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 (e.g., by
// an alarm callback), the service helper will be null.
if (serviceHelper != null)
{
serviceHelper.Logger.Log("Sensus service received start command (startId=" + startId + ", flags=" + flags + ").", LoggingLevel.Normal, GetType());
// update the foreground service notification with information about loaded/running studies.
(SensusContext.Current.Notifier as AndroidNotifier).ReissueForegroundServiceNotification();
// if the service started but there are no protocols that should be running, then stop the app now. there is no
// reason for the app to be running in this situation, and the user will likely be annoyed at the presence of the
// foreground service notification.
if (intent != null && intent.GetBooleanExtra(KEY_STOP_SERVICE_IF_NO_PROTOCOLS_SHOULD_RUN, false) && serviceHelper.RunningProtocolIds.Count == 0)
{
serviceHelper.Logger.Log("Started service without running protocols. Stopping service now.", LoggingLevel.Normal, GetType());
Stop();
return(StartCommandResult.NotSticky);
}
// acquire wake lock before this method returns to ensure that the device does not sleep prematurely, interrupting the execution of a callback.
serviceHelper.KeepDeviceAwakeAsync().Wait();
Task.Run(async() =>
{
try
{
// 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.
await serviceHelper.StartAsync();
if (intent != null)
{
AndroidCallbackScheduler callbackScheduler = SensusContext.Current.CallbackScheduler as AndroidCallbackScheduler;
if (callbackScheduler.IsCallback(intent))
{
await callbackScheduler.RaiseCallbackAsync(intent);
}
}
}
catch (Exception ex)
{
serviceHelper.Logger.Log("Exception while responding to on-start command: " + ex.Message, LoggingLevel.Normal, GetType());
}
finally
{
serviceHelper.LetDeviceSleepAsync().Wait();
}
});
}
// if the service is killed by the system (e.g., due to resource constraints), ask the system to restart
// the service when possible.
return(StartCommandResult.Sticky);
}