How can I disable vertical scrolling in my UITextView? I want it to basically just scroll horizontally.
In some circumstances, when trying to clamp down on unwanted UITextView scrolling I have found it helpful to add something like the following to the UITextView delegate (this is a UIScrollView delegate method but, of course, UITextView inherits from UIScrollView). This might work for you.
- (void)scrollViewDidScroll:(id)scrollView
{
CGPoint origin = [scrollView contentOffset];
[scrollView setContentOffset:CGPointMake(origin.x, 0.0)];
}
What about the scrollEnabled property? Setting the scrollEnabled property to NO stops the user from scrolling (in both directions), but there are occasions where the system sends setContentOffset:animated: messages to a UITextView. The scrollEnabled property applies to both vertical and horizontal scrolling. Given your question, you might want to leave scrollEnabled as is.
You can change it from Xcode -
Solution for disabling vertical scrolling for Swift 4:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let origin: CGPoint = scrollView.contentOffset
scrollView.contentOffset = CGPoint(x: origin.x, y: 0.0)
}
If you have your custom textView subclass, you can override -gestureRecognizerShouldBegin to disable the scroll.
-(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]])
{
if (gestureRecognizer.view == self)
{
return NO;
}
else
{
return [super gestureRecognizerShouldBegin: gestureRecognizer];
}
}
}
why not just use a UITextField if you dont want vertical scrolling?
Just set the contentSize to the height of the view.
You'll use this:
CGSize scrollableSize = CGSizeMake(widthOfContent, heightOfView);
[myScrollView setContentSize:scrollableSize];
place your UITextView in a UIScrollView.
Set your UITextView.frame to a Size the complete Text fits in a Line and set the contenSize of the ScrollView to the size of your UITextView.frame.
Cheers
nettz
Related
I have a UITextField inside a UIScrollView (a few levels deep). I am watching UIKeyboardDidShowNotification, and also calling the same code when I manually change the first responder (I might change to a different text field without momentarily hiding the keyboard). In that code I use scrollRectToVisible:animated: to make sure the UITextField is visible.
I was having a huge headache debugging why that was acting funny, but I realized now that UIScrollView automatically ensures that the first responder is within its bounds. I am changing the frame of the UIScrollView so that none of it is hidden behind the keyboard.
However, my code can be slightly smarter than their code, because I want to show not only the UITextField, but some nearby related views as well. I try to show those views if they will fit; if not whatever, I try to show as much of them as I can but at least ensure that the UITextField is visible. So I want to keep my custom code.
The automatic behavior interferes with my code. What I see is the scroll view gently scroll up so that the bottom edge of my content is visible, then it snaps down to where my code told it to position.
Is there anyway to stop the UIScrollView from doing its default capability of scrolling the first responder into view?
More Info
On reviewing the documentation I read that they advise to change the scroll view's contentInset instead of frame. I changed that and eliminated some unpredictable behavior, but it didn't fix this particular problem.
I don't think posting all the code would necessarily be that useful. But here is the critical call and the values of important properties at that time. I will just write 4-tuples for CGRects; I mean (x, y, width, height).
[scrollView scrollRectToVisible:(116.2, 71.2, 60, 243) animated:YES];
scrollView.bounds == (0, 12, 320, 361)
scrollView.contentInset == UIEdgeInsetsMake(0, 0, 118, 0)
textField.frame == (112.2, 222.6, 24, 24)
converted to coordinates of the immediate subview of scrollView == (134.2, 244.6, 24, 24)
converted to coordinates of scrollView == (134.2, 244.6, 24, 24)
So the scroll view bottom edge is really at y == 243 because of the inset.
The requested rectangle extends to y == 314.2.
The text field extends to y == 268.6.
Both are out of bounds. scrollRectToVisible is trying to fix one of those problems. The standard UIScrollView / UITextField behavior is trying to fix the other. They don't come up with quite the same solution.
I didn't test this particular situation, but I've managed to prevent a scrollview from bouncing at the top and bottom by subclassing the scrollview and overriding setContentOffset: and setContentOffset:animated:. The scrollview calls this at every scroll movement, so I'm fairly certain they will be called when scrolling to the textfield.
You can use the delegate method textFieldDidBeginEditing: to determine when the scroll is allowed.
