so the user doesn't even see it's a tableview but instead the parent view surrounding the tableview should be scrollable. Or in other words, all rows of the table should be always displayed completely within the parent and depending on n the parent becomes scrollable. How can I accomplish this?
I am trying to create a table view, in which the table view cells contain a scroll view. The scroll view can contain one or two pages of one image view each. Note that the scroll view will only scroll horizontally, so it will not interfere with the Table View's scroll view that will scroll vertically. Depending on the content, I want the scroll view to be updated with these image views, and set the scroll view content size according to responses I receive from a server, instructing the application what images to display.
In order to do that, I initially thought of creating a custom UITableViewCell subclass, and do all my initialisation of the views inside that.
However, I am just thinking about performance and memory. I know that iOS automatically deallocates already seen views and cells, when it needs to, and that it reuses the old cells when it tries to display something new (by using a reuse identifier). However, each cell will contain a scroll view with content size and subviews that will change in each cell. I want to use a reuse identifier to ensure maximum performance.
Can anyone point me in a way in which I can set up the reuse of a cell like this, and change the contents of each scroll view successfully?
Thanks.
you can make the reuseIdentifier dynamic
e.g. "cell_with_1","cell_with_2","cell_with_x" where x is the number of images
that way equal cells can be reused when sensible (e.g. when the number of images in the view is the same): 'worst case' is no reusing and a tad overhead for trying but in general I'd deem it beneficial :)
*the allocation deallocation and the basic adding of the subviews is expensive.. changing frames or images seems reasonable to me