从后台任务启动 iOS 7 中的位置管理器

Start Location Manager in iOS 7 from background task

提问by sash

It seems that in iOS 7 an app can not start Location Manager (by calling startUpdatingLocation) from the background task anymore.

似乎在 iOS 7 中，应用程序无法再从后台任务启动位置管理器（通过调用 startUpdatingLocation）。

In iOS 6 I used approach described here: https://stackoverflow.com/a/6465280to run background location update every n minutes. The idea was to run background task with a timer and start Location Manager when the timer triggers it. After that turn off Location Manager and start another background task.

在 iOS 6 中，我使用此处描述的方法：https: //stackoverflow.com/a/6465280每 n 分钟运行一次后台位置更新。这个想法是使用计时器运行后台任务并在计时器触发时启动位置管理器。之后关闭位置管理器并启动另一个后台任务。

After updating to iOS 7 this approach does not work anymore. After starting Location Manager an app does not receive any locationManager:didUpdateLocations. Any ideas?

更新到 iOS 7 后，此方法不再适用。启动位置管理器后，应用程序不会收到任何 locationManager:didUpdateLocations。有任何想法吗？

回答by sash

I found the problem/solution. When it is time to start location service and stop background task, background task should be stopped with a delay (I used 1 second). Otherwise location service wont start. Also Location Service should be left ON for a couple of seconds (in my example it is 3 seconds).

我找到了问题/解决方案。当需要启动位置服务和停止后台任务时，应延迟停止后台任务（我使用了 1 秒）。否则定位服务不会启动。此外，定位服务应保持开启几秒钟（在我的示例中为 3 秒）。

Another important notice, max background time in iOS 7 is now 3 minutes instead of 10 minutes.

另一个重要的注意事项，iOS 7 中的最长后台时间现在是 3 分钟而不是 10 分钟。

Updated on October 29 '16

2016 年 10 月 29 日更新

There is a cocoapod APScheduledLocationManagerthat allows to get background location updates every nseconds with desired location accuracy.

有一个 cocoapod APScheduledLocationManager允许每n秒获取一次具有所需位置精度的后台位置更新。

let manager = APScheduledLocationManager(delegate: self)
manager.startUpdatingLocation(interval: 170, acceptableLocationAccuracy: 100)

The repository also contains an example app written in Swift 3.

该存储库还包含一个用 Swift 3 编写的示例应用程序。

Updated on May 27 '14

2014 年 5 月 27 日更新

Objective-C example:

Objective-C 示例：

1) In ".plist" file set UIBackgroundModesto "location".

1) 在“.plist”文件中设置UIBackgroundModes为“location”。

2) Create instance of ScheduledLocationManageranywhere you want.

2）在ScheduledLocationManager任何你想要的地方创建实例。

@property (strong, nonatomic) ScheduledLocationManager *slm;

3) Set it up

3）设置

self.slm = [[ScheduledLocationManager alloc]init];
self.slm.delegate = self;
[self.slm getUserLocationWithInterval:60]; // replace this value with what you want, but it can not be higher than kMaxBGTime

4) Implement delegate methods

4) 实现委托方法

-(void)scheduledLocationManageDidFailWithError:(NSError *)error
{
    NSLog(@"Error %@",error);
}

-(void)scheduledLocationManageDidUpdateLocations:(NSArray *)locations
{
    // You will receive location updates every 60 seconds (value what you set with getUserLocationWithInterval)
    // and you will continue to receive location updates for 3 seconds (value of kTimeToGetLocations).
    // You can gather and pick most accurate location
    NSLog(@"Locations %@",locations);
}

Here is implementation of ScheduledLocationManager:

这是 ScheduledLocationManager 的实现：

ScheduledLocationManager.h

预定位置管理器.h

#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>

@protocol ScheduledLocationManagerDelegate <NSObject>

-(void)scheduledLocationManageDidFailWithError:(NSError*)error;
-(void)scheduledLocationManageDidUpdateLocations:(NSArray*)locations;

@end

@interface ScheduledLocationManager : NSObject <CLLocationManagerDelegate>

-(void)getUserLocationWithInterval:(int)interval;

@end

ScheduledLocationManager.m

ScheduledLocationManager.m

#import "ScheduledLocationManager.h"

int const kMaxBGTime = 170; // 3 min - 10 seconds (as bg task is killed faster)
int const kTimeToGetLocations = 3; // time to wait for locations

@implementation ScheduledLocationManager
{
    UIBackgroundTaskIdentifier bgTask;
    CLLocationManager *locationManager;
    NSTimer *checkLocationTimer;
    int checkLocationInterval;
    NSTimer *waitForLocationUpdatesTimer;
}

