/*
*只画直线，矩形，椭圆，只能向右下角画
*
*PainterPanel extends JPanel implements MouseListener
*addMouseListener(this);
*
*JToggleButton
*
*hxz*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
class PainterPanel extends JPanel implements MouseListener{
int shape=-1; //图案类型
Point[] point=new Point[2]; //记录鼠标拖动的起始点和终点
public PainterPanel(){
super(); //调用父类构造函数
this.setBackground(Color.white); //设置背景颜色
point[0]=new Point(-1,-1); //初始化变量
point[1]=new Point(-1,-1);
addMouseListener(this); //增加鼠标事件
}
public void mouseReleased(MouseEvent e){ //鼠标释放事件
point[1]=new Point(e.getX(),e.getY()); //设置终点位置
repaint(); //重绘屏幕
}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mouseClicked(MouseEvent e){}
public void mousePressed(MouseEvent e){ //鼠标按下时事件
point[0]=new Point(e.getX(),e.getY()); //设置起始点位置
}
public void paint(Graphics g){
super.paint(g);
switch (shape){ //根据shape值绘制图形
case 0:
g.drawLine(point[0].x,point[0].y,point[1].x,point[1].y); //绘线
break;
case 1:
int width=point[1].x-point[0].x;
int height=point[1].y-point[0].y;
g.drawOval(point[0].x,point[0].y,width,height); //绘椭圆
break;
case 2:
width=point[1].x-point[0].x;
height=point[1].y-point[0].y;
g.drawRect(point[0].x,point[0].y,width,height); //绘矩形
break;
}
}
public void drawShape(int shape){
this.shape=shape;
}
}
/*
*JToggleButton
*
*JToolBar
*
*hxz*/
public class PainterDemo extends JFrame{
JToggleButton[] button=new JToggleButton[3]; //按钮组
PainterPanel painter=new PainterPanel(); //绘图面板
public PainterDemo(){
super("Java画图程序"); //调用父类构造函数
String[] buttonName={"直线","椭圆","矩形"}; //按钮文字
DrawShapeListener buttonListener=new DrawShapeListener(); //按钮事件
JToolBar toolBar=new JToolBar(); //实例化工具栏
ButtonGroup buttonGroup=new ButtonGroup(); //实例化按钮组
for (int i=0;i
button[i]=new JToggleButton(buttonName[i]); //实例化按钮
button[i].addActionListener(buttonListener); //增加按钮事件处理
buttonGroup.add(button[i]); //增加按钮到按钮组
toolBar.add(button[i]); //增加按钮到工具栏
}
Container container=getContentPane(); //得到窗口容器
container.add(toolBar,BorderLayout.NORTH); //增加组件到容器上
container.add(painter,BorderLayout.CENTER);
setSize(300,200); //设置窗口尺寸
setVisible(true); //设置窗口为可视
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //关闭窗口时退出程序
}
//内部类
class DrawShapeListener implements ActionListener{ //按钮事件处理
public void actionPerformed(ActionEvent e){
for (int i=0;i
if (e.getSource()==button[i]){ //判断来自于哪个按钮
painter.drawShape(i); //绘制图形
}
}
}
}
public static void main(String[] args){
new PainterDemo();
}
}
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