UIScrollView not scrolling regardless of large con

问题:

I have created a UIScrollView and added subviews to it in Interface Builder, but I am not able to get it to scroll. I have looked at other similar questions, but I have set my contentSize appropriately. In fact, I have even tried setting incredibly large contentSize and it fails to make a difference. What am I missing? Note that the UIScrollView is an IBOutlet:

@property (strong, nonatomic) IBOutlet UIScrollView *scroll;

This is in my viewDidLoad:

self.scroll.scrollEnabled = YES;
[self.scroll setContentSize: CGSizeMake(2400,8000)];

Here are screenshots from Interface Builder:

Here is the view while running, but any attempt at horizontal or vertical scrolling at any point does not work.

回答1:

Turning Auto Layout off works, but that's not the solution. If you really need Auto Layout, then use it, if you don't need it, turn it off. But that is not the correct fix for this solution.

UIScrollView works differently with other views in Auto Layout. Here is Apple's release note on Auto Layout, I've copied the interesting bit (emphasis mine, at third bullet point):

Here are some notes regarding Auto Layout support for UIScrollView:

• In general, Auto Layout considers the top, left, bottom, and right edges of a view to be the visible edges. That is, if you pin a view to the left edge of its superview, you’re really pinning it to the minimum x-value of the superview’s bounds. Changing the bounds origin of the superview does not change the position of the view.
• The UIScrollView class scrolls its content by changing the origin of its bounds. To make this work with Auto Layout, the top, left, bottom, and right edges within a scroll view now mean the edges of its content view.
• The constraints on the subviews of the scroll view must result in a size to fill, which is then interpreted as the content size of the scroll view. (This should not be confused with the intrinsicContentSize method used for Auto Layout.) To size the scroll view’s frame with Auto Layout, constraints must either be explicit regarding the width and height of the scroll view, or the edges of the scroll view must be tied to views outside of its subtree.
• Note that you can make a subview of the scroll view appear to float (not scroll) over the other scrolling content by creating constraints between the view and a view outside the scroll view’s subtree, such as the scroll view’s superview.

Apple then goes on to show example of how to correctly use UIScrollView with Auto Layout.

As a general rule, one of the easiest fix is to create a constraint between the element to the bottom of the UIScrollView. So in the element that you want to be at the bottom of the UIScrollView, create this bottom space constraint:

Once again, if you do not want to use Auto Layout, then turn it off. You can then set the contentSize the usual way. But what you should understand is that this is an intended behaviour of Auto Layout.

回答2:

Try turning off autolayot by

Select ViewController then file inspector and in interface builder document section you can see Use Autolayout checked or not. If its checked, then uncheck it.

This info UIScrollView And Autolayout may give the details.

回答3:

Try this code to auto set content size

first copy and paste your view controller in viewDidLoad Method

 [self MHAutoContentSizeForScrollViewWithPadding:10 scrl:YOUR_SCROLLVIEW];

then copy and paste in below viewDidLoad Method

-(void)MHAutoContentSizeForScrollViewWithPadding:(CGFloat)padding scrl:(UIScrollView*)view{
    if ([view isKindOfClass:[UIScrollView class]]) {
        CGRect rect = CGRectZero;
        for(UIView * view in YOUR_SCROLLVIEW.subviews){
            rect = CGRectUnion(rect, view.frame);
        }
        [YOUR_SCROLLVIEW setContentSize:CGSizeMake(rect.size.width, rect.size.height+padding)];
    } else {
        NSLog(@"You can only set the ContentSize for ScrollViews");
    }
}

connect YOUR_SCROLLVIEW delegate also and TextFeild Delegate also Happy Coding!!!

回答4:

If you are using auto-layout than Put everything in the UIScrollView into another UIView, and put that UIView as the only child of the UIScrollView. Then you can use AutoLayout.

If things near the end is messed up (the end of whichever direction your UIScrollView scrolls), change the constraint at the end to have the lowest possible priority.