I currently have a table view populated with a series of posts. What I am trying to achieve is to manipulate the table view scroll so that there is always one table view cell centred in the table view. I'd also like this to have some form of scroll snap, similar to a vertical carousel in which the centred / focused cell has a maximum alpha and original size, and the cells visible above and below are smaller and have a lower alpha. I have attempted using scroll target offset but with no luck. I am mainly struggling with the mathematics of the function.
The image below demonstrates what I am trying to achieve.
What I am looking for at the very least is a push in the right direction in regards to how I can manipulate the table view scroll to have this type of carousel function.
EDIT: Is it possible to achieve this with Paging in the Table View?
Related
I’m trying to sync two collection views proportionally for navigation. One of the collection views is menu-like and is at the top, and the second is a larger one below. What I would like is for the top collection view to scroll a distance of the width of one cell (the cells are dynamically sized) when the user scrolls the bottom collection view a distance of the main screen’s width. The closest thing I've seen to this effect would be iOS: Custom top segmented control works as expected only when using debugger. What I would like to change is to have the left most cell in the top menu always selected. In addition, when the user scrolls the bottom collection view the width of the screen, a new cell should Replace the left-most cell in the upper menu and be selected. Any help in Swift would be especially appreciated, but ObjC answers are also welcome.
I want to implement a cross layout just like Wallapop app does on its main feed.
As you can see, it's composed of two groups of cells (Featured items, Items near you). The first group is scrolled horizontally, and the second group is scrolled vertically.
The first UIKit component that came to my mind to make that kind of layout is UICollectionView, having one section for each scrolling direction. Unfortunately UICollectionView current implementation is very limited, forcing the scroll in one direction only, no matter how many sections you declare.
So I wanted to give it a shot with vanilla UIKit components and that's what I got;
The problem with my solution is that the vertical UICollectionViewController (highlighted in green) is scrolling on its own and not pushing the horizontal UICollectionViewControllers upward.
I've also thought about using a single UICollectionViewController for the vertical cells, and setting an UIStackView with horizontal UICollectionViewControllers as needed for the horizontal cells, but it's a messy solution and doesn't scale very well, I even couldn't set a title for the vertical cells section If I opt this way.
Ideally, I want each group of scrollable cells to be it's own UIViewController in order to have a clear separation of concerns and modularity.
Is there a better way to implement a layout like the one I want with vanilla UIKit components?
The easiest and the most stable solution is to use the following view hierarchy:
Use one UICollectionView(1) instance
Horizontally scrollable sections can be implemented as Screen width UICollectionViewCell containing horizontally scrollable UICollectionView
Vertically scrollable sections should be just a regular section of UICollectionView(1)
Pros
UIKit only
Nothing extraordinary is needed - just a UICollectionViewFlowLayout everywhere
Cells are the same for Horizontally scrollable cells and Vertically scrollable cells
Good scalability and separation of concerns. Independent behaviors of Horizontal and Vertical sections each of which can have multiple data sources.
Cons
Horizontally scrollable sections should have fixed height. Otherwise scrolling behavior will be harder to maintain.
Arrow on the image means Uses!
You could use following way:
A collection view with two cell in it. First cell is for featured items and the second cell is for items near you. The first cell will cover full width and height required by your design.
For scalability use a Container View which embed a CollectionViewController which will responsible for showing featured item. This embedded CollectionViewController will scroll horizontally.
Items near you are straight forward direct cell of the initial collection view controller.
So your implementation of featured horizontal collection view remain in the embedded CollectionViewController and the items for cell remains in the primary CollectionViewController which also contain a loose connection (embedding into a container view) to the featured item.
It also does not suffer from the problem like scrolling vertically the items for sale does not scroll up the featured items.
Here is a screenshot which depicts the idea
I haven't worked with collection views a whole lot.
A client wants a horizontal collection view set up with paging enabled.
They want a single cell centered in the collection view, with the edges of neighboring cells peeking into the view to provide a visual cue that they can swipe to see other cells.
If I set up the collection view using paging and a default flow layout, as I page over each cell ends up shifted to the left a bit more.
I implement the UICollectionViewDelegateFlowLayout protocol's collectionView(_:layout:insetForSectionAtIndex:) method, I can set up section insets such that each cell is kept centered, but when I do that the neighboring cells don't appear, and ONLY the current cell is ever visible until you start scrolling.
I assume I need to do something with a custom flow layout, but I'm not sure what, exactly. Can somebody offer some guidance?
(I'm working in Swift 2.3, although I'm "bilingual", so answers in either Swift or Objective-C are fine.)
I am trying to recreate a UIView I have seen in multiple apps, mainly Shazam. The top half of the screen has some interactive buttons, and the bottom half looks like a tableView with custom cells. When the bottom half is panned/swiped up, the tableView scrolls over the top half with velocity, much like a scroll view.
I have been researching this and experimenting for a couple days now. I have gotten close, but not quite there.
My last approach was a view that had a tableView inside it. When the view was panned, the view would move to wherever the finger moved it to, but then would not have any velocity afterwards. Also when the tableView was panned/swiped down, it wouldn't move the whole view down.
Before that I tried a scrollView that took up the whole length of the screen. That gave the desired effect, but the button wasn’t tappable, and you could scroll the view in the button area, which is undesired.
Does it utilize ScrollViews or is it using a tableView that acts much like a ScrollView somehow.
Here is the Shazam UI/UX I am looking to recreate:
The top portion has interactive buttons, and doesn’t scroll. The bottom half shows content and when scrolled, covers up the top portion.
Below is what I have tried so far: This one is the panning view, which sort of works, but doesn’t have velocity and the tableView doesn’t scroll the view back down.
Any thoughts on a direction I can take from here is greatly appreciated. I am using Swift.
Cheers
This sort of thing is perhaps best done with a collection view and a custom layout — you can have some items for which you set layout attributes absolute to the view, and others relative to the scroll content offset.
There's a great (if wandering) discussion of this and other techniques in the Advanced User Interfaces with Collection Views talk from WWDC 2014.
This is actually simple than it seems at first. Here's how you can achieve this:
Create a UIViewController (not a UITableViewController).
Add some buttons to the top area of the screen.
Add a table view spanning the entire view controller's view. Make sure the table view is on top of the buttons added in the previous step.
Configure the top cell of the table view to be transparent (by setting its background color to Clear). Set the background color on the table view to Clear as well. This way it won't obscure the elements at the top of the screen, unless the table is scrolled up.
Because your table view is now transparent, you'll need to explicitly set the background color on the table cells other than the top one.
Profit!
I am aiming for a kind of horizontal table view where each cell (let's now saw column) is also a scrolling area.
Apple discourages you to use a scroll view inside a table view cell however since my table view will be rotated I think it could work out.
Has anyone tried this before and if so would you recommend how I am proposing to do this or would you suggest using some kind of custom view / grid framework out there ?
Quick doodle of the idea: