java，Swing中单击实现两点相连

这是老师给我们的一个作业，做完了，当做自己的第一篇博文吧。

程序运行后，弹出黑色界面，有三个白圈，标有北京，上海，广州，点击任意一圈，即出现云另外两全的连线。Java学的不精，之前一直在思考如何实现在已有的图上的线条绘制。后采用八个参数将其解决。

import java.awt.BasicStroke; import java.awt.BorderLayout; import java.awt.Canvas; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; public class ConnPlace extends JFrame { int x,y,x1,y1,x2,y2,m1,n1,m2,n2; Color col=new Color(200,200,200); private final Font font=new Font("华文琥珀",Font.BOLD,32); JPanel contentPanel=new MyJPanel(); BasicStroke pen = new BasicStroke(2.0f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND); Graphics2D g2=null; public ConnPlace(){ super(); this.setSize(600, 400); contentPanel.setBackground(new Color(0,0,0)); setContentPane(contentPanel); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); this.setTitle("客运连线实验"); addMouseListener(new MouseAdapter() { //继承适配器MouseAdapter，重写单击方法 public void mouseClicked(MouseEvent e) { // 发生单击事件时被触发 x=e.getX(); y=e.getY(); if((x-150)*(x-150)+(y-100)*(y-100)<=2500) {x1=200;y1=100;m1=400;n1=100; x2=150;y2=150;m2=250;n2=250; } else if((x-450)*(x-450)+(y-100)*(y-100)<=2500) {x1=200;y1=100;m1=400;n1=100; x2=450;y2=150;m2=350;n2=250; } else if((x-300)*(x-300)+(y-250)*(y-250)<=2500) {x1=150;y1=150;m1=250;n1=250; x2=450;y2=150;m2=350;n2=250; } else {x1=0;y1=0;m1=0;n1=0; x2=0;y2=0;m2=0;n2=0; }; contentPanel.repaint(); } }); } public static void main(String[] args) { new ConnPlace().setVisible(true); } class MyJPanel extends JPanel { public void paint(Graphics g) { super.paint(g); g2 = (Graphics2D)g; g2.setColor(col); g2.setFont(font); g2.setStroke(pen); g2.drawOval(100,50, 100, 100); // 绘制第1个圆形 g2.drawOval(400,50, 100, 100); // 绘制第2个圆形 g2.drawOval(250,200, 100, 100); // 绘制第3个圆形 g2.drawString("北京", 118, 110); g2.drawString("上海", 418, 110); g2.drawString("广州", 268, 260); g2.drawLine(x1,y1,m1,n1); g2.drawLine(x2,y2,m2,n2); } } }

java，Swing中单击实现两点相连

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