async void MainPage_Loaded(object sender, RoutedEventArgs e)
{
var promise = await BackgroundExecutionManager.RequestAccessAsync();
if (promise == BackgroundAccessStatus.Denied)
{
MessageDialog warningDialog = new MessageDialog("Background execution is disabled. Please re-enable in the Battery Saver app to allow this app to function", "Background GPS");
await warningDialog.ShowAsync();
}
else
{
var defaultSensor = Windows.Devices.Sensors.Accelerometer.GetDefault();
if (defaultSensor != null)
{
var deviceUseTrigger = new DeviceUseTrigger();
deviceUseTask = RegisterBackgroundTask("BackgroundGps.Engine.BackgroundGpsTask", "GpsTask", deviceUseTrigger, null);
try
{
DeviceTriggerResult r = await deviceUseTrigger.RequestAsync(defaultSensor.DeviceId);
System.Diagnostics.Debug.WriteLine(r); //Allowed
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine(ex);
}
}
}
}
/// <summary>
/// Starts the sensor background task.
/// </summary>
/// <param name="deviceId">Device Id for the sensor to be used by the task.</param>
/// <param name="e"></param>
/// <returns>True if the task is started successfully.</returns>
private async Task <bool> StartSensorBackgroundTaskAsync(String deviceId)
{
bool started = false;
// Make sure only 1 task is running.
FindAndCancelExistingBackgroundTask();
// Register the background task.
var backgroundTaskBuilder = new BackgroundTaskBuilder()
{
Name = SampleConstants.Scenario1_DeviceUse_TaskName,
TaskEntryPoint = SampleConstants.Scenario1_DeviceUse_TaskEntryPoint
};
backgroundTaskBuilder.SetTrigger(_deviceUseTrigger);
_deviceUseBackgroundTaskRegistration = backgroundTaskBuilder.Register();
// Make sure we're notified when the task completes or if there is an update.
_deviceUseBackgroundTaskRegistration.Completed += new BackgroundTaskCompletedEventHandler(OnBackgroundTaskCompleted);
try
{
// Request a DeviceUse task to use the accelerometer.
DeviceTriggerResult deviceTriggerResult = await _deviceUseTrigger.RequestAsync(deviceId);
switch (deviceTriggerResult)
{
case DeviceTriggerResult.Allowed:
rootPage.NotifyUser("Background task started", NotifyType.StatusMessage);
started = true;
break;
case DeviceTriggerResult.LowBattery:
rootPage.NotifyUser("Insufficient battery to run the background task", NotifyType.ErrorMessage);
break;
case DeviceTriggerResult.DeniedBySystem:
// The system can deny a task request if the system-wide DeviceUse task limit is reached.
rootPage.NotifyUser("The system has denied the background task request", NotifyType.ErrorMessage);
break;
default:
rootPage.NotifyUser("Could not start the background task: " + deviceTriggerResult, NotifyType.ErrorMessage);
break;
}
}
catch (InvalidOperationException)
{
// If toggling quickly between 'Disable' and 'Enable', the previous task
// could still be in the process of cleaning up.
rootPage.NotifyUser("A previous background task is still running, please wait for it to exit", NotifyType.ErrorMessage);
FindAndCancelExistingBackgroundTask();
}
return(started);
}
private async Task <bool> StartAccelerometerBackGroundTask(String deviceId)
{
bool started = false;
try
{
// Request a DeviceUse task to use the accelerometer.
DeviceTriggerResult accelerometerTriggerResult = await manualTrigger.RequestAsync(deviceId);
#warning background task seems to be run from here
switch (accelerometerTriggerResult)
{
case DeviceTriggerResult.Allowed:
Status = "Background task started";
started = true;
break;
case DeviceTriggerResult.LowBattery:
Error = "Insufficient battery to run the background task";
break;
case DeviceTriggerResult.DeniedBySystem:
// The system can deny a task request if the system-wide DeviceUse task limit is reached.
Error = "The system has denied the background task request";
break;
default:
Error = "Could not start the background task: " + accelerometerTriggerResult;
break;
}
}
catch (InvalidOperationException)
{
// If toggling quickly between 'Disable' and 'Enable', the previous task
// could still be in the process of cleaning up.
Status = "A previous background task is still running, please wait for it to exit";
FindAndCancelExistingBackgroundTask();
}
return(started);
}
/// <summary>
/// Triggers the background task to update firmware for the device. The update will cancel if it's not completed within 2 minutes.
///
/// Before triggering the background task, all UsbDevices that will have their firmware updated must be closed. The background task will open
/// the device to update the firmware, but if the app still has it open, the background task will fail. The reason why this happens is because
/// when a UsbDevice is created, the corresponding device is opened exclusively (no one else can open this device).
///
/// The trigger.RequestAsync() must be started on the UI thread because of the prompt that appears. The caller of UpdateFirmwareForDeviceAsync()
/// is responsible for running this method in the UI thread.
/// </summary>
/// <param name="deviceInformation"></param>
/// <returns>An error message</returns>
private async Task <String> StartFirmwareForDeviceAsync(DeviceInformation deviceInformation)
{
DeviceTriggerResult deviceTriggerResult = await firmwareUpdateBackgroundTaskTrigger.RequestAsync(deviceInformation.Id,
FirmwareUpdateTaskInformation.ApproximateFirmwareUpdateTime);
// Determine if we are allowed to do firmware update
String statusMessage = null;
switch (deviceTriggerResult)
{
case DeviceTriggerResult.Allowed:
isUpdatingFirmware = true;
statusMessage = "Firmware update was allowed";
break;
case DeviceTriggerResult.LowBattery:
isUpdatingFirmware = false;
statusMessage = "Insufficient battery to start firmware update";
break;
case DeviceTriggerResult.DeniedByUser:
isUpdatingFirmware = false;
statusMessage = "User declined the operation";
break;
case DeviceTriggerResult.DeniedBySystem:
// This can happen if the device metadata is not installed on the system.
// The app must be a privileged app
isUpdatingFirmware = false;
statusMessage = "Firmware update operation was denied by the system";
break;
default:
isUpdatingFirmware = false;
statusMessage = "Failed to initiate firmware update - Unknown Reason";
break;
}
return(statusMessage);
}
