CLLocationManager in background thread - iphone

I am doing one application.In that i am using the CLLocationManager Class for getting the updated location latitude and longitude details.But i need to use this CLLocationManager in sepaate thread .I written my code like below.
- (void)viewDidLoad
{
[NSThread detachNewThreadSelector:#selector(fetch) toTarget:self withObject:nil];
}
-(void)fetch
{
manager=[[CLLocationManager alloc]init];
manager.delegate=self;
manager.distanceFilter=kCLDistanceFilterNone;
manager.desiredAccuracy = kCLLocationAccuracyBest;
[manager startUpdatingLocation];
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
NSLog(#"%f",newLocation.coordinate.latitude);
lbl.text=[NSString stringWithFormat:#"%f",newLocation.coordinate.longitude];
}
.But this delegate method is not fired when i run this code.So please guide me how to get the location updates in separate thread.

The methods of your delegate object are called from the thread in which you started the corresponding location services. That thread must itself have an active run loop, like the one found in your application’s main thread. ——from apple document

Could you please tried with this.
dispatch_async(newThread, ^(void) {
[self fetch];
});
hope you'll get solved problem.

in .h file
MainView *ctl;
NSMutableDictionary *dictSubPoses;
- (id)initWithCtl:(MainView*)_ctl;
in .m file
- (id)initWithCtl:(MainView*)_ctl
{
if(self = [super init])
{
ctl = _ctl; //[_ctl retain];
}
return self;
}
- (void)main
{
[ctl performSelector:#selector(yourMethod) withObject:dictSubPoses];
}

in .h file
#import <CoreLocation/CoreLocation.h>
#import <MapKit/MapKit.h>
//Set Delegate
CLLocationManagerDelegate
// Declare
CLLocationManager *locationManager;
in .m file
-(void)ViewDidLoad
{
locationupadate=YES;
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.distanceFilter = 100.0f;
[locationManager startUpdatingLocation];
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
if(locationupadate)
{
NSLog(#"%f",newLocation.coordinate.latitude);
lbl.text=[NSString stringWithFormat:#"%f",newLocation.coordinate.longitude];
}

Related

custom Location Manager class using CLLocationManager

I'm pretty new to iOS development (my first app) and I faced this issue.
I have an iPhone app that should get user's current location in multiple ViewControllers upon user button touch. To prevent redundant code (implementing locationManager:didFailWithError, locationManager:didUpdateToLocation:fromLocation, etc. multiple times in different view controllers) I decided to create a custom class called LocationManager:
LocationManager.h
#interface LocationManager : NSObject <CLLocationManagerDelegate> {
#private
CLLocationManager *CLLocationManagerInstance;
id<LocationManagerAssigneeProtocol> assignee;
}
-(void) getUserLocationWithDelegate:(id) delegate;
LocationManager.m
#implementation LocationManager
-(id)init {
self = [super init];
if(self) {
CLLocationManagerInstance = [[CLLocationManager alloc] init];
CLLocationManagerInstance.desiredAccuracy = kCLLocationAccuracyBest;
CLLocationManagerInstance.delegate = self;
}
return self;
}
-(void) getUserLocationWithDelegate:(id) delegate {
if([CLLocationManager locationServicesEnabled]) {
assignee = delegate;
[CLLocationManagerInstance startUpdatingLocation];
}
}
#pragma CLLocationManagerDelegate
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
...
}
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
[CLLocationManagerInstance stopUpdatingLocation];
[assignee didUpdateToLocation:newLocation];
}
and I have a protocol called LocationManagerAssigneeProtocol that my ViewControllers implement
#protocol LocationManagerAssigneeProtocol <NSObject>
#required
-(void) didUpdateToLocation:(CLLocation *) location;
#end
and in my viewcontroller where needed
- (IBAction)getMyLocation:(id)sender {
[locationMgr getUserLocationWithDelegate:self];
}
This code works perfectly, however, I have a feeling that I'm violating some design patterns here by letting LocationManager be able to call a function of the class that itself initiated a call to Location Manager. On the other hand, I don't want to go with implementing CLLocationManagerDelegate for all my viewcontrollers that are supposed to work with locations.
Are there any better solution to this issue?
I agree with #CarlVeazey on this one. Delegate are great for a 1 to 1 relationship existing at any one time, however in your case it seems that you may need multiple viewControllers to respond to location events at any given time. So just remove anything related to your delegate and its associated protocol.
I'd probably make LocationManager class a singleton and modify the methods for updating:
+(LocationManager *)sharedInstance
{
static LocationManager *_sharedInstance = nil;
static dispatch_once_t oncePredicate;
dispatch_once(&oncePredicate, ^{
_sharedInstance = [[self alloc] init];
});
return _sharedInstance;
}
-(void)getUserLocation
{
if ([CLLocationManager locationServicesEnabled])
[CLLocationManager startUpdatingLocation];
}
-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
[CLLocationManagerInstance stopUpdatingLocation];
[[NSNotificationCenter defaultCenter] postNotificationWithName:#"LocationManagerDidUpdateLocation" object:newLocation];
}
... Then any viewController that needs to use this class would have something like:
-(void)viewDidLoad
{
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserverForName:#"LocationManagerDidUpdateLocation" object:self queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {
CLLocation *location = note.object;
...
}];
}
-(IBAction)getMyLocation:(id)sender {
[[LocationManager sharedInstance] getUserLocation];
}
Hope that helps and makes sense.

