Add Constraint to ScrollView - ios

Question

I am trying to add constraints to UIScrollView with a label (subview of scrollview)
but the scrollview wouldn't scroll and trailing never work.
float y = self.navigationController.navigationBar.frame.size.height + 30;
self.scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0,0, 0,0)];
[self.scrollView setBackgroundColor:[UIColor blueColor]];
[self.scrollView setScrollEnabled:YES];
[transparentImageView addSubview:self.scrollView];
self.scrollView.translatesAutoresizingMaskIntoConstraints = NO;
[transparentImageView addConstraint:[NSLayoutConstraint constraintWithItem:self.scrollView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:transparentImageView attribute:NSLayoutAttributeBottom multiplier:1.0f constant:-120.0]];
//leading
[transparentImageView addConstraint:[NSLayoutConstraint constraintWithItem:self.scrollView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:transparentImageView attribute:NSLayoutAttributeLeading multiplier:1.0f constant:20.0f]];
//trailing
[transparentImageView addConstraint:[NSLayoutConstraint constraintWithItem:self.scrollView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:transparentImageView attribute:NSLayoutAttributeTrailing multiplier:1.0f constant:-20.0]];
[transparentImageView addConstraint:[NSLayoutConstraint constraintWithItem:self.scrollView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:transparentImageView attribute:NSLayoutAttributeTop multiplier:1.0f constant:y]];
self.shineText = [[RQShineLabel alloc]initWithFrame:CGRectMake(0,0, 0, 0)];
[self setupText];
[self.shineText setBackgroundColor:[UIColor redColor]];
[self.scrollView addSubview:self.shineText];
self.shineText.translatesAutoresizingMaskIntoConstraints = NO;
self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width, self.scrollView.frame.size.height);
//bottom
[self.scrollView addConstraint:[NSLayoutConstraint constraintWithItem:self.shineText attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.scrollView attribute:NSLayoutAttributeBottom multiplier:1.0f constant:-10.0f]];
//leading
[self.scrollView addConstraint:[NSLayoutConstraint constraintWithItem:self.shineText attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.scrollView attribute:NSLayoutAttributeLeading multiplier:1.0f constant:10.0f]];
//trailing
[self.scrollView addConstraint:[NSLayoutConstraint constraintWithItem:self.shineText attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:self.scrollView attribute:NSLayoutAttributeTrailing multiplier:1.0f constant:-500.0f]];
[self.scrollView addConstraint:[NSLayoutConstraint constraintWithItem:self.shineText attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.scrollView attribute:NSLayoutAttributeTop multiplier:1.0f constant:20]];

Answer 1

If you have this line self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width, self.scrollView.frame.size.height); then your scroll view never make scroll at all because your content size is the same as the scroller frame, the content size of your scrollView must be greater than the scrollView frame in order to scroll
Try with something like this
self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width, 1000);
then your scrollView must scroll
I hope this helps you

Answer 2

Generally, while working with UIScrollView and auto layouts, we need to add one UIView as child view on scroll view with same size as scroll view.
Here is tutorial which explains this in details.
But this tutorial is for using scroll view in .nib file.
For adding scroll view programatically, go through Apple developer technical note.
It suggest that:
Use constraints to lay out the subviews within the scroll view, being sure that the constraints tie to all four edges of the scroll view and do not rely on the scroll view to get their size.

Answer 3

try this tricky way to work with scrollview in storyboard. I created a small video tutorial to show how easy to work with scroll view. You should have a small knowledge of autolayout.
step 1 : change your viewcontroller size as your need
step 2 : add a scroll view and setup constarints (top, lead, trail and top) to the conatainer view.
step 3 : then add another view on to scroll view(this is your child view where you add your all other IBOutlets)
step 4 : then add constraints to it. (top, lead, trail and top to scroll view) + (width and height to it self)
step 5 : create an outlet to the child view width to your controller and give the width programatically( the device width)
this small tutorial shows you how to do it..
part one : less thant 5 min
part two : less than 5 min
hope this will help to you.