I want to know that locationManager:didUpdateLocations: will call when my phone is in stable position?
In my case its not calling when i put my phone on one place.
I Placed my phone from one location to other location within my room but still its not calling.
Can anyone tell me that when it will call.
When i change location using xcode then its always calling.
I used
self.locMgr.desiredAccuracy=kCLLocationAccuracyBest;
Okay, so you say within the simulator it works, but it does not work when you run your program on the actual iPhone device, right?
You were correct in setting the accuracy. This should work actually unless you have switched off the location update in general for your iPhone (settings under Privacy->Location Services).
If this is all working you maybe want to paste more of your code, but again, I think if it works under the simulator it should work on the device.
The location manager calls for location updates on the accuracy you set. It will not get called on a stable location more than once. you can use distance filter to call it after a certain distance.
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
self.locationManager.distanceFilter = 10; //meters
For updating it on the same location you will have to use a timer which will call for updating after every desired interval.
Probably it depends on the accuracy you set to the locationManager.
1).. Cell Radio 2).. WiFi Map, 3).. GPS
If you set best as accuracy the location manager will continue to
check you position, if the location with better accuracy is out of the
range of the distance filter the delegate method will be called again.
GPS is not exact.some time if you move about a feet and still it will
not update. or some time you didn't moved at all and it will update.
Stop testing GPS and Location Services inside! Go outside and move around to test it.
Make sure that you set the delegate for the Location Manager & also
make sure you get the permission for using "User's Current Location."
Related
I'm monitoring a region using CLLocationManager's startMonitoringForRegion:desiredAccuracy:. I know for sure that the region gets properly added to the location manager's monitoredRegions.
I set this up while my simulator location is set far away from it (2.3 km to be precise). Then I hit the home button, and change the simulator's location to the very location I set a geofence for. locationManager:didEnterRegion: doesn't get called. Same results if I try moving to this location but from a another location, this one 4.3 km away.
There seems to be some threshold I can't pick up, as locationManager:didEnterRegion: gets called when moving from other locations at 7 km and up. But my CLRegion's radius is 100 m. What could possibly be the issue here?
This is truly just a wild guess, but I wonder if this is a result of the location manager attempting to mitigate false positives with a location that is seemingly jumping around. I imagine that changing the location in the simulator while the app is resigned could appear to the location manager as a location update that doesn't conform to the desired accuracy, thus disregarding it when considering whether you've actually entered a new region.
Have you tried simulating a city bike ride or freeway drive to see if it makes a difference? I would just try to test on a device as soon as possible.
I'm writing an app that stores the location of the places you have been throughout the day. I've done a lot of research on CLLocationManager, and have been testing my app for the last 3 weeks. The locations I get with CLLocationManager sometimes is very inaccurate, sometimes 4 or 5 miles away from where I am.
I have a log in my test app and realized that every time I get a new location my DidUpdateToLocation method is called 3 times in a row, like within one second, and I get 3 different locations. One of them is always right, but the other 2 are off. I've tested with it with different accuracies(hundredMeters, nearestTenMeters, and Best), but still had the same problem. So, my first question is:
Is there anyway I can find out which of these locations is the right one so I can store it?
I've also realized that the user's current location on the map view is always very accurate, so I thought about getting the user's location from the mapView(blue dot) instead of the CLLocationManager, but I learned that a mapView object will only return the current location if the map is actually on screen, and this is not the case since I want my app to run in the background. So the second question is:
Is there anyway to get the user's current location from a mapView without the map being on screen? Or at least use the same technique the mapView uses for finding the current location?
If you have any experience with mapKit and CLLocationManager, please share your thoughts.
Thanks for you time. Any help is appreciated.
Is there anyway I can find out which of these locations is the right
one so I can store it?
Look at the horizontalAccuracy property of the locations that you receive. Don't use locations that are less accurate than what you're looking for.
I've also realized that the user's current location on the map view is
always very accurate
The map view probably doesn't have any special access to API's that are more accurate than what you've got, it just uses them better. Instead of starting from scratch each time you need a fix, try caching the location and then updating when you get a new location that's sufficiently accurate.
Take a look at Apple's sample code Locate Me. It uses the variable:
CLLocation *bestEffortAtLocation;
to determine upon updates if the location is less than the last location and less than a time limit set until the most accurate location is found.
In particular look at the GetLocationViewController in the sample code. I've used this code in my apps and it works great.
https://developer.apple.com/library/ios/#samplecode/LocateMe/Listings/Classes_GetLocationViewController_m.html#//apple_ref/doc/uid/DTS40007801-Classes_GetLocationViewController_m-DontLinkElementID_8
We are developing an app that has heavy GPS usage, and we are unable to optimize the battery life.
Even when the device is not moved, there is significant battery drainage that, according to the code, should not happen.
Here is the code:
locationManager = [[CLLocationManager alloc] init];
locationManager.distanceFilter = 100;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
[locationManager startUpdatingLocation];
Ideally we want to trigger GPS every 20 minutes (if there is no location change then save battery) OR every 5 minutes if there is location change. According to my developer this cannot be done
Previously we were using kCLLocationAccuracyBest, which was consuming battery very fast and now we are using kCLLocationAccuracyHundredMeters.
startUpdatingLocation - is to get the GPS coordinates. There is another call startMonitoringSignificantLocationChanges which is to get AGPS coordinates which I believe returns the coordinates whenever cell tower will change, and hence consumes battery really fast.
distanceFilter - The minimum distance (measured in meters) a device must move laterally before an update event is generated. On the basis of distance filter we get the GPS fix from the device and then we send the updated GPS coordinates to the server.
Any help will be greatly appreciated
Thank you!
There is another call startMonitoringSignificantLocationChanges which
is to get AGPS coordinates which I believe returns the coordinates
whenever cell tower will change, and hence consumes battery really
fast.
That's exactly what it does, but you're jumping to conclusions about the power required for that. The GPS receiver and WiFi transceiver can be used to help determine location, but they're extra devices that have to be powered to be useful. But mobile phones like the iPhone need to keep in touch with the nearest cell tower anyway in order to receive phone calls, so using cell towers as a source of location information should be very efficient with respect to power. Here's what the CLLocationManager reference page says about -startMonitoringSignificantLocationChanges:
This interface delivers new events only when it detects changes to the
device’s associated cell towers, resulting in less frequent updates
and significantly lower power usage.
It also describes the service as providing "tremendous power savings," so it seems the right tool for the job you describe. Of course, if you're also using the standard location updating mechanism at the same time you won't see that power savings, so make sure you're not using both.
Ideally we want to trigger GPS every 20 minutes (if there is no
location change then save battery) OR every 5 minutes if there is
location change. According to my developer this cannot be done
It sounds like there's some sort of misunderstanding here. You can certainly fire up the GPS every 20 minutes to get a fix if that's what you want, although you can't do that from the background. The significant location change service will notify your app even if it's running in the background, so perhaps your developer is talking about background updates.
Your belief that startMonitoringSignificantLocationChanges consumes the battery really fast is likely incorrect. Cell tower changes usually occur far less frequently than movements of 100 meters. And an iPhone checks for this event even when idle and all apps are sleeping.
However, keeping a cell phone on (e.g. Airplane mode off) when far from any tower (barely 1 bar) will drain the battery of the device whether or not an app is doing any location monitoring.
On stock iOS devices, an app cannot trigger location monitoring purely on a timer basis such every 20 minutes or every 5 minutes, without keeping the device on and your app running in the foreground, which will drain the battery.
If you require a good level of precision, you should startUpdatingLocation and as soon you get the first fix you should then stopUpdatingLocation and then startMonitoringSignificantLocationChanges.
This is enough for most app purposes.
Ideally we want to trigger GPS every 20 minutes (if there is no
location change then save battery) OR every 5 minutes if there is
location change. According to my developer this cannot be done
This could be done using an NSTimer that calls a startLocating (a custom method that creates the CLLocationManager and calls startLocating on it) method every 20 minutes. Make sure you call CLLocationManager's stopLocating once you've found a CLLocation with an accuracy of your liking.
However, doing so mean that for 20 minutes you might be using a location that is totally off. It depends on how you plan to use the location and how precise it needs to be, but maybe what your dev means by "not possible" is that your app needs the user's actual location at all times.
In my application ,in initial lunch i have to used cllocationmanager class to find current location ([locationManager startUpdatingLocation];) using this method.After find a location i
fired this method ([locationManager stopUpdatingLocation];).
Now a user will move from one place to other place.It will automatically detects newlocation or we need to fire ([locationManager startUpdatingLocation];) this method again.
Help me?
Note:
If i will call ([locationManager startUpdatingLocation];) method again it will give a newlocation or old location.How to differentiate it ?
Whenever you call [locationManager startUpdatingLocation];, this will give you the current location. So, when you call this function again it will give you new location.
In such case, either you have to continuously keep on watch for the updated location, if you want automatic update or after certain duration of time you have to check again for updated location and compare it with previous one. By doing this, you will come to know weather is it new location or old.
Short answer: YES, you need to call [locationManager startUpdatingLocation]; to get a new location. You can stop and then start and then stop and then start, and each time you start, you will get the current (new) location of the device.
Long answer: You can also choose to keep the locationManager on (never call stopUpdatingLocation) and get updates all the time. By setting the distanceFilter property for the locations manager, you can choose when (or, to be exact, at what distance delta from last update) a new location update will be sent to your app. This seems to be the way used in most implementations that take more than one location sample, or need to track the location of the user constantly.
Also note, there is a new startMonitoringSignificantLocationChanges which gives different way to get updates: read the documentation carefully if you want to use this feature, it is not always available.
I implemented background location tracking using standard location services, and it works fine. However, since this implementation uses a lot of power, I decided to switch to significant location changes monitoring. Basically, I just changed all the calls to startUpdatingLocation to startMonitoringSignificantLocationChanges and reused the CLLocationManagerDelegate methods I have implemented before.
The problem is that after switching to significant location changes monitoring, the delegate method locationManager:didUpdateToLocation:fromLocation only gets called once when I start monitoring, and is never called again afterwards. I have moved around the phone for a couple of kilometers, and tried riding a train with it, but still the method never gets called. Am I missing something here? Are there settings I need to enable or special code I need to write in order for this to work?
Thanks!
The significant location change requires cell phone towers in order to operate. If you don't have cell phone reception you will not get any results. You can also call CLLocationManager's significantLocationChangeMonitoringAvailable method to see if it is available.