Parsing Json in Google Maps iOS - ios

Question

I have got the Json response. Here it is:
Directions {
routes = (
{
bounds = {
northeast = {
lat = "39.893397";
lng = "42.2477961";
};
southwest = {
lat = "21.4204199";
lng = "39.2398944";
};
};
copyrights = "Map data \U00a92014 Google, Mapa GISrael, ORION-ME";
legs = (
{
distance = {
text = "2,940 km";
value = 2940341;
};
duration = {
text = "1 day 15 hours";
value = 138793;
};
"end_address" = "Unnamed Road, Erzincan Province, Turkey";
"end_location" = {
lat = "39.893397";
lng = "39.906191";
};
"start_address" = "4289, Al Hajlah, Mecca 24231\U00a06970, Saudi Arabia";
"start_location" = {
lat = "21.4204199";
lng = "39.8258119";
};
steps = (
{
distance = {
text = "0.6 km";
value = 630;
};
duration = {
text = "1 min";
value = 55;
};
"end_location" = {
lat = "21.4235672";
lng = "39.8211613";
};
"html_instructions" = "Head <b>west</b> on <b>Alsouq Alsagheer Tunnel</b>";
polyline = {
points = "stvaCinarFEh#?h#?f#Cd#If#Gb#Yx#Yx#e#bAWb#Y`#CD[b#c#l#ILADIRIVGPKRGJKPILKPWRi#X_Ad#MFSJ]N[N_#P]ROJ";
};
"start_location" = {
lat = "21.4204199";
lng = "39.8258119";
};
"travel_mode" = DRIVING;
and it goes on....
Here is some code from my project:
Direction.h
-(void)retrieveDirectionsFromOrigin:(CLLocationCoordinate2D)origin toDestination:(CLLocationCoordinate2D)destination
{
NSString *directionsURL=[NSString stringWithFormat:#"http://maps.google.com/maps/api/directions/json?origin=%f,%f&destination=%f,%f&sensor=false",origin.latitude,origin.longitude,destination.longitude,destination.longitude];
_directionsURL=[NSURL URLWithString:directionsURL];
[self retrieveDirections:nil withDelegate:self];
}
-(void)retrieveDirections:(SEL)selector withDelegate:(id)delegate{
dispatch_async(dispatch_get_main_queue(), ^{
NSData *data = [NSData dataWithContentsOfURL:_directionsURL];
[self fetchedData:data withDelegate:delegate];
});
}
-(void)fetchedData:(NSData *)data withDelegate:(id)delegate{
NSError* error;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSLog(#"Directions %#",json);
if(!error){
self.steps = json[#"routes"][0][#"legs"][0][#"steps"];
}
//MapViewController.m
marker.position = CLLocationCoordinate2DMake(21.422492, 39.826169);
marker2.position = CLLocationCoordinate2DMake(21.413333, 39.893333);
marker.map = mapView;
marker2.map = mapView;
directions=[[Directions alloc]init];
[directions retrieveDirectionsFromOrigin:marker.position toDestination:marker2.position];
[mapViewView setNeedsDisplay];
[mapView setNeedsDisplay];
[self.view bringSubviewToFront:backButton];
}
I am a beginner. Please let me know what to do next to show directions via polyline. Thanks

Answer 1

Here's a tip on how to create the polyline which should get you started on your way
Gather the polystrings from the steps
NSArray *steps = [valDictionary valueForKey:#"steps"];
for (NSDictionary *stepdic in steps) {
NSString *polyStr = [[stepdic valueForKey:#"polyline"] valueForKey:#"points"];
if (polyStr != nil) [polyStrings addObject:polyStr];
}
Create a single path from the polystrings for a smooth line and create the final polyline
GMSMutablePath *path = [GMSMutablePath path];
for (NSString *polyStr in polyStrings) {
GMSPath *p = [GMSPath pathFromEncodedPath:polyStr];
for (NSUInteger i=0; i < p.count; i++) {
[path addCoordinate:[p coordinateAtIndex:i]];
}
}
GMSPolyline *polyLint = [GMSPolyline polylineWithPath:path];
good luck