0.14 Dragging objects between containers

Table of contents

• Preface
  • General
  • Viewing tip
    • Figures
    • Listings
  • Supplemental material
• General background information
• Preview
• Discussion and sample code
  • The MXML code
  • The ActionScript code
• 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.Most 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. Insofar as 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 . Project file structure.
• Figure 3 . Results of dragging objects.
• Figure 4 . Result of droping the TextArea into the middle Canvas.

Listings

• Listing 1 . The MXML code.
• Listing 2 . Beginning of the Driver class.
• Listing 3 . Beginning of the creationComplete event handler.
• Listing 4 . Register a mouseDown event listener on each draggable object.
• Listing 5 . The beginning of the mouseDown event handler.
• Listing 6 . Get the name of the class from which the drag initiator was instantiated.
• Listing 7 . Populate a new DragSource object with the drag initiator and a format string.
• Listing 8 . Initiate the drag and drop operation.
• Listing 9 . Register a different dragEnter event handler on each Canvas object.
• Listing 10 . Register the same dragDrop event handler on all three Canvas objects.
• Listing 11 . A dragEnter event handler for the top Canvas object.
• Listing 12 . The dragDrop event handler.
• Listing 13 . The MXML code for the program named DragAndDrop04.
• Listing 14 . The ActionScript code for the program named DragAndDrop04.