nslayoutconstraint

I have implemented AutoLayout programmatically using the Code : - (void)addConstraintWithListNavigationViewController:(UIView *)listViewNavigation y:(CGFloat)y height:(CGFloat)height { //WIDTH_ListTableView = 0.4 //set x = 0; NSLayoutConstraint *constraintToAnimate1 = [NSLayoutConstraint constraintWithItem:listViewNavigation attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:0.00 constant:0]; [self.view addConstraint:constraintToAnimate1]; //set y = y; NSLayoutConstraint *constraintToAnimate2 = [NSLayoutConstraint

I want to animate an object, so I declare a constraint and add it to the view. I then update the constant property of the constraint inside an UIView animation. Why doesn't this code move the object? UIView.animateWithDuration(1, animations: { myConstraint.constant = 0 self.view.updateConstraints(myConstraint) }) duan In order to declare an animation, you cannot re-define the constraint and call updateConstraints . You are supposed to change the constant of your constraint and follow the format below: self.view.layoutIfNeeded() UIView.animateWithDuration(1, animations: { self.sampleConstraint

I keep getting 'Unable to simultaneously satisfy constraints' exceptions (Xcode 5, iOS 7, both device and simulator), where one of the constraints in the list is something like this: "<NSLayoutConstraint:0x165b23d0 'UIView-Encapsulated-Layout-Width' H:[StoryPlayerCell:0x165affc0(0)]>" I did not set this constraint myself. It's also not an NSAutoresizingMaskLayoutConstraint . But where does it come from? And how can I get rid of it? I have no idea. And I can't find anything about 'UIView-Encapsulated-Layout-Width' in the Apple's documentation. Even the Google search returns nothing at all. Any

I am preparing a custom view which looks similar to the example shown in the screenshot. I add all user interface components (labels, text fields, radio buttons, ..) at runtime. To position the elements I use Autolayout constraints. This part works fine so far. The number of elements varies from context to context. I wonder how I could use Autolayout constraints to dynamically resize the parent view (most likely the height of the view). The view constraints therefore should consider the height and margins defined for the currently attached subviews. I've done this with the following setup: the

I am trying to understand how one can utilize Auto Layout to position items relative to other views percentage-wise. For example, I recently learned that you can specify a view's bottom should lie 4% higher than its superview's bottom by using this: self.view.addConstraint(NSLayoutConstraint(item: label, attribute: .Bottom, relatedBy: .Equal, toItem: self.view, attribute: .Bottom, multiplier: 0.96, constant: 0)) This makes sense to me because a multiplier of 1 would align it right at the view's bottom, so you can decrease that amount by 4 percent by changing the multiplier to 0.96. But how can

My goal is to animate a UIImageView . I declared a NSLayoutConstraint in viewDidLoad . In viewDidLoad , I used this code: UIView.animateWithDuration(1, animations: { myConstraint.constant = 100 self.view.layoutIfNeeded() }, completion: {finished in }) Why doesn't my image move? By the time you hit viewDidLoad , the constraints engine has not yet been applied and the starting location of the views has not yet been established. So, feel free to add the original constraints in viewDidLoad , but you will want to defer the animateWithDuration until later in the process (e.g. viewDidAppear ). For