I'm trying to make a view like compass in iphone 3gs or iphone4. Do you know somebody how can I start?, I can't find too much information about this issue...I only want to draw an arrow always following the north.
I'm using ios 4.0
Thanks in advance
Start heading updates with:
if([CLLocationManager headingAvailable]) {
CLLocationManager *locationManager = [[CLLocationManager alloc] init];
// myDelegateObject is an instance of a class implementing the CLLocationManagerDelegate protocol
locationManger.delegate = myDelegateObject;
[locationManager startUpdatingHeading];
}
Implement the CLLocationManagerDelegate protocol on one of your classes -- in particular, something like:
-(void)locationManager:(CLLocationManager*)manager didUpdateHeading:(CLHeading*)heading {
// CLLocationDirection is a double typedef
CLLocationDirection headingInDegrees = heading.magneticHeading;
// you'll have to implement this in some fashion...
[myCompassViewController rotateCompassImageToHeading:headingInDegrees];
}
Related
I recently started testing my app on an iPhone 5, and to my alarm, it seems that the CLLocationManager doesn't really work! Although [CLLocationManager headingAvailable] is YES, I don't receive any heading updates at all. Strangely, on an iPhone 4, after 30 or so heading updates, locationManager:didUpdateToHeading: is no longer called. This issue is entirely new. The location manager also returns negative numbers for verticalAccuracy, so I'm assuming the altitude it is invalid. Here's how I'm creating the location manager:
CLLocationManager* locationManager = [[CLLocationManager alloc] init];
if([locationManager respondsToSelector:#selector(disallowDeferredLocationUpdates)]) {
[locationManager disallowDeferredLocationUpdates];
[locationManager setPausesLocationUpdatesAutomatically:NO];
}
locationManager.headingOrientation = CLDeviceOrientationFaceUp;
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.headingFilter = -1;
locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
[sharedSingleton setLocationManager:locationManager];
sharedSingleton is just my singleton class that handles some odds and ends, including holding onto a reference to the location manager.
If I need to post any more code let me know. I just don't know what might be causing this strange issue. Thanks!
You need to retain "locationManager" in memory somewhere, either as a property of your object or as an instance variable.
What I belive is happening is that you're creating your location manager, and then your method exits and "locationManager" falls out of scope and is magically released by ARC.
So, instead, do something like this:
in your #implementation:
#property (strong) CLLocationManager * locationManager;
and in your #interface:
self.locationManager = [[CLLocationManager alloc] init];
if([self.locationManager respondsToSelector:#selector(disallowDeferredLocationUpdates)]) {
[self.locationManager disallowDeferredLocationUpdates];
[self.locationManager setPausesLocationUpdatesAutomatically:NO];
}
self.locationManager.headingOrientation = CLDeviceOrientationFaceUp;
self.locationManager.distanceFilter = kCLDistanceFilterNone;
self.locationManager.headingFilter = -1;
self.locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
You could try a few things. First of all, I don't see a startUpdatingHeading call. Maybe you're doing it somewhere else. You should add the locationManager:didFailWithError: method to the delegate to check for errors, and try returning YES in locationManagerShouldDisplayHeadingCalibration: in case it's a calibration issue.
Seems the solution was obvious and I overlooked it. The delegate was being set to nil just moments after the location manager was started, which explains why on a slower device like the iPhone 4 a few updates were able to come through before the code setting the delegate to nil was run, but on the iPhone 5 it was instantaneous.
I am trying to record a users location over time. If the user is on the move it works fine and the delegate method didUpdateToLocation is invoked reliably.However if the user is stationary and the app is running in the background then after some time, the delegate method is no longer invoked. To restart it, the app needs to be bought into the foreground. Once it is active the delegate method is invoked reliably again.
I initially thought that this could be due to the fact that the CLLocationManager object was declared within a ViewController, so I changed it to be declared within the AppDelegate but that did not help either.
