在iOS中围绕图钉添加多个圆圈 [英] adding multiple circles around a pin in iOS

问题描述

如何在地图(MKMapView)中添加并显示不同颜色的多个圆?我想出了如何添加一个圆圈，但无法弄清楚如何添加各种大小和颜色的多个圆圈...任何帮助将不胜感激！

How can I add and display multiple circles in different colors inside a map (MKMapView)? I figured out how to add one circle, but can't figure out how to add multiple circles in various sizes and colors ... any help would be appreciated!

推荐答案

以下是一些我用来在地图上给定位置绘制两个同心圆的代码.外层是灰色，内层是白色. (在我的示例中，范围"是圆半径)两者都具有一定的透明度:

Here's some code I use to draw two concentric circles at a given location on the map. The outer one is gray, and the inner one is white. (in my example "range" is the circle radius) Both have some transparency:

- (void)drawRangeRings: (CLLocationCoordinate2D) where {
    // first, I clear out any previous overlays:
    [mapView removeOverlays: [mapView overlays]];
    float range = [self.rangeCalc currentRange] / MILES_PER_METER;
    MKCircle* outerCircle = [MKCircle circleWithCenterCoordinate: where radius: range];
    outerCircle.title = @"Stretch Range";
    MKCircle* innerCircle = [MKCircle circleWithCenterCoordinate: where radius: (range / 1.425f)];
    innerCircle.title = @"Safe Range";

    [mapView addOverlay: outerCircle];
    [mapView addOverlay: innerCircle];
}

然后，确保您的类实现了MKMapViewDelegate协议，并通过以下方法定义叠加层的外观:

Then, make sure your class implements the MKMapViewDelegate protocol, and define how your overlays look in the following method:

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {
    MKCircle* circle = overlay;
    MKCircleView* circleView = [[MKCircleView alloc] initWithCircle: circle];
    if ([circle.title compare: @"Safe Range"] == NSOrderedSame) {
        circleView.fillColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.25];
        circleView.strokeColor = [UIColor whiteColor];
    } else {
        circleView.fillColor = [UIColor colorWithRed:0.5 green:0.5 blue:0.5 alpha:0.25];
        circleView.strokeColor = [UIColor grayColor];
    }
    circleView.lineWidth = 2.0;

    return circleView;
}

当然，不要忘记在您的MKMapView对象上设置委托，否则上述方法将永远不会被调用:

And, of course, don't forget to set the delegate on your MKMapView object, or the above method will never get called:

mapView.delegate = self;

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