In code:
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
self.blockingTextViewScroll = YES;
}
-(void)setContentOffset:(CGPoint)contentOffset
{
if(self.blockingTextViewScroll)
{
self.blockingTextViewScroll = NO;
}
else
{
[super setContentOffset:contentOffset];
}
}
-(void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated
{
if(self.blockingTextViewScroll)
{
self.blockingTextViewScroll = NO;
}
else
{
[super setContentOffset:contentOffset animated:animated];
}
}
If your current scroll behaviour works with a setContentOffset: override, just place it inside the else blocks (or preferably, in a method you call from the else blocks).
In my project I have succeeded to achieve this by performing my scroll only after some delay.
- (void)keyboardWillShow:(NSNotification *)note
{
NSDictionary *userInfo = note.userInfo;
CGRect keyboardFrame = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
UIEdgeInsets contentInsets = self.tableView.contentInset;
contentInsets.bottom += keyboardFrame.size.height;
[self.tableView setContentInset:contentInsets];
[self performSelector:#selector(scrollToEditableCell) withObject:nil afterDelay:0];
}
Also there is other possibility to make your view with additional views to be first responder and fool scroll view where to scroll. Haven't tested this yet.
This may turn out to be useless, but have you tried setting scrollView.userInteractionEnabled to NO before calling scrollrectToVisible: & then setting it back to YES? It may prevent the automatic scrolling behavior.
Try changing the view autoresizing to UIViewAutoresizingFlexibleBottomMargin | UIViewAutoresizingFlexibleRightMargin. The default is FlexibleTopMargin so maybe thats the reason. btw scrollRectToVisible: is using the scrollView.contentSize.
The other thing you can try to change the scrollView size first and then apply the scrollRectToVisible: change. First frame change, then content change. (Maybe observe the keyboard did appear event)
The automatic scrolling behavior seems to be especially buggy starting in iOS 14. I alleviated the problem by subclassing UIScrollView and overriding setContentOffset to do nothing. Here is the bases of my code.
class ManualScrollView: UIScrollView {
/// Use this function to set the content offset. This will forward the call to
/// super.setContentOffset(:animated:)
/// - Parameters:
/// - contentOffset: A point (expressed in points) that is offset from the content view’s origin.
/// - animated: true to animate the transition at a constant velocity to the new offset, false to make the transition immediate.
func forceContentOffset(_ contentOffset: CGPoint, animated: Bool) {
super.setContentOffset(contentOffset, animated: animated)
}
/// This function has be overriden to do nothing to block system calls from changing the
/// content offset at undesireable times.
///
/// Instead call forceContentOffset(:animated:)
override func setContentOffset(_ contentOffset: CGPoint, animated: Bool) {
}
}
This works but you have to deal with reimplementing many of the scroll views behaviors and methods that you normally get for free. Since scrollRectToView and scrollToView both use setContentOffset you also have to reimplement these if you want them to work.
I have the UIScrollView with pagingEnabled set to YES, and programmatically scroll its content to bottom:
CGPoint contentOffset = scrollView.contentOffset;
contentOffset.y = scrollView.contentSize.height - scrollView.frame.size.height;
[scrollView setContentOffset:contentOffset animated:YES];
it scrolls successfully, but after that, on single tap its content scrolls up to offset that it has just before it scrolls down. That happens only when I programmaticaly scroll scrollView's content to bottom and then tap. When I scroll to any other offset and then tap, nothing is happened.
That's definitely not what I'd like to get. How that should be fixed?
Much thanks in advance!
Timur.
This small hack prevents the UIScrollView from scrolling when tapped. Looks like this is happening when the scroll view has paging enabled.
In your UIScrollView delegate add this method:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
scrollView.pagingEnabled = self.scrollView.contentOffset.x < (self.scrollView.contentSize.width - self.scrollView.frame.size.width);
}
This disables the paging when the scroll view reaches the right end in horizontal scrolling (my use case, you can adapt it to other directions easily).
I just figured out what causes this problem, and how to avoid it. If you having pagingEnabled set to YES on a scroll view, you must set the contentOffset to be a multiple of the scroll view's visible size (i.e. you should be on a paging boundary).
Concrete example:
If your scroll view was (say) 460 pixels high with a content area of 920, you would need to set the content offset to EITHER 0 or 460 if you want to avoid the "scroll to beginning on tap" problem.