- (id)init
{
    self = [super init];
    if (self) {
        locationManager = [[CLLocationManager alloc] init];
        locationManager.delegate = self;
        locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        locationManager.distanceFilter = kCLDistanceFilterNone;

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationDidEnterBackground:) name:UIApplicationDidEnterBackgroundNotification object:nil];
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationDidBecomeActive:) name:UIApplicationDidBecomeActiveNotification object:nil];
    }
    return self;
}

-(void)getUserLocationWithInterval:(int)interval
{
    checkLocationInterval = (interval > kMaxBGTime)? kMaxBGTime : interval;
    [locationManager startUpdatingLocation];
}

- (void)timerEvent:(NSTimer*)theTimer
{
    [self stopCheckLocationTimer];
    [locationManager startUpdatingLocation];

    // in iOS 7 we need to stop background task with delay, otherwise location service won't start
    [self performSelector:@selector(stopBackgroundTask) withObject:nil afterDelay:1];
}

-(void)startCheckLocationTimer
{
    [self stopCheckLocationTimer];
    checkLocationTimer = [NSTimer scheduledTimerWithTimeInterval:checkLocationInterval target:self selector:@selector(timerEvent:) userInfo:NULL repeats:NO];
}

-(void)stopCheckLocationTimer
{
    if(checkLocationTimer){
        [checkLocationTimer invalidate];
        checkLocationTimer=nil;
    }
}

-(void)startBackgroundTask
{
    [self stopBackgroundTask];
    bgTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
        //in case bg task is killed faster than expected, try to start Location Service
        [self timerEvent:checkLocationTimer];
    }];
}

-(void)stopBackgroundTask
{
    if(bgTask!=UIBackgroundTaskInvalid){
        [[UIApplication sharedApplication] endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    }
}

-(void)stopWaitForLocationUpdatesTimer
{
    if(waitForLocationUpdatesTimer){
        [waitForLocationUpdatesTimer invalidate];
        waitForLocationUpdatesTimer =nil;
    }
}

-(void)startWaitForLocationUpdatesTimer
{
    [self stopWaitForLocationUpdatesTimer];
    waitForLocationUpdatesTimer = [NSTimer scheduledTimerWithTimeInterval:kTimeToGetLocations target:self selector:@selector(waitForLoactions:) userInfo:NULL repeats:NO];
}

- (void)waitForLoactions:(NSTimer*)theTimer
{
    [self stopWaitForLocationUpdatesTimer];

    if(([[UIApplication sharedApplication ]applicationState]==UIApplicationStateBackground ||
        [[UIApplication sharedApplication ]applicationState]==UIApplicationStateInactive) &&
       bgTask==UIBackgroundTaskInvalid){
        [self startBackgroundTask];
    }

    [self startCheckLocationTimer];
    [locationManager stopUpdatingLocation];
}

#pragma mark - CLLocationManagerDelegate methods

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    if(checkLocationTimer){
        //sometimes it happens that location manager does not stop even after stopUpdationLocations
        return;
    }

    if (self.delegate && [self.delegate respondsToSelector:@selector(scheduledLocationManageDidUpdateLocations:)]) {
        [self.delegate scheduledLocationManageDidUpdateLocations:locations];
    }

    if(waitForLocationUpdatesTimer==nil){
        [self startWaitForLocationUpdatesTimer];
    }
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    if (self.delegate && [self.delegate respondsToSelector:@selector(scheduledLocationManageDidFailWithError:)]) {
        [self.delegate scheduledLocationManageDidFailWithError:error];
    }
}

#pragma mark - UIAplicatin notifications

- (void)applicationDidEnterBackground:(NSNotification *) notification
{
    if([self isLocationServiceAvailable]==YES){
        [self startBackgroundTask];
    }
}

- (void)applicationDidBecomeActive:(NSNotification *) notification
{
    [self stopBackgroundTask];
    if([self isLocationServiceAvailable]==NO){
        NSError *error = [NSError errorWithDomain:@"your.domain" code:1 userInfo:[NSDictionary dictionaryWithObject:@"Authorization status denied" forKey:NSLocalizedDescriptionKey]];

        if (self.delegate && [self.delegate respondsToSelector:@selector(scheduledLocationManageDidFailWithError:)]) {
            [self.delegate scheduledLocationManageDidFailWithError:error];
        }
    }
}

#pragma mark - Helpers

-(BOOL)isLocationServiceAvailable
{
    if([CLLocationManager locationServicesEnabled]==NO ||
       [CLLocationManager authorizationStatus]==kCLAuthorizationStatusDenied ||
       [CLLocationManager authorizationStatus]==kCLAuthorizationStatusRestricted){
        return NO;
    }else{
        return YES;
    }
}

@end

回答by Ricky

I tried your method but it didn't work on my side. Can you show me your code?

