如何在MKMapView中设置PlaceMark位置? [英] How to set the PlaceMark position in MKMapView?

问题描述

MKMapView将图钉显示在mapView的中心，我想将图钉位置定位在中心上方.我该怎么办?

MKMapView show the pin on the center of the mapView, I want to position the pin location above the center. How do I do that?

这是我的代码

- (void) location
{
    MKCoordinateRegion region;  
    MKCoordinateSpan span;  
    span.latitudeDelta = 0.1162;  
    span.longitudeDelta = 0.1160;  

    CLLocationCoordinate2D location;  
    location.latitude = 65.494806;  
    location.longitude = -23.577569;  
    region.span=span;  
    region.center=location;  

    PlaceMark *add_Annotation = [[[PlaceMark alloc] initWithCoordinate:location] autorelease];
    [add_Annotation setTitle:@"myTitle"];  
    [add_Annotation setSubTitle:@"myAddress"];  
    [mapView addAnnotation:add_Annotation]; 

    [mapView setRegion:region animated:TRUE];  
    [mapView regionThatFits:region];  
}

推荐答案

如果您希望将图钉保持在这些坐标上，但将地图的中心置于比图钉低的位置，以使图钉位于中心上方一点，则偏移region>的纬度跨度的一部分.

If you want to keep the pin at those coordinates but center the map lower than the pin so that the pin is a little above the center, offset the center of the region by a fraction of the latitude span.

代替此:

region.center=location;

执行以下操作:

region.center = CLLocationCoordinate2DMake(
                    location.latitude - (span.latitudeDelta/5.0), 
                    location.longitude);

增大/减小除数以减小/增大偏移量.

Increase/decrease the divisor to reduce/increase the offset.

另外，不需要行[mapView regionThatFits:region];-您可以将其删除.
首先，setRegion已经完成了regionThatFits本身，其次，regionThatFits 返回了一个值，但是代码没有处理任何返回值.

Also, the line [mapView regionThatFits:region]; is not needed--you can remove it.
First, setRegion already does regionThatFits itself and second, regionThatFits returns a value but the code is not handling any return value.

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