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Device.StartTimer equivalent in Native Xamarin

I'm working on an application that simulates an old phone keypad like the ones in a Nokia 3310 where multiple button clicks changes the letter thats being written from 1 to A, B, etc.
I've originally built the application in Xamarin Forms but the assignment needs it to be in Native Xamarin so I need to pass it there. The original code I used in Xamarin forms was the following:
private void Button_Clicked(object sender, EventArgs e)
{
if (ButtonCount < 1)
{
TimeSpan tt = new TimeSpan(0, 0, 1);
Device.StartTimer(tt, NumberofClicks);
}
ButtonCount++;
}
With the NumberofClicks method being the following:
bool NumberofClicks()
{
if (ButtonCount > 1)
{
//Event for 2 button clicks
}
else
{
//Event for 1 button click
}
ButtonCount = 0;
return false;
Since Xamarin Native supports applying tags to buttons I want to try and make a method for all the buttons to be more efficient where it uses the tag it has, for this purpose I use the expression of var Btn = ((Android.Widget.Button)btnPresionado) so I can simply use Btn.Tag.ToString() when adding it to text. As for what I tried to use as a Device.StarTimer equivalent, I used a System.Threading.Timer as seen in the following code:
public void ButtonClick(object btnPresionado, EventArgs e)
{
if (ButtonCount < 1)
{
System.Threading.Timer timer = new Timer(NumberofClicks,btnPresionado, 2000, Infinite);
}
ButtonCount++;
}
public void NumberofClicks(object btnPresionado)
{
var Btn = ((Android.Widget.Button)btnPresionado);
if (ButtonCount > 1)
{
//Double click event
}
else
{
//Single click event
}
ButtonCount = 0;
}
Unfortunately when testing this, it does not work and makes the app crash in the emulator (I cant see what exactly goes wrong since this is a 3rd party emulator because Hyper-V simply refuses to install itself on my PC at the moment) so I want to ask what would be a good equivalent for Device.StartTimer() or what exactly am I doing wrong here?
Thank you

