Introduction to DnD
Trail: Creating a GUI With JFC/Swing
Lesson: Drag and Drop and Data Transfer

Introduction to DnD

If you are writing an application you will want to support the ability to transfer information between components in your application. But you will also want your application to play well with others — this includes supporting the ability to transfer information between your application and other Java applications, and between your application and native applications. The ability to transfer data takes two forms:

Drag and Drop — Behind the Scenes

Let us say there is a user named Rollo, who is running a Java application. He wants to drag some text from a list and deposit it into a text field. (Note that the process is the same when dragging from a native application to a Java application.) In a nutshell, the drag and drop process works like this:

While this might seem like a daunting process, Swing handles most of the work for you. The framework is designed so that you plug in the details specific to your component, and the rest "just works".

More on this in the next section.


We do not recommend that you create your own drag and drop support using the AWT classes. This implementation would require significant complex support internal to each component. Prior to release 1.4 when the dnd system was reworked, developers did occasionally create their own dnd support, but it does not work with sophisticated components, like tree and table, that have subtle selection and drop issues.

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