我在xamarin.forms工作。我想为Android创建后台服务。 我的要求是跟踪设备位置（纬度，经度，地名，员工代码），并在每5分钟后插入网络服务器。成功登录后，服务已启动，对于特定员工，数据将开始插入。即使应用程序已关闭，仍然应该在后台运行服务，并且数据会继续插入。
我的代码是
using Android.App;
using Android.Content;
using Android.Locations;
using Android.Net;
using Android.OS;
using HRMS;
using HRMS.Interface;
using HRMS.TableAttributes;
using Newtonsoft.Json;
using Plugin.Geolocator;
using Plugin.Geolocator.Abstractions;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Threading;
using System.Xml.Linq;
using Xamarin.Forms;
using static HRMS.ServiceLayer.ServiceClasses;
using HRMS.MenuController;
using HRMS.Droid;
using Android.Provider;
namespace SilverHRMS.Droid.Service
{
[Service]
public class GPSTrackingService : Android.App.Service
{
#region Private Variables
static readonly string TAG = "X:" + typeof(GPSTrackingService).Name;
static int TimerWait = 300000; //150000;//25000 25 Sec; // 10 min 600000 and 20 Min 1200000
Timer _timer;
readonly string logTag = "GPSTrackingService";
private string deviceId = "";
private string googleAPI = "http://maps.googleapis.com/maps/api/geocode/xml?latlng={0},{1}&sensor=false";
#endregion
/// <summary>
///
/// </summary>
/// <param name="intent"></param>
/// <param name="flags"></param>
/// <param name="startId"></param>
/// <returns></returns>
public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
{
try
{
// Log.Debug(TAG, "OnStartCommand called at {2}, flags={0}, startid={1}", flags, startId, DateTime.UtcNow);
//_timer = new Timer(o => { Log.Debug(TAG, "Hello from GPSTrackingService. {0}", DateTime.UtcNow); GetCurrentLocation(); }, null, 0, TimerWait);
_timer = new Timer(o => { GetCurrentLocation(); }, null, 0, TimerWait);
//_timer = new Timer(o => { GetCurrentLocation(); }, null, 0, TimerWait);
}
catch (Exception ex)
{
var fileService = DependencyService.Get<ISaveException>();
fileService.SaveTextAsync(App.FileName, ex.StackTrace);
}
return StartCommandResult.Sticky;
}
/// <summary>
///
/// </summary>
/// <param name="intent"></param>
/// <returns></returns>
public override IBinder OnBind(Intent intent)
{
// This example isn't of a bound service, so we just return NULL.
return null;
}
/// <summary>
/// On Destroy App
/// </summary>
public override void OnDestroy()
{
base.OnDestroy();
_timer.Dispose();
_timer = null;
//Log.Debug(logTag, "Service has been terminated");
}
/// <summary>
/// Get Current Location and Insert to DB
/// </summary>
public async void GetCurrentLocation()
{
try
{
string statusMessage = string.Empty;
var locator = CrossGeolocator.Current;
locator.DesiredAccuracy = 100;
//Log.Debug(TAG, " getting GPS connection...");
if (App.MyEmployeeId != null)
{
#region Check Internet Connection
ConnectivityManager connectivityManager = (ConnectivityManager)GetSystemService(ConnectivityService);
NetworkInfo activeConnection = connectivityManager.ActiveNetworkInfo;
bool isOnline = (activeConnection != null) && activeConnection.IsConnected;
#endregion
#region Check GPS Location Position and Emp Code
//LocationManager locationManager = (LocationManager)GetSystemService(LocationService);
bool isGPSOn = App.CheckGPSConnection();
Position position = null;
if (isGPSOn)
{
try
{
position = await locator.GetPositionAsync(timeoutMilliseconds: 10000);
}
catch (Exception)
{
position = null;
}
}
#endregion
#region Insert Location to Local DB or Server DB
//Device Has Internet Connection
if (isOnline)
{
#region Online Location Insert Direct to the Server Database
if (position != null)
{
List<GPSTrackingLocationClass> lcListOnline = new List<GPSTrackingLocationClass>();
GPSTrackingLocationClass objGPSTrack = new GPSTrackingLocationClass();
objGPSTrack.Latitude = position.Latitude;
objGPSTrack.Longitude = position.Longitude;
objGPSTrack.EmpCd = App.MyEmployeeId;
objGPSTrack.GPS_Track_DateTime = App.GetDateTime(DateTime.Now);
IDevice device = DependencyService.Get<IDevice>();
deviceId = device.GetIdentifier();
deviceId = deviceId.Replace("+", "%2B");
objGPSTrack.DeviceId = deviceId;
string url = string.Format(googleAPI, position.Latitude, position.Longitude);
try
{
XElement xml = XElement.Load(url);
if (xml.Element("status").Value == "OK")
{
objGPSTrack.PlaceName = xml.Element("result").Element("formatted_address").Value;
}
else
{
objGPSTrack.PlaceName = string.Empty;
}
}
catch (Exception ex)
{
}
lcListOnline.Add(objGPSTrack);
if (lcListOnline.Count > 0)
{
string jsonContentsOnline = JsonConvert.SerializeObject(lcListOnline);
var responseOnline = await HRMS.ServiceLayer.GetResponseFromWebService.GetResponsePostData<HRMS.ServiceLayer.ServiceClasses.RootObject>(HRMS.ServiceLayer.ServiceURL.PostGPSLocation, jsonContentsOnline);
