I have a UIScroll view with content in it. If that content overflows, making the scroll view scrollable, I'd like to set the bottom of the view to be a certain color. If it does not, I'd like to set it to a different color.
My issue is, I do not know how to detect if a UIScrollView's content overflows and thus is scrollable.
Check if the scroll view's contentSize is bigger than its bounds.
I know it's an old question, but my scroll view had a content insets set which made the accepted answer slightly off. Here's how to take the content inset into account:
if scrollView.contentSize.height + scrollView.contentInset.bottom > scrollView.bounds.size.height {
// Scroll view is able to scroll.
}
Related
I wanted to show the UIScrollView's scrollbar only when needed, i.e. when the content exceeds the visible size and needs scrolling to see everything.
So I added this code:
self.view.addSubview(self.myScrollView)
self.myScrollView.edgesToSuperView()
print(self.myScrollView.contentSize.height)
print(self.myScrollView.bounds.height)
if self.myScrollView.contentSize.height > self.myScrollView.bounds.height {
self.myScrollView.showsVerticalScrollIndicator = true
}
However, contentSize.height and contentSize.height always print out as zero, although that inside the scrollView there is a stackView that has many text labels that exceeded screen height. So this didn't worked out.
Any better ideas?
This property:
.showsVerticalScrollIndicator = true
only controls the visibility of a scroll indicator while the user is scrolling.
By default, if your content is not "tall enough" to need to scroll, the scroll indicators are never shown.
If your content IS "tall enough" to need to scroll (height is greater than the scroll view's frame height), the scroll indicators are shown while scrolling.
There is no way to have them "always showing."
If you want to indicate to the user that there is more content to be seen by scrolling, you could add something like "arrows" that you show / hide as appropriate, or, you can call `self.myScrollView.flashScrollIndicators() to "flash" the scroll indicators.
So I have the following view hierarchy :
A full size scrollView in my viewController's view with the following constraints :
These are the constraints on containerView (ignore the second last one, its a hacky semi-fix for my problem):
I have the status bar, the navigation bar and the tab bar visible.
The thing is that when I set a breakpoint to check the scrollView's contentInset, it shows 64 on top and 49 on bottom, left and right are zero.
There is no way to set contentInset in IB, I tried setting it in an IBAction to UIEdgeInsetZeio, but that didn't fix it either. This is screwing up my scrollview by adding space above and below my contentView, how can I fix this?
By default the view controller extends the view under the top navigation bar so your content will blur under a translucent navigation bar. This is controlled by edgesForExtendLayout which is managed in Storyboard via the Extend Edges setting.
By default, the scrollview will automatically adjust its content inset so the content appears below the top layout guide. This is controlled by automaticallyAdjustsScrollViewInsets which is also managed in Storyboard.
What you did was constrain the top of your scroll view to the top layout guide instead of the top of its superview. By doing this, you manually offset it by 64 points. However, the scrollview is still automatically insetting its content by 64 points, which is why you're seeing additional space above and below your scroll view.
Either constrain your scrollview to its superview (so its content scrolls under the top/bottom bars), or disable the view controller from automatically adjusting the scroll view inset.
UIScrollview scroll is not working when i tested application in device (iPhone 5), But scroll is working properly in iPhone 5/5s/6/6 Plus simulator. I am developing application using Xcode 6 and UIStoryboard with AutoLayout.
I set the top, bottom, left and right constraints of UIScrollview with relative to Superview. And i also set the constraints of every UIControl which is in the UIScrollview.
Has any one have solution regarding this issue?
Please see below screenshot for reference.
It's probably easiest to have the scroll view contain a single view, which then contains all of your scrollable content. That single view should be anchored to all 4 sides of the scroll view, and if it's only meant to scroll vertically (which is what your screenshot makes it look like), then set the content view to be the same width as the parent of the scroll view.
To make sure an UIScrollView scroll, you have to check
Size
Your content View is bigger than your Scroll View. If you want it to be scrolled vertically, make sure its higher; horizontally, wider.
Constraints
Make sure your Scroll View is pinned to its super view, Top, Bottom, Leading, Trailing.
Make sure your Content view of Scroll View DOES NOT have CenterY constraint set to Scroll View, cause that'd make content view stuck with Scroll View and it'd never be able to scroll. (That happens to me the last time I was stuck)
Interface Builder settings
Make sure the check in Interface Builder under Scroll View is checked:
Scrolling section, Scrolling Enabled.
I would like to create an infinite scrollView (like a slot machine), but without paging. When the user scrolls down, it's easy i just have to increase the contentSize and the scrollView scroll endlessly :
- (void)scrollViewDidScroll:(UIScrollView *)theScrollView {
theScrollView.contentSize = CGSizeMake(45, theScrollView.contentSize.height+45);
}
But how can i create the same effect when the user scrolls upward ? I tried to play with the contentInset but then the contentOfsset doesn't get updated and i end up having weird behaviour.
Do you have any idea how i could achieve that ?
I needed the same, so I created this: http://dev.doukasd.com/2011/04/infinite-scrolling-dial-control-for-ios/
Have a look at the video, I believe it's what you're looking for. Source code is included.
I have developed this kind scroll view. It can scroll infinite.
You can check on github: https://github.com/quangrubify/InfiniteUITableView
I think you should give us more details about the issue. What content do you want the user to see when he is scrolling upwards? You increase the contentSize in scrollViewDidScroll method, but you are not checking the contentOffset, so the contentWill be bigger whenever the user scrolls the scrollView (either way, even horizontal if allowed). Since the contentOffset is already at 0, the user cant scroll upwards because there is nothing that the scroll view can show.
I dont know the content of your scrollView, but I have implemented infinite scrolling horizontally. For details, see: https://stackoverflow.com/a/12856174/936957
PS: Do not use "magic numbers", this is a better alternative:
theScrollView.contentSize = CGSizeMake(theScrollView.contentSize.x, theScrollView.contentSize.height+45);
//Or theScrollView.frame.size.width alternatively
I'd like to provide a few pixels of padding around an NSTextView inside of an NSScrollView. I've reviewed this post and using setTextContainerInset does the trick for the left, right, and bottom margins. But as soon as the text scrolls the top buffer is lost. Same thing with overriding textContainerOrigin. Another answer in that post states:
The way TextEdit does it (when in Wrap to Page mode) is to put the text view inside of a larger view, and set that larger view as the document view of the scroll view.
But if I do that (using, say an NSBox) the content no longer scrolls. Am I missing something regarding that particular trick, or are there any other techniques that folks could suggest?
There's a step that seems to be missing from your quote. You'll need to make sure your new document view tracks the changes in the text view's frame and sizes itself to fit. You can turn on NSViewFrameDidChangeNotification on your text view with -setPostsFrameChangedNotifications:, then have your new document view listen for notifications from your text view..
By the way, I ended up accomplishing this by subclassing NSClipView, overriding setFrame:, setFrameOrigin:, and setFrameSize, and hacking the origin and width in those methods to add my padding.