似乎在iOS 7中，应用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。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，此方法不再有效。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？
答案 0 :(得分：43)
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（在我的例子中为3秒）。
另一个重要的通知是，iOS 7中的最长后台时间现在是3分钟而不是10分钟。
于2016年10月29日更新
cocoapod APScheduledLocationManager允许每隔 n 秒获取背景位置更新，并具有所需的位置准确性。
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2014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的实例。
@property (strong, nonatomic) ScheduledLocationManager *slm;
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）实施委托方法
-(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：
<强> 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
<强> 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
答案 1 :(得分：7)
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。请查看Background Location Services not working in iOS 7以获取更新的帖子，其中包含在Github上发布的完整解决方案以及解释详细信息的博客文章。
答案 2 :(得分：6)
实现此目的的步骤如下：
在项目的info.plist中的“所需背景模式”中的项目0处添加“应用程序寄存器以进行位置更新”。
在应用程序完成启动时写下面的代码。
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(startFetchingLocationsContinously) name:START_FETCH_LOCATION object:nil];
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];
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];
}
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");
}