I have a UICollectionView added to a UIView in an app I am working on. Displayed in the UICollectionView I have a set of images pulled from Core Data. The vertical scrolling works fine but the scrollbar does not display until the user touches the UICollectionView.
How can I make sure the scrollbar at the right is always visible so that an indication is given to the user that it is scrollable?
You can't make them always visible. Instead, you can flash them once, when the user is first presented with the collection view to notify them, that this view can be scrolled.
Since UICollectionView is a subclass of UIScrollView you can do this:
[myCollectionView flashScrollIndicators];
Check out the Settings app for instance. When you go to a settings list that is longer then the screen, the scroll indicator is flashed once.
FYI for Swift:
myCollectionView.flashScrollIndicators()
Related
I've an instance of UIPageViewController in my project with an iPhone picture showing different sceneries as user scrolls.
I want a "fixed-background scrolling layout" i.e when the user scrolls, the iPhone-picture should remain fixed but only the sceneries inside it should change. How could I do that?
For example: In https://sdslabs.co/#muzi, as you scroll down the Mac-picture is fixed but the picture inside it changes.
Another example can be seen in the 'Numerous' iOS app.
I am assuming that you know how to implement UIPageViewController. I am just explaining how to design your Layout to achieve this.
In your FirstViewController's View add a UIImageView containing iPhone's background in which your images will change on scrolling. Add another UIView as a sibling of your UIImageView and add ContainerView in it. Your PageViewController will be embedded in your Container View.
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.
In shorts, my desired screen layout is basically a user profile (iOS 7 + Xcode 5). I used UIScrollView as the top level view. The reason is that I want all its subviews to scroll (user info view - the view with a profile image and some buttons you see on the screen, and the photos collection view - the one with black background) when it is scrolled.
The region with black background will show user photos. I'm wondering if I could use a UICollectionView here, or there's a better way to implement it. The UICollectionView in this case shouldn't be able to scroll itself, it just shows all cells, while the scrolling work is handled by the outermost UIScrollView.
I read following posts:
UICollectionView inside of UIScrollView
UICollectionView in UIScrollView -> Scroll Order
iOS 7 Collection View inside Scroll View
Some said it's not possible (or at least, weird) implemeting UICollectionView inside UIScrollView because UIScrollView is UICollectionView's superclass which leads to unexpected behaviour. Some said it should be implemented in another way (but I didn't see a clear suggestion).
Yes, you can put a UICollectionView inside a UIScrollView. iOS has fully supported nested scroll views since iOS 3.0, and UICollectionView is a subclass of UIScrollView. For example, check out the App Store app on your iOS device. The screen scrolls vertically - it's either a UIScrollView or a UITableView (which is itself a subclass of UIScrollView). And each row of icons scrolls horizontally - each row is a UICollectionView.
However, it's not clear why you need to put a collection view inside a scroll view. It sounds like you only want the photos view to scroll, so just make the photos view be a collection view. Why do you need to put the collection view inside a scroll view?
UPDATE
Just use a collection view. Set the header of section 0 to the profile info view. You don't need a scroll view.
If you put all the photos in one section, you can set up the header in your storyboard with no code. If you use multiple sections, you'll need to implement collectionView:layout:referenceSizeForHeaderInSection: in your delegate and collectionView:viewForSupplementaryElementOfKind:atIndexPath: in your data source.
I'm creating my views programmatically. I have a UITableView in my UIViewController subclass that I want to add a scrolling subview to that is not a cell. I want to add some text-based subview to the UITableView that scrolls with the table and starts out above y=0 so the user will only see it if he pushes the table down. That is, it should reside above the first section of my table. If it helps for visualization, I intend to make something similar to those "scroll down to refresh" features and want some indication to the user that scrolling down causes a refresh. Is there any way to do this without something messy like using another UITableViewCell to represent it or abusing the UITableView delegate methods to move a view around whenever the user scrolls?
Simply using [tableView addSubview:] in my viewWillLoad only makes it appear for a split-second then disappear once the table data is loaded. This seems weird to me because UITableView is a subclass of UIScrollView, which is meant to hold other views in it. Using [tableView.backgroundView addSubview] does nothing.
P.S. Why not use a UIRefreshControl for this? I'm still undecided but leaning towards not using one because I don't like how slow that spinning wheel "feels" when the refreshes are usually very very quick. I've been looking at other options like flashing the background subtly and only showing a wheel if it's taking a longer time than usual.
I You can implement pull to refresh with only a table view
To do this using the scroll view delegate, since tableview is a subclass of scroll view.
Set view controller to be the tableview delegate and implement
(void)scrollViewDidScroll:(UIScrollView *)scrollView
When scrollview content offset y value passed a point, add a label to the viewcontroller.view not tableview. When you scroll back or release, remove the view.
You might also be able to add label to the table view and set the frame origin to negative y value, so when you pull the label will move into view (Never tested this do might not work)
I have a UIScrollView with 3 UITableViews stacked horizontally. I switch between these tableviews using a tab-controller on top. However, when I switch to the 2nd or 3rd tab and switch back quickly to 1st the section headers don't show. They display when I scroll the tableView. These are custom headers (jfyi). I tried calling setNeedsDisplay when the tableView is visible, but that does not help because as per Apple Docs :
If you simply change the geometry of the view, the view is typically not redrawn. Instead, its existing content is adjusted based on the value in the view’s contentMode property. Redisplaying the existing content improves performance by avoiding the need to redraw content that has not changed.
Since, only the geometry of the view is changing here, it does not help. Also this happens on all versions iOS 5~6.1 and on simulator and device. Thankfully, this does not crash the app, but its a problem nevertheless. Could someone help? I am attaching pictures for reference. First shows the problem, second: after scrolling the "head(er)less" tableview
EDIT:
I am using simple scrollRectToVisible:animated: to switch between tableviews. This does the trick but I just observed that when I set ...animated:NO all is okay. The problem happens when ...animated:YES
It seems the issue of displaying and scrolling taking place simultaneously for the respective tableview. So what you can do here is:
Remove the scroll animation
or
Just scroll the tableview to top on the tab press event
or
simply reload the tableView which is made visible