MKMapView 的折线不起作用

Question

我一直在努力让这条折线在 Objective C 中发挥作用。我已经完成了我能找到的所有教程，但一无所获，我看不出它有什么问题。

    CLLocationCoordinate2D coordinateArray2[2]; 
coordinateArray2[1].longitude = 176.8773669;
coordinateArray2[0].longitude = 176.88151896;
coordinateArray2[0].latitude = -39.668593;
coordinateArray2[1].latitude = -39.67018069;
_route1Line = [MKPolyline polylineWithCoordinates:coordinateArray2 count:2]; 
[_GPSView setDelegate:self];
[_GPSView addOverlay:_route1Line];
_testlabel.text = [NSString stringWithFormat:@"%f", coordinateArray2[0].longitude];

谁能看出哪里出了问题？

header:

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>


extern int routenumber; //holds current route ID

extern BOOL inRoute; //holds if on route or not

extern int followYou; //holds if the app should follow the user or predefined coordinates

extern NSArray *routeHolder; //holds array of routes

@interface ViewController : UIViewController <MKMapViewDelegate>

@property (weak, nonatomic) IBOutlet MKMapView *GPSView; //adding the map view to the controller

@property (nonatomic, retain) MKPolyline *route1Line; //line for this route

@property (weak, nonatomic) IBOutlet UILabel *testlabel;

@end

Answer 1

我现在不在 Mac，所以我不能运行你的代码，但看起来你已经创建了你的 MKPolyline，但你错过了MKPolylineView.

_polylineView = [MKPolylineView alloc] initWithPolyline:route1Line]; // Declare it in your header file or in the implementation's interface.
_polylineView.strokeColor = [UIColor redColor];
_polylineView.lineWidth = 5.0

然后确保您符合 MKMapViewDelegate 并实施 mapView:viewForOverlay

- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id<MKOverlay>)overlay {
    return _polylineView;
}

Answer 2

您应该实现 MKMapViewDelegate 的以下方法：

- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay
{
    MKOverlayPathRenderer *theOverlayPathRenderer;
    {
        theOverlayPathRenderer = [[MKPolylineRenderer alloc] initWithPolyline:overlay];
        theOverlayPathRenderer.lineWidth = ...;
        theOverlayPathRenderer.fillColor = ...;
        theOverlayPathRenderer.strokeColor = ...;
    }
    return theOverlayPathRenderer;
}

MKMapView 的折线不起作用

Polyline for MKMapView not working

objective-c

mkmapview

mkpolyline