无法设置maprect以显示所有注释

我有2个注释要显示在mapview上,但无法设置maprect以在屏幕上显示所有这些注释而无需用户缩小.

我试过showAnnotations但没有运气.任何人都可以在Swift和Xcode 6.1.1中做到这一点？

这是我的代码:

class ViewController: UIViewController, MKMapViewDelegate {


    @IBOutlet var map: MKMapView!

    override func viewDidLoad() {
        super.viewDidLoad()

        var mapView = map
        // 1
        let point1 = CLLocationCoordinate2D(latitude: 38.915565, longitude: -77.093524)
        let point2 = CLLocationCoordinate2D(latitude: 38.890693, longitude: -76.933318)

        //2
        let annotation = MKPointAnnotation()
        annotation.setCoordinate(point1)
        annotation.title = "point1"
        map.addAnnotation(annotation)

        let annotation2 = MKPointAnnotation()
        annotation2.setCoordinate(point2)
        annotation2.title = "point2"
        map.addAnnotation(annotation2)

        //3
        // option1: set maprect to cover all annotations, doesn't work
        var points = [annotation, annotation2]
        var rect = MKMapRectNull
        for p in points {
            let k = MKMapPointForCoordinate(p.coordinate)
            rect = MKMapRectUnion(rect, MKMapRectMake(k.x, k.y, 0.1, 0.1))
            println("result: x = \(rect.origin.x) y = \(rect.origin.y)")
        }

        map.setVisibleMapRect(rect, animated: true)

        // option 2: using showAnnotations, doesn't work
        //map.showAnnotations(points, animated: true)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


     }

这就是我目前所得到的:

这是我期望看到的:

谢谢你的帮助.

我终于找到了为什么注释的引脚没有显示在屏幕的可见区域中.我认为MapKit框架的行为与以前的版本略有不同.由于我使用autolayout允许地图扩展到所有设备(iPhone,iPad)的整个屏幕,因此应在mapViewDidFinishLoadingMap中调用setVisibleMapRect或mapView.showAnnotations,而不是在视图控制器的viewDidLoad中调用

例如:

 func mapViewDidFinishLoadingMap(_ mapView: MKMapView) {
     // this is where visible maprect should be set
     mapView.showAnnotations(mapView.annotations, animated: true)  
 }