iOS：后台定位应用程序使用过多电池

Question

我有一个应用程序，它每 2 分钟在后台获取位置更新，每行驶 25 米。我的问题是，虽然位置跟踪运行良好，但它严重耗尽了我的电池。 24 小时内的电池使用量为 30%，而我的下一个最接近的应用程序为 14%。是否有一些技巧可以减少应用的电池使用量，同时保持位置更新的准确性和时间段？

是否会因为调用 didUpdateLocations: 的频率而耗尽电池电量？或者可能是我在每次位置更新时都在后台与 Web 服务进行通信？我真的不知道如何提高电池使用率，非常感谢任何帮助！

以下是我在 AppDelegate 中用于获取位置并向服务器发送更新的代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     self.locationManager = [CLLocationManager new];
    [self.locationManager setDelegate:self];
    if ([self.locationManager respondsToSelector:@selector(requestAlwaysAuthorization)]) {
        [self.locationManager requestAlwaysAuthorization];
    }
    [self.locationManager startUpdatingLocation];
    [self.locationManager startMonitoringSignificantLocationChanges];

    [self initializeRegionMonitoring];
}

-(void) initializeRegionMonitoring {
    self.locationManager = [[CLLocationManager alloc] init];
    self.locationManager.delegate = self;

    // notify changes when the device has moved x meters
    self.locationManager.distanceFilter = 25; // or set to 20 meters
    self.locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
    [self.locationManager startUpdatingLocation];
    [self.locationManager startMonitoringSignificantLocationChanges];
}

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {

    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSDate *lastDate = [defaults objectForKey:@"lastSavedDate"];

    if ([[NSDate date] timeIntervalSinceDate:lastDate] < 120) {
        NSLog(@"LAST SAVE TIME LESS THAN 2 MINUTES");
        return;
    }

    [self saveLocation];    

    //tell the centralManager that you want to deferred this updatedLocation
    if (isBackgroundMode && !_deferringUpdates)
    {
        NSLog(@"THIS IS GETTING CALLED EVERY TIME");
        _deferringUpdates = YES;
        [self.locationManager allowDeferredLocationUpdatesUntilTraveled:CLLocationDistanceMax timeout:120];
    }
}

- (void) locationManager:(CLLocationManager *)manager didFinishDeferredUpdatesWithError:(NSError *)error {

    _deferringUpdates = NO;
}

-(void) saveLocation {
    // This code saves location data to a web service
}

- (void)applicationWillResignActive:(UIApplication *)application {
    isBackgroundMode = YES;

    [self.locationManager stopUpdatingLocation];
    [self.locationManager setDesiredAccuracy:kCLLocationAccuracyNearestTenMeters];
    [self.locationManager setDistanceFilter:25];
    self.locationManager.pausesLocationUpdatesAutomatically = NO;
    self.locationManager.activityType = CLActivityTypeAutomotiveNavigation;
    [self.locationManager startUpdatingLocation];
}


-(BOOL)application:(UIApplication *)application willFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [[UIApplication sharedApplication] setMinimumBackgroundFetchInterval:UIApplicationBackgroundFetchIntervalMinimum];
    return true;
}

-(void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {

    [self saveLocation];

   completionHandler(UIBackgroundFetchResultNewData);
    NSLog(@"Fetch completed");
}

Answer 1

[self.locationManager setDesiredAccuracy:kCLLocationAccuracyNearestTenMeters];    
[self.locationManager setDistanceFilter:25];

将这些属性更改为不太准确。您可以节省大量电池电量。 这些配置取决于它是什么类型的应用程序。如果它是某种卡路里燃烧应用程序，它可能会非常准确。您每 2 分钟更新一次，因此应将其设置为具有一定阈值的时间所覆盖的近似距离的平均值。

Answer 2

self.locationManager.pausesLocationUpdatesAutomatically=YES;
//monitor locations for significant location change
[self.locationManager startMonitoringSignificantLocationChanges];

如果您的应用不需要用户的准确位置，您可以尝试使用显着的位置更改，这是更优化内存的方式，但最终取决于情况，即高定位精度或电池使用情况更重要。我已经对这种方法进行了重要的测试，通常它每 4-5 分钟或 500 米更新一次位置，以最早者为准。