Java版简易画图板的实现

//图形接口
package Cbs;
//图形集合
public interface NetJavaShape {
    public abstract void draw();
}
//直线类
package Cbs;

import java.awt.Color;
import java.awt.Graphics;
import Cbs.NetJavaShape;

public class ImpLine implements NetJavaShape{
    Graphics g;
    int x1, y1,x2, y2;
    Color c;
    public ImpLine(Graphics g,int x1,int y1,int x2,int y2,Color c){
        this.g=g;
        this.c=c;
        this.x1=x1;
        this.y1=y1;
        this.x2=x2;
        this.y2=y2;
    }
    public void draw() {
        g.setColor(c);
        g.drawLine(x1, y1, x2, y2);
    }

}
//DrawListener类
package Cbs;

import java.awt.Color;
import java.awt.Graphics;
import java.util.List;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.util.ArrayList;
import Cbs.NetJavaShape;
import javax.swing.JButton;

public class DrawListener implements ActionListener, MouseListener,
        MouseMotionListener {
    private Color color=Color.BLACK;//颜色属性,初始值为黑色
    private Graphics g;//画笔属性
    private String str;//保存按钮上的字符串，区分不同的按钮
    private int x1,y1,x2,y2;//(x1,y1),(x2,y2)分别为鼠标的按下和释放时的坐标
    private JButton nowColor;//当前颜色按钮
    //保存图形对象的集合
    private List<NetJavaShape> shapesArray = new ArrayList<NetJavaShape>();
    //图形
    private NetJavaShape shape;
    //在draw类中获取集合
    public List<NetJavaShape> getShapesArray() {
        return shapesArray;
    }
    //获取Draw类的画笔对象
    public void setG(Graphics g) {
        this.g = g;
    }
    //获取当前颜色按钮
    public void setNowColor(JButton nowColor) {
        this.nowColor = nowColor;
    }


    @Override
    //鼠标拖动的方法
    public void mouseDragged(MouseEvent e) {
        //画曲线的方法
        if ("画曲线".equals(str)) {
            int x, y;
            x = e.getX();
            y = e.getY();
            //实例化对象，曲线也是直线画的所以不同新建一个曲线类了
            shape=new ImpLine(g,x,y,x1,y1,color);
            //调用画图方法
            shape.draw();
            //将图形存入集合中
            shapesArray.add(shape);
//            g.drawLine(x, y, x1, y1);
            x1 = x;
            y1 = y;
        }
    }

    @Override
    //鼠标移动方法
    public void mouseMoved(MouseEvent e) {

    }

    @Override
    //鼠标单击方法
    public void mouseClicked(MouseEvent e) {

    }

    @Override
    //鼠标按下方法
    public void mousePressed(MouseEvent e) {
        
        g.setColor(color);//改变画笔的颜色
        
        x1=e.getX();//获取按下时鼠标的x坐标
        y1=e.getY();//获取按下时鼠标的y坐标
    }

    @Override
    //鼠标释放方法
    public void mouseReleased(MouseEvent e) {
        x2=e.getX();//获取释放时鼠标的x坐标
        y2=e.getY();//获取释放时鼠标的y坐标
        //画直线的方法
        if ("画直线".equals(str)) {
            //实例化对象，
            shape=new ImpLine(g,x1,y1,x2,y2,color);
            //调用画图方法
            shape.draw();
            //将图形存入集合中
            shapesArray.add(shape);
//            g.drawLine(x1, y1, x2, y2);
        }
    }

    @Override
    //鼠标进入方法
    public void mouseEntered(MouseEvent e) {

    }

    @Override
    //鼠标退出方法
    public void mouseExited(MouseEvent e) {

    }

    @Override
    //处理按钮上的鼠标点击动作
    public void actionPerformed(ActionEvent e) {
        
        if ("".equals(e.getActionCommand())) {
            JButton jb = (JButton) e.getSource();
            color = jb.getBackground();
            nowColor.setBackground(color);//处理当前颜色
        } else {
            str = e.getActionCommand();
        }
    }

