我在理解如何向MKMapView添加多个叠加层时遇到一些麻烦.
我有跟踪的阵列路线.跟踪的路由是CLLocations数组.所以我有一个数组数组.
我可以采取一条路线并在地图视图上绘制它.但是,我需要将所有路径绘制到地图视图中.
以下是我如何为1条路线创建MKPolyline:
-(void) loadRoute { //So we grab an array that holds all the locations of one route. NSArray *locations = [[NSArray alloc] initWithArray:[routesArray objectAtIndex:0]]; // while we create the route points,we will also be calculating the bounding Box of our route // so we can easily zoom in on it. MKMapPoint northEastPoint; MKMapPoint southWestPoint; // create a c array of points. MKMapPoint* pointArr = malloc(sizeof(CLLocationCoordinate2D) *[locations count]); for(int idx = 0; idx < [locations count]; idx++) { CLLocation *tempLoc = (CLLocation*)[locations objectAtIndex:idx]; CLLocationDegrees latitude = tempLoc.coordinate.latitude; CLLocationDegrees longitude = tempLoc.coordinate.longitude; // create our coordinate and add it to the correct spot in the array CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake(latitude,longitude); MKMapPoint point = MKMapPointForCoordinate(coordinate); // if it is the first point,just use them,since we have nothing to compare to yet. if (idx == 0) { northEastPoint = point; southWestPoint = point; } else { if (point.x > northEastPoint.x) northEastPoint.x = point.x; if(point.y > northEastPoint.y) northEastPoint.y = point.y; if (point.x < southWestPoint.x) southWestPoint.x = point.x; if (point.y < southWestPoint.y) southWestPoint.y = point.y; } pointArr[idx] = point; } self.routeLine = [MKPolyline polylineWithPoints:pointArr count:[locations count]]; //Zoom in to fit route on screen _routeRect = MKMapRectMake(southWestPoint.x,southWestPoint.y,northEastPoint.x - southWestPoint.x,northEastPoint.y - southWestPoint.y); // clear the memory allocated earlier for the points free(pointArr); }
这是返回叠加层的MapKit委托调用:
#pragma mark MKMapViewDelegate - (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay { MKOverlayView* overlayView = nil; if(overlay == self.routeLine) { //if we have not yet created an overlay view for this overlay,create it now. if(nil == self.routeLineView) { self.routeLineView = [[MKPolylineView alloc] initWithPolyline:self.routeLine]; self.routeLineView.fillColor = [UIColor redColor]; self.routeLineView.strokeColor = [UIColor redColor]; self.routeLineView.lineWidth = 3; } overlayView = self.routeLineView; } return overlayView; }
所以上面给出的所有代码都可以.我无法弄清楚如何加载更多叠加来显示其他路线.
我认为可能在loadRoute方法中,运行所有路由并为每个路由创建MKOverlayView.将所有MKOverlayView存储在一个数组中然后执行:
[self.mapView addOverlays:array];
但它不起作用.问题是在委托方法中我不知何故需要知道返回哪个叠加层.
所以,如果我可以做的事情:
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay { int tag = overlay.tag; return (MKOverlayView*)[arrayOfViews objectAtIndex:tag]; }
它会工作正常.但不幸的是它不像那样:(
任何帮助将非常感谢!
编辑:
我在ViewDidLoad中使用它来添加叠加层:
[self loadRoute]; // add the overlay to the map if (nil != self.routeLine) { [self.mapView addOverlay:self.routeLine]; } // zoom in on the route. [self zoomInOnRoute];
这是在标题中:
// the data representing the route points. MKPolyline* _routeLine; // the view we create for the line on the map MKPolylineView* _routeLineView; // the rect that bounds the loaded points MKMapRect _routeRect;
解决方法
routeLine和routeLineView变量一次只能指向一个叠加层和叠加层视图,因此理论上你需要一个这样的变量数组.
我建议删除routeLine和routeLineView变量.
然后,您只需在本地创建一个覆盖对象,并在viewForOverlay中返回所请求的覆盖参数的视图.
在loadRoute方法中,您可以循环遍历routesArray,并为每个路由创建一个本地覆盖对象,并在其上调用addOverlay.
还有一种更简单的方法来构造一个界定所有路径的地图矩形,以便您可以设置地图的区域以显示所有路线.
例:
-(void) loadRoute { _routeRect = MKMapRectNull; for (int raIndex = 0; raIndex < routesArray.count; raIndex++) { //So we grab an array that holds all the locations of one route. NSArray *locations = [[NSArray alloc] initWithArray: [routesArray objectAtIndex:raIndex]]; //note we are getting object at raIndex (not 0) above //...no change to existing code here... //self.routeLine = [MKPolyline polylineWithPoints:pointArr count:[locations count]]; //replace above line with this... MKPolyline *pl = [MKPolyline polylineWithPoints:pointArr count:[locations count]]; [mapView addOverlay:pl]; //Zoom in to fit route on screen //_routeRect = MKMapRectMake(southWestPoint.x,northEastPoint.y - southWestPoint.y); //replace above line with this to create a rect around ALL routes... if (MKMapRectIsNull(_routeRect)) _routeRect = pl.boundingMapRect; else _routeRect = MKMapRectUnion(_routeRect,pl.boundingMapRect); // clear the memory allocated earlier for the points free(pointArr); } }
在viewDidLoad中,只需调用loadRoute,不要调用addOverlay.
viewForOverlay方法变得更加简单:
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay { MKPolylineView *pv = [[MKPolylineView alloc] initWithPolyline:overlay]; pv.fillColor = [UIColor redColor]; pv.strokeColor = [UIColor redColor]; pv.lineWidth = 3; return pv; }
顺便说一句,在loadRoute中,这一行:
MKMapPoint* pointArr = malloc(sizeof(CLLocationCoordinate2D) *[locations count]);
应该:
MKMapPoint* pointArr = malloc(sizeof(MKMapPoint) *[locations count]);
它应该使用MKMapPoint的大小(而不是CLLocationCoordinate2D).它们不是一回事(即使结构碰巧是相同的字节大小).