iOS 7 では、アプリはバックグラウンド タスクから (startUpdatingLocation を呼び出して) Location Manager を起動できなくなったようです。
iOS 6 では、 https ://stackoverflow.com/a/6465280 で説明されているアプローチを使用して、n 分ごとにバックグラウンドでの位置情報の更新を実行しました。アイデアは、タイマーを使用してバックグラウンド タスクを実行し、タイマーがトリガーされたときに Location Manager を開始することでした。その後、Location Manager をオフにして、別のバックグラウンド タスクを開始します。
iOS 7 にアップデートした後、このアプローチは機能しなくなりました。Location Manager を開始した後、アプリは locationManager:didUpdateLocations を受け取りません。何か案は？
問題/解決策を見つけました。位置情報サービスを開始してバックグラウンド タスクを停止する時間になると、バックグラウンド タスクは遅延して停止する必要があります (私は 1 秒を使用しました)。そうしないと、位置情報サービスが開始されません。また、位置情報サービスを数秒間オンのままにしておく必要があります (私の例では 3 秒です)。
もう 1 つの重要な通知として、iOS 7 の最大バックグラウンド時間が 10 分ではなく 3 分になりました。
16年10月29日更新
必要な位置精度でn秒ごとにバックグラウンド位置更新を取得できるcocoapod APScheduledLocationManagerがあります。
let manager = APScheduledLocationManager(delegate: self)
manager.startUpdatingLocation(interval: 170, acceptableLocationAccuracy: 100)
リポジトリには、Swift 3 で記述されたサンプル アプリも含まれています。
2014 年 5 月 27 日更新
Objective-C の例:
UIBackgroundModes1) 「場所」に設定された「.plist」ファイル。
2) 必要な場所のインスタンスを作成しますScheduledLocationManager。
@property (strong, nonatomic) ScheduledLocationManager *slm;
3) 設定する
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) デリゲート メソッドを実装する
-(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);
}
以下は、ScheduledLocationManager の実装です。
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
これを実装する手順は次のとおりです。
プロジェクトの info.plist の「必要なバックグラウンド モード」の項目 0 に「位置情報更新用のアプリ登録」を追加します。
アプリケーションが起動を完了したときに以下のコードを記述します。
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(startFetchingLocationsContinously) name:START_FETCH_LOCATION object:nil];
追跡を開始したい場所から以下のコードを記述します
[[NSNotificationCenter defaultCenter] postNotificationName:START_FETCH_LOCATION object:nil];
AppDelegate *appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
[appDelegate startUpdatingDataBase];
次のコードを AppDelegate.m に貼り付けます
#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];
}
「LocationUtil」という名前でクラスを追加し、次のコードをヘッダー ファイルに貼り付けます。
#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;
次のコードを LocationUtil.m に貼り付けます。
-(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");
}