Integrating GPS to my application

I am following a tutorial to integrate GPS to my application. I want to display the Latitude and Longitude values in the viewDidLoad method. According to the tutorial they have displayed it from another method. But i need it to be displayed in viewDidLoad. How can i modify the following code to display it in viewDidLoad ?
The HelloThereController.h view controller
#import "MyCLController.h"
#interface HelloThereViewController : UIViewController <MyCLControllerDelegate> {
MyCLController *locationController;
}
- (void)locationUpdate:(CLLocation *)location;
- (void)locationError:(NSError *)error;
#end
The HelloThereController.m view controller
#import "HelloThereViewController.h"
#implementation HelloThereViewController
- (void)viewDidLoad {
locationController = [[MyCLController alloc] init];
locationController.delegate = self;
[locationController.locationManager startUpdatingLocation];
//I need to print the latitude and logitude values here..
}
My MyCLController.h class
#protocol MyCLControllerDelegate
#required
- (void)locationUpdate:(CLLocation *)location;
- (void)locationError:(NSError *)error;
#end
#interface MyCLController : NSObject {
CLLocationManager *locationManager;
id delegate;
}
#property (nonatomic, retain) CLLocationManager *locationManager;
#property (nonatomic, assign) id delegate;
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation;
- (void)locationManager:(CLLocationManager *)manager
didFailWithError:(NSError *)error;
#end
My MyCLController.m class
#import "MyCLController.h"
#implementation MyCLController
#synthesize locationManager;
#synthesize delegate;
- (id) init {
self = [super init];
if (self != nil) {
self.locationManager = [[[CLLocationManager alloc] init] autorelease];
self.locationManager.delegate = self;
}
return self;
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
[self.delegate locationUpdate:newLocation];
}
- (void)locationManager:(CLLocationManager *)manager
didFailWithError:(NSError *)error
{
[self.delegate locationError:error];
}
- (void)dealloc {
[self.locationManager release];
[super dealloc];
}
#end
If this view controller loads as soon as the app loads, you can't.
it takes time for the location manager to get gps updates.
you'll need to display some ui component that lets the user know you're getting the location, such as UIActivityIndicatorView, and setup another method for displaying the coordinates when you get them.
In general you can accelerate the process sacrificing some accuracy setting the desiredAccuracy property. According to the documentation the values are:
kCLLocationAccuracyBestForNavigation
kCLLocationAccuracyBest
kCLLocationAccuracyNearestTenMeters
kCLLocationAccuracyHundredMeters
kCLLocationAccuracyKilometer
kCLLocationAccuracyThreeKilometers
Anyway you are interested in the first location, so still according to the documentation:
When requesting high-accuracy location data, the initial event delivered by the location
service may not have the accuracy you requested. The location service delivers the initial
event as quickly as possible. It then continues to determine the location with the accuracy
you requested and delivers additional events, as necessary, when that data is available.
You can try starting the location manager in the AppDelegate didFinishLaunchingWithOptions to have some more time before the view appears. As said by Frederick Cheung, locationManager.location can be nil, so it's better do the operations in the location manager delegate.