我试过你的方法，但对我来说不起作用。你能告诉我你的代码吗？

I actually found a solution to solve the location service problem in iOS 7.

我实际上找到了解决iOS 7中位置服务问题的解决方案。

In iOS 7, you can not start the location service in background. If you want the location service to keep running in the background, you have to start it in foregroundand it will continue to run in the background.

在 iOS 7 中，您无法在后台启动位置服务。如果你想让定位服务一直在后台运行，你必须在前台启动它，它会继续在后台运行。

If you were like me, stop the location service and use timer to re-start it in the background, it will NOT work in iOS 7.

如果你像我一样，停止定位服务并使用计时器在后台重新启动它，它在 iOS 7 中不起作用。

For more detailed information, you can watch the first 8 minutes of video 307 from WWDC 2013: https://developer.apple.com/wwdc/videos/

更多详细信息，您可以观看 WWDC 2013 视频 307 的前 8 分钟：https: //developer.apple.com/wwdc/videos/

Update:The location service can work in backgroundas well. Please check Background Location Services not working in iOS 7for the updated post with complete solution posted on Github and a blog post explaining the details.

更新：位置服务也可以在后台工作。请检查后台定位服务在 iOS 7 中不工作以获取更新后的帖子，其中包含在 Github 上发布的完整解决方案和解释详细信息的博客帖子。

回答by Utkarsh Goel

Steps to get this implemented are as follows:

实现这一点的步骤如下：

1. Add "App registers for location updates" at item 0 in "Required background modes" in info.plist of your project.

2. Write below code at application did finish launching.

   [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(startFetchingLocationsContinously) name:START_FETCH_LOCATION object:nil];
   

3. Write below code from where you want to start tracking

   [[NSNotificationCenter defaultCenter] postNotificationName:START_FETCH_LOCATION object:nil];
   
   AppDelegate *appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
               [appDelegate startUpdatingDataBase];
   

4. Paste following code to AppDelegate.m

   #pragma mark - Location Update
   -(void)startFetchingLocationsContinously{
       NSLog(@"start Fetching Locations");
       self.locationUtil = [[LocationUtil alloc] init];
       [self.locationUtil setDelegate:self];
       [self.locationUtil startLocationManager];
   }
   
   -(void)locationRecievedSuccesfullyWithNewLocation:(CLLocation*)newLocation oldLocation:(CLLocation*)oldLocation{
       NSLog(@"location received successfullly in app delegate for Laitude: %f and Longitude:%f, and Altitude:%f, and Vertical Accuracy: %f",newLocation.coordinate.latitude,newLocation.coordinate.longitude,newLocation.altitude,newLocation.verticalAccuracy);
   }
   
   -(void)startUpdatingDataBase{
       UIApplication*    app = [UIApplication sharedApplication];
   
       bgTask = UIBackgroundTaskInvalid;
   
       bgTask = [app beginBackgroundTaskWithExpirationHandler:^(void){
           [app endBackgroundTask:bgTask];
       }];
   
       SAVE_LOCATION_TIMER =  [NSTimer scheduledTimerWithTimeInterval:300
                                                               target:self selector:@selector(startFetchingLocationsContinously) userInfo:nil repeats:YES];
   }
   

5. Add a class by name "LocationUtil" and paste following code into the header file:

   #import <Foundation/Foundation.h>
   #import <CoreLocation/CoreLocation.h>
   @protocol LocationRecievedSuccessfully <NSObject>
   @optional
   -(void)locationRecievedSuccesfullyWithNewLocation:(CLLocation*)newLocation oldLocation:(CLLocation*)oldLocation;
   -(void)addressParsedSuccessfully:(id)address;
   
   @end
   @interface LocationUtil : NSObject <CLLocationManagerDelegate> {
   }
   
   //Properties
   @property (nonatomic,strong) id<LocationRecievedSuccessfully> delegate;
   -(void)startLocationManager;
   

   And paste following code in LocationUtil.m

   -(void)startLocationManager{
   
        locationManager = [[CLLocationManager alloc] init];
        locationManager.delegate = self;
        [locationManager setPausesLocationUpdatesAutomatically:YES]; //Utkarsh 20sep2013
        //[locationManager setActivityType:CLActivityTypeFitness];
        locationManager.distanceFilter = kCLDistanceFilterNone;
        locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
        [locationManager startUpdatingLocation];
   
        //Reverse Geocoding.
        geoCoder=[[CLGeocoder alloc] init];
   
       //set default values for reverse geo coding.
   }
   
   //for iOS<6
   - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
     //call delegate Method
     [delegate locationRecievedSuccesfullyWithNewLocation:newLocation oldLocation:oldLocation];
   
     NSLog(@"did Update Location");
   }
   
   //for iOS>=6.
   
