ios - 当 iOS 应用程序在后台甚至被杀死时获取它的位置

Question

我的应用程序需要在应用程序处于事件状态以及处于非事件状态和被终止时获取用户的位置。当用户的位置靠近商店时，应用程序必须发送本地通知。

我不确定到底发生了什么，但我无法让我的应用在后台获取位置并在被杀死时将其唤醒。

我有一个位置管理器(单例，用于 whenInUse 和 Always 两种情况)，并且我在 .plist 中定义了 NSLocationAlwaysUsageDescription 和 NSLocationWhenInUseUsageDescription

我正在做的是:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    //The app has been killed/terminated (not in background) by iOS or the user.
    if ([launchOptions objectForKey:UIApplicationLaunchOptionsLocationKey]){

        _locationManager = [CoreLocationManager sharedInstance];
        _locationManager.isAppActive = NO;
        _locationManager.locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
        _locationManager.locationManager.activityType = CLActivityTypeOtherNavigation;

        if ([_locationManager.locationManager respondsToSelector:@selector(requestAlwaysAuthorization)]) {
            [_locationManager.locationManager requestAlwaysAuthorization];
        }

        [_locationManager addLocationManagerDelegate:self];
    }
}


- (void)applicationDidBecomeActive:(UIApplication *)application
{
    if (_locationManager.locationManager){
        _locationManager.isAppActive = YES;
        [_locationManager.locationManager stopMonitoringSignificantLocationChanges];
    }

    _locationManager = [CoreLocationManager sharedInstance];

    if ([_locationManager respondsToSelector:@selector(requestAlwaysAuthorization)]) {
        [_locationManager.locationManager requestAlwaysAuthorization];
    }

    if ([_locationManager.locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
        [_locationManager.locationManager requestWhenInUseAuthorization];
    }

    [_locationManager addLocationManagerDelegate:self];

    [_locationManager.locationManager startUpdatingLocation];

}


- (void)applicationDidEnterBackground:(UIApplication *)application
{
    _locationManager.isAppActive = NO;

    if (_locationManager.locationManager){
        [_locationManager.locationManager stopUpdatingLocation];
        [_locationManager.locationManager stopMonitoringSignificantLocationChanges];
    }

    if ([_locationManager.locationManager respondsToSelector:@selector(requestAlwaysAuthorization)]) {
        [_locationManager.locationManager requestAlwaysAuthorization];
    }

    [_locationManager.locationManager startMonitoringSignificantLocationChanges];

}

我做错了吗？我不确定是否绝对有必要使用地理围栏，但对于我通过 startMonitoringSignificantLocationChanges 阅读的内容就足够了。

Answer 1

要在后台获取位置，请使用以下代码。每次重新启动后台任务，将使您的应用程序在后台运行很长时间。

要使用它，您需要在项目设置的Capabilities中打开Background ModeBackground Fetch和Location Updates 开启。

- (void)applicationDidEnterBackground:(UIApplication *)application {

    if ([[UIDevice currentDevice] respondsToSelector:@selector(isMultitaskingSupported)]) { //Check if our iOS version supports multitasking I.E iOS 4

        if ([[UIDevice currentDevice] isMultitaskingSupported]) { //Check if device supports mulitasking
            UIApplication *application = [UIApplication sharedApplication]; //Get the shared application instance

            __block UIBackgroundTaskIdentifier background_task; //Create a task object

            background_task = [application beginBackgroundTaskWithExpirationHandler: ^{
                [application endBackgroundTask:background_task]; //Tell the system that we are done with the tasks
                background_task = UIBackgroundTaskInvalid; //Set the task to be invalid
                //System will be shutting down the app at any point in time now
            }];
        }
    }
}