Question

为一位遛狗的朋友做了一个快速的应用程序，他想知道他走多远，速度和准确度高。无论如何，我通过计时器使应用程序跟踪距离和位置。一切正常，但是当更新屏幕上的统计数据（每8秒执行一次）时，似乎存在性能问题，因为时间将暂停，然后跳跃2秒，好像说更新部分需要一秒或2.

这是代码

List<GeoCoordinate> Locations;
Geolocator Locator = new Geolocator();
Locator.DesiredAccuracy = PositionAccuracy.High;
Locator.MovementThreshold = 1;
Locator.PositionChanged += Locator_PositionChanged;

DispatcherTimer _timer = new DispatcherTimer();
_timer.Interval = TimeSpan.FromSeconds(1);
_timer.Tick += Timer_Tick;
_timer.Start();
long _startTime = System.Enviroment.TickCount;

private void Locator_PositionChanged(Geolocator sender, PostionChangedEventArgs args)
{
    CurrentLocation = args.Position;

    if(GetPositionTime >= 8) // Checks to see if 8 seconds has passed
    {           
       Deployment.Current.Dispatcher.BeginInvoke(new Action(() =>
       {
            GeoCoordinate cord = new GeoCoordinate(CurrentLocation.Coordinate.Latitude,
                                    CurrentLocation.Coordinate.Longitude);
         if(Locations.Count > 0)
         {
            GeoCoordinate PreviousLocation = Locations.Last();

            // This part will update the stats on the screen as a textbox is bound to
            // DistanceMoved
            DistanceMoved = cord.GetDistanceTo(PreviousLocation);             
         }

         Locations.Add(cord);
       }));
    }
}

private void Timer_Tick(object sender, EventArgs e)
{
    GetPositionTime++;
    TimeSpan time = TimeSpan.FromMilliseconds(System.Enviroment.TickCount - _startTime);

    // Update the timer on the screen
    Duration = time.ToString(@"hh\:mm\:ss");
}

Answer 1

需要在UI线程上更新UI控件 - 包装Dispatcher.BeginInvoke 在持续时间周围，它应该工作。

Deployment.Current.Dispatcher.BeginInvoke(new Action(() =>
{
        Duration = time.ToString(@"hh\:mm\:ss"); 
}

Windows Phone 8上的GPS跟踪性能问题

1 个答案: