public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
{
AndroidSensusServiceHelper serviceHelper = SensusServiceHelper.Get() as AndroidSensusServiceHelper;
// there might be a race condition between the calling of this method and the stopping/disposal of the service helper.
// if the service helper is stopped/disposed before the service is stopped but after this method is called, the service
// helper will be null.
if (serviceHelper != null)
{
serviceHelper.Logger.Log("Sensus service received start command (startId=" + startId + ", flags=" + flags + ").", LoggingLevel.Normal, GetType());
// acquire wake lock before this method returns to ensure that the device does not sleep prematurely, interrupting the execution of a callback.
serviceHelper.KeepDeviceAwake();
// the service can be stopped without destroying the service object. in such cases,
// subsequent calls to start the service will not call OnCreate. therefore, it's
// important that any code called here is okay to call multiple times, even if the
// service is running. calling this when the service is running can happen because
// sensus receives a signal on device boot and for any callback alarms that are
// requested. furthermore, all calls here should be nonblocking / async so we don't
// tie up the UI thread.
serviceHelper.StartAsync(() =>
{
if (intent != null)
{
// is this a callback intent?
if (intent.GetBooleanExtra(SensusServiceHelper.SENSUS_CALLBACK_KEY, false))
{
string callbackId = intent.GetStringExtra(SensusServiceHelper.SENSUS_CALLBACK_ID_KEY);
// if the user removes the main activity from the switcher, the service's process will be killed and restarted without notice, and
// we'll have no opportunity to unschedule repeating callbacks. when the service is restarted we'll reinitialize the service
// helper, restart the repeating callbacks, and we'll then have duplicate repeating callbacks. handle the invalid callbacks below.
// if the callback is scheduled, it's fine. if it's not, then unschedule it.
if (serviceHelper.CallbackIsScheduled(callbackId))
{
bool repeating = intent.GetBooleanExtra(SensusServiceHelper.SENSUS_CALLBACK_REPEATING_KEY, false);
int repeatDelayMS = intent.GetIntExtra(SensusServiceHelper.SENSUS_CALLBACK_REPEAT_DELAY_KEY, -1);
bool repeatLag = intent.GetBooleanExtra(SensusServiceHelper.SENSUS_CALLBACK_REPEAT_LAG_KEY, false);
bool wakeLockReleased = false;
// raise callback and notify the user if there is a message. we wouldn't have presented the user with the message yet.
serviceHelper.RaiseCallbackAsync(callbackId, repeating, repeatDelayMS, repeatLag, true,
// schedule a new callback at the given time.
repeatCallbackTime =>
{
serviceHelper.ScheduleCallbackAlarm(serviceHelper.CreateCallbackPendingIntent(intent), callbackId, repeatCallbackTime);
},
// if the callback indicates that it's okay for the device to sleep, release the wake lock now.
() =>
{
wakeLockReleased = true;
serviceHelper.LetDeviceSleep();
serviceHelper.Logger.Log("Wake lock released preemptively for scheduled callback action.", LoggingLevel.Normal, GetType());
},
// release wake lock now if we didn't while the callback action was executing.
() =>
{
if (!wakeLockReleased)
{
serviceHelper.LetDeviceSleep();
serviceHelper.Logger.Log("Wake lock released after scheduled callback action completed.", LoggingLevel.Normal, GetType());
}
});
}
else
{
serviceHelper.UnscheduleCallback(callbackId);
serviceHelper.LetDeviceSleep();
}
}
else if (intent.GetStringExtra(SensusServiceHelper.NOTIFICATION_ID_KEY) == SensusServiceHelper.PENDING_SURVEY_NOTIFICATION_ID)
{
serviceHelper.BringToForeground();
// display the pending scripts page if it is not already on the top of the navigation stack
SensusContext.Current.MainThreadSynchronizer.ExecuteThreadSafe(async() =>
{
IReadOnlyList <Page> navigationStack = Xamarin.Forms.Application.Current.MainPage.Navigation.NavigationStack;
Page topPage = navigationStack.Count == 0 ? null : navigationStack.Last();
if (!(topPage is PendingScriptsPage))
{
await Xamarin.Forms.Application.Current.MainPage.Navigation.PushAsync(new PendingScriptsPage());
}
serviceHelper.LetDeviceSleep();
});
}
else
{
serviceHelper.LetDeviceSleep();
}
}
else
{
serviceHelper.LetDeviceSleep();
}
});
}
return(StartCommandResult.Sticky);
}
