From Wikipedia, the free encyclopedia Drag and drop
Drag and drop
In computer graphical user interfaces, drag-and-drop is get. This issue has been dealt with in Mac OS X with the
the action of (or support for the action of) selecting a vir- introduction of Exposé.
tual object by "grabbing" it 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 vari-
In Mac OS
ous types of associations between two abstract objects. Drag-and-drop, called "Click and Drag" at the time, was
As a feature, support for drag-and-drop is not found used in the original Macintosh to manipulate files (for ex-
in all software, though it is sometimes a fast and easy- ample, copying them between disks [3] or folders.[4]). Sys-
to-learn technique for users to perform tasks. However, tem 7 introduced the ability to open a document in an ap-
the lack of affordances in drag-and-drop implementa- plication by dropping the document icon onto the appli-
tions means that it is not always obvious that an item can cation’s icon.
be dragged.[1] In System 7.5 drag-and-drop was extended to com-
mon clipboard operations like copying or moving textual
content within a document. Content could also be
dragged into the filesystem to create a "clipping file"
which could then be stored and reused.
Apple bought this idea from a 19 year old Dutch pro-
grammer called Martijn Scheffer.[citation needed]
In Mac OS X, the user can install software without us-
ing a setup program. The application packaging scheme
of OS X allows the program to simply copy any required
Drag image and drop onto browser in Windows support files upon startup.
For most of its history Mac OS has used a one button
mouse with the button covering a large portion of the top
Actions surface of the mouse. This may mitigate the ergonomic
The basic sequence involved in drag-and-drop is: concerns of keeping the button pressed while dragging.
• Move the pointer to the object
• Press, and hold down, the button on the mouse or In Windows
other pointing device, to "grab" the object,
• "Drag" the object to the desired location, Jeffrey Greenberg claims that the first drag & drop im-
• "Drop" the object by releasing the button. plementation for Windows was his shareware program
Dragging requires more physical effort than moving the called Aporia in 1988 under Windows 2.0, and later com-
same pointing device without holding down any buttons. mercialized as WinTools.[citation needed] In Aporia/
Because of this, a user cannot move as quickly and pre- WinTools all icons had functions that could be obtained
cisely while dragging (see Fitts’ law). However, drag-and- by double clicking the left mouse button, by clicking on
drop operations have the advantage of thoughtfully the right mouse button, or by dragging onto one of sev-
chunking together two operands (the object to drag, and eral functional icons, such as printing, copying, viewing,
the drop location) into a single action.[2] Extended drag- and other actions. If an icon was double-clicked on and
ging and dropping (as in graphic design) can stress the ran a program, the icon changed to indicate that a pro-
mousing hand. gram was running, and if it was then dragged to the
A design problem appears when the same button se- trash, the program was exited. (A defect in the imple-
lects and drags items. Imprecise movement can cause a mentation led to a workaround being built into the Win-
dragging when the user just wants to select. dows operating system Aporia Bits)
Another problem is that the target of the dropping Subsequently numerous other competitors provided
can be hidden under other objects. The user would have drag & drop desktop replacements to the standard Win-
to stop the dragging, make both the source and the target dows interface including the Norton Desktop, Xerox,
visible and start again. In classic Mac OS the top-of- NewWave, and Central Point. In Windows 95, Microsoft
screen menu bar served as a universal "drag cancel" tar- prevented developers from taking over the desktop, and
released a drag & drop model of their own.
1
From Wikipedia, the free encyclopedia Drag and drop
In OS/2 window signifies "Open this document as a new
document in Word"
The Workplace Shell of OS/2 uses dragging and dropping • Moving or copying files to a new location/directory/
extensively with the secondary mouse button, leaving folder,
the primary one for selection and clicking. Its use like • Adding objects to a list of objects to be processed,
that of other advanced Common User Access features dis- • Rearranging widgets in a graphical user interface to
tinguished native OS/2 applications from platform-inde- customize their layout,
pendent ports. • Dragging an attribute onto an object to which the
command is to be applied,
In HTML • e.g. dragging a color onto a graphical object to
change its color,
The HTML5 specification is reported to include support • Dragging a tool to a canvas location to apply the tool
for drag & drop. at that location,
Google’s web-based e-mail application Gmail sup- • Creating a hyperlink from one location or word to
ports drag-and-drop of images and attachments in the another location or document.
latest Google Chrome browser and Apple’s Safari (5.x). • Most word processors allow dragging selected text
from one point to another.
On a touch screen • JavaScript to drag-and-drop the list DOM nodes.
Very few touch screen interfaces include Click and
drag.[citation needed] More common is long press, and then Footnotes
drag, e.g. on the iPhone or Android home screens. [1] Jakob Nielsen, "Top-10 Application-Design
Mistakes," http://www.useit.com/alertbox/
In end-user programming [2]
application-mistakes.html (19 February 2008).
Buxton, W. (1986). "Chunking and Phrasing and the
Drag-and-drop is considered an important program con- Design of Human-Computer Dialogues". Proceedings
struction approach in many end-user development sys- of the IFIP World Computer Congress. pp. 475–480.
tems. In contrast to more traditional, text-based pro- http://www.billbuxton.com/chunking.html.
gramming languages many end-user programming lan- [3] "Disk Swapper’s Elbow". folklore.org.
guages are based on visual components such as tiles or http://www.folklore.org/
icons that are manipulated by end users through drag- StoryView.py?project=Macintosh&story=Disk_Swappers_Elbow.tx
and-drop interfaces. [4] "The Grand Unified Model (2): The Finder".
folklore.org. http://www.folklore.org/
Examples StoryView.py?project=Macintosh&story=The_Grand_Unified_Mod
A common example is dragging an icon on a virtual desk-
top to a special trashcan icon to delete a file. See also
Further examples include: • Mouse gesture
• Dragging a data file onto a program icon or window • Point-and-click
for viewing or processing. For instance, dropping an • Snap (computer graphics)
icon that represents a text file into a Microsoft Word
Retrieved from "http://en.wikipedia.org/w/index.php?title=Drag_and_drop&oldid=468319247"
Categories:
• User interface techniques
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