从MKMapView获取用户位置

Question

Is it possible to use the MKMapView's own location manager to return the users current location to pass into a webservice?

I have mapView.showsUserLocation=YES; and this does return a valid blue dot at my location, but in the simulator, its Cupertino - which is fine, but when i look at

mapView.userLocation.coordinate.latitude , its equal to 180, whereas a CLLocationManager returns the correct one, 37.3317.

I want to avoid having multiple location managers for my three tabs, so using the mapViews own would be helpful.

Thanks.

Answer 1

You can get the user location from the MKMapView. You are just missing a property in your retrieval of it. It should be:

mapView.userLocation.location.coordinate.latitude;

userLocation only stores a CLLocation location attribute and a BOOL updating attribute. You must go to the location attribute to get coordinates.

-Drew

EDIT: The MKMapView's userLocation does not update until the map has finished loading, and checking too early will return zeros. To avoid this, I suggest using the MKMapViewDelegate method -(void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation .

Answer 2

So, to use a unique CLLocateManager, you can create a class to be the delegate for all you maps., so, instead of doing:

self.locationManager = [[CLLocationManager alloc] init];
    _locationManager.delegate = self;

Do something like:

self.locationManager = [[CLLocationManager alloc] init];
    _locationManager.delegate = mySharedDelegate;

Where mySharedDelegate is your class with all the CLLocationManager delegate methods.

You can only get a valid coordinate for the userLocation, after the first calling of

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation

When this method is called it is because the GPS has found the new location and so the blue dot will be moved to there and the userLocation will have the new coordinate.

Use the following method on your CLLocationManager delegate to log the current location when it is found:

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"---------- locationManager didUpdateToLocation");
    location=newLocation.coordinate;

    NSLog(@"Location after calibration, user location (%f, %f)", _mapView.userLocation.coordinate.latitude, _mapView.userLocation.coordinate.longitude);
}

Have you got the idea?

Cheers,
VFN

Answer 3

    - (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation
    {
        NSLog(@"welcome into the map view annotation");

        // if it's the user location, just return nil.
        if ([annotation isKindOfClass:[MyMapannotation class]])
        {
            MyMapannotation *annotation12=(MyMapannotation *)annotation;
            // try to dequeue an existing pin view first
            static NSString* AnnotationIdentifier = @"AnnotationIdentifier";
            MKPinAnnotationView* pinView = [[MKPinAnnotationView alloc]
                                            initWithAnnotation:annotation reuseIdentifier:AnnotationIdentifier] ;
            pinView.animatesDrop=YES;
            pinView.canShowCallout=YES;
            pinView.pinColor=MKPinAnnotationColorPurple;
            pinView.tag=annotation12.tag;

            UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
            [rightButton setTitle:annotation.title forState:UIControlStateNormal];
            rightButton.tag=annotation12.tag;
            [rightButton addTarget:self
                            action:@selector(showDetails:)
                  forControlEvents:UIControlEventTouchUpInside];
            pinView.rightCalloutAccessoryView = rightButton;
            UIImageView *profileIconView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"artpin"]];
            pinView.image = profileIconView.image;
            return pinView;
        }
        else
            return nil;
     }

    -(IBAction)showDetails:(id)sender
    {
        UIButton *btn=(UIButton *)sender;

    }


    -(void)Load_mapview
    {


        for (int i=0; i<[arr_nearby count]; i++)
        {
            NSNumber *latitude = [[[[arr_nearby objectAtIndex:i] valueForKey:@"geometry"] valueForKey:@"location"] valueForKey:@"lat"];

            NSNumber *longitude = [[[[arr_nearby objectAtIndex:i] valueForKey:@"geometry"] valueForKey:@"location"] valueForKey:@"lng"];

            NSString *title = [[arr_nearby objectAtIndex:i] valueForKey:@"name"];

            //Create coordinates from the latitude and longitude values

            CLLocationCoordinate2D coord;

            coord.latitude = latitude.doubleValue;

            coord.longitude = longitude.doubleValue;

            MyMapannotation *annotation = [[MyMapannotation alloc] initWithTitle:title AndCoordinate:coord andtag:i];
            [_map_nearby addAnnotation:annotation];


          //  [annotations addObject:annotation];

        }

        [self zoomToLocation];


    }
    -(void)zoomToLocation

    {

        CLLocationCoordinate2D zoomLocation;

        zoomLocation.latitude = [[[[[arr_nearby objectAtIndex:0] valueForKey:@"geometry"] valueForKey:@"location"] valueForKey:@"lat"] floatValue];

        zoomLocation.longitude= [[[[[arr_nearby objectAtIndex:0] valueForKey:@"geometry"] valueForKey:@"location"] valueForKey:@"lng"] floatValue];

        MKCoordinateRegion viewRegion = MKCoordinateRegionMakeWithDistance(zoomLocation, 7.5*5,7.5*5);

        [_map_nearby setRegion:viewRegion animated:YES];

        [_map_nearby regionThatFits:viewRegion];

    }

//
//  MyMapannotation.h
//  IOS_Googgle
//
//  Created by Vivek Chauhan on 27/06/16.
//  Copyright (c) 2016 anand. All rights reserved.
//

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


@interface MyMapannotation : NSObject <MKAnnotation>

@property (nonatomic,copy) NSString *title;
@property (nonatomic,assign) int tag;


@property (nonatomic, readonly) CLLocationCoordinate2D coordinate;

-(id) initWithTitle:(NSString *) title AndCoordinate:(CLLocationCoordinate2D)coordinate andtag:(int)tagofbutton;


@end


//
//  MyMapannotation.m
//  IOS_Googgle
//
//  Created by Vivek Chauhan on 27/06/16.
//  Copyright (c) 2016 anand. All rights reserved.
//

#import "MyMapannotation.h"

@implementation MyMapannotation

@synthesize coordinate=_coordinate;

@synthesize title=_title;
@synthesize tag=_tag;


-(id) initWithTitle:(NSString *) title AndCoordinate:(CLLocationCoordinate2D)coordinate andtag:(int)tagofbutton

{

    self = [super init];

    _title = title;

    _coordinate = coordinate;
    _tag=tagofbutton;

    return self;

}
@end