My UIScrollView has 3 pages, with a separate UIView on each page. This is set up using auto layout. When the app launches, there is one view offscreen to the left, another that is onscreen, and a third offscreen to the right.
When the user pages to either side, there will be one view onscreen, with two views offscreen on the same side. What I want to be able to do is move the view furthest offscreen to the other side of the scrollview, to make it so that the scroll view can page infinitely.
I tried changing the constraints in scrollViewDidEndDragging(_:willDecelerate), but this approach is not working.
Is this effect plausible? If so, how can I achieve this effect?
Edit: One reason the approach before doesn't work is because the user can scroll past the paging without this delegate method being called. I am currently trying to see if the didScroll method will allow for the effect I am going for, but I haven't gotten this to the point where I can test it yet.
Related
I have a scroll view which works fine. Almost. I'm building in Any/Any. The problem is that the scroll view won't scroll past the view controller. I have a switch that is mostly in the view controller window, but the rest is off the box (not really sure how to describe it; it's in the view in the scroll view, but the view is longer than the view controller so part of it is hidden).
The scroll view will scroll down until it hits the part where the view controller would end if you were looking at it in Xcode. There is some more stuff under the switch (labels and another switch). To view these you have to forcefully scroll down. Xcode shows no constraint errors (little red circle with white arrow).
Hopefully this makes sense
A ScrollView needs to know the height and width of the content it is holding in order to know how much to scroll and which direction. Here is a quick read on how ScrollViews work in iOS: https://www.objc.io/issues/3-views/scroll-view/
You can set this programmatically using the contentSize property, but this requires you to know and or calculate the contentSize, which is pretty tedious in most cases.
The correct way of defining the contentSize in iOS is to define AutoLayout constraints in your View. Here is an excellent tutorial on doing just that:
https://www.natashatherobot.com/ios-autolayout-scrollview/
I've been trying to replicate this effect for a couple days which was inspired by Tumblr.
I've previously asked questions on here with different approaches of the same problem but to no avail. I'm just curious as to how the engineers at Tumblr created a horizontal collection view, with two vertical collection views, and is able to scroll down without affecting the view above (without resetting the position of the view when you scroll vertically in a different tab).
Header Views
I tried this, but the header view was isolated and I had to scroll to the right to see the collectionView cells. This did not work.
Changing the topLayoutConstraint constant of my UIView (not cv header) with respect to the contentOffSet of the vertical collectionView.
This almost got the effect I wanted, except that when I scrolled horizontally, there was a huge gap between my collection view and if I scrolled in that new tab, the UIView would appear again because, again, topLayoutConstraint gets scrolled up depending on the contentOffSet of my vertical collectionView contentOffset.
Changing the position of the UICollectionView frame, and scrolling the super view up simultaneously with NSNotificationCenter.
Alas, this method did the same as method #2, except that the vertical collection view cells scrolled faster than the super view.
I ran out of options to make this work so I will show you in detail what's attempted to be replicated (also note the scroll bar on the right):
Note when I scroll down the first tab. I switch, and then scroll down further. Originally, as I've said, there would be a gap between the second main CV, and when I scrolled, the view would reposition as if were scrolling up again. On here, the view on top keeps going up. So I'm curious as to what method Tumblr engineers used to do this. UICollectionView inside UIScrollView? Other suggestions?
I believe there is no UICollectionView involved. It looks like UIPageViewController and each its page is a UITableView.
Perhaps the UIPageViewController sits in a UITableView as well - the header also moves up when you scroll. This main table has only one cell (and a header) which is occupied by the UIPageViewController.
Hope it helps.
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 have the following layout
So it's basically a scroll view that occupies whole screen. Content size is set to triple-width and same height. Inside the scroll view - there is container view and three table views - one per page. Only middle table view is visible initially.
This allows me to use scroll view horizontal scrolling to navigate between the tables and vertical scrolling inside the middle table.
I know that Apple doesn't really recommend putting UITableView inside UIScrollView, but in this particular case I don't know how to implement it differently, and until iOS8 everything was working fine.
UIScrollView would not recognize any vertical scrolling (since content height was equal to scroll view height) and these gestures were passed directly to UITableView.
But starting in iOS8 - this getting broken. UIScrollView would allow some vertical scrolling and basically intercept scrolling gestures sent to UITableView.
I created a simple project that works fine in iOS7 but is broken in iOS8. Anybody has any idea how to fix this problem?
Link to the project: https://dl.dropboxusercontent.com/u/6402890/TablePaging.zip
I haven't been able to solve this and as I mentioned in comments had to re-write logic using built-in UIPageViewController class.
If I change the Class of your ScrollView in Interface Builder to UIScrollView, it fixes part of the problem. Now just the UITableView goes up and down, and I go left-and-right, but haven't gotten rid of the space at the top.
I have a UISCrollview loading webviews, as the user starts scrolling to go to the next page, I need to have the the coming webpage to scroll into the screen from underneath another UIView that is stationary, I tried changing the alpha but its not really what I am looking for. how can I accomplish that?
For example, the scroll direction is top to bottom, now I have a uiview at the top of the screen which has some static data showing ( title, location, and other text labels ), and as the user scrolls down I want the content to scroll underneath the label ui view. Hope this clarifies it.
If I understand this question correctly I'd say you can't do this with a UIScrollView. Instead, you could have separate views for each UIWebView and handle the panning of one view under another with a UIPanGestureRecognizer.
Also, did you know there can be conflicts when using UIWebView's inside UIScrollView's?