Subview height resize - xcode

Question

I have a UIView with 2 subviews. Only 1 subview is visible at a time, controlled by a segmented control. The subviews have different heights. How do I set the UIView height to be dependent on the visible subview?
EDIT -
The below code works for the initial back and forth segue of the segmented control but then stays at 30px. The debugger shows that there is an issue satisfying the constrains but I'm not sure how to correct it.
Error:
Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints)
("<NSLayoutConstraint:0x7f84f84b3b80 V:[UIView:0x7f84f852bc60(60)]>",
"<NSLayoutConstraint:0x7f84f8494d20 V:[UIView:0x7f84f852bc60(30)]>")
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x7f84f84b3b80 V:[UIView:0x7f84f852bc60(60)]>
Code:
- (IBAction)segmentValueChanged:(UISegmentedControl *)sender {
switch (sender.selectedSegmentIndex) {
case 0:
[_ParentView setTranslatesAutoresizingMaskIntoConstraints:NO];
[_ParentView addConstraint:[NSLayoutConstraint
constraintWithItem:_ParentView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0
constant:30.0]];
self.1stView.hidden = NO;
self.2ndView.hidden = YES;
break;
case 1:
[_ParentView setTranslatesAutoresizingMaskIntoConstraints:NO];
[_ParentView addConstraint:[NSLayoutConstraint
constraintWithItem:_ParentView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0
constant:60.0]];
self.1stView.hidden = YES;
self.2ndView.hidden = NO;
break;
default:
break;
}
}
Thanks

Answer 1

Okay I set this up in storyboard and got it to work.
So you have your three UIViews for the story board
in your .h file
#property (nonatomic, retain) IBOutlet UIView *parentView;
#property (nonatomic, retain) IBOutlet UIView *HDDView;
#property (nonatomic, retain) IBOutlet UIView *SSDView;
Then in your .m file
#synthesize parentView, HDDView, SSDView;
- (void)viewDidLoad {
//so here you can set which uiview is hidden when the view loads
//or you probably did it in your storyboard, either way works
self.SSDView.hidden = YES;
}
- (IBAction)segmentValueChanged:(UISegmentedControl *)sender {
switch (sender.selectedSegmentIndex) {
case 0:
self.HDDView.hidden = NO;
self.SSDView.hidden = YES;
CGRect newFrame = parentView.frame;
newFrame.size.height = HDDView.frame.size.height;
parentView.frame = newFrame;
break;
case 1:
self.HDDView.hidden = YES;
self.SSDView.hidden = NO;
CGRect otherFrame = parentView.frame;
otherFrame.size.height = SSDView.frame.size.height;
parentView.frame = otherFrame;
break;
default:
break;
}
}
Now in your storyboard add your SSDView and HDDView UIViews and hook them up to their IBOutlets. Then add your parentView UIView and hook it up too. Then drag SSDView and HDDView inside of the parentView UIView. **Make sure that you put SSDView and HDDView at the top of the parentView so that each UIView's top bounds are flush. Also make sure that you did not drag one of subviews into the other. And finally add some constraints to the parentView so that it is in the position that you will want. Then hook up your segmented controller and you are good to go.
All in all, I would suggest not to use Interface Builder for complex things like this. You can do this with code and it will be much more customizable and easier to adjust. I started out using IB but it is much better to do these things programmatically because you can have much more control. I hope this helps you out.

Answer 2

Its probably not the cleanest but I was able to get the below code to work. Thanks to #AJB for the help.
- (IBAction)segmentValueChanged:(UISegmentedControl *)sender {
switch (sender.selectedSegmentIndex) {
case 0:
self.1stView.hidden = NO;
self.2ndView.hidden = YES;
_1stconstraint = [NSLayoutConstraint
constraintWithItem:_ParentView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0
constant:30.0];
[_ParentView setTranslatesAutoresizingMaskIntoConstraints:NO];
[_ParentView removeConstraint:_2ndconstraint];
[_ParentView addConstraint:_1stconstraint];
break;
case 1:
self.1stView.hidden = YES;
self.2ndView.hidden = NO;
_2ndconstraint = [NSLayoutConstraint
constraintWithItem:_ParentView
attribute:NSLayoutAttributeHeight
relatedBy:NSLayoutRelationEqual
toItem:nil
attribute:NSLayoutAttributeNotAnAttribute
multiplier:1.0
constant:60.0];
[_ParentView setTranslatesAutoresizingMaskIntoConstraints:NO];
[_ParentView removeConstraint:_1stconstraint];
[_ParentView addConstraint:_2ndconstraint];
break;
default:
break;
}
}