Draw polyline in mapview iOS 6 - ios

Question

Hi I'm doing an app that must to show a map with the route. I parsed a Json to obtain the points to draw the polyline. I found a a code in the web to draw this polyline. The code I found it's on this link: http://iosguy.com/2012/05/22/tracing-routes-with-mapkit/
Where it says "Create the MKPolyline annotation" I tried to import this in my app, but I'm having problems to create the array of the coordinates. My method is this:
- (void)createMKpolylineAnnotation {
NSInteger numberOfSteps = self.path.count;
CLLocationCoordinate2D *coords = malloc(sizeof(CLLocationCoordinate2D) * numberOfSteps);
for (NSInteger index = 0; index < numberOfSteps; index++) {
CLLocation *location = [self.path objectAtIndex:index];
CLLocationCoordinate2D coordinate = location.coordinate;
coords[index] = coordinate;
}
MKPolyline *polyLine = [MKPolyline polylineWithCoordinates:coords count:numberOfSteps];
[self.mapView addOverlay:polyLine];
}
When I try to look the value of coords is setted only the first time, why's that?
Can you help me to solve this problem or i should make in another mode?
I post here the code of the view controller that handle the map view.
MapViewController.h
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#interface MapViewController : UIViewController <MKMapViewDelegate>
#property (weak, nonatomic) IBOutlet MKMapView *mapView;
#property (nonatomic, strong) NSString *fromCity;
#property (nonatomic, strong) NSString *toCity;
- (IBAction)chooseKindOfMap:(id)sender;
#end
MapViewController.m
#import "MapViewController.h"
#import "AppDelegate.h"
#import "PlaceAnnotation.h"
#interface MapViewController ()
#property (nonatomic, strong)NSMutableArray *mapAnnotation;
#property (nonatomic) BOOL needUpdateRegion;
#property (nonatomic, strong)NSMutableArray *path;
#end
#implementation MapViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self parseGoogleJsonToObtainPointsForPolyline];
[self.mapView setDelegate:self];
self.needUpdateRegion = YES;
//[self centerMap];
self.mapAnnotation = [[NSMutableArray alloc]initWithCapacity:2];
AppDelegate *appDelegate = (AppDelegate*)[[UIApplication sharedApplication]delegate];
NSLog(#"%d", appDelegate.dataForMap.count);
NSArray* coords = [self getCoords:appDelegate.dataForMap];
NSLog(#"coords = %#", coords);
PlaceAnnotation *fromPlace = [[PlaceAnnotation alloc] initWithCoordinateAndName:coords[0] andLong:coords[1] andName:self.fromCity];
PlaceAnnotation *toPlace = [[PlaceAnnotation alloc] initWithCoordinateAndName:coords[2] andLong:coords[3] andName:self.toCity];
[self.mapAnnotation insertObject:fromPlace atIndex:0];
[self.mapAnnotation insertObject:toPlace atIndex:1];
NSLog(#"mapAnnotation.count: %d", self.mapAnnotation.count);
if (self.mapAnnotation) {
[self.mapView removeAnnotations:self.mapView.annotations];
}
[self.mapView addAnnotation:self.mapAnnotation[0]];
[self.mapView addAnnotation:self.mapAnnotation[1]];
NSLog(#"MapAnnotation = %#", self.mapView.annotations);
[self updateRegion];
[self createMKpolylineAnnotation];
}
//- (void)viewDidAppear:(BOOL)animated {
// [super viewDidAppear:animated];
// if (self.needUpdateRegion) [self updateRegion];
//}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (MKAnnotationView*)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation {
MKPinAnnotationView *pin = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:nil];
pin.pinColor = MKPinAnnotationColorRed;
return pin;
}
- (void)mapView:(MKMapView *)mapView didAddAnnotationViews:(NSArray *)views {
MKPinAnnotationView *ulv = [mapView viewForAnnotation:mapView.userLocation];
ulv.hidden = YES;
}
- (NSArray*)getCoords:(NSDictionary*)data {
NSArray *legs = [data objectForKey:#"legs"];
NSDictionary *firstZero = [legs objectAtIndex:0];
NSDictionary *endLocation = [firstZero objectForKey:#"end_location"];
NSDictionary *startLocation = [firstZero objectForKey:#"start_location"];
NSString *latFrom = [startLocation objectForKey:#"lat"];
NSString *lngFrom = [startLocation objectForKey:#"lng"];
NSString *latTo = [endLocation objectForKey:#"lat"];
NSString *lngTo = [endLocation objectForKey:#"lng"];