Close secondary view completely in UWP

I am using a secondary view to run my media files, but When I close my secondary view with close button on it (while media is still playing) the secondary view/window closes but the media somehow keeps playing because I can hear the sound and source of sound seems to be the primary view (main app window). How can I completely terminate the secondary window when I close it?
Here is my code to create the secondary view.
await CoreApplication.CreateNewView().Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
var frame = new Frame();
frame.MinHeight = 200;
frame.MinWidth = 200;
compactViewId = ApplicationView.GetForCurrentView().Id;
frame.Navigate(typeof(CompactNowPlayingPage), caption);
Window.Current.Content = frame;
Window.Current.Activate();
ApplicationView.GetForCurrentView().Title = Title;
});
bool viewShown = await ApplicationViewSwitcher.TryShowAsViewModeAsync(compactViewId, ApplicationViewMode.Default);
Update
After some debugging I've come to know that close button pressed on the secondary view only hides the view but it keeps on running on its thread, I just want that close button to completely close the secondary view, close its thread and destroy the window as a whole.
Update 2
I followed windows samples multiple views and was able to complete all steps, the code runs fine until it reaches Windows.Current.Close() in released event.
Then it gives an exception when it tries "Window.Current.Close()" with in the released event. according to documentation exception occurs due to any on going changes ( which might be because of media file playing ), but I need to force close the window even when media file is playing how can I do that? Here is the exception:
Message = "COM object that has been separated from its underlying RCW cannot be used."
Update 3
This is the latest updated, I am not following official sample now, just following simpler approach now.
Code to open secondary view:
await Helpers.DeviceTypeHelper.CompactOpen(e.ClickedItem as Video, identifier); //where identified is just a string for some custom logic in the secondary view.
//following method is located in a helper class within the project
internal static async Task CompactOpen(Video PlayingVideo, string caption)
{
ApplicationView newView = null;
await CoreApplication.CreateNewView().Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
var frame = new Frame();
frame.Navigate(typeof(CompactNowPlayingPage),new object[] { PlayingVideo,caption});
Window.Current.Content = frame;
Window.Current.Activate();
newView = ApplicationView.GetForCurrentView();
newView.Title = PlayingVideo.MyVideoFile.DisplayName;
});
await ApplicationViewSwitcher.TryShowAsStandaloneAsync(newView.Id);
}
Secondary View:
public sealed partial class CompactNowPlayingPage : Page
{
public CompactNowPlayingViewModel ViewModel { get; } = new CompactNowPlayingViewModel();
private CustomMediaTransportControls controls;
public CompactNowPlayingPage()
{
InitializeComponent();
this.Loaded += MediaPage_Loaded;
this.Unloaded += MediaPage_Unloaded;
Microsoft.Toolkit.Uwp.UI.Extensions.ApplicationView.SetExtendViewIntoTitleBar(this, true);
Microsoft.Toolkit.Uwp.UI.Extensions.TitleBar.SetButtonBackgroundColor(this, Colors.Transparent);
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
string chk = "";
var paramm = e.Parameter as object[];
NowPlayingVideo = paramm[0] as Video;
var vis = Visibility.Collapsed;
chk = paramm[1].ToString();
switch (chk)
{
case "library":
vis = Visibility.Visible;
break;
case "playlist":
vis = Visibility.Visible;
break;
case "history":
vis = Visibility.Collapsed;
break;
case "directplay":
vis = Visibility.Collapsed;
break;
default:
break;
}
controls = new CustomMediaTransportControls(NowPlayingVideo,vis);
Media.TransportControls = controls;
PlayVideo();
}
private Video NowPlayingVideo { get; set; }
private void PlayVideo()
{
if (NowPlayingVideo != null)
{
string token = "";
if (StorageApplicationPermissions.FutureAccessList.Entries.Count == 800)
{
var en = StorageApplicationPermissions.FutureAccessList.Entries;
StorageApplicationPermissions.FutureAccessList.Remove(en.Last().Token);
}
token = StorageApplicationPermissions.FutureAccessList.Add(NowPlayingVideo.MyVideoFile);
Media.Source = null;
Media.Source = $"winrt://{token}";
SetViews();
}
}
private void SetViews()
{
NowPlayingVideo.Views++;
Database.DbHelper.UpdateViews(NowPlayingVideo.MyVideoFile.Path);
}
private void MediaPage_Loaded(object sender, RoutedEventArgs e)
{
Windows.UI.ViewManagement.ApplicationView.GetForCurrentView().Consolidated += MediaPage_Consolidated;
}
private void MediaPage_Unloaded(object sender, RoutedEventArgs e)
{
Windows.UI.ViewManagement.ApplicationView.GetForCurrentView().Consolidated -= MediaPage_Consolidated;
}
private void MediaPage_Consolidated(Windows.UI.ViewManagement.ApplicationView sender, Windows.UI.ViewManagement.ApplicationViewConsolidatedEventArgs args)
{
Window.Current.Close();
}
}
Secondary View XAML:
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<vlc:MediaElement AreTransportControlsEnabled="True"
Name="Media"
HardwareAcceleration="True"
AutoPlay="True">
</vlc:MediaElement>
</Grid>
Case 1 : Everything runs perfect if I place a video file in Assets folder and give it as a source to the media element and comment the whole OnanvigatdTo method on secondary page. And I am able to successfully close the window as well.
...
Case 2 : But when I try to set the media through the NowPlayingVideo object as shown in the code above and I also use default Transport Controls, so I don't comment the lines used to assign custom transport controls in the above code it runs fine, but when I then try to close the window I get following exception in App.i.g.cs file but stacktrace doesn't exist:
Message = "Attempt has been made to use a COM object that does not have a backing class factory." Message = "COM object that has been separated from its underlying RCW cannot be used.
Case 3 : Exactly like case 2 but here I uncomment Custom transport controls lines so now I am assigning custom transport controls to my media element, this time exception is a bit different with some stacktrace as well
StackTrace = " at System.StubHelpers.StubHelpers.GetCOMIPFromRCW_WinRT(Object objSrc, IntPtr pCPCMD, IntPtr& ppTarget)\r\n at Windows.UI.Xaml.DependencyObject.get_Dispatcher()\r\n at VLC.MediaElement.d__160.MoveNext()\r\n--- End of stack trace ...
Message = "Attempt has been made to use a COM object that does not have a backing class factory."

