I'm currently facing a design problem with drag and drop on tablets.
Scenario: The screen is split in half, on the right side, I have a list of items and on the left side I have a list of boxes. I can pick up an item and drop it in a box.
On the right side, it's possible to scroll the list if there are so many items that don't all fit on the screen.
I have three solutions for picking up an item to drag, all of them have problems:
Touch and hold for 0.5s, then the item is picked up, then it's possible to drag. Problem: Most people just don't hold and try to drag right away. They fail and it annoys them.
Instant drag on touch, the item is draggable instantly on touch. Problem: When they try to scroll, they pick up the item instead of scrolling the list. It doesn't do that they wanted and it annoys them.
Have a drag handle, so if they touch on the handle, they instantly pick up the item and can drag it. If they touch elsewhere, the item is not picked up. Problem: Has to make the item icon bigger. The draggable area (drag handle) can be small so harder to pick up an item.
I think drag and drop is the most natural interaction for this scenario, but I can't find a perfect way to do it. Do you guys have any suggestions?
It's possible to avoid drag and drop totally, but I would resort to that as the last solution.