org.openstreetmap.josm.gui

Class FileDrop

java.lang.Object

org.openstreetmap.josm.gui.FileDrop

public class FileDrop
extends java.lang.Object

This class makes it easy to drag and drop files from the operating system to a Java program. Any Component can be dropped onto, but only JComponents will indicate the drop event with a changed border.

To use this class, construct a new FileDrop by passing it the target component and a Listener to receive notification when file(s) have been dropped. Here is an example:

JPanel myPanel = new JPanel(); new FileDrop( myPanel, new FileDrop.Listener() { public void filesDropped( java.io.File[] files ) { // handle file drop ... } // end filesDropped }); // end FileDrop.Listener

You can specify the border that will appear when files are being dragged by calling the constructor with a Border. Only JComponents will show any indication with a border.

You can turn on some debugging features by passing a PrintStream object (such as System.out) into the full constructor. A null value will result in no extra debugging information being output.

I'm releasing this code into the Public Domain. Enjoy.

Original author: Robert Harder, rharder@usa.net

2007-09-12 Nathan Blomquist -- Linux (KDE/Gnome) support added.

Since:

1231

Version:

1.0.1

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	FileDrop.Listener Implement this inner interface to listen for when files are dropped.
static class	FileDrop.TransferableObject At last an easy way to encapsulate your custom objects for dragging and dropping in your Java programs! When you need to create a Transferable object, use this class to wrap your object.

Field Summary

Fields

Modifier and Type	Field and Description
private static java.awt.Color	defaultBorderColor
private java.awt.dnd.DropTargetListener	dropListener
private javax.swing.border.Border	normalBorder
private static java.lang.Boolean	supportsDnD Discover if the running JVM is modern enough to have drag and drop.
private static java.lang.String	ZERO_CHAR_STRING

Constructor Summary

Constructors

Constructor and Description
FileDrop(java.awt.Component c) Constructor for JOSM file drop
FileDrop(java.awt.Component c, javax.swing.border.Border dragBorder, boolean recursive, FileDrop.Listener listener) Full constructor with a specified border and debugging optionally turned on.

Method Summary

Modifier and Type	Method and Description
private static java.io.File[]	createFileArray(java.io.BufferedReader bReader)
private boolean	isDragOk(java.awt.dnd.DropTargetDragEvent evt) Determine if the dragged data is a file list.
private void	makeDropTarget(java.awt.Component c, boolean recursive)
static boolean	remove(java.awt.Component c) Removes the drag-and-drop hooks from the component and optionally from the all children.
static boolean	remove(java.awt.Component c, boolean recursive) Removes the drag-and-drop hooks from the component and optionally from the all children.
private static boolean	supportsDnD()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

normalBorder

private transient javax.swing.border.Border normalBorder

dropListener

private transient java.awt.dnd.DropTargetListener dropListener

supportsDnD

private static java.lang.Boolean supportsDnD

Discover if the running JVM is modern enough to have drag and drop.

defaultBorderColor

private static java.awt.Color defaultBorderColor

ZERO_CHAR_STRING

private static final java.lang.String ZERO_CHAR_STRING

See Also:

Constant Field Values

Constructor Detail

FileDrop

public FileDrop(java.awt.Component c)

Constructor for JOSM file drop

Parameters:

c - The drop target

FileDrop

public FileDrop(java.awt.Component c,
                javax.swing.border.Border dragBorder,
                boolean recursive,
                FileDrop.Listener listener)

Full constructor with a specified border and debugging optionally turned on. With Debugging turned on, more status messages will be displayed to out. A common way to use this constructor is with System.out or System.err. A null value for the parameter out will result in no debugging output.

Parameters:

c - Component on which files will be dropped.

dragBorder - Border to use on JComponent when dragging occurs.

recursive - Recursively set children as drop targets.

listener - Listens for filesDropped.

Method Detail

supportsDnD

private static boolean supportsDnD()

createFileArray

private static java.io.File[] createFileArray(java.io.BufferedReader bReader)

makeDropTarget

private void makeDropTarget(java.awt.Component c,
                            boolean recursive)

isDragOk

private boolean isDragOk(java.awt.dnd.DropTargetDragEvent evt)

Determine if the dragged data is a file list.

remove

public static boolean remove(java.awt.Component c)

Removes the drag-and-drop hooks from the component and optionally from the all children. You should call this if you add and remove components after you've set up the drag-and-drop. This will recursively unregister all components contained within c if c is a Container.

Parameters:

c - The component to unregister as a drop target

Returns:

true if at least one item has been removed, false otherwise

remove

public static boolean remove(java.awt.Component c,
                             boolean recursive)

Removes the drag-and-drop hooks from the component and optionally from the all children. You should call this if you add and remove components after you've set up the drag-and-drop.

Parameters:

c - The component to unregister

recursive - Recursively unregister components within a container

Returns:

true if at least one item has been removed, false otherwise