void Start()
{
itemSelectionHandler = ItemSelectionHandler.itemSelectionHandler;
itemBackgroundImage = transform.GetChild(0).GetComponent <Image>();
itemBackgroundImage.color = normalColor;
}
void Awake()
{
if (itemSelectionHandler == null)
{
itemSelectionHandler = this;
}
else if (itemSelectionHandler != this)
{
Destroy(gameObject);
}
}
public MenuItem(String name, String text, ItemSelectionHandler itemSelected)
{
this.name = name;
this.text = text;
this.OnItemSelected = itemSelected;
}
/// <summary>
/// Called when a touch event has been passed to the list view for processing.
/// Process according to the event type
/// </summary>
/// <param name="touchedView">The view given the event - not used assumed to be owner ShoppingListView</param>
/// <param name="touchEvent">THe touch event</param>
/// <returns>True if the event has been consumed and should not be further processed</returns>
public bool OnTouch(View touchedView, MotionEvent touchEvent)
{
// Assume the event is not consumed
bool touchConsumed = false;
switch (touchEvent.Action)
{
case MotionEventActions.Down:
{
// Adjust touch position to be relative to the parent view
int[] viewCoords = new int[2];
monitoredView.GetLocationOnScreen(viewCoords);
int relX = ( int )touchEvent.RawX - viewCoords[0];
int relY = ( int )touchEvent.RawY - viewCoords[1];
// Work out if a child of the parent view has been selected
// This is a bit of a brute force way of doing this but can cope with different height items.
int childIndex = 0;
bool childFound = false;
Rect hitRect = new Rect();
while ((childIndex < monitoredView.ChildCount) && (childFound == false))
{
View child = monitoredView.GetChildAt(childIndex);
child.GetHitRect(hitRect);
// Check if this child has been selected - all coordinates relative to the parent
if (hitRect.Contains(relX, relY) == true)
{
childFound = true;
// Save the view
selectedView = child;
selectedPosition = monitoredView.GetPositionForView(child);
// Check if this child can be selected
if (ItemSelectionHandler != null)
{
SelectionEventArgs args = new SelectionEventArgs {
Position = selectedPosition, ViewSelected = child
};
ItemSelectionHandler.Invoke(this, args);
if (args.Cancel == true)
{
selectedView = null;
}
}
}
else
{
childIndex++;
}
}
// If a child hasn't been selected check whether or not group swipes are allowed
if (childFound == false)
{
selectedPosition = -1;
// If group swiping is allowed (in either direction) then specify the parent view as the selected view
if ((RightGroupSwipe == true) || (LeftGroupSwipe == true))
{
selectedView = monitoredView;
}
}
// If a view has been selected then set up a velocity tracker and record the initial x coordinate
if (selectedView != null)
{
velocity = VelocityTracker.Obtain();
velocity.AddMovement(touchEvent);
// Record the raw starting X position to determine how far to translate the view in response to user
// moves
initialDownX = touchEvent.RawX;
touchConsumed = true;
}
break;
}
case MotionEventActions.Move:
{
// If a view has been selected then determine how far it has been moved
if (selectedView != null)
{
// Add the current movement to those held by the tracker
velocity.AddMovement(touchEvent);
float deltaX = touchEvent.RawX - initialDownX;
if (swiping == false)
{
// Not already swiping. Check if the movement is deliberate and is more horizontal than vertical
// Get the velocity in pixels / sec
// Check if swiping is actually allowed
if (SwipingAllowed(deltaX) == true)
{
velocity.ComputeCurrentVelocity(1000);
if ((Math.Abs(deltaX) > wander) &&
(Math.Abs(velocity.XVelocity) > Math.Abs(velocity.YVelocity)))
{
swiping = true;
}
}
}
if (swiping == true)
{
// Move the view unless swiping is not allowed
if (SwipingAllowed(deltaX) == true)
{
// Move the selected view
// If this is a group swipe then move the parent view instead
if (((deltaX > 0) && (RightGroupSwipe == true)) ||
((deltaX < 0) && (LeftGroupSwipe == true)))
{
monitoredView.TranslationX = deltaX;
// If moving left and there is a right reveal view then move it as well
if ((deltaX < 0) && (RightRevealView != null))
{
RightRevealView.TranslationX = monitoredView.Width + deltaX;
RightRevealView.Visibility = ViewStates.Visible;
}
// If moving right and there is a left reveal view then move it as well
if ((deltaX > 0) && (LeftRevealView != null))
{
LeftRevealView.TranslationX = deltaX - monitoredView.Width;
LeftRevealView.Visibility = ViewStates.Visible;
}
// If we've been moving an individual child then make sure it is put back where
// we found it. Don't so this if the selected child is the parent
if ((selectedView != monitoredView) && (selectedView.TranslationX != 0))
{
selectedView.TranslationX = 0;
}
}
else
{
// Only move this view if it is not the parent view
if (selectedView != monitoredView)
{
selectedView.TranslationX = deltaX;
}
}
}
touchConsumed = true;
}
}
break;
}
case MotionEventActions.Up:
{
if (swiping == true)
{
// Assume no fling detected
bool flingRightDetected = false;
bool flingLeftDetected = false;
// Assume a slow drag rather than a fast fling
bool wasFlung = false;
// Add the current movement to those held by the tracker and detemine the curent velocities
velocity.AddMovement(touchEvent);
velocity.ComputeCurrentVelocity(1000);
float absXVelocity = Math.Abs(velocity.XVelocity);
float absYVelocity = Math.Abs(velocity.YVelocity);
float deltaX = touchEvent.RawX - initialDownX;
// First of all detect a fling.