return #[latFrom,lngFrom,latTo,lngTo];
}
- (void)centerMap {
MKCoordinateRegion region;
region.center.latitude = 41.178654;
region.center.longitude = 11.843262;
region.span.latitudeDelta = 11.070406;
region.span.longitudeDelta = 12.744629;
[self.mapView setRegion:region];
}
- (IBAction)chooseKindOfMap:(id)sender {
if ([sender tag] == 0) {
self.mapView.mapType = MKMapTypeStandard;
}
if ([sender tag] == 1) {
self.mapView.mapType = MKMapTypeSatellite;
}
if ([sender tag] == 2) {
self.mapView.mapType = MKMapTypeHybrid;
}
}
- (void)updateRegion
{
self.needUpdateRegion = NO;
CGRect boundingRect;
BOOL started = NO;
for (id <MKAnnotation> annotation in self.mapView.annotations) {
CGRect annotationRect = CGRectMake(annotation.coordinate.latitude, annotation.coordinate.longitude, 0, 0);
if (!started) {
started = YES;
boundingRect = annotationRect;
} else {
boundingRect = CGRectUnion(boundingRect, annotationRect);
}
}
if (started) {
boundingRect = CGRectInset(boundingRect, -0.2, -0.2);
if ((boundingRect.size.width < 20) && (boundingRect.size.height < 20)) {
MKCoordinateRegion region;
region.center.latitude = boundingRect.origin.x + boundingRect.size.width / 2;
region.center.longitude = boundingRect.origin.y + boundingRect.size.height / 2;
region.span.latitudeDelta = boundingRect.size.width;
region.span.longitudeDelta = boundingRect.size.height;
[self.mapView setRegion:region animated:YES];
}
}
}
- (void)parseGoogleJsonToObtainPointsForPolyline {
NSDictionary *polyline;
NSMutableArray *points = [[NSMutableArray alloc]init];;
AppDelegate *appDelegate = (AppDelegate*)[[UIApplication sharedApplication]delegate];
NSArray *legs = [appDelegate.dataForMap objectForKey:#"legs"];
NSDictionary *firstZero =[legs objectAtIndex:0];
NSArray *steps = [firstZero objectForKey:#"steps"];
for (int i = 0; i < steps.count; i++) {
polyline = [steps[i] objectForKey:#"polyline"];
[points addObject:polyline[#"points"]];
NSLog(#"POINTS = %#", polyline[#"points"]);
self.path = [self decodePolyLine:points[i]];
}
NSLog(#"path = %#", self.path);
}
-(NSMutableArray *)decodePolyLine:(NSString *)encodedStr {
NSMutableString *encoded = [[NSMutableString alloc] initWithCapacity:[encodedStr length]];
[encoded appendString:encodedStr];
[encoded replaceOccurrencesOfString:#"\\\\" withString:#"\\"
options:NSLiteralSearch
range:NSMakeRange(0, [encoded length])];
NSInteger len = [encoded length];
NSInteger index = 0;
NSMutableArray *array = [[NSMutableArray alloc] init];
NSInteger lat=0;
NSInteger lng=0;
while (index < len) {
NSInteger b;
NSInteger shift = 0;
NSInteger result = 0;
do {
b = [encoded characterAtIndex:index++] - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
NSInteger dlat = ((result & 1) ? ~(result >> 1) : (result >> 1));
lat += dlat;
shift = 0;
result = 0;
do {
b = [encoded characterAtIndex:index++] - 63;
result |= (b & 0x1f) << shift;
shift += 5;
} while (b >= 0x20);
NSInteger dlng = ((result & 1) ? ~(result >> 1) : (result >> 1));
lng += dlng;
NSNumber *latitude = [[NSNumber alloc] initWithFloat:lat * 1e-5];
NSNumber *longitude = [[NSNumber alloc] initWithFloat:lng * 1e-5];
CLLocation *location = [[CLLocation alloc] initWithLatitude:[latitude floatValue] longitude:[longitude floatValue]];
[array addObject:location];
}
return array;
}
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id <MKOverlay>)overlay {
MKPolylineView *polylineView = [[MKPolylineView alloc] initWithPolyline:overlay];
polylineView.strokeColor = [UIColor redColor];
polylineView.lineWidth = 1.0;
return polylineView;
}
- (void)createMKpolylineAnnotation {
NSInteger numberOfSteps = self.path.count;
CLLocationCoordinate2D *coords = malloc(sizeof(CLLocationCoordinate2D) * numberOfSteps);
for (NSInteger index = 0; index < numberOfSteps; index++) {
CLLocation *location = [self.path objectAtIndex:index];
CLLocationCoordinate2D coordinate = location.coordinate;
coords[index] = coordinate;
}
MKPolyline *polyLine = [MKPolyline polylineWithCoordinates:coords count:numberOfSteps];
[self.mapView addOverlay:polyLine];
}
#end
I used the AppDelegate to have the Json (I parsed it in another class)