issue about iOS Core Location GPS

When initializing a new class, which methods of this class will be executed automatically.. Please take a look at codes below:
CoreLocationDemoViewController.m
- (void)viewDidLoad {
NSLog(#"CORE_LOCATION_DEMO_VIEW_CONTROLLER=======>VIEW_DID_LOAD");
[super viewDidLoad];
CLController = [[CoreLocationController alloc] init]; // line 1
CLController.delegate = self; // line 2
[CLController.locMgr startUpdatingLocation];
}
CoreLocationController.m
- (id)init {
NSLog(#"CORE_LOCATION_CONTROLLER=======>INIT");
}
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
NSLog(#"CORE_LOCATION_CONTROLLER=======>DID_UPDATE_TO_LOCATION");
}
From debugging, I got
2011-10-11 23:44:31.682 CoreLocationDemo[77470:207] CORE_LOCATION_CONTROLLER=======>INIT
2011-10-11 23:44:31.707 CoreLocationDemo[77470:207] CORE_LOCATION_CONTROLLER=======>DID_UPDATE_TO_LOCATION
It seems that init and locationManager are executed automatically...I am not so sure about this...
Another question is at line 2, what
CLController.delegate = self ( delegate is declared as id delegate in CoreLocationController.h )
does
Please help if you were experiencing before and all comments are welcomed here
init() is called because of this
CLController = [[CoreLocationController alloc] init];
didUpdateToLocation is called because of this as a delegate call back
[CLController.locMgr startUpdatingLocation];
As a sidenote, I am noticing your init neither calls super init nor returns self. I guess you trimmed down that for the post.

