未绘制 Mkpolyline
Mkpolyline is not being drawn
明明在做路线,却没有画折线。我能够找到总距离,并已验证我们使用的坐标不是 (0,0)。委托有问题吗,因为 addOverlay 和 addAnnotation(在下面显示的名为 createAndAddAnnotationForCoordinate 的自定义方法中调用)方法似乎都不起作用?
-(void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
//generates map view
mapView = [[MKMapView alloc]initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width,
self.view.bounds.size.height)];
//setting delegate to self is not fixing the error
mapView.delegate = self;
mapView.mapType = MKMapTypeStandard;
//converting CLLocationCoordinate2D to MKPlacemark
MKPlacemark *startPlacemark = [[MKPlacemark alloc]
initWithCoordinate: addressOneCoords addressDictionary:
[NSDictionary dictionaryWithObjectsAndKeys:nil]];
MKPlacemark *endPlacemark = [[MKPlacemark alloc]initWithCoordinate: addressTwoCoords addressDictionary:[NSDictionary dictionaryWithObjectsAndKeys:nil]];
//converting MKPlacemark to MKMapItem
MKMapItem *start = [[MKMapItem alloc ]initWithPlacemark:startPlacemark];
MKMapItem *end = [[MKMapItem alloc]initWithPlacemark:endPlacemark];
MKDirectionsRequest *request = [MKDirectionsRequest new];
[request setSource:start];
[request setDestination:end];
[request setTransportType:MKDirectionsTransportTypeAutomobile];
request.requestsAlternateRoutes = YES;
//Just to check if the coordinates were transferred successfully between view controllers and they did transfer successfully
NSLog(@"address one lat is %f",addressOneCoords.latitude);
NSLog(@"address one lon is %f",addressOneCoords.longitude);
NSLog(@"address two lat is %f",addressTwoCoords.latitude);
NSLog(@"address two lon is %f",addressTwoCoords.longitude);
MKDirections *directions = [[MKDirections alloc]initWithRequest:request];
[directions calculateDirectionsWithCompletionHandler:^(MKDirectionsResponse response, NSError error){
//if the route can't be created
if(error){
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Unable to create route" message:@"Go back to check if addresses are valid" delegate:nil cancelButtonTitle:@"Ok"otherButtonTitles:nil];
[alert show];
}
else{
[mapView removeOverlays:self.mapView.overlays];
MKRoute *mainRoute = [response.routes firstObject];
routeLine = mainRoute.polyline;
if(routeLine){
[self.mapView removeOverlay:routeLine];
}
//the addOverlay method is not drawing the polyline
[self.mapView addOverlay: routeLine level:MKOverlayLevelAboveRoads];
//proof that route is being created successfully
NSLog(@"Total distance is %f", mainRoute.distance);
MKMapPoint middlePoint = mainRoute.polyline.points[mainRoute.polyline.pointCount/2];
//also, the addannotation method is not being called either it seems like
[self createAndAddAnnotationForCoordinate:MKCoordinateForMapPoint(middlePoint)];
}
}];
}
我们的 createAndAddAnnotationForCoordinate 方法,
-(void) createAndAddAnnotationForCoordinate : (CLLocationCoordinate2D)coordinate{
MKPointAnnotation* annotation = [[MKPointAnnotation alloc]init];
annotation.coordinate = coordinate;
annotation.title = @"Point";
annotation.subtitle = @"subtitle";
[mapView addAnnotation:annotation];
}
我们重写的 mapviewdelegate 方法,
-(MKOverlayRenderer )mapView:(MKMapView )mapView rendererForOverlay:(id<MKOverlay>)overlay{
if([overlay isKindOfClass:[MKPolyline class]]){
MKPolylineRenderer *renderer = [[MKPolylineRenderer alloc]initWithOverlay:overlay];
renderer.strokeColor = [UIColor redColor];
renderer.lineWidth = 10.0f;
return renderer;
}
else
return nil;
}
如果地址一在 NJ 某处,地址二在 CA 某处,则输出:
address one lat is 40.902599
address one lon is -74.407097
address two lat is 34.054435
address two lon is -118.253393
Total distance is 4459771.000000
Ron,我怀疑你的折线 (mainRoute.polyline
) - 你的 rendererForOverlay 看起来几乎和我成功使用的一模一样。除了最基本的错误,比如没有设置 MKMapView 委托,或者将它设置为其他对象,我几乎可以肯定你添加到地图的多段线不包含有效的 CLLocationCoordinate2D 结构。
在 Swift 中,创作就像
var coordinatePtr = UnsafeMutablePointer<CLLocationCoordinate2D>(track2DCoordinates)
let trackPolygon = MKPolyline(coordinates: coordinatePtr, count: track2DCoordinates.count)
mapView.removeOverlays(mapView.overlays)
mapView.addOverlay(trackPolygon)
首先验证您确实拥有有效的 MKPolyline。
我也不确定你的 middlePoint
计算。
MKMapPoint middlePoint = mainRoute.polyline.points[mainRoute.polyline.pointCount/2];
这种方法现在可能有效,但在 Swift 中,您需要更加小心用作索引的数据类型。如果您的点数为奇数或零怎么办?
