定位MKMapView以一次显示多个注释 [英] Positioning MKMapView to show multiple annotations at once

问题描述

我有几个注释，我想添加到我的MKMapView（它可以0-n项，其中n通常约为5）。我可以添加注释，但我想调整地图的大小，以适应屏幕上的所有注释，我不知道如何这样做。

I've got several annotations I want to add to my MKMapView (it could 0-n items, where n is generally around 5). I can add the annotations fine, but I want to resize the map to fit all annotations onscreen at once, and I'm not sure how to do this.

我一直在看着 -regionThatFits：但我不知道该怎么办。我会发布一些代码，以显示我到目前为止。我认为这应该是一个通常很简单的任务，但我感觉有点不知所措的MapKit到目前为止。

I've been looking at -regionThatFits: but I'm not quite sure what to do with it. I'll post some code to show what I've got so far. I think this should be a generally straightforward task but I'm feeling a bit overwhelmed with MapKit so far.

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{

location = newLocation.coordinate;
//One location is obtained.. just zoom to that location

MKCoordinateRegion region;
region.center = location;

//Set Zoom level using Span
MKCoordinateSpan span;
span.latitudeDelta = 0.015;
span.longitudeDelta = 0.015;
region.span = span;
// Set the region here... but I want this to be a dynamic size
// Obviously this should be set after I've added my annotations
[mapView setRegion:region animated:YES];

// Test data, using these as annotations for now
NSArray *arr = [NSArray arrayWithObjects:@"one", @"two", @"three", @"four", nil];
float ex = 0.01;
for (NSString *s in arr) {
    JBAnnotation *placemark = [[JBAnnotation alloc] initWithLat:(location.latitude + ex) lon:location.longitude];
    [mapView addAnnotation:placemark];
    ex = ex + 0.005;
}
    // What do I do here?
    [mapView setRegion:[mapView regionThatFits:region] animated:YES];
}

注意，这一切都发生在我收到位置更新...我不知道这是否是一个合适的地方。如果不是，在哪里会是一个更好的地方？ -viewDidLoad ？

Notice, this all happens as I receive a location update... I don't know if that's an appropriate place to do this. If not, where would be a better place? -viewDidLoad?

提前感谢。

推荐答案

从iOS7开始，您可以使用 showAnnotations：animated：

As of iOS7 you can use showAnnotations:animated:

[mapView showAnnotations:annotations animated:YES];

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