在iOS7中检测MKOverlay上的触摸(MKOverlayRenderer)

Question

我有一个可能有数百个多边形的MKMapView.iOS7上假设使用MKPolygon和MKPolygonRenderer.

我需要的是一种对用户触摸其中一个多边形的方式.它们代表地图上具有一定人口密度的区域.在iOS6上,MKOverlay被绘制为MKOverlayViews,因此触摸检测更直接.现在使用渲染器我真的不明白这是怎么做的.

我不确定这会有所帮助甚至是相关的,但作为参考,我会发布一些代码:

这会使用mapData将所有MKOverlay添加到MKMapView.

-(void)drawPolygons{
    self.polygonsInfo = [NSMutableDictionary dictionary];
    NSArray *polygons = [self.mapData valueForKeyPath:@"polygons"];

    for(NSDictionary *polygonInfo in polygons){
        NSArray *polygonPoints = [polygonInfo objectForKey:@"boundary"];
        int numberOfPoints = [polygonPoints count];

        CLLocationCoordinate2D *coordinates = malloc(numberOfPoints * sizeof(CLLocationCoordinate2D));
        for (int i = 0; i < numberOfPoints; i++){
            NSDictionary *pointInfo = [polygonPoints objectAtIndex:i];

            CLLocationCoordinate2D point;
            point.latitude = [[pointInfo objectForKey:@"lat"] floatValue];
            point.longitude = [[pointInfo objectForKey:@"long"] floatValue];

            coordinates[i] = point;
        }

        MKPolygon *polygon = [MKPolygon polygonWithCoordinates:coordinates count:numberOfPoints];
        polygon.title = [polygonInfo objectForKey:@"name"];
        free(coordinates);
        [self.mapView addOverlay:polygon];
        [self.polygonsInfo setObject:polygonInfo forKey:polygon.title]; // Saving this element information, indexed by title, for later use on mapview delegate method
    }
}

然后有一个委托方法为每个MKOverlay返回一个MKOverlayRenderer:

-(MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay{
    /* ... */

    MKPolygon *polygon = (MKPolygon*) overlay;
    NSDictionary *polygonInfo = [self.polygonsInfo objectForKey:polygon.title]; // Retrieving element info by element title
    NSDictionary *colorInfo = [polygonInfo objectForKey:@"color"];

    MKPolygonRenderer *polygonRenderer = [[MKPolygonRenderer alloc] initWithPolygon:polygon];

    polygonRenderer.fillColor = [UIColor colorWithRed:[[colorInfo objectForKey:@"red"] floatValue]
                                               green:[[colorInfo objectForKey:@"green"] floatValue]
                                                blue:[[colorInfo objectForKey:@"blue"] floatValue]
                                               alpha:[[polygonInfo objectForKey:@"opacity"] floatValue]];

    return polygonRenderer;

    /* ... */
}

Answer 1

我做到了

感谢incanus和Anna!

基本上我将一个TapGestureRecognizer添加到MapView,将点击的点转换为地图坐标,浏览我的叠加层并使用CGPathContainsPoint进行检查.

添加TapGestureRecognizer.我做了添加第二个双击手势的技巧,这样当双击缩放地图时,不会触发单击手势.如果有人知道更好的方式,我很高兴听到!

UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleMapTap:)];
tap.cancelsTouchesInView = NO;
tap.numberOfTapsRequired = 1;

UITapGestureRecognizer *tap2 = [[UITapGestureRecognizer alloc] init];
tap2.cancelsTouchesInView = NO;
tap2.numberOfTapsRequired = 2;

[self.mapView addGestureRecognizer:tap2];
[self.mapView addGestureRecognizer:tap];
[tap requireGestureRecognizerToFail:tap2]; // Ignore single tap if the user actually double taps

然后,在点击处理程序上:

-(void)handleMapTap:(UIGestureRecognizer*)tap{
    CGPoint tapPoint = [tap locationInView:self.mapView];

    CLLocationCoordinate2D tapCoord = [self.mapView convertPoint:tapPoint toCoordinateFromView:self.mapView];
    MKMapPoint mapPoint = MKMapPointForCoordinate(tapCoord);
    CGPoint mapPointAsCGP = CGPointMake(mapPoint.x, mapPoint.y);

    for (id<MKOverlay> overlay in self.mapView.overlays) {
        if([overlay isKindOfClass:[MKPolygon class]]){
            MKPolygon *polygon = (MKPolygon*) overlay;

            CGMutablePathRef mpr = CGPathCreateMutable();

