polyline and overlay on mkmapview problems - objective-c

Question

i got this problem, with the polyline and overlay on my mapview. maybe someone else also have problems with that? i can't get the polyline to work but everything else is working. tracking user etc, but just that thing with adding polyline to the map dosent work.
here´s my code.
h-file
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#import <CoreLocation/CoreLocation.h>
#class Walk;
#interface DetailViewController : UIViewController <MKMapViewDelegate, CLLocationManagerDelegate>
#property (strong, nonatomic) Walk *walk; //walk
#property (strong, nonatomic) IBOutlet MKMapView *MKMapView; //mapview
#property (strong, nonatomic) CLLocationManager *locationManager; //locationmanager
#property (strong, nonatomic) IBOutlet UIProgressView *myprogressView; //progressbar
#property (strong, nonatomic) IBOutlet UILabel *distLabel; //distancelabel
#property (strong, nonatomic) NSMutableArray *trackPointArray; //trackpointarray
#property (strong, nonatomic) CLLocationManager *locationCoordinates; //locationcoordinates
#property (nonatomic, assign) CLLocationDegrees *currentLocation; //currentlocation
#property (strong, nonatomic) UIActionSheet *saveWalk;
#end
and here are my m-file
m-file
#import "DetailViewController.h"
#import <MapKit/MapKit.h>
#import <CoreLocation/CoreLocation.h>
#import "Location.h" //imports the locations
#import "MathController.h"
#import "Walk.h"
static NSString * const detailSegueName = #"WalkDetails"; //walkdetails
#interface DetailViewController () <MKMapViewDelegate, CLLocationManagerDelegate, UIActionSheetDelegate,MKAnnotation>
#property (strong, nonatomic) MKMapView *mapView;
#end
#implementation DetailViewController
#synthesize MKMapView; //mapview
#synthesize trackPointArray; //trackpointarray
#synthesize coordinate;
#pragma mark - Managing the detail item
- (void)setWalk:(Walk *)walk //settings for walk
{
if (_walk != walk) {
_walk = walk;
[self configureView];
}
}
- (void)configureView
{
self.distLabel.text = [MathController stringifyDistance:self.walk.distance.floatValue];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateStyle:NSDateFormatterMediumStyle];
[self loadMap];
}
- (void) viewDidAppear:(BOOL)animated {
[super viewDidLoad];
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
if ([self.locationManager respondsToSelector:#selector(requestWhenInUseAuthorization)]) { //request authorization
[self.locationManager requestWhenInUseAuthorization]; //request when in use
self.MKMapView.showsUserLocation =YES; //shows users location
CLLocationManager* tempLocationManager = [[CLLocationManager alloc] init];
MKCoordinateRegion tRegion =MKCoordinateRegionMakeWithDistance([tempLocationManager.location coordinate],500,500);
[self.MKMapView setRegion:tRegion animated:animated]; //sets region to animated
}
}
- (MKCoordinateRegion)mapRegion
{
MKCoordinateRegion region;
Location *initialLoc = self.walk.locations.firstObject;
float minLat = initialLoc.latitude.floatValue;
float minLng = initialLoc.longitude.floatValue;
float maxLat = initialLoc.latitude.floatValue;
float maxLng = initialLoc.longitude.floatValue;
for (Location *location in self.walk.locations) {
if (location.latitude.floatValue < minLat) {
minLat = location.latitude.floatValue;
}
if (location.longitude.floatValue < minLng) {
minLng = location.longitude.floatValue;
}
if (location.latitude.floatValue > maxLat) {
maxLat = location.latitude.floatValue;
}
if (location.longitude.floatValue > maxLng) {
maxLng = location.longitude.floatValue;
}
}
region.center.latitude = (minLat + maxLat) / 2.0f;
region.center.longitude = (minLng + maxLng) / 2.0f;
region.span.latitudeDelta = (maxLat - minLat) * 1.1f; // 10% padding
region.span.longitudeDelta = (maxLng - minLng) * 1.1f; // 10% padding
return region;
}
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id < MKOverlay >)overlay
{
if ([overlay isKindOfClass:[MKPolyline class]]) {
MKPolyline *polyLine = (MKPolyline *)overlay;
MKPolylineRenderer *aRenderer = [[MKPolylineRenderer alloc] initWithPolyline:polyLine];
aRenderer.strokeColor = [UIColor blackColor];
aRenderer.lineWidth = 3;
return aRenderer;
}
return nil;
//coordinates for the polyline
}
- (MKPolyline *)polyLine {
CLLocationCoordinate2D coords[self.walk.locations.count];
for (int i = 0; i < self.walk.locations.count; i++) {
Location *location = [self.walk.locations objectAtIndex:i];
coords[i] = CLLocationCoordinate2DMake(location.latitude.doubleValue, location.longitude.doubleValue);
}
return [MKPolyline polylineWithCoordinates:coords count:self.walk.locations.count];
}
//loading map
- (void)loadMap
{
if (self.walk.locations.count > 0) {
self.mapView.hidden = NO;
// set the map bounds
[self.mapView setRegion:[self mapRegion]];
// make the line(s!) on the map
[self.mapView addOverlay:[self polyLine]];
} else {
// no locations were found!
self.mapView.hidden = YES;
UIAlertView *alertView = [[UIAlertView alloc]
initWithTitle:#"Error"
message:#"Sorry, this run has no locations saved."
delegate:nil
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alertView show];
}
}
- (IBAction)stopPressed:(id)sender {
UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:#""delegate:self //sets the delgate
cancelButtonTitle:#"Cancel" destructiveButtonTitle:nil //cancel button
otherButtonTitles:#"Save", #"Discard", nil]; //button to destruct
actionSheet.actionSheetStyle = UIActionSheetStyleDefault; //actionsheet for sender
[actionSheet showInView:self.view]; //attribute to show in view
}
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex //action for clicked button
{
if (buttonIndex == 0) {
[self saveWalk]; //saves the walk
[self.navigationController popToRootViewControllerAnimated:YES];
//[self performSegueWithIdentifier:detailSegueName sender:nil]; /check this later if it works
} else if (buttonIndex == 1) { //discard
[self.navigationController popToRootViewControllerAnimated:YES]; //button will call rootview (homescreen)
}
}
#end
so, i need help with the polyline, so can anybody se whats wrong?:)