如何在viewForOverlay中区分两个MKPolyline： [英] How to distinguish two MKPolyline's in viewForOverlay:

问题描述

我将多个 MKPolylines 作为重叠加载到 MKMapView 。我希望能够区分这些如何改变颜色，线宽等等。

I am loading multiple MKPolylines as overlays onto an MKMapView. I would like to be able to distinguish these some how so change things like color, line width, etc.

但是，当 viewForOverlay：被调用，它看到所有 MKPolylines 相同，这不允许我更改任何一个。

But, when viewForOverlay: gets called, it sees all my MKPolylines the same, which doesn't allow me to change any of them.

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {

    if ([overlay isKindOfClass:[MKPolyline class]]) {
        MKPolylineView *aView = [[[MKPolylineView alloc] initWithPolyline:(MKPolyline*)overlay] autorelease];
        aView.strokeColor = [[UIColor blueColor] colorWithAlphaComponent:0.7];
        MKZoomScale currentZoomScale = (CGFloat)(mapView.bounds.size.width / mapView.visibleMapRect.size.width);
        aView.lineWidth = MKRoadWidthAtZoomScale(currentZoomScale);

        return aView;
    }

    // Want to color my next overlay red

    return  nil;
}

我该怎么做？我可以以某种方式将标签附加到每个 MKPolyline 吗？或者，另一种更好的方法吗？

How can I do this? Could I somehow attach tag to each MKPolyline? Or, another, better way to do this?

推荐答案

MKPolyline 继承来自 MKShape ，其中有一个可设置的标题（以及字幕）您可以用来告诉他们的财产。

MKPolyline inherits from MKShape which has a settable title (and subtitle) property which you can use to tell them apart.

这个答案有一个如何与 MKPolygon 对象一起使用的例子。

This answer has an example of how to use it with MKPolygon objects.

如果 title 和 subtitle 不足以满足您的要求，那么您可以将子类命名为Mundi。

If title and subtitle are not sufficient for your requirements, then you can subclass as Mundi commented.

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