As a bonus, the end result will probably look better since your scroll view will be aligned with the paging boundaries. :)
The following workaround did help (assume that one extends UIScrollView with a category, so 'self' refers to its instance):
-(BOOL) scrolledToBottom
{
return (self.contentSize.height <= self.frame.size.height) ||
(self.contentOffset.y == self.contentSize.height - self.frame.size.height);
}
Then, one should sometimes turn pagingEnabled off, just at the position where scroll view reaches its bottom. In the delegate (pagingEnabled is initialy on of course, since the problem occurs only when it is enabled):
-(void) scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.pagingEnabled == YES)
{
if ([scrollView scrolledToBottom] == YES)
scrollView.pagingEnabled = NO;
}
else
{
if ([scrollView scrolledToBottom] == NO)
scrollView.pagingEnabled = YES;
}
}
This seems to be a bug:
UIScrollView doesn't remember the position
I have tested this on iOS 4.2 (Simulator) and the issue remains.
When scrolling a ScrollView I would suggest using
[scrollView scrollRectToVisible:CGRectMake(0,0,1,1) animated:YES];
Where the rect is the position you're after. (In this case the rect would be the top of the scrollview).
Changing the content offset is not the correct way of scrolling a scrollview.
I am using UIScrollView and an image in it as paging one image per page. I have a problem while rotating the iPhone
When I rotate the iPhone then scrollViewDidScroll (Scroll view delegate method) is calling.
Due to this, my paging is disturbed and the page number changes.
What is the solution?
Raphaël's answer is an excellent description of the problem, and a neat fix. I had the exact same problem and ended up fixing with a scrollingLocked flag that I set to YES (locked) before the rotation starts, and NO (unlocked) when it ends. Perhaps slightly less hacky than temporarily changing the contentSize:
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)orientation
duration:(NSTimeInterval)duration
{
self.photoViewer.scrollingLocked = YES;
}
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromOrientation
{
self.photoViewer.scrollingLocked = NO;
}
- (void)scrollViewDidScroll:(UIScrollView*)scrollView
{
if (self.scrollingLocked)
{
return;
}
/* do normal scrollViewDidScroll: stuff */
}
I found a strange undocumented behavior when rotating a paged UIScrollView.
When the scrollview is positioned at the last page and the user changes the orientation, the OS scrolls the UIScrollView a few pixels back to compensate for the difference between height and width.
Basically I received the following calls for any page.
willRotateToInterfaceOrientation:duration
willAnimateRotationToInterfaceOrientation:duration:
didRotateFromInterfaceOrientation:
And for the last page:
willRotateToInterfaceOrientation:duration
scrollViewDidScroll:
willAnimateRotationToInterfaceOrientation:duration:
didRotateFromInterfaceOrientation:
That messed up with my pages too. The problem is that in willRotate, the bounds have not been updated by the OS yet, and in willAnimate you have the new bounds and can compute the new size, but it's too late...
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
CGSize tempSize = [self.pagingScrollView contentSize];
NSUInteger padding = abs(pagingScrollView.frame.size.width - pagingScrollView.frame.size.height);
tempSize.width += padding;
[self.pagingScrollView setContentSize:tempSize];
[...]
}
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation duration:(NSTimeInterval)duration{
CGSize newSize = ... // Compute new content size based on new orientation
[self.pagingScrollView setContentSize:newSize];
}
This is just a workaround, but I spent countless hours on this issue and could not find an elegant solution.
Swift 4 solution:
override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
super.traitCollectionDidChange(previousTraitCollection)
lui.l("apply previousTraitCollection: \(previousTraitCollection)")
canScroll = true
}
You can try this method for Swift:
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
super.viewWillTransition(to: size, with: coordinator)
coordinator.animate(alongsideTransition: { _ in
// Execute before rotation
}) { _ in
//Execute after rotation
}
}
My task is to allow scrolling the landscape. The design is for portait. I came up with an idea to add a ScrollView to components, or in "Embed in Scroll View" in Interface Builder. I have expected it will work, but no. I am using Xcode 4.4, iOS 5.1, (office project need support for 4.2 too), but the problem is the same.
In Stack Overflow question iPhone SDK: UIScrollView does not scroll there is one row which solve a problem.
Other try is in Stack Overflow question iOS - UIScrollView is not working (it doesn't scroll at all - the image stays fixed), and this helped me, combined with other, so here is my portait-to-scrollable landscape code:
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromOrientation
{
if( UIInterfaceOrientationIsPortrait( [[UIApplication sharedApplication] statusBarOrientation] ) ){
scrollView.contentSize = portaitScrollSize;
}
else{//statusbar is Landscape
scrollView.contentSize = landscapeScrollSize;
}
}
The scrollView in bound to an iVar view in Interface Builder. portaitScrollSize and landscapeScrollSize are private variables. They are initialized and doesn't change.
