在 iOS 7 地图上显示路线:addOverlay 没有效果 [英] display route on iOS 7 maps: addOverlay has no effect

问题描述

我想在我的地图视图中显示一个点到点的路线，我使用这个代码来创建路线:

i want display a point to point route inside my mapView, i use this code for create the route:

- (IBAction)backToYourCar {
    MKPlacemark *sourcePlacemark = [[MKPlacemark alloc] initWithCoordinate:self.annotationForCar.coordinate addressDictionary:nil];
    NSLog(@"coordiante : locationIniziale %f", sourcePlacemark.coordinate.latitude);
    MKMapItem *carPosition = [[MKMapItem alloc] initWithPlacemark:sourcePlacemark];
    MKMapItem *actualPosition = [MKMapItem mapItemForCurrentLocation];
    NSLog(@"coordiante : source %f, ActualPosition %f", carPosition.placemark.coordinate.latitude ,actualPosition.placemark.coordinate.latitude);
    MKDirectionsRequest *request = [[MKDirectionsRequest alloc] init];
    request.source = actualPosition;
    request.destination = carPosition;
    request.requestsAlternateRoutes = YES;

    MKDirections *directions = [[MKDirections alloc] initWithRequest:request];
    [directions calculateDirectionsWithCompletionHandler:^(MKDirectionsResponse *response, NSError *error) {
        if (error) {
            NSLog(@"Error : %@", error);
        }
        else {
            [self showDirections:response]; //response is provided by the CompletionHandler
        }
    }];
}

这是为了在地图上显示路线:

and this for show the route on the map:

- (void)showDirections:(MKDirectionsResponse *)response
{
    for (MKRoute *route in response.routes) {
        [self.mapView addOverlay:route.polyline level:MKOverlayLevelAboveRoads];
    }
}

实际上这段代码什么都不做.

actually this code does nothing.

如果我尝试打印路线的距离，我会得到正确的值:

if i try to print the the distance of route i get the correct value:

route distance: 1910.000000

那么路线是对的，但我不明白为什么它没有出现在地图上！

then the route is right, but i can't understand why it doesn't appear on the map!

有什么建议吗?

推荐答案

经过一天的研究，我已经通过这 3 个步骤解决了:

after a day of research i have solved with this 3 steps:

1. 设置委托(self.mapView.delegate = self).
2. 导入MKMapViewDelegate
3. 实现新的 iOS7 MapView 委托方法:- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay(id)overlay:

这是我的实现:

- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay
{
    if ([overlay isKindOfClass:[MKPolyline class]]) {
        MKPolyline *route = overlay;
        MKPolylineRenderer *routeRenderer = [[MKPolylineRenderer alloc] initWithPolyline:route];
        routeRenderer.strokeColor = [UIColor blueColor];
        return routeRenderer;
    }
    else return nil;
}

当您在地图上添加折线时，委托会自动调用此方法.

this method is automatically called by the delegate when you add the polyline on the map.

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