Mk Mapview keeps resetting on users location?

问题

I currently have a map displaying 10 or so co ordinates.The map gets the users location and centers on it as soon as it is opened. When panning the page or zooming different levels it eventually resets and centers in on the first position of the user.I have tried "stopupdating location" and Animated as "NO".I can not get it to stay in positon when the user scrolls the map.

- (void)viewDidLoad {
[super viewDidLoad];
self.petrolMap.delegate = self;
self.location = [[CLLocationManager alloc] init];
[location setDelegate:self];
[location setDistanceFilter:0];  // Do not apply a distance filter to the map
[location setDesiredAccuracy:kCLLocationAccuracyBest]; // Use the best accuracy possible when displaying the map
petrolMap.delegate=self; // Display on "Petrol Map" , the mapview for the application}



-(void) mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation{MKCoordinateRegion mapRegion;
mapRegion.center = petrolMap.userLocation.coordinate;
mapRegion.span.latitudeDelta=0.02;
mapRegion.span.longitudeDelta=0.02;
[petrolMap setRegion:mapRegion animated:NO];}

回答1:

Your 'location' is a location manager, when it works out where you are it'll send its delegate

locationManager:didUpdateToLocation:fromLocation:

which you don't seem to have, so all those settings you're doing to 'location' are wasted (as far as the code you've given us, it may be useful elsewhere) and telling it to stop tracking the user is of no use.

"(void) mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation{MKCoordinateRegion mapRegion;" is what petrolMap is sending to its delegate. Somewhere you must have set petrolMap to track the user, it can be done in the .xib.

Anyway, to stop petrolMap sending messages make sure you run

[petrolMap setUserTrackingMode:MKUserTrackingModeNone animated:NO];

Some extra notes:

Within didUpdateUserLocation you don't need to refer to petrolMap directly because the mapView parameter is set to which ever MKMapView sent the message.
Also within didUpdateUserLocation you are using petrolMap's userLocation instead of the parameter userLocation, and even building your region. The entire code for that function could be one line
```
[mapView setRegion:mapRegion animated:NO];
```
'Animated' controls how the change in region is done. Yes means it will slide between locations, No means it will snap from one to the other instantly, either way the map will move to the new region.
Your viewDidLoad method could be cut to two lines like follows
```
[super viewDidLoad];
self.petrolMap.delegate = self;
```

Addendum:

locationManager:didUpdateToLocation:fromLocation

is deprecated in iOS6.

标签

mkmapview