I have also experimented with the distanceFilter property to no avail. I am currently setting it up using the following code from within a View controller. Note that the object itself is declared and initialized in the AppDelegate object.
app.locationManager.delegate = self;
app.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
app.locationManager.distanceFilter = kCLDistanceFilterNone;
[app.locationManager startUpdatingLocation];
Has anyone else run into this issue? Any pointers would be appreciated. I have been struggling with this for a few days now.
iOS 6 introduces the CLLocationManager property pausesLocationUpdatesAutomatically. It needs to be set to NO when you set up your CLLocationManager, as described here: http://www.stackoverflow.com/a/12781634/700769
Add this code in UpdateLocation method
- (void) updateLocation{
self.locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.pausesLocationUpdatesAutomatically = NO;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
if ([CLLocationManager locationServicesEnabled]) {
[locationManager startUpdatingLocation];
} else {
NSLog(#"Location services is not enabled");
}
}
also edit setting in Schemes: Scheme/Edit Scheme/Options/Allow Location Simulation checked but don't have a default location set.
You need to add location in UIBackgroundModes at app plist file.
if #available(iOS 9.0, *){
locationManager.allowsBackgroundLocationUpdates = true;
}
I am displaying current location for iPad in map view for this i am using following code
if ([CLLocationManager locationServicesEnabled])
{
lm = [[CLLocationManager alloc] init];
lm.delegate = self;
lm.desiredAccuracy = kCLLocationAccuracyBest;
lm.distanceFilter = 100.0f;
[lm startUpdatingLocation];
}
and i am calculating lat and longitude and passing it the url as
NSString *urlString = [NSString stringWithFormat:#"http://maps.google.com/maps?z=15&daddr=%##%#,%#&saddr=%##%#,%#",n,lat_New,lng_New,currentLocation,currentLatt,currentLong];
I am not getting the correct direction for initial starting point and ending point for iPad in map view.
Is there anything alternative for showing correct initial and staring point in iPad map view?
Does app store rejects apps for such problems and Pleas suggest me some good alternative for this.
There are couple of things .One simulator cannot give you GPS locations.Secondly Usually gps coordinates returned first time may not be accurate.so try receiving location updates by implementing the delegate.
What i want to do is read the acceleration.y and do something like:
if (acceleration.y > 0.8) {
// Do something
}
As didAccelerate is deprecated I wonder how to get the y-value:
motionManager = [[[CMMotionManager alloc] init] autorelease];
motionManager.accelerometerUpdateInterval = kUpdateInterval;
if (motionManager.accelerometerAvailable) {
[motionManager startAccelerometerUpdates];
}
else {
//this device doesn't have accelerometer notice somewhere??
}
- (void)startAccelerometerUpdates {
// READ Y-VALUE?????
}
I want to use raw accelerometer data so the app also works on 3GS. Is it possible to read the Y-value?
EDIT: the answer below is deprecated, check these posts for the right way.
Old answer:
Use a UIAccelerometer singleton instance for this, for example in your AppDelegate
//in your launching method
UIAccelerometer * accel = [UIAccelerometer sharedAccelerometer];
accel.delegate = self;
//delegate method:
-(void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration{
// use the y-property of the acceleration
}
Look at the CMMotionManager class reference and search section named "Handing Motion Updates at Specified Intervals". In the "Accelerometer" bullet, it says
Set the accelerometerUpdateInterval property to specify an update interval. Call the startAccelerometerUpdatesToQueue:withHandler: method, passing in a block of type CMAccelerometerHandler. Accelerometer data is passed into the block as CMAccelerometerData objects.
CMAccelerometerData has a reference to CMAcceleration which is a struct that holds per axis acceleration.
Here is my code:
- (void) viewWillAppear:(BOOL)animated
{
// SETUP THE LOCATION MANAGER.
self.locManager = [[CLLocationManager alloc] init];
self.locManager.delegate = self;
[self.locManager startUpdatingLocation];
}
- (void) viewWillDisappear:(BOOL)animated
{
[self.locManager stopUpdatingLocation];
[self.locManager.delegate release];
}
When the View Controller exits the CLLocationManager arrow logo in the top right corner is still showing. This is both on iOS 4.3 and 5.0. Any explanation?
I believe the system indicates the location badge on any app that has used Core Location in last hour or so.
The purple arrow should disappear as soon as you call:
[self.locManager stopUpdatingLocation];
While allocating your locManager, you need not call self.locManager. That will bump up the retain count to 2. Instead use:
locManager = [[CLLocationManager alloc] init];
Also, put a breakpoint in your viewWillDisappear: method and make sure it does get called. Also, set the delegate to nil at the end.
After following these points, your code shall work.
The purple arrow is for Location Services and consumes battery heavily. Make sure the arrow disappears as soon as you call stopUpdatingLocation: