ios - 电池电量不足时如何暂停(和恢复)后台位置监控？

Question

我正在为 iOS 7.1 (iPhone) 编写一个位置跟踪应用程序，它需要在电池电量为 30% 或更低时停止或暂停后台位置监控。当电池电量改善时，位置监控应在后台恢复。我怎样才能做到这一点？我正在使用重要的位置更改更新(CLLocationManager API 方法)进行后台位置监控。

谢谢!

Answer 1

根据 startMonitoringSignificantLocationChanges: 的文档

If you start this service and your application is subsequently terminated, the system automatically relaunches the application into the background if a new event arrives. In such a case, the options dictionary passed to the application:didFinishLaunchingWithOptions: method of your application delegate contains the key UIApplicationLaunchOptionsLocationKey to indicate that your application was launched because of a location event. Upon relaunch, you must still configure a location manager object and call this method to continue receiving location events. When you restart location services, the current event is delivered to your delegate immediately. In addition, the location property of your location manager object is populated with the most recent location object even before you start location services.

第一步:-

因此，当应用程序在后台启动时，请检查 UIApplicationLaunchOptionsLocationKey 的启动选项键。然后您将了解位置事件的应用程序启动原因。

The application tracks location updates in the background, was purged, and has now been relaunched. In this case, the dictionary contains a key indicating that the application was relaunched because of a new location event.

第二步:- 获取电量百分比

//This will give you the battery between 0.0 (empty) and 1.0 (100% charged)
[[UIDevice currentDevice] setBatteryMonitoringEnabled:YES];
float batteryLevel = [[UIDevice currentDevice] batteryLevel];

//If you want it as a percentage, you can do this:
batteryLevel *= 100;

第三步:- 检查应用程序状态(如果需要的话)

如果应用程序在后台，则执行下一步

[UIApplication sharedApplication].applicationState == UIApplicationStateBackground

第四步:- 停止监控重大位置变化

应用检查电池百分比，如果低于 30%，则停止监控位置更新。

如果您发现电池电量超过 30% 且未启用位置监控，则 startMonitoringLocationUpdate

此检查可以在 didUpdateToLocation:fromLocation 中完成，并且可以在应用程序激活时或根据您的应用程序要求进行。

希望这对你有帮助......!!!