ios - 将 MKMapView 缩放到 MKAnnotationView 的框架

Question

我有一个要放大的分组图钉。当然，我知道引脚的坐标，并且有它的视图。我只想将地图缩放到正确的区域，以便集群完全展开，显示所有引脚（加上一点填充）。这样做的好方法是什么？

旁注：
在我的设置中，当缩放级别增加时，集群引脚将自动扩展为单个引脚，所以我很好。我需要知道的是如何根据集群引脚的框架和坐标将 MapView 设置为新区域。

Answer 1

您可以使用：

mapView.showAnnotations(groupedAnnotations, animated: true)

此方法将自动放大并定位地图，以便所有注释都可见。

Answer 2

首先删除组别针

[mapView removeAnnotation:groupAnnotation];

然后在集群中添加引脚

[mapView addAnnotations:clusterAnnotations];

然后确定要缩放的区域

CLLocationDegrees minLat = 90;
CLLocationDegrees maxLat = -90;
CLLocationDegress minLong = 180;
CLLocationDegrees maxLong = -180
[clusterAnnotations enumerateUsingBlock:^(id<MKAnnotation> annotation, NSUInteger idx, BOOL *stop) {
    CLLocationCoordinate2D coordinate = annotation.coordinate;
    minLat = MIN(minLat, coordinate.latitude);
    maxLat = MAX(maxLat, coordinate.latitude);
    minLong = MIN(minLong, coordinate.longitude);
    maxLong = MAX(maxLong, coordinate.longitude);
}
CLLocationCoordinate2D center = CLLocationCoordinate2DMake((minLat + maxLat)/2.f, (minLong + maxLong)/2.f);
MKCoordinateSpan span = MKCoordinateSpanMake((maxLat - minLat)*1.25, (maxLong - minLong)*1.25); //1.25 is for padding
MKCoordinateRegion region = MKCoordinateRegionMake(center, span);
[mapView setRegion:[mapView regionThatFits:region] animated:YES];

Answer 3

当用户点击集群引脚时，您将收到回调

func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView)

现在您只需要将您的MKAnnotationViewto 转换为MKClusterAnnotation，然后您就可以访问其成员 pin 的集合：

if let clustered = view.annotation as? MKClusterAnnotation {
    clustered.memberAnnotations.forEach { (annotation) in
        // Calculate region boundaries
    }
}

尼克计算的完整解决方案：

if let clustered = view.annotation as? MKClusterAnnotation {
    var minLat = CLLocationDegrees(exactly: 90)!
    var maxLat = CLLocationDegrees(exactly: -90)!
    var minLong = CLLocationDegrees(exactly: 180)!
    var maxLong = CLLocationDegrees(exactly: -180)!
    clustered.memberAnnotations.forEach { (annotation) in
        let coordinate = annotation.coordinate
        minLat = min(minLat, coordinate.latitude)
        maxLat = max(maxLat, coordinate.latitude)
        minLong = min(minLong, coordinate.longitude)
        maxLong = max(maxLong, coordinate.longitude)
    }

    let centerLat = (minLat + maxLat) / 2
    let centerLong = (minLong + maxLong) / 2
    let center = CLLocationCoordinate2D(latitude: centerLat, longitude: centerLong)
    let span = MKCoordinateSpan(latitudeDelta: (maxLat - minLat) * 1.5, longitudeDelta: (maxLong - minLong) * 1.5) // with some padding
    let region = MKCoordinateRegion(center: center, span: span)

    <your MKMapView>.setRegion(region, animated: true)
}