floatingbutton.java

PIY(Program It Yourself)是一个基于Java的应用程序开发环境

package piy;

import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import javax.swing.AbstractButton;


/**
* A button that doesn't have a border until the mouse moves over it.
* @author David Vivash
* @version 1.0, 25/11/00
*/
public class FloatingButton extends AbstractButton implements MouseListener, MouseMotionListener
{
	protected static boolean dragged = false;

	private Image image;
	private boolean down = false;
	private boolean over = false;
	private String commandString = "";
	private int halfImageWidth=0, halfImageHeight=0;
	private boolean selectable = false;
	private boolean selected = false;
	private ArrayList listeners = new ArrayList(1);

	/**
	* Creates a floating button that will highlight itself with a surrounding box
	* when the mouse moves over it.
	* @param image the image on the button
	* @param highlight the highlight color of the surrounding box
	* @param command the command string to send to the action listener of this button
	*/
	public FloatingButton(Image image, String command, boolean selectable) {
		this.image = image;
		this.commandString = command;

		halfImageWidth = image.getWidth(this)/2;
		halfImageHeight = image.getHeight(this)/2;


		addMouseListener(this);
		addMouseMotionListener(this);

		this.selectable = selectable;
		setSelected(false);
	}

	public void paint(Graphics g) {
		g.setColor(getBackground());

		if (down && over) {
			g.draw3DRect(0,0,getSize().width-1,getSize().height-1, false);
			g.drawImage(image, getWidth()/2 - halfImageWidth + 1, getHeight()/2 - halfImageHeight + 1, this);
		} else if ((over && !down) && !isSelected()) {
			g.draw3DRect(0,0,getSize().width-1,getSize().height-1, true);
			g.drawImage(image, getWidth()/2 - halfImageWidth, getHeight()/2 - halfImageHeight, this);
		} else if (!isSelected()) {
			g.drawImage(image, getWidth()/2 - halfImageWidth, getHeight()/2 - halfImageHeight, this);
		} else {
			g.draw3DRect(0,0,getSize().width-1,getSize().height-1, false);
			g.drawImage(image, getWidth()/2 - halfImageWidth, getHeight()/2 - halfImageHeight, this);
		}
	}

	public boolean isSelected() { return selected; }

	public void setSelected(boolean val) { 
		if (selected != val) {
			selected = val; 
			repaint();
		}
	}

	/**
	* Adds a new action listener for the button.
	* @param actionListener the new ActionListener
	*/
	public void addActionListener(ActionListener actionListener)
	{
		listeners.add(actionListener);
	}

	/**
	* Sets the command string for this button.  When the button is clicked, the
	* action listener is informed and is told this command string.
	* @param commandString the command string to notify to the action listener of 
	* when this button is clicked
	*/
	public void setActionCommand(String commandString) {
		this.commandString = commandString;
	}
	
	
	//This is an extra identifier number when more than the command string is needed
	private int identifier = 0;
	public void setIdentifier(int id) { identifier = id; }
	public int getIdentifier() { return identifier;	}

	//--- Mouse listener methods ---
	public void mouseClicked(MouseEvent e) { /*this is caught in mousePressed/mouseReleased pair*/}

	public void mousePressed(MouseEvent e) {
		down = true; repaint();		
	}

	public void mouseReleased(MouseEvent e) {
		down = false; FloatingButton.dragged = false; repaint();

		if (over) {
			if (selectable) setSelected(!isSelected());	
			notifyListeners();
		}

	}

	public void mouseEntered(MouseEvent e) {
		if (!FloatingButton.dragged) {
			over = true; repaint();
		}
	}
	public void mouseExited(MouseEvent e) {
		over = false; repaint();
	}

	//--- Mouse motion listener methods ---
	public void mouseDragged(MouseEvent e) {
		FloatingButton.dragged = true;
		int x = (int)e.getX();
		int y = (int)e.getY();

		boolean newOver = (x>=0) && (x<=getSize().width) && (y>=0) && (y<=getSize().height);
		if (over != newOver) repaint();
		over = newOver;
	}
	public void mouseMoved(MouseEvent e) {	}

	/**
	* Notifies all action listeners that this buton has been clicked
	*/
	private void notifyListeners()
	{
		for (int i=0; i<listeners.size(); i++)
			((ActionListener)listeners.get(i)).actionPerformed(new ActionEvent(this, 0, commandString));
	}
}