drawfigurepanel.java

Java实例入门

package drawfigure;

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

public class DrawFigurePanel extends JPanel {
  public Vector figures = new Vector(10,10);
  public Figure figure = null;

  public DrawFigurePanel() {
    try {
      jbInit();
    }
    catch(Exception ex) {
      ex.printStackTrace();
    }
  }
  void jbInit() throws Exception {
    this.setBackground(UIManager.getColor("window"));
    this.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
      public void mouseDragged(MouseEvent e) {
        this_mouseDragged(e);
      }
    });
    this.addMouseListener(new java.awt.event.MouseAdapter() {
      public void mouseClicked(MouseEvent e) {
        this_mouseClicked(e);
      }
      public void mousePressed(MouseEvent e) {
        this_mousePressed(e);
      }
      public void mouseReleased(MouseEvent e) {
        this_mouseReleased(e);
      }
    });
  }

  void this_mouseClicked(MouseEvent e) {
    if(figure == null)
      return;
    Graphics g = this.getGraphics() ;
    g.setXORMode(Color.green);
    if(figure instanceof LineFigure){
      LineFigure lineFigure = (LineFigure)figure;
      lineFigure.draw(g);
      figures.add(lineFigure.clone());
    }
    if(figure instanceof RectangleFigure){
      RectangleFigure rectangleFigure = (RectangleFigure)figure;
      rectangleFigure.draw(g);
      figures.add(rectangleFigure.clone());
    }
    if(figure instanceof OvalFigure){
      OvalFigure ovalFigure = (OvalFigure)figure;
      ovalFigure.draw(g);
      figures.add(ovalFigure.clone());
    }
  }

  void this_mouseDragged(MouseEvent e) {
    if(figure == null)
      return;
    Graphics g = this.getGraphics();
    g.setXORMode(Color.green);
    if(figure instanceof LineFigure){
      LineFigure lineFigure = (LineFigure)figure;
      if(lineFigure.firstDraw){
        lineFigure.draw(g);
        lineFigure.firstDraw = false;
      }else{
        lineFigure.draw(g);
        lineFigure.endPoint = e.getPoint();
        lineFigure.draw(g);
      }
    }
    if(figure instanceof RectangleFigure){
      RectangleFigure rectangleFigure = (RectangleFigure)figure;
      if(rectangleFigure.firstDraw){
        rectangleFigure.draw(g);
        rectangleFigure.firstDraw = false;
      }else{
        rectangleFigure.draw(g);
        rectangleFigure.endPoint = e.getPoint();
        rectangleFigure.draw(g);
      }
    }
    if(figure instanceof OvalFigure){
      OvalFigure ovalFigure = (OvalFigure)figure;
      if(ovalFigure.firstDraw){
        ovalFigure.draw(g);
        ovalFigure.firstDraw = false;
      }else{
        ovalFigure.draw(g);
        ovalFigure.endPoint = e.getPoint();
        ovalFigure.draw(g);
      }
    }
  }

  void this_mousePressed(MouseEvent e) {
    if(figure != null){
      figure.startPoint = e.getPoint();
      figure.endPoint = e.getPoint();
      figure.firstDraw = true;
    }
  }

  void this_mouseReleased(MouseEvent e) {
    if(figure instanceof LineFigure){
      LineFigure lineFigure = (LineFigure)figure;
      figures.add(lineFigure.clone());
    }
    if(figure instanceof RectangleFigure){
      RectangleFigure rectangleFigure = (RectangleFigure)figure;
      figures.add(rectangleFigure.clone());
    }
    if(figure instanceof OvalFigure){
      OvalFigure ovalFigure = (OvalFigure)figure;
      figures.add(ovalFigure.clone());
    }
  }

  protected void paintComponent(Graphics parm1) {
    /**@todo: Override this javax.swing.JComponent method*/
    super.paintComponent( parm1);
    parm1.setXORMode(Color.green);
    int i;
    for(i=0;i<figures.size();i++){
      Object x = figures.get(i);
      if(x instanceof LineFigure){
        LineFigure lineFigure = (LineFigure)x;
        lineFigure.draw(parm1);
      }
      if(x instanceof RectangleFigure){
        RectangleFigure rectFigure = (RectangleFigure)x;
        rectFigure.draw(parm1);
      }
      if(x instanceof OvalFigure){
        OvalFigure ovalFigure = (OvalFigure)x;
        ovalFigure.draw(parm1);
      }
    }
  }

}