访问 alertView 的调用视图 [英] access an alertView's calling view

问题描述

我有一个 UIAlertView，当用户想要删除 RegionAnnotation 时，它会显示为确认.

I have a UIAlertView which appears as a confirmation when a user wants to delete a RegionAnnotation.

我在弄清楚如何访问调用 UIAlertView 的 RegionAnnotationView 时遇到了问题，我需要它来删除 RegionAnnotation.

I'm having trouble figuring out how to access the RegionAnnotationView that called the UIAlertView which I need in order to delete the RegionAnnotation.

这是我损坏的代码 - 您可以看到我试图将 AlertView 的超级视图转换为 RegionAnnotationView 的位置(这是一个公认的坏主意).

Here's my broken code - you can see where I'm trying to cast the AlertView's superview into a RegionAnnotationView (an admittedly bad idea).

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if(buttonIndex==0)
    {
        NSLog(@"alertView.superview is a %@",alertView.superview);
        RegionAnnotationView *regionView = (RegionAnnotationView *)alertView.superview;
        RegionAnnotation *regionAnnotation = (RegionAnnotation *)regionView.annotation;

        [self.locationManager stopMonitoringForRegion:regionAnnotation.region];
        [regionView removeRadiusOverlay];
        [self.mapView removeAnnotation:regionAnnotation];    
    }

}

推荐答案

由于注解在用户删除之前被选中，因此您可以从地图视图的 selectedAnnotations 属性中获取对该注解的引用.

Since the annotation is selected before the user can delete it, you can get a reference to the annotation from the map view's selectedAnnotations property.

在警报视图委托方法中，您可以执行以下操作:

In the alert view delegate method, you can do something like this:

if (mapView.selectedAnnotations.count == 0)
{
    //shouldn't happen but just in case
}
else
{
    //since only one annotation can be selected at a time,
    //the one selected is at index 0...
    RegionAnnotation *regionAnnotation 
       = [mapView.selectedAnnotations objectAtIndex:0];

    //do something with the annotation...
}

如果注释未被选中，另一种简单的替代方法是使用 ivar 来保存对需要删除的注释的引用.

If the annotation wasn't selected, another simple alternative is to use an ivar to hold a reference to the annotation that needs to be deleted.

MSK 评论的另一个选项是使用 objc_setAssociatedObject.

Another option as MSK commented is to use objc_setAssociatedObject.

无论如何，假设视图层次结构以某种方式使用超级视图并不是一个好主意.

Regardless, using the superview assuming the view hierarchy is in a certain way is not a good idea.

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