Question

In my viewDidLoad method, I have code to create a MKMapView, some constraints, and a UIToolbar:

I have a MKMapView:

MKMapView *mapView = [[MKMapView alloc] init];
[mapView setTranslatesAutoresizingMaskIntoConstraints:NO];
mapView.userInteractionEnabled = TRUE;
mapView.showsUserLocation = TRUE;
mapView.mapType = MKMapTypeHybrid;
mapView.delegate = self;

[mapView setUserTrackingMode:MKUserTrackingModeFollow animated:YES];

[self.view addSubview:mapView];

I create 2 constraints to make it full screen:

NSMutableArray *constraints = [NSMutableArray array];

[constraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[mapView]|"
                                                                         options:0
                                                                         metrics:nil
                                                                           views:NSDictionaryOfVariableBindings(mapView)]];

[constraints addObjectsFromArray:[NSLayoutConstraint constraintsWithVisualFormat:@"|[mapView]|"
                                                                         options:0
                                                                         metrics:nil
                                                                           views:NSDictionaryOfVariableBindings(mapView)]];

[self.view addConstraints:constraints];

Works great. But when I try to add anything to the map view:

 UIToolbar *topBar = [[UIToolbar alloc ]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 44)];
[topBar setTranslatesAutoresizingMaskIntoConstraints:NO];
topBar.barStyle = UIBarStyleBlackTranslucent;

[mapView addSubview:topBar];

it throws an error:

*** Assertion failure in -[MKMapView layoutSublayersOfLayer:], /SourceCache/UIKit_Sim/UIKit-2372/UIView.m:5776
2013-01-10 10:24:17.503 Landscout 2[2001:14003] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Auto Layout still required after executing -layoutSubviews. MKMapView's implementation of -layoutSubviews needs to call super.'

From my understanding, since I am adding a new view to the map view, the map view needs to re-calculate all the constraints in it? Basically a drawRect method for constraints.

How can I fix this?

Answer 1

I solved the issue by simply using a content view to stuff everything into. Instead of adding the tool bar to myMapView, i add it to myContentView.

I’m pretty sure MKMapView isn’t set up to use constraints yet. MapView won’t call [super layoutSubviews] which would eventually lead to [UIView layoutSubviews].

Another possible solution i’d imagine is to add a category to MKMapView that would override -layoutSubview to call [super layoutSubview], but i don’t know how to find out what else is in the [MKMapView layoutSubview] that i would need to add.