Answer 1

Here is a tutorial how to add a polyline to a mapView. Hope this helps!
EDIT:
Unfortunately, the link provided above is now broken, and I am not able to find the tutorial referred to.

Answer 2

simple, just copy and paste my code and modify some variables
- (IBAction)traceRoute:(UIButton *)sender {
double latDouble = 39.7540615;
double lngDouble = -8.8059587;
// double latDouble = [self.sheetDetail.data.locationLat doubleValue];
// double lngDouble = [self.sheetDetail.data.locationLng doubleValue];
CLLocationCoordinate2D c2D = CLLocationCoordinate2DMake(latDouble, lngDouble);
MKPlacemark *placemark = [[MKPlacemark alloc] initWithCoordinate:c2D addressDictionary:nil];
MKMapItem *mapItem = [[MKMapItem alloc] initWithPlacemark:placemark];
[mapItem setName:#"Mobile Edge"];
MKPlacemark *placemark2;
MKMapItem *mapItem2;
if(kIS_OS_8_OR_LATER) {
placemark2 = [[MKPlacemark alloc] initWithCoordinate:_userLoc addressDictionary:nil];
mapItem2 = [[MKMapItem alloc] initWithPlacemark:placemark2];
[mapItem2 setName:#"Me"];
} else {
placemark2 = [[MKPlacemark alloc] initWithCoordinate:_mapView.userLocation.coordinate addressDictionary:nil];
mapItem2 = [[MKMapItem alloc] initWithPlacemark:placemark2];
[mapItem2 setName:#"Me"];
}
MKDirectionsRequest *request = [[MKDirectionsRequest alloc] init];
request.source = mapItem2;
request.destination = mapItem;
request.requestsAlternateRoutes = NO;
MKDirections *directions = [[MKDirections alloc] initWithRequest:request];
[directions calculateDirectionsWithCompletionHandler:
^(MKDirectionsResponse *response, NSError *error) {
if (error) {
// Handle error
[[NSNotificationCenter defaultCenter] postNotificationName:#"finishedLocationRoute" object:nil];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle: NSLocalizedString(#"Route error title", nil)
message: NSLocalizedString(#"Route error", nil)
delegate:self
cancelButtonTitle:#"OK"
otherButtonTitles:nil];
[alert show];
} else {
for (MKRoute *route in response.routes)
{
//MKMapPoint middlePoint = route.polyline.points[route.polyline.pointCount/2];
//[self createAndAddAnnotationForCoordinate:MKCoordinateForMapPoint(middlePoint) andRoute:route];
[self.mapView addOverlay:route.polyline level:MKOverlayLevelAboveRoads];
}
//notifies parent menu
//[[NSNotificationCenter defaultCenter] postNotificationName:#"finishedLocationRoute" object:nil];
}
}];
}
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id)overlay
{
if (![overlay isKindOfClass:[MKPolygon class]]) {
MKPolyline *route = overlay;
MKPolylineRenderer *renderer = [[MKPolylineRenderer alloc] initWithPolyline:route];
renderer.strokeColor = [UIColor blueColor];
renderer.lineWidth = 5.0;
return renderer;
} else {
return nil;
}
}