UIScrollView contentSize not working

I tried viewWillLayoutSubviews to update scrollView's contentSize, it worked for me.

- (void)viewDidLayoutSubviews
{
  [self.bgScrollView setContentSize:CGSizeMake(320, self.view.frame.size.height* 1.5)];
}

Apple Doc

-(void)viewDidLayoutSubviews

Called to notify the view controller that its view has just laid out its subviews.

Discussion

When the bounds change for a view controller’s view, the view adjusts the positions of its subviews and then the system calls this method. However, this method being called does not indicate that the individual layouts of the view’s subviews have been adjusted. Each subview is responsible for adjusting its own layout.

Your view controller can override this method to make changes after the view lays out its subviews. The default implementation of this method does nothing.

I had the same problem. Auto Layout for UIScrollView is messed up.

Work around: Put everything in the UIScrollView into another UIView, and put that UIView as the only child of the UIScrollView. Then you can use Auto Layout.

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.