iphone - 从 MKMapView 上的用户交互创建覆盖？

Question

我有两个问题，

如何根据用户的触摸事件在 MKMapkitView 上创建叠加层？即，为了简单起见，用户按下并创建一个 MKCircle 覆盖

Maps 应用程序如何在触地时实现“dropped pin”？任何人都知道或有一些关于如何完成类似事情的代码示例？

任何指针将不胜感激。如您所见，我一直在谷歌搜索和阅读大量文档，但没有取得多大成功。

Answer 1

下面是一个示例，它创建一个圆圈并在用户触摸并按住手指 1 秒钟的位置放置一个图钉。它使用了一个 UILongPressGestureRecognizer，它被添加到 mapView 的任何初始化 map 的位置(例如 viewDidLoad)。

确保也设置了 mapView 的委托(delegate)。

// In viewDidLoad or where map is initialized...
UILongPressGestureRecognizer *lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];
lpgr.minimumPressDuration = 1.0;  //user must hold for 1 second
[mapView addGestureRecognizer:lpgr];
[lpgr release];

...

- (void)handleLongPress:(UIGestureRecognizer *)gestureRecognizer
{
    if (gestureRecognizer.state != UIGestureRecognizerStateBegan)
        return;

    CGPoint touchPoint = [gestureRecognizer locationInView:mapView];    
    CLLocationCoordinate2D touchMapCoordinate = [mapView convertPoint:touchPoint toCoordinateFromView:mapView];

    //add pin where user touched down...
    MKPointAnnotation *pa = [[MKPointAnnotation alloc] init];
    pa.coordinate = touchMapCoordinate;
    pa.title = @"Hello";
    [mapView addAnnotation:pa];
    [pa release];

    //add circle with 5km radius where user touched down...
    MKCircle *circle = [MKCircle circleWithCenterCoordinate:touchMapCoordinate radius:5000];
    [mapView addOverlay:circle];
}

-(MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id)overlay 
{
    MKCircleView* circleView = [[[MKCircleView alloc] initWithOverlay:overlay] autorelease];
    circleView.fillColor = [UIColor redColor];
    return circleView;
}

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
{
    static NSString *AnnotationIdentifier = @"Annotation";
    MKPinAnnotationView* pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:AnnotationIdentifier];
    if (!pinView)
    {
        pinView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:AnnotationIdentifier] autorelease];
        pinView.pinColor = MKPinAnnotationColorGreen;
        pinView.animatesDrop = YES;
    }
    else
    {
        pinView.annotation = annotation;
    }
    return pinView;
}