Unable to simultaneously satisfy constraints - No

Question

I have gone through and removed every single user constraint yet I am still getting the following error ONLY after I rotate the device. I have absolutely no clue why though. Does anyone have any ideas?

2013-01-14 21:30:31.363 myApp[35869:c07] 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) 
(
    "<NSAutoresizingMaskLayoutConstraint:0x84543d0 h=--& v=--& V:[UIView:0xa330270(768)]>",
    "<NSLayoutConstraint:0xa338350 V:[UIView:0xa331260]-(-1)-|   (Names: '|':UIView:0xa330270 )>",
    "<NSLayoutConstraint:0xa338390 V:|-(841)-[UIView:0xa331260]   (Names: '|':UIView:0xa330270 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0xa338350 V:[UIView:0xa331260]-(-1)-|   (Names: '|':UIView:0xa330270 )>

Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.

Answer 1

I've fixed this problem be deleting all translatesAutoresizingMaskIntoConstraints properties from xib file (Open xib as a source code).

Answer 2

This issue of the generated message "Unable to simultaneously satisfy contraints" in the debug console, is also experienced in XCode 9.4.
In my particular instance on the iPad simulator, the message would generate:
1) Only when placing the focus on a particular UITextField.
2) Even with all view contraints removed.
2) Even with all view contraints "Reset to Suggested Contraints".

However, when the software keyboard was toggled on to display, the message would not be generated. Therefore, how much time should I spend on this issue, that in my instance is only generated when the software keyboard is toggled off.

Answer 3

Let's look at these one by one.

"<NSAutoresizingMaskLayoutConstraint:0x84543d0 h=--& v=--& V:[UIView:0xa330270(768)]>"

This is saying view 0xa330270 (A) must be 768 points high.

"<NSLayoutConstraint:0xa338350 V:[UIView:0xa331260]-(-1)-| (Names: '|':UIView:0xa330270 )>"

This is saying view 0xa331260 (B)'s bottom edge must be a gap of -1 from the bottom of A, which is it's superview.

"<NSLayoutConstraint:0xa338390 V:|-(841)-[UIView:0xa331260] (Names: '|':UIView:0xa330270 )>"

This is saying that B's top edge must be a gap of 841 points from the top of its superview, A.

These three things can't all be true - A can't be 768 points high, and contain a subview with a top edge 841 points inset from the top and -1 points inset from the bottom. Where have you defined each of these constraints?

You haven't said what layout you are trying to achieve, but it looks like you might have an autoresizing mask on the superview that is preventing it changing in height when you rotate the device. As far as I know the autoresizing constraints only appear if you have added views programmatically, since a storyboard or xib is either all-autolayout, or not. Unless you are doing something like adding an auto laid out view (loaded from a nib?) to another view from a non-autolayout nib?

Answer 4

One note. You get this error in logs if you are testing using a personal hotspot connection, and the hotspot status bar is at the top. It throws off the constraints.

Hope this helps someone.. was driving me nuts.

Answer 5

For me this error was spitted when I gave tableView.estimatedRowHeight = UITableViewAutomaticDimension

This should have been tableView.estimatedRowHeight = "Some hardcoded value"

Answer 6

Its worth knowing the basics, and understand what Apple/Xcode is trying to tell you through the logs

H = Horizontal constraint(for leading and Trailing)
V = Vertical constraint(top and bottom edge)
h = height
w = width

TopEdge    -> V:|-(points)-[VIEW:memoryAddress] 
BottomEdge -> V:[VIEW:memoryAddress]-(points)-|
Leading    -> H:|-(points)-[VIEW:memoryAddress] 
Trailing   -> H:[VIEW:memoryAddress] -(points)-|
height     -> h= --& v=--& V:[VIEW:memoryAddress((points)] 
width      -> VIEW:memoryAddress.width == points 
between    -> H:[VIEW 1]-(51)-[VIEW 2] 

Once you understand this, reading your specific error is pretty easy