如何在Swift中更改MKMapView的大小？

Question

I can't seem to change the size of my MKMapView in Swift. How would one go on about it?

I've tried two different methods but without any luck:

var rect: CGRect = self.view.frame;
rect.origin.y = 0;
self.mapView.frame = rect;

and one where I used constraints and autolayout but it made the app crash. Any ideas?

EDIT:

When I write this code it doesn't crash but writes some warnings in the output:

    let height = UIScreen.mainScreen().bounds.height
    let width = UIScreen.mainScreen().bounds.width

    let widthConstraint = NSLayoutConstraint(item: mapView, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: width)
    self.view.addConstraint(widthConstraint)

    let heightConstraint = NSLayoutConstraint(item: mapView, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: height)
    self.view.addConstraint(heightConstraint)

The output says:

2016-03-09 18:43:02.697 Map[19782:3177712] 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. ( "", "" )

Will attempt to recover by breaking constraint

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger. The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in may also be helpful. Message from debugger: Terminated due to signal 15

I don't really understand this, any ideas?

Answer 1

In this case you should use

self.mapView.addConstraint(widthConstraint)

and

self.mapView.addConstraint(heightConstraint)

You are trying to add a constraint that belongs to the mapView to its superview, that's not the way it's supposed to be. If you were adding a vertical distance between the mapview and another view you would add it to the superview, but not in this case.

Answer 2

For the constraint warning you try to add constraint without disabling the autorisizing mask into constraint translation.

Try adding this line:

mapView.translatesAutoresizingMaskIntoConstraints = false

Regards