How can I use GestureRecognizer in a Xaml based app?

Question

I've encountered a problem when I'm trying to use gestures in my app:

I'm trying to retrieve info from input on a rectangle using GestureRecognizer responding to the PointerPressed event. When the user taps on it, the textblock shows information. However, I failed to get any info after following the code samples. There was no response and through debugging, I found the tapped event was not responded to.

First, I added:

Platform::Agile<Windows::UI::Input::GestureRecognizer> m_gestureRecognizer;

in the header of the class.

And in the constructor:

MainPage::MainPage()
{
	InitializeComponent();
	m_gestureRecognizer = ref new GestureRecognizer();

	m_gestureRecognizer->GestureSettings =
		GestureSettings::DoubleTap | GestureSettings::Tap;

	m_gestureRecognizer->Tapped += ref new Windows::Foundation::TypedEventHandler<Windows::UI::Input::GestureRecognizer ^, Windows::UI::Input::TappedEventArgs ^>(this, &App4::MainPage::OnTapped);	
}

Next, I responded to the PointerPressed event:

void App4::MainPage::OnPressed(Platform::Object^ sender, Windows::UI::Xaml::Input::PointerRoutedEventArgs^ e)
{
	unsigned int id = e->Pointer->PointerId;//debug breakpoint
	m_gestureRecognizer->ProcessDownEvent(Windows::UI::Input::PointerPoint::GetCurrentPoint(id));
	e->Handled = true;
}

But when I came to the Tapped event, nothing happened:

void MainPage::OnTapped(GestureRecognizer^ gesrec, Windows::UI::Input::TappedEventArgs^ args)
{
	int i = args->TapCount;//debug breakpoint
	if (i == 2)
	{
		info->Text = "You double-tapped the point at X: " + args->Position.X + ", Y: " + args->Position.Y + ".";
	}
	else
	{
		info->Text = "You tapped the point X: " + args->Position.X + ", Y: " + args->Position.Y + ".";
	}
}

Why there was no info when I tapped the rectangle? Do I lack of something in the code? 

Answer 1

You need to pass the PointerMoved and PointerReleased events to the GestureRecognizer so it has full information to recognize the gestures.

Tap is a down and up, so if you only pass through down then it won't be generated.

Answer 2

Oh, it's very kind of you! Thank you so much and the problem has been solved by adding two handlers:

void App4::MainPage::OnMoved(Platform::Object^ sender, Windows::UI::Xaml::Input::PointerRoutedEventArgs^ e)
{ 
	m_gestureRecognizer->ProcessMoveEvents(e->GetIntermediatePoints(wpRect/*name of the rectangle*/));
}


void App4::MainPage::OnReleased(Platform::Object^ sender, Windows::UI::Xaml::Input::PointerRoutedEventArgs^ e)
{
	m_gestureRecognizer->ProcessUpEvent(Windows::UI::Input::PointerPoint::GetCurrentPoint(e->Pointer->PointerId));
}

I've been haunted by this issue for days...