   - (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
   
     CLLocation *newLocation = [locations objectAtIndex:0];
     CLLocation *oldLocation = [locations objectAtIndex:0];
   
     [delegate locationRecievedSuccesfullyWithNewLocation:newLocation oldLocation:oldLocation];
     NSLog(@"did Update Locationsssssss");
   }
   

1. 在项目的 info.plist 的“必需的后台模式”中的第 0 项添加“应用程序注册位置更新”。

2. 在应用程序完成启动时写入下面的代码。

   [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(startFetchingLocationsContinously) name:START_FETCH_LOCATION object:nil];
   

3. 从您要开始跟踪的位置编写以下代码

   [[NSNotificationCenter defaultCenter] postNotificationName:START_FETCH_LOCATION object:nil];
   
   AppDelegate *appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
               [appDelegate startUpdatingDataBase];
   

4. 将以下代码粘贴到 AppDelegate.m

   #pragma mark - Location Update
   -(void)startFetchingLocationsContinously{
       NSLog(@"start Fetching Locations");
       self.locationUtil = [[LocationUtil alloc] init];
       [self.locationUtil setDelegate:self];
       [self.locationUtil startLocationManager];
   }
   
   -(void)locationRecievedSuccesfullyWithNewLocation:(CLLocation*)newLocation oldLocation:(CLLocation*)oldLocation{
       NSLog(@"location received successfullly in app delegate for Laitude: %f and Longitude:%f, and Altitude:%f, and Vertical Accuracy: %f",newLocation.coordinate.latitude,newLocation.coordinate.longitude,newLocation.altitude,newLocation.verticalAccuracy);
   }
   
   -(void)startUpdatingDataBase{
       UIApplication*    app = [UIApplication sharedApplication];
   
       bgTask = UIBackgroundTaskInvalid;
   
       bgTask = [app beginBackgroundTaskWithExpirationHandler:^(void){
           [app endBackgroundTask:bgTask];
       }];
   
       SAVE_LOCATION_TIMER =  [NSTimer scheduledTimerWithTimeInterval:300
                                                               target:self selector:@selector(startFetchingLocationsContinously) userInfo:nil repeats:YES];
   }
   

5. 按名称“LocationUtil”添加一个类并将以下代码粘贴到头文件中：

   #import <Foundation/Foundation.h>
   #import <CoreLocation/CoreLocation.h>
   @protocol LocationRecievedSuccessfully <NSObject>
   @optional
   -(void)locationRecievedSuccesfullyWithNewLocation:(CLLocation*)newLocation oldLocation:(CLLocation*)oldLocation;
   -(void)addressParsedSuccessfully:(id)address;
   
   @end
   @interface LocationUtil : NSObject <CLLocationManagerDelegate> {
   }
   
   //Properties
   @property (nonatomic,strong) id<LocationRecievedSuccessfully> delegate;
   -(void)startLocationManager;
   

   并在 LocationUtil.m 中粘贴以下代码

   -(void)startLocationManager{
   
        locationManager = [[CLLocationManager alloc] init];
        locationManager.delegate = self;
        [locationManager setPausesLocationUpdatesAutomatically:YES]; //Utkarsh 20sep2013
        //[locationManager setActivityType:CLActivityTypeFitness];
        locationManager.distanceFilter = kCLDistanceFilterNone;
        locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
        [locationManager startUpdatingLocation];
   
        //Reverse Geocoding.
        geoCoder=[[CLGeocoder alloc] init];
   
       //set default values for reverse geo coding.
   }
   
   //for iOS<6
   - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
     //call delegate Method
     [delegate locationRecievedSuccesfullyWithNewLocation:newLocation oldLocation:oldLocation];
   
     NSLog(@"did Update Location");
   }
   
   //for iOS>=6.
   
   - (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
   
     CLLocation *newLocation = [locations objectAtIndex:0];
     CLLocation *oldLocation = [locations objectAtIndex:0];
   
     [delegate locationRecievedSuccesfullyWithNewLocation:newLocation oldLocation:oldLocation];
     NSLog(@"did Update Locationsssssss");
   }