Constraint warnings only when transitioning views through TabBarController

Question

I keep getting a whole bunch of constraint warnings but they seem to only happen when transitioning view controller through a tab bar controller.

so when i use this code, i get no errors:

let tbc = self.storyboard!.instantiateViewController(withIdentifier: "myViewController") as! myViewController
self.present(tbc, animated: false, completion: nil)

but when i transition with this code, lots of errors:

let tbc = self.storyboard!.instantiateViewController(withIdentifier: "MyTabController") as! UITabBarController
tbc.selectedIndex = 1
tbc.modalTransitionStyle = .coverVertical
self.present(tbc, animated: true, completion: nil)

This is just a simple of the error printed to console:

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
2017-02-16 19:09:28.038332 ParseStarterProject-Swift[42916:640604] [LayoutConstraints] 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:0x60800029e500 h=--& v=--& UIView:0x7fb66b551680.width == 142.8   (active)>",
    "<NSAutoresizingMaskLayoutConstraint:0x60800029e4b0 h=--& v=--& UIView:0x7fb66b551680.height == 140   (active)>",
    "<NSLayoutConstraint:0x60800029be90 UIImageView:0x7fb66b551820.width == UIImageView:0x7fb66b551820.height   (active)>",
    "<NSLayoutConstraint:0x60800029ba80 V:[UIImageView:0x7fb66b551820]-(50)-|   (active, names: '|':UIView:0x7fb66b551680 )>",
    "<NSLayoutConstraint:0x60800029c0c0 V:|-(0)-[UIImageView:0x7fb66b551820]   (active, names: '|':UIView:0x7fb66b551680 )>",
    "<NSLayoutConstraint:0x60800029c110 H:[UIImageView:0x7fb66b551820]-(15)-|   (active, names: '|':UIView:0x7fb66b551680 )>",
    "<NSLayoutConstraint:0x60800029c160 H:|-(15)-[UIImageView:0x7fb66b551820]   (active, names: '|':UIView:0x7fb66b551680 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x60800029be90 UIImageView:0x7fb66b551820.width == UIImageView:0x7fb66b551820.height   (active)>

So the only constraint i can think this may be related to is shown in the image below:

enter image description here

I've tried the symbolic breakpoint

UIViewAlertForUnsatisfiableConstraints

with action

expr -l objc++ -O -- [[UIWindow keyWindow] _autolayoutTrace]

and get the following report but it doesn't identify any constraints or UI elements.

•UIWindow:0x7fb66b405490
|   UITransitionView:0x7fb66b516fa0
|   |   UILayoutContainerView:0x7fb66b514e80
|   |   |   UINavigationTransitionView:0x7fb66b613980
|   |   |   |   UIViewControllerWrapperView:0x7fb66b40e580
|   |   UITransitionView:0x7fb66b449f90
|   UITransitionView:0x7fb66b45bd90
|   |   UILayoutContainerView:0x7fb66d831410
|   |   |   UITransitionView:0x7fb66b605eb0
|   |   |   |   UIViewControllerWrapperView:0x7fb66b5567a0
|   |   |   |   |   •UIView:0x7fb66b4300c0
|   |   |   |   |   |   *UICollectionView:0x7fb66b970400
|   |   |   |   |   |   |   •ParseStarterProject_Swift.PackCollectionViewCell:0x7fb66d836fb0
|   |   |   |   |   |   |   |   +UIView:0x7fb66d8371d0
|   |   |   |   |   |   |   |   |   *PFImageView:0x7fb66d837370
|   |   |   |   |   |   |   |   |   *UILabel:0x7fb66d837560'This is a series of breat...'
|   |   |   |   |   |   |   •ParseStarterProject_Swift.PackCollectionViewCell:0x7fb66b4651f0
|   |   |   |   |   |   |   |   +UIView:0x7fb66b465020
|   |   |   |   |   |   |   |   |   *PFImageView:0x7fb66b465410
|   |   |   |   |   |   |   |   |   *UILabel:0x7fb66b465600'Ever had trouble falling ...'
|   |   |   |   |   |   |   •ParseStarterProject_Swift.PackCollectionViewCell:0x7fb66b560e60
|   |   |   |   |   |   |   |   +UIView:0x7fb66b561080
|   |   |   |   |   |   |   |   |   *PFImageView:0x7fb66b561220
|   |   |   |   |   |   |   |   |   *UILabel:0x7fb66b561410'This is a week long intro...'
|   |   |   |   |   |   |   UIImageView:0x7fb66b4305c0
|   |   |   |   |   |   *_UILayoutGuide:0x7fb66b430260
|   |   |   |   |   |   *_UILayoutGuide:0x7fb66b430410
|   |   |   UITabBar:0x7fb66b54c280
|   |   |   |   _UIBarBackground:0x7fb66d830680
|   |   |   |   |   UIImageView:0x7fb66d830b20
|   |   |   |   |   UIVisualEffectView:0x7fb66d830d00
|   |   |   |   |   |   _UIVisualEffectBackdropView:0x7fb66d8310a0
|   |   |   |   |   |   _UIVisualEffectFilterView:0x7fb66b40ddd0
|   |   |   |   |   |   _UIVisualEffectFilterView:0x7fb66b556940
|   |   |   |   UITabBarButton:0x7fb66d82f890
|   |   |   |   |   UITabBarSwappableImageView:0x7fb66b43c280
|   |   |   |   |   UITabBarButtonLabel:0x7fb66d82fb30'Menu'
|   |   |   |   UITabBarButton:0x7fb66b63e100
|   |   |   |   |   UITabBarButtonLabel:0x7fb66b63e3a0
|   |   |   |   UITabBarButton:0x7fb66d830120
|   |   |   |   |   UITabBarSwappableImageView:0x7fb66d828260
|   |   |   |   |   UITabBarButtonLabel:0x7fb66d8303c0'Path'
|   |   |   UIButton:0x7fb66b63e820
|   |   |   |   UIImageView:0x7fb66b4513c0

Legend:
    * - is laid out with auto layout
    + - is laid out manually, but is represented in the layout engine because translatesAutoresizingMaskIntoConstraints = YES
    • - layout engine host

(lldb)

How can i resolve this or at least how do i specifically find which instances are being reported???? It doesn't seem to effect anything and I've tested it on multiple simulator sizes and devices.

score 0 · Accepted Answer · edited May 23 '17 at 11:45

0

Try to resolve it using DEBUG VIEW HIERARCHY For more detail go through below link - it has the best solution to resolve these type of constraint issue.

Unable to simultaneously satisfy constraints, will attempt to recover by breaking constraint

edited May 23 '17 at 11:45

Community

1
1

answered Feb 16 '17 at 09:40

Prema Janoti

836
5
18

1

Thanks that was a great link. Because i was loading pages through tabbar it loaded all pages associated with the tab bar and not just the index specified. So i used (lldb) expr ((UIView *)0x7f9ea3d43410).backgroundColor = [UIColor redColor] to highlight the view in question then the link you shared and specified ids and traced everything back :) – WanderingScouse Feb 16 '17 at 21:46

score 0 · Answer 2 · answered Feb 16 '17 at 10:10

0

let tbc = self.storyboard!.instantiateViewController(withIdentifier: "MyTabController") as! UITabBarController

It should be your class name not UITabBarController

answered Feb 16 '17 at 10:10

Punit

1,330
6
13

If i don't use UITabBarController then the UITabBarController is not visible. – WanderingScouse Feb 16 '17 at 19:40

Constraint warnings only when transitioning views through TabBarController

2 Answers2