if (responseOnline.Flag == true)
{
statusMessage = responseOnline.Message;
}
}
}
#endregion
#region Local Database Entries Insert to Server Database
List<LocationTracking> lcListOffline = SideMenu.repoLocation.GetAllLocationAsync();
if (lcListOffline != null)
{
if (lcListOffline.Count > 0)
{
ObservableCollection<LocationTracking> lvCollection = new ObservableCollection<LocationTracking>(lcListOffline);
List<GPSTrackingLocationClass> lcListGoingtoOnline = new List<GPSTrackingLocationClass>();
foreach (var item in lvCollection)
{
GPSTrackingLocationClass objGPSTrackOffline = new GPSTrackingLocationClass();
objGPSTrackOffline.Latitude = item.Latitude;
objGPSTrackOffline.Longitude = item.Longitude;
objGPSTrackOffline.EmpCd = item.EmpCd;
objGPSTrackOffline.GPS_Track_DateTime = item.GPS_Track_DateTime;
objGPSTrackOffline.DeviceId = item.DeviceID;
string urlAPI = string.Format(googleAPI, item.Latitude, item.Longitude);
try
{
XElement xmlURL = XElement.Load(urlAPI);
if (xmlURL.Element("status").Value == "OK")
{
objGPSTrackOffline.PlaceName = xmlURL.Element("result").Element("formatted_address").Value;
}
else
{
objGPSTrackOffline.PlaceName = string.Empty;
}
}
catch (Exception exe)
{
}
if (!string.IsNullOrEmpty(objGPSTrackOffline.PlaceName))
{
lcListGoingtoOnline.Add(objGPSTrackOffline);
}
}
if (lcListGoingtoOnline.Count == lvCollection.Count)
{
string jsonContentsOffline = JsonConvert.SerializeObject(lcListGoingtoOnline);
var responseOffline = await HRMS.ServiceLayer.GetResponseFromWebService.GetResponsePostData<HRMS.ServiceLayer.ServiceClasses.RootObject>(HRMS.ServiceLayer.ServiceURL.PostGPSLocation, jsonContentsOffline);
if (responseOffline.Flag == true)
{
statusMessage = responseOffline.Message;
SideMenu.repoLocation.RemoveLocationAsync();
}
}
}
}
#endregion
}
//Device Has No Internet Connection
else
{
try
{
if (position != null)
{
IDevice device = DependencyService.Get<IDevice>();
deviceId = device.GetIdentifier();
deviceId = deviceId.Replace("+", "%2B");
string newDate = App.GetDateTime(DateTime.Now);
SideMenu.repoLocation.AddNewLocationAsync(newDate, position.Latitude, position.Longitude, App.MyEmployeeId, deviceId, "--");
}
}
catch (Exception ex)
{
//Log.Debug(TAG, "Please turn on GPS in your headset");
}
}
#endregion
}
}
catch (Exception ex)
{
var fileService = DependencyService.Get<ISaveException>();
await fileService.SaveTextAsync(App.FileName, ex.StackTrace);
}
}
/// <summary>
/// Start Location Service
/// </summary>
public static void StartLocationService()
{
// Starting a service like this is blocking, so we want to do it on a background thread
//new Task(() =>
//{
// Start our main service
try
{
Intent intent = new Intent(Android.App.Application.Context, typeof(GPSTrackingService));
Android.App.Application.Context.StartService(intent);
}
catch (Exception ex)
{
var fileService = DependencyService.Get<ISaveException>();
fileService.SaveTextAsync(App.FileName, ex.StackTrace);
}
//}).Start();
}
/// <summary>
/// Start Location Service
/// </summary>
public static void StartApplication()
{
try
{
Intent start = new Intent(Android.App.Application.Context, typeof(MainActivity));
// my activity name is MainActivity replace it with yours
start.AddFlags(ActivityFlags.NewTask);
Android.App.Application.Context.ApplicationContext.StartActivity(start);
}
catch (Exception ex)
{
var fileService = DependencyService.Get<ISaveException>();
fileService.SaveTextAsync(App.FileName, ex.StackTrace);
}
}
public static void SendEmail(string text)
{
var email = new Intent(Android.Content.Intent.ActionSend);
email.PutExtra(Android.Content.Intent.ExtraEmail, new string[] { "pankit.patel@silvertouch.com" });
email.PutExtra(Android.Content.Intent.ExtraSubject, "Send Crash Report");
email.PutExtra(Android.Content.Intent.ExtraText, "Hello, " + text);
email.AddFlags(ActivityFlags.NewTask);
email.SetType("message/rfc822");
Android.App.Application.Context.ApplicationContext.StartActivity(email);
}
/// <summary>
/// Stop Location Service
/// </summary>
public static void StopLocationService()
{
// Check for nulls in case StartLocationService task has not yet completed.
//Log.Debug("App", "StopGPSTrackingService");
try
{
Intent intent = new Intent(Android.App.Application.Context, typeof(GPSTrackingService));
Android.App.Application.Context.StopService(intent);
}
catch (Exception ex)
{
var fileService = DependencyService.Get<ISaveException>();
fileService.SaveTextAsync(App.FileName, ex.StackTrace);
}
}
}
}
此服务仅在应用程序打开时运行（即使在后台）但如果我关闭应用程序，则服务会自动停止工作。如何解决这个问题？我有很多关于这个主题的xamarin博客，但我还没有得到任何解决方法。
即使在应用关闭后，如何制作应该运行的后台服务？