缩放MKMapView以适合注释引脚？ [英] Zooming MKMapView to fit annotation pins?

问题描述

我使用MKMapView并在地图上添加了大量5-10公里的注释针脚。当我运行应用程序时，我的地图开始缩小以显示整个世界，什么是缩放地图的最佳方式，以便引脚适合视图？

I am using MKMapView and have added a number of annotation pins to the map about a 5-10 kilometre area. When I run the application my map starts zoomed out to show the whole world, what is the best way to zoom the map so the pins fit the view?

EDIT：
我的初步想法是使用MKCoordinateRegionMake并从我的注释计算坐标中心，经度和纬度。我确定这将工作，但我只是想检查我没有丢失任何明显的。

My initial thinking would be to use MKCoordinateRegionMake and calculate the coordinate centre, longitudeDelta and latitudeDelta from my annotations. I am pretty sure this will work, but I just wanted to check I was not missing anything obvious.

代码添加，BTW：FGLocation是一个符合 MKAnnotation ，locationFake是这些对象的 NSMutableArray 。

Code added, BTW: FGLocation is an class that conforms to MKAnnotation, locationFake is an NSMutableArray of these objects. Comments are always welcome ....

- (MKCoordinateRegion)regionFromLocations {
    CLLocationCoordinate2D upper = [[locationFake objectAtIndex:0] coordinate];
    CLLocationCoordinate2D lower = [[locationFake objectAtIndex:0] coordinate];

    // FIND LIMITS
    for(FGLocation *eachLocation in locationFake) {
        if([eachLocation coordinate].latitude > upper.latitude) upper.latitude = [eachLocation coordinate].latitude;
        if([eachLocation coordinate].latitude < lower.latitude) lower.latitude = [eachLocation coordinate].latitude;
        if([eachLocation coordinate].longitude > upper.longitude) upper.longitude = [eachLocation coordinate].longitude;
        if([eachLocation coordinate].longitude < lower.longitude) lower.longitude = [eachLocation coordinate].longitude;
    }

    // FIND REGION
    MKCoordinateSpan locationSpan;
    locationSpan.latitudeDelta = upper.latitude - lower.latitude;
    locationSpan.longitudeDelta = upper.longitude - lower.longitude;
    CLLocationCoordinate2D locationCenter;
    locationCenter.latitude = (upper.latitude + lower.latitude) / 2;
    locationCenter.longitude = (upper.longitude + lower.longitude) / 2;

    MKCoordinateRegion region = MKCoordinateRegionMake(locationCenter, locationSpan);
    return region;
}

推荐答案

。查找您的最大和最小纬度和经度，应用一些简单的算术，并使用 MKCoordinateRegionMake 。

You've got it right. Find your maximum and minimum latitudes and longitudes, apply some simple arithmetic, and use MKCoordinateRegionMake.

（参考MKMapView.h）：//定位地图，使得提供的注释数组尽可能全部可见。

For iOS 7 and above (Referring MKMapView.h) : // Position the map such that the provided array of annotations are all visible to the fullest extent possible.

- （void）showAnnotations：（NSArray *）annotations animated：（BOOL）animated NS_AVAILABLE（10_9，7_0）;

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