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1 package com.opensymphony.workflow.designer.swing;
2
3 import java.awt.*;
4 import java.awt.datatransfer.DataFlavor  ;
5 import java.awt.datatransfer.Transferable ;
6 import java.awt.datatransfer.UnsupportedFlavorException ;
7 import java.awt.dnd.*;
8 import java.awt.event.HierarchyEvent ;
9 import java.awt.event.HierarchyListener ;
10 import java.io.File ;
11 import java.io.IOException ;
12 import java.util.List ;
13 import java.util.TooManyListenersException ;
14 import javax.swing.*;
15
16 public abstract class FileDropHandler
17 {
18 private transient java.awt.dnd.DropTargetListener dropListener;
19
20 public FileDropHandler(Component target)
21 {
22 this(target, true);
23 }
24
25 public FileDropHandler(final Component target, final boolean recursive)
26 {
27 dropListener = new DropTargetListener()
28 {
29 public void dragEnter(DropTargetDragEvent evt)
30 {
31 if(isDragOk(evt))
32 {
33 evt.acceptDrag(DnDConstants.ACTION_COPY);
34 }
35 else
36 {
37 evt.rejectDrag();
38 }
39 }
40
41 public void dragOver(DropTargetDragEvent evt)
42 {}
43
44 public void drop(DropTargetDropEvent evt)
45 {
46 try
47 {
48 Transferable tr = evt.getTransferable();
49
50 if(tr.isDataFlavorSupported(DataFlavor.javaFileListFlavor))
51 {
52 evt.acceptDrop(DnDConstants.ACTION_COPY);
53
54 List fileList = (List )tr.getTransferData(DataFlavor.javaFileListFlavor);
55
56 File [] filesTemp = new File [fileList.size()];
57 fileList.toArray(filesTemp);
58 final File [] files = filesTemp;
59
60 filesDropped(files);
61
62 evt.getDropTargetContext().dropComplete(true);
63 }
64 else
65 {
66 evt.rejectDrop();
67 }
68 }
69 catch(IOException io)
70 {
71 io.printStackTrace();
72 evt.rejectDrop();
73 }
74 catch(UnsupportedFlavorException ufe)
75 {
76 ufe.printStackTrace();
77 evt.rejectDrop();
78 }
79 }
80
81 public void dragExit(DropTargetEvent evt)
82 {
83 }
84
85 public void dropActionChanged(DropTargetDragEvent evt)
86 {
87 if(isDragOk(evt))
88 {
89 evt.acceptDrag(DnDConstants.ACTION_COPY);
90 }
91 else
92 {
93 evt.rejectDrag();
94 }
95 }
96 };
97
98 makeDropTarget(target, recursive);
99 }
100
101 private void makeDropTarget(final Component target, boolean recursive)
102 {
103 final DropTarget dt = new DropTarget();
104 try
105 {
106 dt.addDropTargetListener(dropListener);
107 }
108 catch(TooManyListenersException e)
109 {
110 e.printStackTrace();
111 }
112
113 target.addHierarchyListener(new HierarchyListener ()
114 {
115 public void hierarchyChanged(HierarchyEvent evt)
116 {
117 Component parent = target.getParent();
118 if(parent == null)
119 {
120 target.setDropTarget(null);
121 }
122 else
123 {
124 new DropTarget(target, dropListener);
125 }
126 }
127 });
128 if(target.getParent() != null)
129 new DropTarget(target, dropListener);
130
131 if(recursive && (target instanceof Container))
132 {
133 Container cont = (Container)target;
134 Component[] comps = cont.getComponents();
135
136 for(int i = 0; i < comps.length; i++)
137 makeDropTarget(comps[i], recursive);
138 }
139 }
140
141 private boolean isDragOk(final DropTargetDragEvent evt)
142 {
143 boolean ok = false;
144
145 DataFlavor [] flavors = evt.getCurrentDataFlavors();
146 int i = 0;
147 while(!ok && i < flavors.length)
148 {
149 if(flavors[i].equals(DataFlavor.javaFileListFlavor))
150 ok = true;
151 i++;
152 }
153 return ok;
154 }
155
156 public abstract void filesDropped(File [] files);
157
158 public static void main(String [] args)
159 {
160 JFrame frame = new JFrame("FileDrop");
161 final JTree tree = new JTree();
162 frame.getContentPane().add(new JScrollPane(tree), BorderLayout.CENTER);
163
164 new FileDropHandler(tree)
165 {
166 public void filesDropped(File [] files)
167 {
168 for(int i = 0; i < files.length; i++)
169 {
170 System.out.println("dropped " + files[i]);
171 }
172 }
173 };
174
175 frame.setBounds(100, 100, 300, 400);
176 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
177 frame.show();
178 }
179 } |
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