0.13 Drag and drop basics

Table of contents

• Preface
  • General
  • Viewing tip
    • Figures
    • Listings
  • Supplemental material
• General Background Information
• Preview
• Discussion and sample code
  • The MXML file
  • The ActionScript file
• Run the program
• Resources
• Complete program listings
• Miscellaneous

Preface

General

This tutorial lesson is part of a series of lessons dedicated to object-oriented programming(OOP) with ActionScript.

Several ways to create and launch ActionScript programs

There are several ways to create and launch programs written in the ActionScript programming language.Many of the lessons in this series will use Adobe Flex as the launch pad for the sample ActionScript programs.

An earlier lesson titled The Default Application Container provided information on how to get started programming with Adobe's Flex Builder 3. (See Baldwin's Flex programming website .) You should study that lesson before embarking on the lessons in this series.

Some understanding of Flex MXML will be required

I also recommend that you study all of the lessons on Baldwin's Flex programming website in parallel withyour study of these ActionScript lessons. Eventually you will probably need to understand both ActionScript and Flex and the relationships that exist betweenthem in order to become a successful ActionScript programmer.

Will emphasize ActionScript code

It is often possible to use either ActionScript code or Flex MXML code to achieve the same result. Insofaras this series of lessons is concerned, the emphasis will be on ActionScriptcode even in those cases where Flex MXML code may be a suitable alternative.

Viewing tip

I recommend that you open another copy of this document in a separate browser window and use the following links to easily find and view the figures andlistings while you are reading about them.

Figures

• Figure 1 . Program output at startup.
• Figure 2 . Program file structure.
• Figure 3 . Program output after dragging the images.

Listings

• Listing 1 . The MXML file for DragAndDrop01.
• Listing 2 . Beginning of the Driver class for DragAndDrop01.
• Listing 3 . Beginning of the constructor for the Driver class.
• Listing 4 . Prepare the three images.
• Listing 5 . Register a creationComplete event handler.
• Listing 6 . Beginning of the creationComplete event handler.
• Listing 7 . Register a mouseDown event handler on each Image object.
• Listing 8 . Register dragDrop and dragEnter event handlers on the Canvas object.
• Listing 9 . Beginning of the mouseDown event handler.
• Listing 10 . Get and save the drag initiator.
• Listing 11 . Populate a DragSource object with a copy of the image being dragged.
• Listing 12 . Initiate the drag and drop operation by calling the doDrag method.
• Listing 13 . The dragEnter event handler.
• Listing 14 . Beginning of the dragDrop event handler.
• Listing 15 . Do the drop.
• Listing 16 . The MXML file for DragAndDrop01.
• Listing 17 . The ActionScript file for DragAndDrop01.