In my.h file:
IBOutlet UIScrollView *scrollView;
In my.m file:
CGSize portaitScrollSize, landscapeScrollSize;
...
portaitScrollSize = CGSizeMake(320,440);
landscapeScrollSize = CGSizeMake(480,480);
I hope it will help somebody to add a rotating + scroll feature to a portait design.
Don't forget to allow portait+landscape on the top component:
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return TRUE;
}
In addition to Raphaël Mor's answer. If you are switching from portrait to landscape, the contentsize and the page structure will brake. Therefore, in order to maintain the current page structure just add extra content size to width:
-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration{
[self.scrollView setContentSize:CGSizeMake(self.scrollView.contentSize.width + 400, self.scrollView.contentSize.height)];
}
And make sure you set the contentsize and offset again after the orientation changed:
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
[self.scrollView setContentSize:CGSizeMake(self.scrollView.bounds.size.width *3, self.scrollView.bounds.size.height)];
[self.scrollView setContentOffset:CGPointMake(self.scrollView.bounds.size.width * self.pageControl.currentPage, 0) animated:NO];
}
I have a UIScrollView that is scrolling a fairly large UIView.
At certain times I want to limit the area the user can scroll around in. For example, I may only want to allow them to view the bottom quarter of the view.
I am able to limit the area by overriding scrollViewDidScroll and then calling setContentOffset if the view has scrolled too far. But this way I can't get it bounce back as smoothly as the UIScrollView can naturally do when scrolling beyond the bounds of the UIView.
Is there a better way to limit the scrollable area in a UIScrollView?
I would change the contentSize property of the scroll view to the size of the area you want the user to be able to scroll around in and adjust the frame.origin of the subview such the upper left boundary you want appears at (0, 0) relative to the scroll view. For example, if your view is 800 points tall and you want to show the bottom quarter, set the height of contentSize to 200 and set the y component of view.frame.origin to -600.
I've found something that works for me. It let's you scroll to point 0,0 but no further:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if (scrollView.contentOffset.x <= -1) {
[scrollView setScrollEnabled:NO];
[self.scrollView setContentOffset:CGPointMake(0, 0) animated:YES];
[scrollView setScrollEnabled:YES];
}
}
You could do the same for top, bottom or right (x or y)
a small improvement on Yoko's answer in Swift 4 will be
override func scrollViewWillBeginDecelerating(_ scrollView: UIScrollView) {
if scrollView.contentOffset.y > 600 {
let anim = UIViewPropertyAnimator(duration: 1, dampingRatio: 0.5) {
scrollView.isScrollEnabled = false
scrollView.setContentOffset(CGPoint(x: 0, y: 600), animated: false)
scrollView.isScrollEnabled = true
}
anim.startAnimation()
}
}
which will make the scrollview animate really similar to what its supposed to do. The slower drag when you are in the "bounce" area will not work and animation duration has to depend on the distance (not constant like here) if you want to be exact. You can also try to do this logic in scrollViewDidScroll and see how it differs. The key thing is that setContentOffset(_:,animated:) has to be with animated: false so that the UIViewPropertyAnimator's block can capture it and animate it
Another approach is to override the UIScrollView's method:
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event.
Returning YES will allow the user to scroll. Returning NO will not.
NOTE: This will disable all touches to any views imbedded inside the UIScrollView that pointInside returns NO to. Useful if the area you don't want to scroll from doesn't have any interaction.
This example only allows the UIScrollView to scroll when the user is scrolling over a UITableView. (A UITableView and two UIViews are imbedded inside the UIScrollView)
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
for (UIView *subview in self.subviews) {
if ([subview pointInside:[self convertPoint:point toView:subview] withEvent:event] && ![subview isKindOfClass:[UITableView class]]) {
return NO;
}
}
return YES;
}
I'm using an UIScrollView and I have an image that indicates to the user that there is more content that they can scroll through vertically. I would like this image to be hidden when the scrollview is all the way at the bottom. Is there a way to do this? Would I have to subclass UIScrollView and make my own?
your scroll view's delegate should repsond to scrollViewDidEndScrollingAnimation: and use that to check where you are
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
// Get some details about the view
CGSize size = [scrollView frame].size;
CGPoint offset = [scrollView contentOffset];
CGSize contentSize = [scrollView contentSize];
// Are we at the bottom?
if (-offset.y + size.height <= contentSize.height)
NSLog(#"bottom");
else
NSLog(#"not bottom");
}
NB The if statement was done in my head so it might be the wrong way round ;)