使用颤振的设备的定期位置报告答案

【问题标题】：Periodic location report of device using flutter使用颤振的设备的定期位置报告
【发布时间】：2019-09-08 12:57:23
【问题描述】：

我需要使用 Flutter 应用报告设备的当前位置。即使应用程序关闭，我也需要继续这样做。我目前使用background_fetch 实现它，它大约每 15 分钟完成一次。当应用程序打开或最小化时，它运行良好。但是当应用程序关闭时，它会在 Headless 模式下运行，并且不起作用。例外是：

MissingPluginException(No implementation found for method getLocation on channel lyokone/location)

似乎在 Headless 模式下，并非所有应用程序都加载到内存中。我不知道如何解决它。

我也尝试使用隔离，但遇到了一个新异常：

native function 'Window_sendPlatformMessage' (4 arguments) cannot be found.

有人知道如何解决这些问题或有任何新的想法来进行位置跟踪吗？

【问题讨论】：

标签： android flutter background-fetch

【解决方案1】：

另一种选择是使用包https://github.com/Lyokone/flutterlocation https://github.com/Lyokone/flutterlocation/wiki/Background-Location-Updates
支持即使您的应用关闭也能获取位置更新，https://github.com/Lyokone/flutterlocation/wiki/Background-Location-Updates 可能存在错误

同样来自晶体管软件并提供 Android Headless Mod 但需要许可证
晶体管软件包https://github.com/transistorsoft/flutter_background_geolocation/wiki/Android-Headless-Mode
Android Headless Mod https://github.com/transistorsoft/flutter_background_geolocation/wiki/Android-Headless-Mode

代码sn-p

import 'package:flutter_background_geolocation/flutter_background_geolocation.dart' as bg;

void headlessTask(bg.HeadlessEvent headlessEvent) async {
  print('[BackgroundGeolocation HeadlessTask]: $headlessEvent');
  // Implement a 'case' for only those events you're interested in.
  switch(headlessEvent.name) {
    case bg.Event.TERMINATE:
      bg.State state = headlessEvent.event;
      print('- State: $state');
      break;
    case bg.Event.HEARTBEAT:
      bg.HeartbeatEvent event = headlessEvent.event;
      print('- HeartbeatEvent: $event');
      break;
    case bg.Event.LOCATION:
      bg.Location location = headlessEvent.event;
      print('- Location: $location');
      break;
    case bg.Event.MOTIONCHANGE:
      bg.Location location = headlessEvent.event;
      print('- Location: $location');
      break;
    case bg.Event.GEOFENCE:
      bg.GeofenceEvent geofenceEvent = headlessEvent.event;
      print('- GeofenceEvent: $geofenceEvent');
      break;
    case bg.Event.GEOFENCESCHANGE:
      bg.GeofencesChangeEvent event = headlessEvent.event;
      print('- GeofencesChangeEvent: $event');
      break;
    case bg.Event.SCHEDULE:
      bg.State state = headlessEvent.event;
      print('- State: $state');
      break;
    case bg.Event.ACTIVITYCHANGE:
      bg.ActivityChangeEvent event = headlessEvent.event;
      print('ActivityChangeEvent: $event');
      break;
    case bg.Event.HTTP:
      bg.HttpEvent response = headlessEvent.event;
      print('HttpEvent: $response');
      break;
    case bg.Event.POWERSAVECHANGE:
      bool enabled = headlessEvent.event;
      print('ProviderChangeEvent: $enabled');
      break;
    case bg.Event.CONNECTIVITYCHANGE:
      bg.ConnectivityChangeEvent event = headlessEvent.event;
      print('ConnectivityChangeEvent: $event');
      break;
    case bg.Event.ENABLEDCHANGE:
      bool enabled = headlessEvent.event;
      print('EnabledChangeEvent: $enabled');
      break;
  }
}

void main() {
  runApp(HelloWorld());
  // Register your headlessTask:
  BackgroundGeolocation.registerHeadlessTask(headlessTask);
}

【讨论】：