MKAnnotation - 地图图钉标注弹出在其他地图图钉后面

Question

My map pins can be quite densely populated so that when a pin is selected the callout pops up but is mostly obscured by all the other map pins - I can bring the Map Pin to the front it there were a delegate for selected map大头针（未点击标注，已选择大头针）。

对解决方法有什么建议吗？

Answer 1

如果您使用自定义注释视图，您可以为选定的属性添加一个观察者，该观察者在选择引脚时充当代理。

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation{
    MKAnnotation *annview = ...code to either dequeue or create new object...
    [annview addObserver:self forKeyPath:@"selected" options:NSKeyValueObservingOptionNew context:@"selectedmapannotation"];               
    return annview;
}

那么你就可以用

来监控选中的状态了

- (void)observeValueForKeyPath:(NSString *)keyPath
                  ofObject:(id)object
                    change:(NSDictionary *)change
                   context:(void *)context;

Mugunth Kumar 链接的答案也将为您提供所需的结果，只是您在问题中提到了类似委托的功能。

编辑：

这里是observeValueForKeyPath:ofObject:change:context:方法的内容示例

NSString *action = (NSString*)context;

if([action isEqualToString:@"selectedmapannotation"]){
    BOOL annotationAppeared = [[change valueForKey:@"new"] boolValue];
    MKAnnotationView *ann = (MKAnnotationView *)object;

    if (annotationAppeared) {
        // do something with the annotation when it is selected
    }
    else {
        // do something with the annotation when it is de-selected
    }
}

Answer 2

UICallout 视图是 MKAnnotationView 的子视图。所以，我想如果你把 Map ping 放在前面，UICalloutView 也会在那里。