/*
* This file is part of WebLookAndFeel library.
*
* WebLookAndFeel library is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* WebLookAndFeel library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with WebLookAndFeel library. If not, see <http://www.gnu.org/licenses/>.
*/
package com.alee.extended.drag;
import com.alee.utils.DragUtils;
import com.alee.utils.drag.FileTransferable;
import javax.swing.*;
import java.awt.datatransfer.Transferable;
import java.io.File;
import java.util.Arrays;
import java.util.List;
/**
* Custom TransferHandler that provides easy and convenient way to support files DnD to/from any Swing component.
* <p/>
* To provide drag functionality override {@code filesDropped()} method and enable drag operation through methods or constructor.
* You will also have to call "exportAsDrag" method of TransferHandler to initialize drag operation from where you want it to start.
* Usually that action is done from MouseMotionListener drag method.
* <p/>
* To provide drop functionality imply override {@code filesDropped()} method and enable drop operation through methods or constructor.
*
* @author Mikle Garin
*/
public class FileDragAndDropHandler extends TransferHandler
{
/**
* Whether files drag is enabled or not.
*/
protected boolean dragEnabled;
/**
* Desired drag action.
*/
protected int dragAction = COPY;
/**
* Whether files drop is enabled or not.
*/
protected boolean dropEnabled;
/**
* Constructs new FileDragAndDropHandler that allows only file drop operations.
*/
public FileDragAndDropHandler ()
{
this ( false, true );
}
/**
* Constructs new FileDragAndDropHandler that might allow drag and/or drop operations.
*
* @param dragEnabled whether drag operations are allowed
* @param dropEnabled whether drop operations are allowed
*/
public FileDragAndDropHandler ( final boolean dragEnabled, final boolean dropEnabled )
{
super ();
setDragEnabled ( dragEnabled );
setDropEnabled ( dropEnabled );
}
/**
* Returns whether drag is enabled or not.
* If {@code false} is set any drag actions will be blocked.
*
* @return true if drag is enabled, false otherwise
*/
public boolean isDragEnabled ()
{
return dragEnabled;
}
/**
* Sets whether drag is enabled or not.
* If {@code false} is set any drag actions will be blocked.
*
* @param enabled whether drag is enabled or not
*/
public void setDragEnabled ( final boolean enabled )
{
this.dragEnabled = enabled;
}
/**
* Returns desired drag action.
* This is either {@code TransferHandler.COPY} or {@code TransferHandler.MOVE} constant.
*
* @return desired drag action
*/
public int getDragAction ()
{
return dragAction;
}
/**
* Sets desired drag action.
* This should be either {@code TransferHandler.COPY} or {@code TransferHandler.MOVE} constant.
*
* @param action new desired drag action
*/
public void setDragAction ( final int action )
{
this.dragAction = action;
}
/**
* {@inheritDoc}
*/
@Override
public int getSourceActions ( final JComponent c )
{
return getDragAction ();
}
/**
* {@inheritDoc}
*/
@Override
protected Transferable createTransferable ( final JComponent c )
{
if ( isDragEnabled () )
{
final List<File> draggedFiles = filesDragged ();
return draggedFiles != null && draggedFiles.size () > 0 ? new FileTransferable ( draggedFiles ) : null;
}
else
{
return null;
}
}
/**
* Informs that drag action has started and list of dragged files should be provided.
* You can override this method to provide custom list of dragged files.
*
* @return list of dragged files
*/
public List<File> filesDragged ()
{
final File file = fileDragged ();
return file != null ? Arrays.asList ( file ) : null;
}
/**
* Informs that drag action has started and dragged file should be provided.
* You can override this method to provide custom dragged file.
*
* @return dragged file
*/
public File fileDragged ()
{
return null;
}
/**
* Returns whether drop is enabled or not.
* If {@code false} is returned any drop actions are blocked.
*
* @return true if drop is enabled, false otherwise
*/
public boolean isDropEnabled ()
{
return dropEnabled;
}
/**
* Sets whether drop is enabled or not.
* If {@code false} is set any drop actions will be blocked.
*
* @param enabled whether drop is enabled or not
*/
public void setDropEnabled ( final boolean enabled )
{
this.dropEnabled = enabled;
}
/**
* {@inheritDoc}
*/
@Override
public boolean canImport ( final TransferHandler.TransferSupport info )
{
return isDropEnabled ();
}
/**
* {@inheritDoc}
*/
@Override
public boolean importData ( final TransferHandler.TransferSupport info )
{
return info.isDrop () && importData ( info.getTransferable () );
}
/**
* Performs data import checks and action.
* Returns whether drop was completed or not.
*
* @param t dropped transferable
* @return true if drop was completed, false otherwise
*/
public boolean importData ( final Transferable t )
{
return isDropEnabled () && filesDropped ( DragUtils.getImportedFiles ( t ) );
}
/**
* Informs that specified files were dropped.
* You can override this method to perform desired actions.
*
* @param files list of dropped files
* @return true if drop was completed, false otherwise
*/
public boolean filesDropped ( final List<File> files )
{
return true;
}
}