如何将MKCircleView在一个位置移动到MKMapView中的另一个位置？

Question

我使用MkCircle声明位置现在我必须将MK位置中的圆圈位置改为另一个位置（拖动&拖放）。我怎么能做到这一点。任何帮助将不胜感激。

Answer 1

首先，我建议你有一些类属性来跟踪覆盖的：

@property (nonatomic, weak) MKCircle *overlay; 

然后，定义一个UIPanGestureRecognizer执行拖放：

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)]; 
[self.mapView addGestureRecognizer:pan]; 

要使该姿势可取消，则应导入以下标题：

#import <UIKit/UIGestureRecognizerSubclass.h> 

而你编辑撰写对这一手势识别，增加了你拖到那里覆盖并删除旧的处理程序（但取消手势，如果它没有启动过覆盖）：

- (void)handlePan:(UIPanGestureRecognizer *)gesture 
{ 
    static CGPoint originalPoint; 

    if (gesture.state == UIGestureRecognizerStateBegan) { 
     CGPoint point = [gesture locationInView:gesture.view]; 
     CLLocationCoordinate2D tapCoordinate = [self.mapView convertPoint:point toCoordinateFromView:gesture.view]; 
     CLLocation *tapLocation = [[CLLocation alloc] initWithLatitude:tapCoordinate.latitude longitude:tapCoordinate.longitude]; 

     CLLocationCoordinate2D originalCoordinate = [self.overlay coordinate]; 
     CLLocation *originalLocation = [[CLLocation alloc] initWithLatitude:originalCoordinate.latitude longitude:originalCoordinate.longitude]; 

     if ([tapLocation distanceFromLocation:originalLocation] > [self.overlay radius]) { 
      gesture.state = UIGestureRecognizerStateCancelled; 
      return; 
     } 
     else 
      originalPoint = [self.mapView convertCoordinate:originalCoordinate toPointToView:gesture.view]; 
    } 

    if (gesture.state == UIGestureRecognizerStateChanged) { 
     CGPoint translation = [gesture translationInView:gesture.view]; 
     CGPoint newPoint = CGPointMake(originalPoint.x + translation.x, originalPoint.y + translation.y); 

     CLLocationCoordinate2D newCoordinate = [self.mapView convertPoint:newPoint toCoordinateFromView:gesture.view]; 

     MKCircle *circle = [MKCircle circleWithCenterCoordinate:newCoordinate radius:[self.overlay radius]]; 
     [self.mapView addOverlay:circle]; 
     [self.mapView removeOverlay:self.overlay]; 
     self.overlay = circle; 
    } 
} 

注意，地图的scrollEnabled必须关闭此手势才能被识别。