CLLocationManager startUpdatingLocation using a UIButton

This is the first time I am using CLLocationManager. I am not sure if i am doing the right thing. Correct me if i am wrong.
I initialize the locationManager in my viewDidLoad Method and tell the locationManager to startUpdatingLocation in the same method.
When the delegate receives
-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{
[locationManager stopUpdatingLocation];
//do stuff with the coordinates
}
to avoid repeated calls to this delegate method.
I have a UIButton where users can click to update the location
//called by user action
-(IBAction)updateLocation{
//start updating delegate
locationManager.delegate=self;
[locationManager startUpdatingLocation];
}
However when the location changes and when I click the UIbutton, the location coordinates donot change at all. :(
What am i doing wrong? Is this the right of doing or should i not stop the locationManager at all ?
Help would be appreciated.
CLLocationManager caches your last location and returns it as soon as you call -startUpdatingLocation. So, you are starting updates, receiving the old location, and then stopping updates.
This isn't how -startUpdatingLocation/-stopUpdatingLocation are meant to be used. As I asked above, what's wrong with calling the delegate method multiple times? If you only want to get the location when the user taps a button, leave the CLLocationManager updating, and just check CLLocationManger's location property when the user taps your button.
If the reason you're trying to avoid multiple calls to the delegate method is because you're worried about power consumption, etc., adjust the desiredAccuracy property of the CLLocationManager with something like: locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters.
All told, it might look something like this...
.h file:
#interface YourController : NSObject <CLLocationManagerDelegate>
#property (nonatomic, retain) CLLocationManager *locationMgr;
#property (nonatomic, retain) CLLocation *lastLocation;
- (IBAction)getNewLocation:(id)sender;
#end
.m file:
#interface YourController
#synthesize locationMgr = _locationMgr;
#synthesize lastLocation = _lastLocation;
- (id)init
{
if (self = [super init]) {
self.locationMgr = [[CLLocationManager alloc] init];
self.locationMgr.desiredAccuracy = kCLLocationAccuracyBest;
self.locationMgr.delegate = self;
}
return self;
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
if (!self.lastLocation) {
self.lastLocation = newLocation;
}
if (newLocation.coordinate.latitude != self.lastLocation.coordinate.latitude &&
newLocation.coordinate.longitude != self.lastLocation.coordinate.longitude) {
self.lastLocation = newLocation;
NSLog(#"New location: %f, %f",
self.lastLocation.coordinate.latitude,
self.lastLocation.coordinate.longitude);
[self.locationMgr stopUpdatingLocation];
}
}
- (IBAction)getNewLocation:(id)sender
{
[self.locationMgr startUpdatingLocation];
NSLog(#"Old location: %f, %f",
self.lastLocation.coordinate.latitude,
self.lastLocation.coordinate.longitude);
}
- (void)dealloc
{
[self.locationMgr release];
self.locationMgr = nil;
[self.lastLocation release];
self.lastLocation = nil;
[super dealloc];
}
#end
Am assuming you have included #import <CoreLocation/CoreLocation.h> framework to being with. This is the way you start getting location updates.
CLLocationManager *locationMgr = [[CLLocationManager alloc] init];
locationMgr.desiredAccuracy = kCLLocationAccuracyBest;
locationMgr.delegate = self;
[locationMgr startUpdatingLocation];
You are correct here. After this you start getting location updates, here in this delegate-
-(void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
// Handle location updates
}
-(void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
// Handle error
}

iPhone Help: Odd Memory Leak In CoreLocation Framework

I've been working to iron out memory leaks in my program and I'm down to a few stragglers. The strange thing is that they're coming from when I use CoreLocation to get a gps location. The code is properly returning the location, but it's leaking all over the place: CFHTTPMessage, CFURLConnection, CFURLRequest, CFURLResponse, GeneralBlock-16,-32,-48, HTTPRequest, etc... Could anyone please guide me how to fix this?
Initialization of MyCLController
locationController = [[MyCLController alloc] init];
locationController.delegate = self;
[locationController.locationManager startUpdatingLocation];
Do some things and get a call back through the delegate:
[locationController release];
MyCLController.h:
#import <Foundation/Foundation.h>
#protocol MyCLControllerDelegate
#required
- (void)locationUpdate:(CLLocation *)location;
- (void)locationError:(NSError *)error;
#end
#interface MyCLController : NSObject {
CLLocationManager *locationManager;
id delegate;
}
#property (nonatomic, retain) CLLocationManager *locationManager;
#property (nonatomic, assign) id delegate;
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation;
- (void)locationManager:(CLLocationManager *)manager
didFailWithError:(NSError *)error;
#end
MyCLController.m:
#import "MyCLController.h"
#implementation MyCLController
#synthesize locationManager;
#synthesize delegate;
- (id) init {
self = [super init];
if (self != nil) {
self.locationManager = [[[CLLocationManager alloc] init] autorelease];
self.locationManager.delegate = self; // send loc updates to myself
}
return self;
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation {
[locationManager stopUpdatingLocation];
[self.delegate locationUpdate:newLocation];
}
- (void)locationManager:(CLLocationManager *)manager
didFailWithError:(NSError *)error {
[self.delegate locationError:error];
}
- (void)dealloc {
[super dealloc];
}
#end
You need to release the LocationManager. Make sure that you set its delegate to NULL prior to releasing. And also, it's not a good idea to just return the first result. Make sure horizontal accuracy is not < 0 and is also below some threshold, like 5000 meters. And to make it more robust, you might want to add a timer to make it stop after a given amount of time, if it couldn't find your location accurately enough.
you never release locationController