            MKMapPoint *polygonPoints = polygon.points;

            for (int p=0; p < polygon.pointCount; p++){
                MKMapPoint mp = polygonPoints[p];
                if (p == 0)
                    CGPathMoveToPoint(mpr, NULL, mp.x, mp.y);
                else
                    CGPathAddLineToPoint(mpr, NULL, mp.x, mp.y);
            }

            if(CGPathContainsPoint(mpr , NULL, mapPointAsCGP, FALSE)){
                // ... found it!
            }

            CGPathRelease(mpr);
        }
    }
}

我可以要求已经具有"path"属性并使用它的MKPolygonRenderer,但由于某种原因它总是为零.我确实读过有人说我可以在渲染器上调用invalidatePath并且它确实填充了path属性但它似乎错了,因为在任何多边形中都找不到该点.这就是我从点重建路径的原因.这样我甚至不需要渲染器,只需使用MKPolygon对象.

Answer 2

UPDATED(对于Swift 3和4)我不确定为什么人们在mapView已经运行了许多手势识别器时向mapView添加了UIGestureRecognizer.我发现这些方法会抑制mapView的正常功能,特别是点击注释.相反,我建议继承mapView并覆盖touchesEnded方法.然后我们可以使用其他人在这个线程中建议的方法,并使用委托方法告诉ViewController做任何需要做的事情."touches"参数有一组我们可以使用的UITouch对象:

import UIKit
import MapKit

protocol MapViewTouchDelegate: class {
    func polygonsTapped(polygons: [MKPolygon])
}

class MyMapViewSubclass: MapView {

    weak var mapViewTouchDelegate: MapViewTouchDelegate?

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {

       if let touch = touches.first {
           if touch.tapCount == 1 {
               let touchLocation = touch.location(in: self)
               let locationCoordinate = self.convert(touchLocation, toCoordinateFrom: self)
               var polygons: [MKPolygon] = []
               for polygon in self.overlays as! [MKPolygon] {
                   let renderer = MKPolygonRenderer(polygon: polygon)
                   let mapPoint = MKMapPointForCoordinate(locationCoordinate)
                   let viewPoint = renderer.point(for: mapPoint)
                   if renderer.path.contains(viewPoint) {
                       polygons.append(polygon)                        
                   }
                   if polygons.count > 0 {
                       //Do stuff here like use a delegate:
                       self.mapViewTouchDelegate?.polygonsTapped(polygons: polygons)
                   }
               }
           }
       }

    super.touchesEnded(touches, with: event)
}

不要忘记将ViewController设置为mapViewTouchDelegate.我还发现为MKPolygon做一个扩展很方便:

import MapKit

extension MKPolygon {
   func contains(coordinate: CLLocationCoordinate2D) -> Bool {
       let renderer = MKPolygonRenderer(polygon: self)
       let mapPoint = MKMapPointForCoordinate(coordinate)
       let viewPoint = renderer.point(for: mapPoint)
       return renderer.path.contains(viewPoint)
   }
}

然后该功能可以更清洁,扩展可能在其他地方有用.再加上它太快了!

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {

    if let touch = touches.first {
        if touch.tapCount == 1 {
            let touchLocation = touch.location(in: self)
            let locationCoordinate = self.convert(touchLocation, toCoordinateFrom: self)            
            var polygons: [MKPolygon] = []
            for polygon in self.overlays as! [MKPolygon] {
                if polygon.contains(coordinate: locationCoordinate) {
                    polygons.append(polygon)
                }
            }
            if polygons.count > 0 {
            //Do stuff here like use a delegate:
                self.mapViewTouchDelegate?.polygonsTapped(polygons: polygons)
            }
        }
    }

    super.touchesEnded(touches, with: event)
}

Answer 3

我找到了一个类似于@manecosta的解决方案,但它使用现有的Apple API来更轻松地检测交集.

从视图中的点按位置创建MKMapRect.我使用0.000005作为lat/long delta来表示用户的触摸.

    CGPoint tapPoint = [tap locationInView:self.mapView];
    CLLocationCoordinate2D tapCoordinate = [self.mapView convertPoint:tapPoint toCoordinateFromView:self.mapView];
    MKCoordinateRegion tapCoordinateRection = MKCoordinateRegionMake(tapCoordinate, MKCoordinateSpanMake(0.000005, 0.000005));
    MKMapRect touchMapRect = MKMapRectForCoordinateRegion(tapCoordinateRection);

搜索所有MapView叠加层并使用'intersectsMapRect:'函数来确定当前叠加层是否与您在上面创建的MapRect相交.

    for (id<MKOverlay> overlay in self.mapView.overlays) {
        if([overlay isKindOfClass:[MKPolyline class]]){
            MKPolyline *polygon = (MKPolyline*) overlay;
            if([polygon intersectsMapRect:touchMapRect]){
                NSLog(@"found polygon:%@",polygon);
            }
        }
    }