The short answer is: you need to make sure nothings holds on to your view instance, and you call Window.Close in the view's Consolidated event. The longer answer with code is here in the official sample. Take a look at the ViewLifetimeControl.cs source file: https://github.com/Microsoft/Windows-universal-samples/tree/master/Samples/MultipleViews/cs

Memory Leak playing videos on Windows IoT | UWP

I've built an app that can read video files from an USB drive and switch between them using physical buttons. The app works well for a while, but after a while the device (DragonBoard 410c, latest Windows Insider Preview Build 15051) crashes due to the fact that all memory has been consumed by the app.
Looking at the processes in the device portal, I can see the "Working Set" memory jump each time I switch a video file while the "Private Working Set" roughly stays the same (around 30MB).
Here's how I load the video file:
C#
private IReadOnlyList<StorageFile> _videofiles
// list all available video files
public void Init(){
var queryOptions = new QueryOptions();
queryOptions.FolderDepth = depth;
foreach (var fileType in fileTypes)
{
queryOptions.FileTypeFilter.Add(fileType);
}
var query = KnownFolders.RemovableDevices.CreateFileQueryWithOptions(queryOptions);
_videofiles = await query.GetFilesAsync();
}
private async void SelectVideo(int videoId)
{
StorageFile videofile = _videofiles.Where(x => x.DisplayName == videoId.ToString()).FirstOrDefault();
if (videofile != null)
{
Debug.WriteLine($"Video {videofile.DisplayName} was selected");
var stream = await videofile.OpenAsync(FileAccessMode.Read);
VideoPlayer.SetSource(stream, videofile.FileType);
}
}
// since the button interrupt is not on the UI thread, SelectVideo() is called like this
private async void SelectVideoMarshalled(int videoId)
{
await Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(CoreDispatcherPriority.Normal,
() =>
{
SelectVideo(videoId);
});
}
XAML
<ContentControl x:Name="VideoPlayer" Content="{x:Bind ViewModel.VideoPlayer, Mode=OneWay}"/>
I have tried running GC.Collect() manually in several places, but no luck yet. Any ideas?

Since you have a StorageFile object, I recommend using the Source property and the file's Path instead of SetSource and opening the Stream manually.
Additionally, you should always null out the MediaElement when you're done with it (best done in OnNavigatingFrom).
Here's your code, simplified:
private void SelectVideo(string videoId)
{
var videofile = _videofiles.FirstOrDefault(x => x.DisplayName == videoId.ToString());
if (videofile == null) return;
Debug.WriteLine($"Video {videofile.DisplayName} was selected");
VideoPlayer.Source = new Uri(videofile.Path);
}
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
VideoPlayer.Stop();
VideoPlayer.Source = null;
base.OnNavigatedFrom(e);
}
I also have a side comment, you can x:Bind event handlers to the ViewModel.
For example, if your video file list is a ListView of string:
public void VideosListView_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e?.AddedItems?.Count > 0)
{
var fileDisplayName = e.AddedItems.FirstOrDefault() as string;
if (!string.IsNullOrEmpty(fileDisplayName))
SelectVideo(fileDisplayName);
}
}
Notice I only need to change the method signature to public and then in the XAML you can do this:
<ListView ItemsSource="{x:Bind ViewModel.VideoFiles, Mode=OneTime}"
SelectionChanged="{x:Bind ViewModel.VideosListView_OnSelectionChanged}"/>
No need to marshal back to the UI thread :)
Lastly, you can check out the demo here on GitHub where I've implemented something similar to this.

Turns out my code was fine after all. I had a Windows Update stuck / failing several times which I didn't notice.
When the update finally completed successfully the memory leaks were gone.