明明在做路线,却没有画折线。我能够找到总距离,并已验证我们使用的坐标不是 (0,0)。委托有问题吗,因为 addOverlay 和 addAnnotation(在下面显示的名为 createAndAddAnnotationForCoordinate 的自定义方法中调用)方法似乎都不起作用?
-(void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
//generates map view
mapView = [[MKMapView alloc]initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width,
self.view.bounds.size.height)];
//setting delegate to self is not fixing the error
mapView.delegate = self;
mapView.mapType = MKMapTypeStandard;
//converting CLLocationCoordinate2D to MKPlacemark
MKPlacemark *startPlacemark = [[MKPlacemark alloc]
initWithCoordinate: addressOneCoords addressDictionary:
[NSDictionary dictionaryWithObjectsAndKeys:nil]];
MKPlacemark *endPlacemark = [[MKPlacemark alloc]initWithCoordinate: addressTwoCoords addressDictionary:[NSDictionary dictionaryWithObjectsAndKeys:nil]];
//converting MKPlacemark to MKMapItem
MKMapItem *start = [[MKMapItem alloc ]initWithPlacemark:startPlacemark];
MKMapItem *end = [[MKMapItem alloc]initWithPlacemark:endPlacemark];
MKDirectionsRequest *request = [MKDirectionsRequest new];
[request setSource:start];
[request setDestination:end];
[request setTransportType:MKDirectionsTransportTypeAutomobile];
request.requestsAlternateRoutes = YES;
//Just to check if the coordinates were transferred successfully between view controllers and they did transfer successfully
NSLog(@"address one lat is %f",addressOneCoords.latitude);
NSLog(@"address one lon is %f",addressOneCoords.longitude);
NSLog(@"address two lat is %f",addressTwoCoords.latitude);
NSLog(@"address two lon is %f",addressTwoCoords.longitude);
MKDirections *directions = [[MKDirections alloc]initWithRequest:request];
[directions calculateDirectionsWithCompletionHandler:^(MKDirectionsResponse response, NSError error){
//if the route can't be created
if(error){
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Unable to create route" message:@"Go back to check if addresses are valid" delegate:nil cancelButtonTitle:@"Ok"otherButtonTitles:nil];
[alert show];
}
else{
[mapView removeOverlays:self.mapView.overlays];
MKRoute *mainRoute = [response.routes firstObject];
routeLine = mainRoute.polyline;
if(routeLine){
[self.mapView removeOverlay:routeLine];
}
//the addOverlay method is not drawing the polyline
[self.mapView addOverlay: routeLine level:MKOverlayLevelAboveRoads];
//proof that route is being created successfully
NSLog(@"Total distance is %f", mainRoute.distance);
MKMapPoint middlePoint = mainRoute.polyline.points[mainRoute.polyline.pointCount/2];
//also, the addannotation method is not being called either it seems like
[self createAndAddAnnotationForCoordinate:MKCoordinateForMapPoint(middlePoint)];
}
}];
}
我们的 createAndAddAnnotationForCoordinate 方法,
-(void) createAndAddAnnotationForCoordinate : (CLLocationCoordinate2D)coordinate{
MKPointAnnotation* annotation = [[MKPointAnnotation alloc]init];
annotation.coordinate = coordinate;
annotation.title = @"Point";
annotation.subtitle = @"subtitle";
[mapView addAnnotation:annotation];
}
我们重写的 mapviewdelegate 方法,
-(MKOverlayRenderer )mapView:(MKMapView )mapView rendererForOverlay:(id<MKOverlay>)overlay{
if([overlay isKindOfClass:[MKPolyline class]]){
MKPolylineRenderer *renderer = [[MKPolylineRenderer alloc]initWithOverlay:overlay];
renderer.strokeColor = [UIColor redColor];
renderer.lineWidth = 10.0f;
return renderer;
}
else
return nil;
}
如果地址一在 NJ 某处,地址二在 CA 某处,则输出:
address one lat is 40.902599
address one lon is -74.407097
address two lat is 34.054435
address two lon is -118.253393
Total distance is 4459771.000000
Ron,我怀疑你的折线 (mainRoute.polyline
) - 你的 rendererForOverlay 看起来几乎和我成功使用的一模一样。除了最基本的错误,比如没有设置 MKMapView 委托,或者将它设置为其他对象,我几乎可以肯定你添加到地图的多段线不包含有效的 CLLocationCoordinate2D 结构。
在 Swift 中,创作就像
var coordinatePtr = UnsafeMutablePointer<CLLocationCoordinate2D>(track2DCoordinates)
let trackPolygon = MKPolyline(coordinates: coordinatePtr, count: track2DCoordinates.count)
mapView.removeOverlays(mapView.overlays)
mapView.addOverlay(trackPolygon)
首先验证您确实拥有有效的 MKPolyline。
我也不确定你的 middlePoint
计算。
MKMapPoint middlePoint = mainRoute.polyline.points[mainRoute.polyline.pointCount/2];
这种方法现在可能有效,但在 Swift 中,您需要更加小心用作索引的数据类型。如果您的点数为奇数或零怎么办?