我正在编写一个应用程序,每隔x秒发送一次位置数据,并在后台运行。我正在调用以下方法。
public void StartListening()
{
UpdateGpsService();
if(CLLocationManager.LocationServicesEnabled)
{
locationManager.DesiredAccuracy = 10;
nint taskId = UIApplication.SharedApplication.BeginBackgroundTask(() =>
{
timer = new Timer((o) =>
{
CLLocation location = locationManager.Location;
Nmea nmea = new IOSNmea(location);
Gprmc gprmc = new Gprmc();
gprmc.url = this.Url;
gprmc.Id = this.DeviceId;
gprmc.GprmcString = nmea.ToString();
}, null, 0, UpdateInterval * 1000);
});
App.Database.SaveItemAsync(new TodoItem() { key = LOCATOR_SERVICE_ID, value = taskId.ToString() });
}
}
但是,它似乎没有在计时器回调中调用代码。我试着在那里放一个断点,它永远不会被调用。我的代码有明显错误吗?谢谢你的帮助。
BeginBackgroundTask
只告诉iOS你正在开始一个长时间运行的任务,并且处理程序不是用于执行该任务,但它是一个完成处理程序,当操作系统即将关闭时调用它...
Timer timer = null;
nint taskId = UIApplication.SharedApplication.BeginBackgroundTask(() =>
{
// Clean up as the background task is begin shutdown by iOS
timer?.Dispose();
});
timer = new Timer((o) =>
{
Console.WriteLine("Timer Update");
}, null, TimeSpan.Zero, TimeSpan.FromSeconds(1));
// Must call EndBackgroundTask when you are done with this...
// UIApplication.SharedApplication.EndBackgroundTask(taskId);