Ejemplo n.º 1
0
        private void MoveSoundClassUp()
        {
            int index = _soundClasses.IndexOf(_selectedSoundClass);

            IsChanged = true;
            _soundClasses.Move(index, index - 1);
        }
        private void updateArrangement()
        {
            var localPos = ListContainer.ToLocalSpace(screenSpaceDragPosition);
            int srcIndex = Items.IndexOf(currentlyDraggedItem.Model);

            // Find the last item with position < mouse position. Note we can't directly use
            // the item positions as they are being transformed
            float heightAccumulator = 0;
            int   dstIndex          = 0;

            for (; dstIndex < Items.Count; dstIndex++)
            {
                var drawable = itemMap[Items[dstIndex]];

                if (!drawable.IsLoaded)
                {
                    continue;
                }

                // Using BoundingBox here takes care of scale, paddings, etc...
                float height = drawable.BoundingBox.Height;

                // Rearrangement should occur only after the mid-point of items is crossed
                heightAccumulator += height / 2;

                // Check if the midpoint has been crossed (i.e. cursor is located above the midpoint)
                if (heightAccumulator > localPos.Y)
                {
                    if (dstIndex > srcIndex)
                    {
                        // Suppose an item is dragged just slightly below its own midpoint. The rearrangement condition (accumulator > pos) will be satisfied for the next immediate item
                        // but not the currently-dragged item, which will invoke a rearrangement. This is an off-by-one condition.
                        // Rearrangement should not occur until the midpoint of the next item is crossed, and so to fix this the next item's index is discarded.
                        dstIndex--;
                    }

                    break;
                }

                // Add the remainder of the height of the current item
                heightAccumulator += height / 2 + ListContainer.Spacing.Y;
            }

            dstIndex = Math.Clamp(dstIndex, 0, Items.Count - 1);

            if (srcIndex == dstIndex)
            {
                return;
            }

            Items.Move(srcIndex, dstIndex);

            // Todo: this could be optimised, but it's a very simple iteration over all the items
            reSort();
        }