当应用程序被杀死时，如何获取准确的位置更新? [英] How to get accurate location update when application is killed?

问题描述

我正在开发一个基于位置的应用程序，用户可以在其中存储多个位置，并且当用户经过该存储位置附近时，应用程序将通过本地通知来通知用户.

I'm developing a location based application where user can stored number of locations and when user passed near by that stored location, application will notify user by local notification.

我使用以下代码来实现此功能:

I've used following code to achieve this feature:

-(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   if([[UIApplication sharedApplication] backgroundRefreshStatus] == UIBackgroundRefreshStatusDenied){

         [self showAlertWithTitle:@"" andMessage:@"The app doesn't work without the Background App Refresh enabled. To turn it on, go to Settings > General > Background App Refresh."];
  }else if([[UIApplication sharedApplication] backgroundRefreshStatus] == UIBackgroundRefreshStatusRestricted){

    [self showAlertWithTitle:@"" andMessage:@"The functions of this app are limited because the Background App Refresh is disable."];
  } else {
    if ([launchOptions objectForKey:UIApplicationLaunchOptionsLocationKey]) {

        // This "afterResume" flag is just to show that he receiving location updates
        self.shareModel.afterResume = YES;

        self.shareModel.anotherLocationManager = [[CLLocationManager alloc]init];
        self.shareModel.anotherLocationManager.delegate = self;
        self.shareModel.anotherLocationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; //kCLLocationAccuracyBestForNavigation
        self.shareModel.anotherLocationManager.activityType = CLActivityTypeOtherNavigation;
        [self.shareModel.anotherLocationManager startUpdatingLocation];
                 self.shareModel.anotherLocationManager.pausesLocationUpdatesAutomatically = YES;


        if(IS_OS_8_OR_LATER) {
            if ([self.shareModel.anotherLocationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
                [self.shareModel.anotherLocationManager requestWhenInUseAuthorization];
            }
            [self.shareModel.anotherLocationManager requestAlwaysAuthorization];
        }

        [self.shareModel.anotherLocationManager startMonitoringSignificantLocationChanges];
    }
  }
}

---

-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {

CLLocation *currentLocation = [locations lastObject];

latitudeTemp = currentLocation.coordinate.latitude;
longitudeTemp = currentLocation.coordinate.longitude;

[self locationChangeLogic];    

//If the timer still valid, return it (Will not run the code below)
if (self.shareModel.timer)
    return;

self.shareModel.bgTask = [BackgroundTaskManager sharedBackgroundTaskManager];
[self.shareModel.bgTask beginNewBackgroundTask];

//Restart the locationMaanger after 30 Seconds
self.shareModel.timer = [NSTimer scheduledTimerWithTimeInterval:30
                                                         target:self
                                                       selector:@selector (restartLocationUpdates)
                                                       userInfo:nil
                                                        repeats:YES];

//Will only stop the locationManager after 10 seconds, so that we can get some accurate locations
//The location manager will only operate for 10 seconds to save battery
NSTimer * delay10Seconds;
delay10Seconds = [NSTimer scheduledTimerWithTimeInterval:10
                                                  target:self
                                                selector:@selector(stopLocationDelayBy10Seconds)
                                                userInfo:nil
                                                 repeats:YES];
}

---

- (void)applicationDidEnterBackground:(UIApplication *)application {
      [self.shareModel.anotherLocationManager startMonitoringSignificantLocationChanges];
}

---

- (void)applicationDidBecomeActive:(UIApplication *)application {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.


//Remove the "afterResume" Flag after the app is active again.
self.shareModel.afterResume = NO;

if(self.shareModel.anotherLocationManager)
    [self.shareModel.anotherLocationManager stopMonitoringSignificantLocationChanges];

self.shareModel.anotherLocationManager = [[CLLocationManager alloc]init];
self.shareModel.anotherLocationManager.delegate = self;
self.shareModel.anotherLocationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; //kCLLocationAccuracyBestForNavigation;
self.shareModel.anotherLocationManager.activityType = CLActivityTypeOtherNavigation;
[self.shareModel.anotherLocationManager startUpdatingLocation];

if(IS_OS_8_OR_LATER) {
    if ([self.shareModel.anotherLocationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
        [self.shareModel.anotherLocationManager requestWhenInUseAuthorization];
    }
    [self.shareModel.anotherLocationManager requestAlwaysAuthorization];
}
[self.shareModel.anotherLocationManager startMonitoringSignificantLocationChanges];
}

---

通过使用以上代码，我甚至可以获得位置被用户杀死的应用程序，但不够准确.有时我没有获得位置，有时我在通过存储的位置后获得了位置.当用户输入该特定半径时，我需要准确显示位置通知.

---

By using above code, i'm able to get location even application killed by User but not as accurate as it should be. Sometime i didn't get location and sometime i get location after passing that stored location. I need to show location notification exactly when user enter in that specific radius.

请帮助我解决此问题.

谢谢.

推荐答案

区域监视(Geofencing)可以满足我的要求.

Region Monitoring (Geofencing) serve my requirement.

您可以使用以下几个链接来获取更多信息:

You can use few following link for more information:

1. https://developer .apple.com/library/ios/documentation/UserExperience/Conceptual/LocationAwarenessPG/RegionMonitoring/RegionMonitoring.html

http://www.rapidvaluesolutions.com/tech_blog/geofencing-using-core-location-for-regional-monitoring-in-ios-applications/

谢谢..

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