iOS刷新mapview上的注释 [英] iOS refresh annotations on mapview

问题描述

我有一个mapview，其中注释的坐标不断更新，但是当我使用setCoordinate时，注释不会移动。如何刷新注释以反映其坐标？

I have a mapview where the annotation's coordinates are constantly being updated but when I use setCoordinate, the annotation does not move. How do I refresh the annotations to reflect their coordinates?

- (void)updateUnits {

    PFQuery *query = [PFQuery queryWithClassName:@"devices"];
    [query whereKeyExists:@"location"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {

        if (!error) {

            for (PFObject *row in objects) {

                PFGeoPoint *geoPoint = [row objectForKey:@"location"];
                CLLocationCoordinate2D coord = { geoPoint.latitude, geoPoint.longitude };

                for (id<MKAnnotation> ann in mapView.annotations) {

                    if ([ann.title isEqualToString:[row objectForKey:@"deviceid"]]) {

                        [ann setCoordinate:coord];

                        NSLog(@"latitude is: %f" , coord.latitude);
                        NSLog(@"Is called");
                        break;
                    }
                    else {

                        //[self.mapView removeAnnotation:ann];
                    }
                }
            }
        }
        else {

        }
    }];
}

推荐答案

更新（以反映解决方案） ）：

Updated (to reflect the solution):

拥有自己的自定义注释并实现setCoordinate和/或合成坐标可能会导致问题。

Having your own custom annotations and implementing setCoordinate and/or synthesizing coordinate may cause issues.

来源： http://developer.apple.com/library/ios/ #documentation / UserExperience / Conceptual / LocationAwarenessPG / AnnotatingMaps / AnnotatingMaps.html

上一个解决方案：

您只需删除所有注释，然后重新添加它们。

You can simply remove all of the annotations and then re-add them.

[mapView removeAnnotations:[mapView.annotations]];

[mapView addAnnotations:(NSArray *)];

或删除它们并逐个重新添加：

or remove them and re-add them one by one:

for (id<MKAnnotation> annotation in mapView.annotations)
{
    [mapView removeAnnotation:annotation];
    // change coordinates etc
    [mapView addAnnotation:annotation]; 
}

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