我正在寻找一种方法来获得背景位置更新每n分钟在我的iOS应用程序。我使用的是iOS 4.3,解决方案应该适用于未越狱的iphone。

我尝试/考虑了以下选项:

CLLocationManager startUpdatingLocation/startMonitoringSignificantLocationChanges: This works in the background as expected, based on the configured properties, but it seems not possible to force it to update the location every n minutes NSTimer: Does work when the app is running in the foreground but doesn't seem to be designed for background tasks Local notifications: Local notifications can be scheduled every n minutes, but it's not possible to execute some code to get the current location (without the user having to launch the app via the notification). This approach also doesn't seem to be a clean approach as this is not what notifications should be used for. UIApplication:beginBackgroundTaskWithExpirationHandler: As far as I understand, this should be used to finish some work in the background (also limited in time) when an app is moved to the background rather than implementing "long-running" background processes.

如何实现这些定期的后台位置更新?


当前回答

if ([self.locationManager respondsToSelector:@selector(setAllowsBackgroundLocationUpdates:)]) {
    [self.locationManager setAllowsBackgroundLocationUpdates:YES];
}

自iOS 9以来,这是后台位置跟踪所需要的。

其他回答

给其他做噩梦的人想想这个。我有一个简单的解决办法。

look this example from raywenderlich.com-> have sample code, this works perfectly, but unfortunately no timer during background location. this will run indefinitely. Add timer by using : -(void)applicationDidEnterBackground { [self.locationManager stopUpdatingLocation]; UIApplication* app = [UIApplication sharedApplication]; bgTask = [app beginBackgroundTaskWithExpirationHandler:^{ [app endBackgroundTask:bgTask]; bgTask = UIBackgroundTaskInvalid; }]; self.timer = [NSTimer scheduledTimerWithTimeInterval:intervalBackgroundUpdate target:self.locationManager selector:@selector(startUpdatingLocation) userInfo:nil repeats:YES]; } Just don't forget to add "App registers for location updates" in info.plist.

不幸的是,你所有的假设似乎都是正确的,我认为没有办法做到这一点。为了节省电池寿命,iPhone的定位服务是基于移动的。如果手机放在一个位置,定位服务就看不见它。

CLLocationManager只会在手机接收到位置更新时调用locationManager:didUpdateToLocation:fromLocation:,这只会发生在三个位置服务(蜂窝塔,gps, wifi)之一感知到变化时。

其他一些事情可能有助于进一步的解决方案:

Starting & Stopping the services causes the didUpdateToLocation delegate method to be called, but the newLocation might have an old timestamp. Region Monitoring might help When running in the background, be aware that it may be difficult to get "full" LocationServices support approved by Apple. From what I've seen, they've specifically designed startMonitoringSignificantLocationChanges as a low power alternative for apps that need background location support, and strongly encourage developers to use this unless the app absolutely needs it.

好运!

更新:这些想法现在可能已经过时了。看起来人们在@wjans的回答上取得了成功。

在苹果开发者论坛的帮助下,我找到了一个解决方案:

指定位置背景模式 在后台用UIApplication:beginBackgroundTaskWithExpirationHandler创建一个NSTimer: 当n小于UIApplication: backgroundtimerremain时,它会正常工作。当n较大时,应该在没有剩余时间之前再次启用(并禁用)位置管理器,以避免后台任务被终止。

这是因为位置是三种允许的后台执行类型之一。

注意:我在模拟器中测试了一些时间,在那里它不起作用。不过,它在我的手机上运行得很好。

I did this in an application I'm developing. The timers don't work when the app is in the background but the app is constantly receiving the location updates. I read somewhere in the documentation (i can't seem to find it now, i'll post an update when i do) that a method can be called only on an active run loop when the app is in the background. The app delegate has an active run loop even in the bg so you dont need to create your own to make this work. [Im not sure if this is the correct explanation but thats how I understood from what i read]

首先,在应用的info.plist中添加关键UIBackgroundModes的location对象。现在,你需要做的是启动位置更新在你的应用程序的任何地方:

    CLLocationManager locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;//or whatever class you have for managing location
    [locationManager startUpdatingLocation];

Next, write a method to handle the location updates, say -(void)didUpdateToLocation:(CLLocation*)location, in the app delegate. Then implement the method locationManager:didUpdateLocation:fromLocation of CLLocationManagerDelegate in the class in which you started the location manager (since we set the location manager delegate to 'self'). Inside this method you need to check if the time interval after which you have to handle the location updates has elapsed. You can do this by saving the current time every time. If that time has elapsed, call the method UpdateLocation from your app delegate:

NSDate *newLocationTimestamp = newLocation.timestamp;
NSDate *lastLocationUpdateTiemstamp;

int locationUpdateInterval = 300;//5 mins

NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
if (userDefaults) {

        lastLocationUpdateTiemstamp = [userDefaults objectForKey:kLastLocationUpdateTimestamp];

        if (!([newLocationTimestamp timeIntervalSinceDate:lastLocationUpdateTiemstamp] < locationUpdateInterval)) {
            //NSLog(@"New Location: %@", newLocation);
            [(AppDelegate*)[UIApplication sharedApplication].delegate didUpdateToLocation:newLocation];
            [userDefaults setObject:newLocationTimestamp forKey:kLastLocationUpdateTimestamp];
        }
    }
}

这将每5分钟调用你的方法,即使你的应用程序是在后台。 Imp:这个实现耗尽电池,如果你的位置数据的准确性不是关键,你应该使用[locationManager startMonitoringSignificantLocationChanges]

在将此添加到应用程序之前,请阅读位置感知编程指南

似乎stopUpdatingLocation是什么触发后台看门狗定时器,所以我在didUpdateLocation替换它:

     [self.locationManager setDesiredAccuracy:kCLLocationAccuracyThreeKilometers];
     [self.locationManager setDistanceFilter:99999];

这似乎有效地关闭了GPS。然后,背景NSTimer的选择器变成:

- (void) changeAccuracy {
[self.locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
[self.locationManager setDistanceFilter:kCLDistanceFilterNone];
}

我所做的是每隔几分钟定期切换精度以获得高精度坐标,因为locationManager没有停止,backgroundtimerremain保持在其最大值。这将我的设备上的电池消耗从每小时~10%(在后台使用恒定的kCLLocationAccuracyBest)降低到每小时~2%