从后台任务启动iOS 7中的位置管理器

Question

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）。

在iOS 6中，我使用了这里描述的方法： https ： //stackoverflow.com/a/6465280每n分钟运行一次后台位置更新。 我们的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。

更新到iOS 7后，此方法不再起作用。 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？

Answer 1

我发现了问题/解决方案。 当是时候启动位置服务并停止后台任务时，应该延迟后台任务（我使用1秒钟）。 否则位置服务不会启动。 位置服务也应保持开启几秒钟（在我的例子中，它是3秒）。

另一个重要的通知，iOS 7中的最长后台时间现在是3分钟而不是10分钟。

于16年10月29日更新

有一个cocoapod APScheduledLocationManager ，它允许每n秒获得具有所需位置精度的背景位置更新。

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

存储库还包含一个用Swift 3编写的示例应用程序。

于14年5月27日更新

Objective-C示例：

1）在“.plist”文件中将UIBackgroundModes设置为“location”。

2）在任何地方创建ScheduledLocationManager实例。

@property (strong, nonatomic) ScheduledLocationManager *slm;

3）设置它

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）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);
}

这是ScheduledLocationManager的实现：

ScheduledLocationManager.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

#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

Answer 2

我试过你的方法，但它不适合我。 你能告诉我你的代码吗？

我实际上找到了解决iOS 7中位置服务问题的解决方案。

在iOS 7中，您无法在后台启动位置服务。 如果您希望位置服务在后台继续运行，则必须在前台启动它，它将继续在后台运行。

如果你像我一样，停止位置服务并使用计时器在后台重新启动它，它将无法在iOS 7中运行。

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

更新：位置服务也可以在后台运行 。 请检查在iOS 7中无效的后台位置服务，以获取在Github上发布的完整解决方案的更新帖子以及解释详细信息的博客文章。

Answer 3

实现这一目标的步骤如下：

1. 在项目的info.plist中的“所需后台模式”中的项目0处添加“应用程序寄存器以进行位置更新”。

2. 在应用程序上写下面的代码确实完成了启动。

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

3. 在下面写下您要开始跟踪的代码

    [[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"); }