我想创建一个程序，用户点击窗口，第一次鼠标按下会创建一个三角形对象，其中p [0]（Point2D.Float变量）具有从鼠标按下位置设置的值，然后绘制一个小点，第二次按下在第二次鼠标按下时从位置创建一个点（p [1]），然后从第一次按下的第一点到第二次按下的第二点绘制一条线。第三次按下创建第三个点（p [2]）然后从鼠标被按下的所有3个点绘制一条线 - 创建一个三角形。
到目前为止我只用了一个三角形，但我想动态制作超过1个三角形。
我怎么能这样做？我只是在寻求任何帮助，需要建议。
import javax.swing.JFrame;
public class Main {
public static void main(String[] args){
Window window = new Window();
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setSize(700,500);
window.setLocation(400,100);
window.setTitle("Draw");
window.initialize();
window.setVisible(true);
}
}
三角类
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Point2D;
import javax.swing.JPanel;
public class Triangle extends JPanel {
private Point2D.Float[] p = new Point2D.Float[3];
private Color color;
public Triangle(int x, int y, int index){
p[index] = new Point2D.Float(x,y);
}
public void setColor(Color c){
color = c;
}
public Color getColor(){
return color;
}
public void setPoint(int x, int y, int index){
p[index] = new Point2D.Float(x,y);
}
public void draw(Graphics2D g){
g.setColor(color);
if(p[0] != null && p[1] == null && p[2] == null){
g.fill(new Ellipse2D.Float((int)p[0].x,(int)p[0].y,3,3));
}else if(p[0] != null && p[1] != null && p[2] == null){
g.drawLine((int)p[0].x, (int)p[0].y, (int)p[1].x,(int)p[1].y);
}else if(p[0] != null && p[1] != null && p[2] != null){
g.drawLine((int)p[0].x, (int)p[0].y, (int)p[1].x,(int)p[1].y);
g.drawLine((int)p[0].x, (int)p[0].y, (int)p[2].x,(int)p[2].y);
g.drawLine((int)p[1].x, (int)p[1].y, (int)p[2].x,(int)p[2].y);
}
repaint();
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
draw(g2);
}
}
窗口类
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.geom.Point2D;
import java.util.ArrayList;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.border.EtchedBorder;
import javax.swing.border.TitledBorder;
public class Window extends JFrame {
private JRadioButton redRadioButton, blueRadioButton, greenRadioButton,
blackRadioButton;
private Container contentPane;
private Triangle triangle;
private JPanel colorPanel;
private JPanel clearPanel;
private JButton clearButton;
private ButtonGroup buttonGroup;
private int index = 0;
private int mousePressed = 0;
private Color c;
public void initialize(){
contentPane = getContentPane();
buttonGroup = new ButtonGroup();
colorPanel = new JPanel();
clearPanel = new JPanel();
clearButton = new JButton("CLEAR");
triangle = new Triangle();
triangle.addMouseListener(new MouseGuide());
clearButton.setFocusable(false);
ButtonListener buttonListener = new ButtonListener();
clearButton.addActionListener(buttonListener);
redRadioButton = new JRadioButton("RED");
redRadioButton.setFocusable(false);
redRadioButton.setSelected(true);
redRadioButton.addActionListener(buttonListener);
blueRadioButton = new JRadioButton("BLUE");
blueRadioButton.setFocusable(false);
blueRadioButton.addActionListener(buttonListener);
greenRadioButton = new JRadioButton("GREEN");
greenRadioButton.setFocusable(false);
greenRadioButton.addActionListener(buttonListener);
blackRadioButton = new JRadioButton("BLACK");
blackRadioButton.setFocusable(false);
blackRadioButton.addActionListener(buttonListener);
buttonGroup.add(redRadioButton);
buttonGroup.add(blueRadioButton);
buttonGroup.add(greenRadioButton);
buttonGroup.add(blackRadioButton);
colorPanel.add(redRadioButton);
colorPanel.add(blueRadioButton);
colorPanel.add(greenRadioButton);
colorPanel.add(blackRadioButton);
clearPanel.add(clearButton);
colorPanel.setBorder(new TitledBorder(new EtchedBorder(), "Pick a Color"));
contentPane.add("North", colorPanel);
contentPane.add("Center", triangle);
contentPane.add("South",clearPanel);
System.out.println(index);
}
public void setShapeColor(){
if(redRadioButton.isSelected()){
c = Color.RED;
contentPane.revalidate();
contentPane.repaint();
}else if(blueRadioButton.isSelected()){
c = Color.BLUE;
triangle.setColor(c);
contentPane.revalidate();
contentPane.repaint();
}else if(greenRadioButton.isSelected()){
c = Color.GREEN;
contentPane.revalidate();
contentPane.repaint();
}else if(blackRadioButton.isSelected()){
c = Color.BLACK;
contentPane.revalidate();
contentPane.repaint();
}
}
public class ButtonListener implements ActionListener{
@Override
public void actionPerformed(ActionEvent ae) {
setShapeColor();
Object source = ae.getSource();
if(source == clearButton){
mousePressed = 0;
index = 0;
}
}
}
public class MouseGuide implements MouseListener{
@Override
public void mouseClicked(MouseEvent me) {
}
@Override
public void mousePressed(MouseEvent me) {
mousePressed++;
if(mousePressed == 1){
triangle.setPoint(me.getX(),me.getY(),index);
contentPane.validate();
contentPane.repaint();
}else if(mousePressed == 2){
index++;
triangle.setPoint(me.getX(), me.getY(), index);
contentPane.validate();
contentPane.repaint();
}else if(mousePressed == 3){
index++;
triangle.setPoint(me.getX(),me.getY(),index);
contentPane.validate();
contentPane.repaint();
mousePressed = 0;
index = 0;
}
System.out.println("Mouse Pressed: " + mousePressed + ", [" + triangle.getPoint(0) + "]," + "[" + triangle.getPoint(1) + "]" + "[" + triangle.getPoint(2) + "]");
}
@Override
public void mouseReleased(MouseEvent me) {
}
@Override
public void mouseEntered(MouseEvent me) {
}
@Override
public void mouseExited(MouseEvent me) {
}
}
}
答案 0 :(得分：1)
public class Triangle extends JPanel {
此类不应扩展JComponent JPanel。
相反，它应该提供一个draw(Graphics)方法，在需要时绘制三角形。然后存储这些ArrayList个对象的列表（例如Triangle），并将其放在自定义绘制的JPanel范围内，同时绘制所有这些对象。自定义绘制的面板还应为首选大小返回合理的尺寸（考虑到要绘制的整个三角形列表的边界）。