private void ScrollViewer_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
Debug.WriteLine("scrollViewer_MouseLeftButtonUp");
if (!IsActive)
return;
// hide the pull down item by locating it off screen
_pullDownItem.VerticalOffset = -ToDoItemHeight;
// if the list was pulled down far enough, add a new item
if (_distance > ToDoItemHeight)
{
var newItem = new ToDoItemViewModel("");
var todoModel = newItem.ToModel();
_todoManager.Save(todoModel);
newItem.Update(todoModel);
_todoItems.Insert(0, newItem);
// when the new item has been rendered, use the edit interaction to place the UI
// into edit mode
_todoList.InvokeOnNextLayoutUpdated(() => _editInteraction.EditItem(newItem));
}
IsActive = false;
_effectPlayed = false;
}
private void Touch_FrameReported(object sender, TouchFrameEventArgs e)
{
if (!IsEnabled)
return;
if (IsActive)
{
var touchPoints = e.GetTouchPoints(_todoList);
// if we still have two touch points continue the pinch gesture
if (touchPoints.Count == 2)
{
double currentDelta = GetDelta(touchPoints[0], touchPoints[1]);
double itemsOffset = 0;
// is the delta bigger than the initial?
if (currentDelta > _initialDelta)
{
double delta = currentDelta - _initialDelta;
itemsOffset = delta / 2;
// play a sound effect if the users has pinched far enough to add a new item
if (delta > ToDoItemHeight && !_effectPlayed)
{
_effectPlayed = true;
_popSound.Play();
}
_addNewThresholdReached = delta > ToDoItemHeight;
// stretch and fade in the new item
var cappedDelta = Math.Min(ToDoItemHeight, delta);
((ScaleTransform)_pullDownItem.RenderTransform).ScaleY = cappedDelta / ToDoItemHeight;
_pullDownItem.Opacity = cappedDelta / ToDoItemHeight;
// set the text
_pullDownItem.Text = cappedDelta < ToDoItemHeight ? "Pull to create new item" : "Release to add new item";
}
// offset all the items in the list so that they 'part'
for (int i = 0; i < _todoItems.Count; i++)
{
var container = _todoList.ItemContainerGenerator.ContainerFromIndex(i) as FrameworkElement;
var translateTransform = (TranslateTransform)container.RenderTransform;
translateTransform.Y = i <= _itemOneIndex ? -itemsOffset : itemsOffset;
}
}
else
{
// if we no longer have two touch points, end the interactions
IsActive = false;
RefreshView();
// hide the pull-down item
_pullDownItem.VerticalOffset = -ToDoItemHeight;
if (_addNewThresholdReached)
{
var newItem = new ToDoItemViewModel("");
var todoModel = newItem.ToModel();
_todoManager.Save(todoModel);
newItem.Update(todoModel);
_todoItems.Insert(_itemOneIndex, newItem);
// when the new item has been rendered, use the edit interaction to place the UI
// into edit mode
_todoList.InvokeOnNextLayoutUpdated(() => _editInteraction.EditItem(newItem));
}
}
}
else
{
var touchPoints = e.GetTouchPoints(_todoList);
if (touchPoints.Count == 2)
{
_addNewThresholdReached = false;
_effectPlayed = false;
// find the items that were touched ...
var itemOne = GetToDoItemAtLocation(touchPoints[0].Position);
var itemTwo = GetToDoItemAtLocation(touchPoints[1].Position);
if (itemOne != null && itemTwo != null)
{
// find their indices
_itemOneIndex = _todoItems.IndexOf(itemOne);
_itemTwoIndex = _todoItems.IndexOf(itemTwo);
// are the two items next to each other?
if (Math.Abs(_itemOneIndex - _itemTwoIndex) == 1)
{
if (_itemOneIndex > _itemTwoIndex)
{
// We need to swap the two
int tempIndex = _itemOneIndex;
_itemOneIndex = _itemTwoIndex;
_itemTwoIndex = tempIndex;
var tempItem = itemOne;
itemOne = itemTwo;
itemTwo = tempItem;
}
IsActive = true;
// determine where to locate the new item placeholder
var itemOneContainer = _todoList.ItemContainerGenerator.ContainerFromItem(itemOne) as FrameworkElement;
var itemOneContainerPos = itemOneContainer.GetRelativePosition(_todoList);
_newItemLocation = itemOneContainerPos.Y + ToDoItemHeight - (ToDoItemHeight / 2);
// position the placeholder and add a scale transform
_pullDownItem.VerticalOffset = _newItemLocation;
_pullDownItem.Opacity = 0;
_pullDownItem.RenderTransform = new ScaleTransform()
{
ScaleY = 1,
CenterY = ToDoItemHeight / 2
};
// record the initial distance between touch point
_initialDelta = GetDelta(touchPoints[0], touchPoints[1]);
AddTranslateTransfromToElements();
_pullDownItem.Opacity = 1;
}
}
}
}
}