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Supplemental material

I recommend that you also study the other lessons in my extensive collection of online programmingtutorials. You will find a consolidated index at www.DickBaldwin.com .

General Background Information

For Adobe online documentation on this topic, see Using Drag and Drop .

A drag and drop operation is carried out in three stages:

  • Initiation
  • Dragging
  • Dropping

Initiation

As you are probably already aware, initiation consists of the user pointing to an item with the mouse and pressing the mouse button.

Dragging

During the drag operation, the user drags the item to another location on the screen without releasing the mouse button.

Dropping

When the item has been dragged to the new location, the user releases the mouse button causing the item to remain in the new location.

Copying

It is also possible to copy an item using the drag and drop gestures, but that capability won't be illustrated in this lesson. Instead, this lesson willconcentrate on moving a Flex component from one location in its container to a different location in its container.

Classes and events

The sample program that I will explain in this lesson will use the following classes, methods, and events:

  • MouseEvent class
    • mouseDown event
  • DragEvent class
    • dragDrop event
    • dragEnter event
  • DragManager class
    • acceptDragDrop method
    • doDrag method
  • DragSource class
    • addData method
    • hasFormat method

Preview

I will explain a program named DragAndDrop01 . This program illustrates the fundamentals of drag and drop in ActionScript 3. The program places three imagesin the upper-left corner of a Canvas object as shown in Figure 1.

Program output at startup.

Program output at startup image.
Program output at startup.

The program file structure

The program file structure, taken from the Flex Builder 3 Navigator panel is as shown in Figure 2.

Program file structure.

Program file structure.
Program file structure.

Three image files

As you can see in Figure 2, the program uses the following image files :

  • 0 - space.jpg
  • 1 - snowscene.jpg
  • 2 - frog.jpg

The z-axes indices

The program sets the z-axis indices in the order shown in the above list on the Image objects produced using the image files. This causes the space image to be in the back (0), the frog image to be in the front (2), and the snowscene image to be in the middle (1).

The three images are initially placed in the upper-left corner of the canvas, which is shown as a cyan rectangle in Figure 1.

Any image can be dragged

If you run this program, you will see that any any of the images can be dragged and dropped anywhere within the canvas as long as the mouse pointer doesn't leave the canvas. However, if the edge of thedragged image goes outside the left edge or the top of the canvas, the drag and drop operation is aborted.

If the dragged image goes outside the right side or the bottom of the canvas, scroll bars automatically appear on the canvas as shown in Figure 3.

Program output after dragging the images

Figure 3 shows the program output after dragging the three images to different locations.

Program output after dragging the images.

Program output after dragging the images.
Program output after dragging the images.

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Object-oriented programming (oop) with actionscript. OpenStax CNX. Jun 04, 2010 Download for free at http://cnx.org/content/col11202/1.19
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