Drag-and-drop

From Wikipedia, the free encyclopedia

In computer graphical user interfaces, drag-and-drop is the action of (or support for the action of) clicking on a virtual object and dragging it to a different location or onto another virtual object. In general, it can be used to invoke many kinds of actions, or create various types of associations between two abstract objects.

Dragging requires more physical effort than moving the same pointing device without holding down any buttons. Because of this, a user cannot move as quickly and precisely while dragging (see Fitts' law). However, drag-and-drop operations have the advantage of thoughtfully chunking together two operands (the object to drag, and the drop location) into a single action (see, for example, ^[1]). Extended dragging and dropping (as in graphic design) can stress the mousing hand.

As a feature, support for drag-and-drop is not found in all software, though it is sometimes a fast and easy-to-learn technique for users to perform tasks.

A design problem appears when the same button selects and drags items. Imprecise movement can cause a dragging when the user just want to select.

Another problem is that the target of the dropping can be hidden under other objects. The user would have to stop the dragging, make both the source and the target visible and start again.

The Workplace Shell of OS/2 uses dragging and dropping extensively with the secondary mouse button, leaving the primary one for selection and clicking. Its use like that of other advanced Common User Access features distinguished native OS/2 applications from platform-independent ports.

1 Actions
2 Examples
3 Footnotes
4 See also
5 External links

[edit] Actions

The basic sequence involved in drag-and-drop is:

Press, and hold down, the button on the mouse or other pointing device, to "grab" the object,
"Drag" the object/cursor/pointing device to the desired location,
"Drop" the object by releasing the button.

[edit] Examples

A common example is dragging an icon on a virtual desktop to a special trashcan icon to delete a file.

Further examples include:

Dragging a data file onto a program icon or special window for viewing or processing,
Moving or copying files to a new location/directory/folder,
Adding objects to a list of objects to be processed,
Rearranging widgets in a graphical user interface to customize their layout,
Dragging a command onto an object to which the command is to be applied,
- e.g. dragging a color onto a graphical object to change its color,
Dragging a tool to a canvas location to apply the tool at that location,
Creating a hyperlink from one location or word to another location or document.
Some editors like Visual Studio allow dragging selected text from one point to another.