CODEWITHSUNDEEP
iosobjective-ccore-locationcllocationmanager
Poles
Poles

Reputation: 3682

Accessing CLLocationManager variable from one viewcontroller to another viewcontroller

In iOS, I have declared the CLLocationManager variable like this:

DashBoardViewController.h

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

@class AppDelegate;
@interface DashBoardViewController : UIViewController<CLLocationManagerDelegate, UIAlertViewDelegate>{

    AppDelegate *appDel;
}
@property(nonatomic,strong) CLLocationManager *locationManager;
@property (nonatomic,retain) CLLocation *current;

-(void)localnotification;
@end

And in the DashBoardViewController.m file:

#import "DashBoardViewController.h"
#import "AppDelegate.h"

#define IS_OS_8_OR_LATER ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)

@interface DashBoardViewController ()
@end

@implementation DashBoardViewController

@synthesize current,locationManager;
- (void)viewDidLoad
{
    [super viewDidLoad];
    appDel = (AppDelegate*)[UIApplication sharedApplication].delegate;
    [self localnotification];
}

-(void)localnotification{ 
    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
    locationManager.distanceFilter = kCLDistanceFilterNone;
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;

    if(IS_OS_8_OR_LATER) {
        [locationManager requestAlwaysAuthorization];
    }

    [locationManager startMonitoringSignificantLocationChanges];
}

I also Implemented 

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
  //some code
}

Now I'm accessing the "locationManager" and "localnotification" method like this in SettingsViewController.m

#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>
#import "DashBoardViewController.h"

//To stop the Location Manager service
- (IBAction)stopButtonAction:(id)sender {
DashBoardViewController *dash=[[DashBoardViewController alloc] init];
    dash.locationManager=nil;
}

//To start the Location Manager service
- (IBAction)startButtonAction:(id)sender {

    DashBoardViewController *dash=[[DashBoardViewController alloc] init];
    [dash localnotification];
}

But it's not working. All time locationManager returning null. What's wrong in this code?

Upvotes: 2

Views: 611

Answers (2)

ugur
ugur

Reputation: 842

When you 

DashBoardViewController *dash=[[DashBoardViewController alloc] init];

it creates a new DashBoardViewController instance. You can define locationManager in AppDelegate and access directly to it from anywhere in your code.

AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
appDelegate.locationManager = nil;

Upvotes: 3

Jesper Schl&#228;ger
Jesper Schl&#228;ger

Reputation: 375

viewDidLoad is not called when you alloc-init the view controller. It is called when loading the view which is done later when you actually show it. That is why it is nil. I would suggest to create the location manager in the AppDelegate if you want to access it across multiple view controllers.

Upvotes: 3

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