?? testdroptarget.java
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import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.event.*;
import java.awt.dnd.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.imageio.*;
/**
* Description:
* <br/>Copyright (C), 2005-2008, Yeeku.H.Lee
* <br/>This program is protected by copyright laws.
* <br/>Program Name:
* <br/>Date:
* @author Yeeku.H.Lee kongyeeku@163.com
* @version 1.0
*/
public class TestDropTarget
{
final int DESKTOP_WIDTH = 480;
final int DESKTOP_HEIGHT = 360;
final int FRAME_DISTANCE = 30;
JFrame jf = new JFrame("測試拖放目標——把圖片文件拖入該窗口");
//定義一個虛擬桌面
private JDesktopPane desktop = new JDesktopPane();
//保存下一個內部窗口的座標點
private int nextFrameX;
private int nextFrameY;
//定義內部窗口為虛擬桌面的1/2大小
private int width = DESKTOP_WIDTH / 2;
private int height = DESKTOP_HEIGHT / 2;
public void init()
{
desktop.setPreferredSize(new Dimension(DESKTOP_WIDTH, DESKTOP_HEIGHT));
//將當前窗口創建成拖放源
new DropTarget(jf, DnDConstants.ACTION_COPY , new ImageDropTargetListener());
jf.add(desktop);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.pack();
jf.setVisible(true);
}
class ImageDropTargetListener extends DropTargetAdapter
{
public void drop(DropTargetDropEvent event)
{
//接受復制操作
event.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
//獲取拖放的內容
Transferable transferable = event.getTransferable();
DataFlavor[] flavors = transferable.getTransferDataFlavors();
//遍歷拖放內容里的所有數據格式
for (int i = 0; i < flavors.length; i++)
{
DataFlavor d = flavors[i];
try
{
//如果拖放內容的數據格式是文件列表
if (d.equals(DataFlavor.javaFileListFlavor))
{
//取出拖放操作里的文件列表
java.util.List fileList
= (java.util.List) transferable.getTransferData(d);
for (Object f : fileList)
{
//顯示每個文件
showImage((File)f , event);
}
}
}
catch (Exception e)
{
e.printStackTrace();
}
//強制拖放操作結束,停止阻塞拖放源
event.dropComplete(true);
}
}
//顯示每個文件的工具方法
private void showImage(File f , DropTargetDropEvent event)throws java.io.IOException
{
Image image = ImageIO.read(f);
if (image == null)
{
//強制拖放操作結束,停止阻塞拖放源
event.dropComplete(true);
JOptionPane.showInternalMessageDialog(desktop , "系統不支持這種類型的文件");
//方法返回,不會繼續操作
return;
}
ImageIcon icon = new ImageIcon(image);
//創建內部窗口顯示該圖片
JInternalFrame iframe = new JInternalFrame(f.getName()
,true , true , true , true);
JLabel imageLabel = new JLabel(icon);
iframe.add(new JScrollPane(imageLabel));
desktop.add(iframe);
//設置內部窗口的原始位置(內部窗口默認大小是0X0,放在0,0位置)
iframe.reshape(nextFrameX, nextFrameY, width, height);
//使該窗口可見,并嘗試選中它
iframe.show();
//計算下一個內部窗口的位置
nextFrameX += FRAME_DISTANCE;
nextFrameY += FRAME_DISTANCE;
if (nextFrameX + width > desktop.getWidth()) nextFrameX = 0;
if (nextFrameY + height > desktop.getHeight()) nextFrameY = 0;
}
}
public static void main(String[] args)
{
new TestDropTarget().init();
}
}
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