// If the absolute velocity is greater than the fling minimum and the movement is still
// in a mainly horizontal direction then its a fling.
// Also ensure that the current delta is in the same direction as the fling, i.e. make sure that
// the view has been repositioned back to where it started before processing a fling in the opposite
// direction
if ((absXVelocity > minimumFlingVelocity) && (absXVelocity > (absYVelocity * 2)))
{
// Check if the fling is in an allowed direction - may have changed direction since last move
if (SwipingAllowed(velocity.XVelocity) == true)
{
// Make sure that the fling direction agrees with the current position of the view
if (Math.Sign(velocity.XVelocity) == Math.Sign(deltaX))
{
flingRightDetected = (velocity.XVelocity > 0);
flingLeftDetected = (velocity.XVelocity < 0);
wasFlung = true;
}
}
}
// More than half the width moved?
else if ((SwipingAllowed(deltaX) == true) && (Math.Abs(deltaX) > (monitoredView.Width / 2)))
{
flingRightDetected = (deltaX > 0);
flingLeftDetected = (deltaX < 0);
}
// Animate the selected view either to the right, left or back to the start
// Work out whether the selected child or the parent view needs to be animated
// Assume the child
View animatedView = selectedView;
if (((deltaX > 0) && (RightGroupSwipe == true)) ||
((deltaX < 0) && (LeftGroupSwipe == true)))
{
animatedView = monitoredView;
}
// If the animated view has not changed position then skip the animation processing
// Thius assumes that a velocity based fling will only occur after the view has
// moved a little first TBD
if (animatedView.TranslationX != 0)
{
if (flingRightDetected == true)
{
// Animate the view fully off to the right and report the event back to the view at the
// end of the animation
SimpleAnimate(animatedView, monitoredView.Width,
new ObjectAnimatorListenerAdapter((animation) =>
{
FlingRightHandler?.Invoke(this, new SwipeEventArgs {
Position = selectedPosition, WasFlung = wasFlung
});
if (animatedView != monitoredView)
{
animatedView.TranslationX = 0;
}
}));
// If this is a parent view swipe and there's a left reveal then animate it across as well
if ((animatedView == monitoredView) && (LeftRevealView != null))
{
SimpleAnimate(LeftRevealView, 0, null);
}
}
else if (flingLeftDetected == true)
{
// Animate the view fully off to the left and report the event back to the view at the
// end of the animation
SimpleAnimate(animatedView, -monitoredView.Width,
new ObjectAnimatorListenerAdapter((animation) =>
{
FlingLeftHandler?.Invoke(this, new SwipeEventArgs {
Position = selectedPosition, WasFlung = wasFlung
});
if (animatedView != monitoredView)
{
animatedView.TranslationX = 0;
}
}));
// If this is a parent view swipe and there's a right reveal then animate it across as well
if ((animatedView == monitoredView) && (RightRevealView != null))
{
SimpleAnimate(RightRevealView, 0, null);
}
}
else
{
// No fling so animate the views back to their starting positions
SimpleAnimate(animatedView, 0, null);
// If the parent view was being moved and there's a left or right review then animate them back
// to their starting positions as well
if (animatedView == monitoredView)
{
if ((deltaX > 0) && (LeftRevealView != null))
{
// Animate the view back to the left
SimpleAnimate(LeftRevealView, -monitoredView.Width, null);
}
if ((deltaX < 0) && (RightRevealView != null))
{
// Animate the view back to the right
SimpleAnimate(RightRevealView, monitoredView.Width, null);
}
}
}
}
}
// Reset state variables
selectedView = null;
swiping = false;
// Free up the VelocityTracker
if (velocity != null)
{
velocity.Recycle();
velocity = null;
}
break;
}
}
return(touchConsumed);
}
void Start()
{
itemSelectionHandler = ItemSelectionHandler.itemSelectionHandler;
}