Windows phone 8.1 universal app DataTransferManager UI not showing

In my windows phone 8.1 universal app project I am trying to make a share option.
But when I click on the button (ShareCommand) the Share UI is not showing up, I have tried this in the emulator and on a device.
The event is correctly wired up since the DataRequested event gets called, but after this event there is no Share UI showing.
Here is the code I use in my ViewModel (using prism framework).
private DataTransferManager _dataTransferManager;
private DelegateCommand _shareCommand;
// Share button
public DelegateCommand ShareCommand
{
get
{
return _shareCommand ?? (_shareCommand = new DelegateCommand(() =>
{
DataTransferManager.ShowShareUI();
}));
}
}
public override async void OnNavigatedTo(object navigationParameter, NavigationMode navigationMode, Dictionary<string, object> viewModelState)
{
base.OnNavigatedTo(navigationParameter, navigationMode, viewModelState);
// get data transfer manager and register events
_dataTransferManager = DataTransferManager.GetForCurrentView();
_dataTransferManager.DataRequested += DataTransferMangerDataRequested;
_dataTransferManager.TargetApplicationChosen += DataTransferMangerTargetApplicationChosen;
}
public override void OnNavigatedFrom(Dictionary<string, object> viewModelState, bool suspending)
{
base.OnNavigatedFrom(viewModelState, suspending);
// clean up events
_dataTransferManager.DataRequested -= DataTransferMangerDataRequested;
_dataTransferManager.TargetApplicationChosen -= DataTransferMangerTargetApplicationChosen;
}
private void DataTransferMangerTargetApplicationChosen(DataTransferManager sender, TargetApplicationChosenEventArgs args)
{
}
private void DataTransferMangerDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
var request = args.Request;
var deferral = request.GetDeferral();
request.Data.Properties.Title = "title test";
request.Data.Properties.Description = "description test";
request.Data.SetText("test hello");
request.Data.SetUri(new Uri("https://www.google.com"));
request.FailWithDisplayText("fail");
deferral.Complete();
}
I have tried setting different properties in the DataRequested event but still nothing.
Does anyone know what it could be? Do I need to set some permissions?
Edit:
Ok, weird I tried this in a new solution with only this code and it is working fine. But no idea why its not working in my current solution.

Ok I found out what was causing the problem.
I had to remove this, since this will cancel the operation. (I thought this will show if it failed for some reason and not cancel directly).
request.FailWithDisplayText("fail");

C# show gps location on map

I am working in a windows mobile application and I want to show my current location with google maps. I used the Location dll from the samples. As you see below in my code, I call the proper method for updating the map in the gps_Locationchanged event where I use the Invoke method to update the pictureboxe's image. The problem is that I can't use the main menu and the context menu of the application whenever i want. It's like they freeze until the new map finish downloading. Is there another way to do that in different thread so they can be used anytime?
void gps_LocationChanged(object sender, LocationChangedEventArgs args)
{
if (args.Position.LatitudeValid && args.Position.LongitudeValid)
{
pictureBox1.Invoke((UpdateMap)delegate()
{
center.Latitude = args.Position.Latitude;
center.Longitude = args.Position.Longitude;
LatLongToPixel(center);
image_request2(args.Position.Latitude, args.Position.Longitude);
});
}
}

Maybe something along these lines?
bool m_fetching;
void gps_LocationChanged(object sender, LocationChangedEventArgs args)
{
if (m_fetching) return;
if (args.Position.LatitudeValid && args.Position.LongitudeValid)
{
ThreadPool.QueueUserWorkItem(UpdateProc, args);
}
}
private void UpdateProc(object state)
{
m_fetching = true;
LocationChangedEventArgs args = (LocationChangedEventArgs)state;
try
{
// do this async
var image = image_request2(args.Position.Latitude, args.Position.Longitude);
// now that we have the image, do a synchronous call in the UI
pictureBox1.Invoke((UpdateMap)delegate()
{
center.Latitude = args.Position.Latitude;
center.Longitude = args.Position.Longitude;
LatLongToPixel(center);
image;
});
}
finally
{
m_fetching = false;
}
}

It's hard to say for sure, but it looks like the image_request2() method that (I assume) gets the actual image from the server is the problem. If you were to run this method on a worker thread, and provide a simple callback method that would paint the image on the screen once it's completely downloaded, this would leave your UI thread open to receive events from the user.