Detecting Drag and Drop and detecting long press (XNA or as3) - input

Question

i am trying to implement a drag and drop behaviour for an object, i need to register when the touch is being pressed and after moving it a bit it should start dragging.
unfortunately i am using a custom framework that is implemented in C# and it's something like XNA.
How would you do it on XNA?
(it's for an android tablet) .

Answer 1

Obviously this example should be refactored to use input services and better handling for the touch up/down concepts, but the core of the answer remains the same:
// I don't remember the exact property names, but you probably understand what I mean
public override void Update(GameTime time)
{
var currentState = TouchPanel.GetState();
var gestures = currentState.TouchGestures;
var oldGests = this.oldState.TouchGestures;
if (oldGests.Count == 0 && gestures.Count == 1 && gestures[0].State == Pressed)
{
// Went from Released to Pressed
this.touchPressed = true;
}
else
{
// Not the frame it went to Pressed
this.touchPressed = false;
}
if (oldGests.Count == 1 && gestures.Count == 1 && oldGests[0].State == Pressed && gestures[0].State == Pressed)
{
// Touch is down, and has for more than 1 frame (aka. the user is dragging)
this.touchDown = true;
}
else
{
this.touchDown = false;
}
if (oldGests.Count == 1 && oldGests[0].State == Pressed && gestures.Count == 0)
{
// Went from Released to Pressed
this.touchReleased = true;
}
else
{
// Not the frame it went to Pressed
this.touchReleased = false;
}
this.oldState = currentState;
}
You might have to fiddle with the 'ifs' a bit, since I don't actually remember if Gestures goes down to 0 the first frame after you release your finger, or if it still shows 1 Gesture called 'Released'. Test it, and you shall have your answer!
Now you can use 'this.touchDown' elsewhere in your code to determine if your object should move or not.