}

//draw类
package Cbs;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

/**
 * Draw类，用于界面的初始化
 * @author CBS
 */
@SuppressWarnings("serial")
public class Draw extends JFrame {
    private DrawListener dl;
    private Graphics g;
    //保存图形对象的集合
    private List<NetJavaShape> shapesArray = new ArrayList<NetJavaShape>();
    // 界面初始化方法
    public void showUI() {
        setTitle("画图");//窗体名称
        setSize(1200, 900);//窗体大小
        setDefaultCloseOperation(3);
        setLocationRelativeTo(null);//窗体居中
        FlowLayout layout = new FlowLayout(FlowLayout.LEFT);//流式布局左对齐
        setLayout(layout);//窗体使用流式布局管理器
        this.setResizable(false);//窗体大小不变
        
        //使用数组保存按钮名
        String buttonName[] = { "画直线", "画椭圆", "画曲线", "多边形",     "橡皮擦", "拖动线","三角形", "画球形", "笔刷", "喷枪", "色子", "立体矩形", "立体圆", "立体三角","迭代分形", "现代分形", "枫叶", "画树", "mandelbrot集", "L-System", "迭代画线","迭代三角形", "谢尔宾斯基地毯", "画字符", "清空","吸管" ,"矩形","五角星","多线","字符"};
        JPanel jp1=new JPanel(new GridLayout(15, 2,10,10));//用于保存图形按钮，使用网格布局
        jp1.setPreferredSize(new Dimension(200, 800));
        
        //实例化DrawListener对象
        dl=new DrawListener();
        //循环为按钮面板添加按钮
        for (int i = 0; i < buttonName.length; i++) {
            JButton jbutton = new JButton(buttonName[i]);
            jbutton.addActionListener(dl);//为按钮添加监听
            jp1.add(jbutton);
        }
        
        JPanel jp2=new JPanel();//画布面板
        jp2.setPreferredSize(new Dimension(970, 800));
        jp2.setBackground(Color.WHITE);
        

        // 定义Color数组，用来存储按钮上要显示的颜色信息
        Color[] colorArray = { Color.BLUE, Color.GREEN, Color.RED, Color.BLACK,Color.ORANGE,Color.PINK,Color.CYAN,Color.MAGENTA,Color.DARK_GRAY,Color.GRAY,Color.LIGHT_GRAY,Color.YELLOW};
        //用于保存颜色按钮的面板
        JPanel jp3=new JPanel(new GridLayout(1,colorArray.length,3,3));
        // 循环遍历colorArray数组，根据数组中的元素来实例化按钮对象
        for (int i = 0; i < colorArray.length; i++) {
            JButton button = new JButton();
            button.setBackground(colorArray[i]);
            button.setPreferredSize(new Dimension(30, 30));
            button.addActionListener(dl);//为按钮添加监听
            jp3.add(button);
        }
        //将面板添加到主窗体
        this.add(jp1);
        this.add(jp2);
        this.add(jp3);
        //添加按钮，作为当前颜色
        JButton nowColor=new JButton();
        nowColor.setPreferredSize(new Dimension(40,40));
        nowColor.setBackground(Color.BLACK);//默认黑色
        add(nowColor);
        //设置窗体的组件可见，如果为FALSE就看不到任何组件
        setVisible(true);    
        //获取画笔对象
        g=jp2.getGraphics();
        dl.setG(g);
        dl.setNowColor(nowColor);
        //获取保存的集合
        shapesArray=dl.getShapesArray();
        //为面板添加鼠标监听，用于绘制图形
        jp2.addMouseListener(dl);
        jp2.addMouseMotionListener(dl);
    }
    @Override
    //重写paint方法
    public void paint(Graphics g) {
        //调用父类的paint方法，绘制界面上的组件
        super.paint(g);
        //foreach遍历集合
        for (NetJavaShape l : shapesArray) {
            l.draw();
        }
    }

}