Question

I just wanted to add a Polyline to my Map which is displayed in a tableviewcell. Unfortunately
the delegate methods are not called… Would be nice if someone knows why.

My tableview.h:

#import <UIKit/UIKit.h>
#import "Route.h"
#import <MapKit/MapKit.h>
#import <QuartzCore/QuartzCore.h>

@interface RoutesDetailView : UITableViewController<MKMapViewDelegate>{
    Route *myRoute;
    MKMapView *mapView;
    // the view we create for the line on the map
    MKPolylineView* _routeLineView;

    // the rect that bounds the loaded points
    MKMapRect _routeRect;
    MKPolyline* _routeLine;
}

@property (nonatomic, retain) Route *myRoute;
@property (nonatomic,retain) MKMapView *mapView;
@property (nonatomic, retain) MKPolyline* routeLine;
@property (nonatomic, retain) MKPolylineView* routeLineView;

-(MKPolyline *) loadRoute: (Route *) theRoute;
@end

And my tableview.m:

    @implementation RoutesDetailView
    @synthesize myRoute,mapView;
    @synthesize routeLine = _routeLine;
    @synthesize routeLineView = _routeLineView;

    - (id)initWithStyle:(UITableViewStyle)style
    {
        self = [super initWithStyle:style];
        if (self) {
            // Custom initialization
        }
        return self;
    }

    - (void)didReceiveMemoryWarning
    {
        // Releases the view if it doesn't have a superview.
        [super didReceiveMemoryWarning];

        // Release any cached data, images, etc that aren't in use.
    }

    #pragma mark - View lifecycle

    - (void)viewDidLoad
    {    
        [super viewDidLoad];
        MKMapView *myMap = [[MKMapView alloc] initWithFrame:CGRectMake(10, 1, 300 , 300)];
        myMap.layer.cornerRadius = 10.0;
        [self setMapView:myMap];
        [mapView setDelegate:self];
        CLLocationCoordinate2D annotationCoord;
        annotationCoord.latitude = [[NSString stringWithFormat:@"%@",NSLocalizedString(@"DefaultPointLAT", nil)] doubleValue];
        annotationCoord.longitude = [[NSString stringWithFormat:@"%@",NSLocalizedString(@"DefaultPointLONG", nil)] doubleValue];
        MKPointAnnotation *annotationPoint = [[MKPointAnnotation alloc] init];
        annotationPoint.coordinate = annotationCoord;
        MKCoordinateRegion region =
        MKCoordinateRegionMakeWithDistance (annotationPoint.coordinate,[[NSString stringWithFormat:@"%@",NSLocalizedString(@"DefaultCircle", nil)] doubleValue], [[NSString stringWithFormat:@"%@",NSLocalizedString(@"DefaultCircle", nil)] doubleValue]);
        [mapView setRegion:region animated:NO];
        // Uncomment the following line to preserve selection between presentations.
        // self.clearsSelectionOnViewWillAppear = NO;

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem;
    }

    - (void)viewDidUnload
    {
        [super viewDidUnload];
        // Release any retained subviews of the main view.
        // e.g. self.myOutlet = nil;
    }

    - (void)viewWillAppear:(BOOL)animated
    {
        [super viewWillAppear:animated];
    }

    - (void)viewDidAppear:(BOOL)animated
    {
        [super viewDidAppear:animated];
    }

    - (void)viewWillDisappear:(BOOL)animated
    {
        [super viewWillDisappear:animated];
    }

    - (void)viewDidDisappear:(BOOL)animated
    {
        [super viewDidDisappear:animated];
    }

    - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
    {
        // Return YES for supported orientations
        return (interfaceOrientation == UIInterfaceOrientationPortrait);
    }

    #pragma mark - Table view data source


    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
    {
.
.
.

            static NSString *CellIdentifier = @"CellMap";
            UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
            [mapView setFrame:CGRectMake(10, 1, cell.frame.size.width-20 , cell.frame.size.height-1)];
            [cell addSubview:mapView];
            [mapView addOverlay:[self loadRoute:myRoute]];
            return cell;
.
.
.

    }




    #pragma mark - Table view delegate
    -(MKPolyline *) loadRoute: (Route *) theRoute
    {

        MKMapPoint northEastPoint;
        MKMapPoint southWestPoint; 

        // create a c array of points.
        MKMapPoint* pointArr = malloc(sizeof(CLLocationCoordinate2D) * theRoute.latitude.count);

        for(int idx = 0; idx < theRoute.latitude.count; idx++)
        {

            CLLocationDegrees latitude = [[[theRoute latitude] objectAtIndex:idx] doubleValue];
            CLLocationDegrees longitude = [[[theRoute longitude] objectAtIndex:idx] doubleValue];

            // create our coordinate and add it to the correct spot in the array
            CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake(latitude, longitude);

            MKMapPoint point = MKMapPointForCoordinate(coordinate);

            //
            // adjust the bounding box
            //

            // 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;

        }

        // create the polyline based on the array of points.
        self.routeLine = [MKPolyline polylineWithPoints:pointArr count:theRoute.latitude.count];

        _routeRect = MKMapRectMake(southWestPoint.x, southWestPoint.y, northEastPoint.x - southWestPoint.x, northEastPoint.y - southWestPoint.y);

        // clear the memory allocated earlier for the points
        free(pointArr);
        return self.routeLine;


    }

    - (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id )overlay
    {
        NSLog(@"DELEGATE CALL");
        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 = 15;
            }

            overlayView = self.routeLineView;

        }

        return overlayView;

    }


    - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
    {
        // Navigation logic may go here. Create and push another view controller.
        /*
         <#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:@"<#Nib name#>" bundle:nil];
         // ...
         // Pass the selected object to the new view controller.
         [self.navigationController pushViewController:detailViewController animated:YES];
         */
    }

    @end

Answer 1

Try this, I was having the same issue. After trying many combinations this is the one which works.

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

@interface MapViewController : UIViewController<MKMapViewDelegate> {

    MKMapView   *mapView;
}

and the implementation…

- (void)viewDidLoad {

    [super viewDidLoad];

    mapView = [[MKMapView alloc] initWithFrame: CGRectMakeFullScreenIphone];
    mapView.delegate = self;
    [mapView setMapType: MKMapTypeStandard];
    [self.view addSubview: mapView]; 


    MKCoordinateRegion newRegion;
    // configure region...
    [mapView setRegion:newRegion animated:YES];

    CLLocationCoordinate2D coordinate;
    //configure coordinate...

    MKPointAnnotation *annotation = [[MKPointAnnotation alloc]init];
    [annotation setCoordinate:coordinate];
    [annotation setTitle:@"TEST"];
    [mapView addAnnotation:annotation];
}

The simple code above works fine and delegate’s methods were called.