test.java

java2图形设计卷1:awt 源码

import java.applet.Applet;
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
import java.awt.event.*;
import java.io.*;
import java.lang.reflect.*;

public class Test extends Frame {
	public Test() {
		super("Drag and Drop Test");

		List drag = new List(), drop = new List();

		StringDragSource source = new StringDragSource(
					drag, "getSelectedItem", new Class[]{});

		StringDropTarget target = new StringDropTarget(
					drop, "add", new Class[]{String.class});

		drag.add("one");
		drag.add("two");
		drag.add("three");
		drag.add("four");
		drag.add("five");
		drag.add("six");

		setLayout(new GridLayout(0,2));

		add(new Label("Drag Source"));
		add(drag);
		add(new Label("Drop Target"));
		add(drop);
	}
	public static void main(String[] args) {
		Frame f = new Test();
		f.setBounds(300,300,250,300);
		f.setVisible(true);

		f.addWindowListener (new WindowAdapter() {
        	public void windowClosing(WindowEvent e) {
        		System.exit(0);
        	}
        });			
	}
}
class StringDragSource 
			implements DragSourceListener, DragGestureListener {
	Component component;
	DragSource dragSource;
	DragGestureRecognizer recognizer;
	Method dragMethod;
	String s;

	public StringDragSource(Component component, 
							String methodName,
							Class[] args) {
		this.component = component;
   		dragSource = new DragSource();

   		recognizer = 
				dragSource.createDefaultDragGestureRecognizer(
   					component, // Component 
					DnDConstants.ACTION_COPY_OR_MOVE, // actions
					this); // DragGestureListener
		try {
			dragMethod = 
				component.getClass().getMethod(methodName, args);
		}
		catch(NoSuchMethodException ex) {
			ex.printStackTrace();
		}
	}
	public void dragGestureRecognized(DragGestureEvent e) {
		try {
			s = (String)dragMethod.invoke(
									component, new Object[]{});
		}
		catch(InvocationTargetException ex) {
			ex.printStackTrace();
		}
		catch(IllegalAccessException iae) {
			iae.printStackTrace();
		}
   		e.startDrag(DragSource.DefaultCopyDrop,  // cursor
					new StringSelection(s), // transferable
					this); // DragSourceListener
   }
   public void dragDropEnd(DragSourceDropEvent e) {}
   public void dragEnter(DragSourceDragEvent e) {}
   public void dragExit(DragSourceEvent e) {}
   public void dragOver(DragSourceDragEvent e) {}
   public void dropActionChanged(DragSourceDragEvent e) {}
}
class StringDropTarget implements DropTargetListener {
	Component component;
	DropTarget dropTarget;
	Method dropMethod;

	public StringDropTarget(Component component, 
							String methodName,
							Class[] args) {
		this.component = component;

 		dropTarget = new DropTarget(component, 
							DnDConstants.ACTION_COPY_OR_MOVE,
							this); 
		try {
			dropMethod = 
				component.getClass().getMethod(methodName, args);
		}
		catch(NoSuchMethodException ex) {
			ex.printStackTrace();
		}
	}
	public void dragEnter(DropTargetDragEvent e) {
		e.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
	}
	public void drop(DropTargetDropEvent e) {
		try {
			Transferable tr = e.getTransferable();

			if(tr.isDataFlavorSupported(DataFlavor.stringFlavor)){
				e.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
				String s = (String)tr.getTransferData (
										DataFlavor.stringFlavor);

				dropMethod.invoke(component, new Object[]{s});
				e.dropComplete(true);
			}		
		} 
		catch(IOException io) {
			io.printStackTrace();
			e.rejectDrop();
		} 
		catch(UnsupportedFlavorException ufe) {
			ufe.printStackTrace();
			e.rejectDrop();
		}
		catch(IllegalAccessException iae) {
			iae.printStackTrace();	
			e.rejectDrop();
		}
		catch(InvocationTargetException ite) {
			ite.printStackTrace();
			e.rejectDrop();
		}
	}
	public void dragExit (DropTargetEvent e) { }
	public void dragOver (DropTargetDragEvent e) { }
	public void dropActionChanged (DropTargetDragEvent e) { }
}