ios - NSArray 元素无法匹配 mapView.annotations 循环中的 Swift 数组元素类型

Question

我想在 mapView 中缩放 PinImages(当它缩小或放大时)，为此我这样做:

func resizePin(scale: CGFloat, image: UIImage) -> UIImage {

    var newSize = CGSizeMake(image.size.width * scale, image.size.height * scale)
    UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0)
    image.drawInRect(CGRectMake(0, 0, newSize.width, newSize.height))
    var newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return newImage
}

在委托(delegate)方法中我找到比例并想在 mapView 注释循环中使用 resizePin 方法来调整它们的大小

func mapView(mapView: MKMapView!, regionWillChangeAnimated animated: Bool) {
    oldZoomLatitude = mapView.region.span.latitudeDelta
    oldZoomLongitude = mapView.region.span.longitudeDelta

}

func mapView(mapView: MKMapView!, regionDidChangeAnimated animated: Bool) {
    newZoomLatitude = mapView.region.span.latitudeDelta
    newZoomLongitude = mapView.region.span.longitudeDelta

    mapScale = (newZoomLongitude! / oldZoomLongitude!)
    println(mapScale)

    for annotation in mapView.annotations as [MKAnnotationView]  { // EXCEPTION - fatal error: NSArray element failed to match the Swift Array Element type
    }
}

不知道如何正确处理，以及异常的原因是什么。有什么想法吗？

Answer 1

mapView.annotations 属性是 MKAnnotation 类型。如果您想修改每个注释的 View ，请尝试以下代码:

for annotation in mapView.annotations {
    let view = mapView.viewForAnnotation(annotation)
    // modify the view.
}