package com;

import java.awt.*;
import java.awt.datatransfer.DataFlavor;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DropTarget;
import java.awt.dnd.DropTargetAdapter;
import java.awt.dnd.DropTargetDropEvent;
import java.io.File;
import java.util.List;
import javax.swing.*;

/**
 * 最簡單的Java拖拽代碼示例
 * @author 劉顯安
 * 2013年1月24日
 */
public class DragTest extends JFrame
{

    JPanel panel;//要接受拖拽的面板
    public DragTest()
    {
        panel = new JPanel();
        panel.setBackground(Color.YELLOW);
        getContentPane().add(panel, BorderLayout.CENTER);
        setSize(500, 200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocation(400, 200);
        setTitle("最簡單的拖拽示例：拖拽文件到下面（20130124）");
        drag();//啟用拖拽
    }
    public static void main(String[] args) throws Exception
    {
        UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");//設置皮膚
        new DragTest().setVisible(true);;
    }
    public void drag()//定義的拖拽方法
    {
        //panel表示要接受拖拽的控件
        new DropTarget(panel, DnDConstants.ACTION_COPY_OR_MOVE, new DropTargetAdapter()
        {
            @Override
            public void drop(DropTargetDropEvent dtde)//重寫適配器的drop方法
            {
                try
                {
                    if (dtde.isDataFlavorSupported(DataFlavor.javaFileListFlavor))//如果拖入的文件格式受支持
                    {
                        dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);//接收拖拽來的數據
                        List<File> list =  (List<File>) (dtde.getTransferable().getTransferData(DataFlavor.javaFileListFlavor));
                        String temp="";
                        for(File file:list)
                            temp+=file.getAbsolutePath()+";\n";
                        JOptionPane.showMessageDialog(null, temp);
                        dtde.dropComplete(true);//指示拖拽操作已完成
                    }
                    else
                    {
                        dtde.rejectDrop();//否則拒絕拖拽來的數據
                    }
                }
                catch (Exception e)
                {
                    e.printStackTrace();
                }
            }
        });
    }
}