windows-phone-7 - 如何在WP7上进行GPS查找时捕获错误

Question

我试图在GPS不可用时提醒用户(基本上是在他们关闭地理位置服务的情况下)

以下是我的查询用例语句，我注意到在模拟器中我达到了“”状态，因此我无法在此处返回错误，因为它仍按预期运行

    void MyStatusChanged(GeoPositionStatusChangedEventArgs e)
    {
        switch (e.Status)
        {
            case GeoPositionStatus.Disabled:
                client.ClientCallBackWithError("fail");
                break;
            case GeoPositionStatus.Initializing:
                var y = "initializing location service,";
                break;
            case GeoPositionStatus.NoData:
                // The location service is working, but it cannot get location data
                // Alert the user and enable the Stop Location button
                var z = "data unavailable,";
                break;
            case GeoPositionStatus.Ready:
                var zzz = "receiving data, ";
                break;

        }
    }

因此，在我的调用页面/ View 内部，我决定也许可以等待10秒钟，以查看是否被击中..否则，我可能会抛出错误/等

警告巨大的骇客，因为我失去了希望

    private void FindByGps_Click(object sender, RoutedEventArgs e)
    {
        gpsStarted = false;
        gpsEnded = false;

        progressHelper.StartProgressStuff(this.progress);
        gpsStarted = true;
        gpsLocationLookupService.StartLocationService();
        this.Dispatcher.BeginInvoke(() => ListenForCallbackDuringGpsLookup(0));
    }

    private object ListenForCallbackDuringGpsLookup(int counter)
    {
        if (gpsStarted && !gpsEnded && counter < 12)
        {
            //keep looking until the timer runs out ...
            counter = counter + 1;
            this.Dispatcher.BeginInvoke(() => SleepForASec());
            ListenForCallbackDuringGpsLookup(counter);
        }
        else if (gpsStarted && gpsEnded)
        {
            gpsStarted = false;
            gpsEnded = false;
        }else{
            this.Dispatcher.BeginInvoke(() => SetCurrentLocationAndLaunchFindKiosks(null, "Failed to locate you by GPS"));
        }

        return null;
    }

    private object SleepForASec()
    {
        Thread.Sleep(1000);

        return null;
    }

但是第二次我启动了一个线程，它似乎锁定了应用程序，直到线程完成为止。

所以我的问题-我应该如何捕获此类gps错误信息以提供正确的反馈？

Answer 1

您看过这个API了吗？

http://msdn.microsoft.com/en-us/library/system.device.location.geocoordinatewatcher.trystart(v=VS.92).aspx

根据此处的说明，您应该可以在以下框架内进行操作:

public partial class MainPage : PhoneApplicationPage
{
    GeoCoordinateWatcher watcher;

    // Constructor
    public MainPage()
    {
        InitializeComponent();
        Loaded += (source, args) =>
        {
            watcher = new GeoCoordinateWatcher(GeoPositionAccuracy.High);

            watcher.PositionChanged += (sender, e) =>
            {
                // update the user
            };

            watcher.StatusChanged += (sender, e) =>
            {
                // update the user
            };

            if (!watcher.TryStart(false, TimeSpan.FromSeconds(5)))
            {
                // show the error somewhere
            }
        };
    }
}

然后，在应用程序执行期间，如果GPS出现问题(信号丢失等)，则可以在StatusChanged事件处理程序内进行适当响应。

让我知道我是否不满意，我将继续考虑更好的解决方案...