java - 当 ArrayList 中删除索引时，如何自动删除 JPanel 上的形状？

Question

我想知道如何从 JPanel 中删除特定形状。该形状存储在 ArrayList 中，当删除该形状的索引时，我希望该形状也从我的 JPanel 中删除。

任何人都可以指导我找到解决方案吗？我应该使用什么来删除 JPanel 上的形状？

即使在ArrayList中删除了形状的索引，该形状仍然存在于JPanel上，有人有解决方案吗？

编辑代码:

import java.awt.AlphaComposite;
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Iterator;
import javax.swing.Box;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;


public class Testing_1 extends JFrame {
    private int len;
    
  // public int getSizes(){
 // return len;
//}

    private static final long serialVersionUID = -140274271716086522L;

    JMenuBar menubar;
    JMenu File, Exit;
    JMenuItem New, Open;
    JComponent DrawingBoard;
    JPanel panel;
    int option;

    JButton  lineBut, ellipseBut, rectBut, strokeBut, trianBut, mulBut, diamondBut,
            arrowBut, derivedBut, primaryBut;
    
    JTextField check, defaultCon, length,attName;

    DecimalFormat dec = new DecimalFormat("#.##");

    // Contains all of the rules for drawing

    Graphics2D graphSettings, dotted;

   
    // Going to be used to monitor what shape to draw next

    int currentAction = 1;
    int x, y;
    
    double a = 10.0;
    double b =10.0;
    
    String checkCon;

    // Transparency of the shape

    // Default stroke and fill colors

    Color strokeColor = Color.BLACK;

    public static void main(String[] args) {
        new Testing_1();
    }

    public Testing_1() {
        // Define the defaults for the JFrame

        this.setSize(800, 600);
        this.setTitle("ERD BUILDER");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setJMenuBar(menubar);

        JMenuBar menuBar = new JMenuBar();

        // Add the menubar to the frame

        

        JPanel buttonPanel = new JPanel();
       
        JPanel FieldPanel = new JPanel();

        // Swing box that will hold all the buttons

        Box theBox = Box.createVerticalBox();
        Box theBoxs = Box.createVerticalBox();

        // Make all the buttons in makeMeButtons by passing the
        // button icon.

        
        lineBut = makeMeButtons("./src/line.png", 2);
        ellipseBut = makeMeButtons("./src/ellipse.png", 3);


        // Make all the buttons in makeMeColorButton by passing the
        // button icon and true for stroke color or false for fill

        strokeBut = makeMeColorButton("./src/stroke.png", 5, true);
        
        check = new JTextField();
        defaultCon = new JTextField();
        length = new JTextField();
        attName = new JTextField();


        // Add the fields to the boxs

        

        //theBox.add(brushBut);
        theBox.add(lineBut);
        theBox.add(ellipseBut);
       
        buttonPanel.add(theBox);
        FieldPanel.add(theBoxs);
        

        this.add(buttonPanel, BorderLayout.WEST);
        this.add(FieldPanel, BorderLayout.EAST);
        buttonPanel.setPreferredSize(new Dimension(200,480));        
        FieldPanel.setPreferredSize(new Dimension(200,480));
        // Make the drawing area take up the rest of the frame

        // this.add(new DrawingBoard(), BorderLayout.CENTER);
        final DrawingBoard drawPanel = new DrawingBoard();
        this.add(drawPanel, BorderLayout.CENTER);
        this.getContentPane().setBackground(Color.WHITE);

        
        
        
        

        // Show the frame
        this.setVisible(true);
    }

    public JButton makeMeButtons(String iconFile, final int actionNum) {
        JButton theBut = new JButton();
        Icon butIcon = new ImageIcon(iconFile);
        theBut.setIcon(butIcon);

         theBut.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                currentAction = actionNum;
            }
        });
        return theBut;
    }

    public JButton makeMeColorButton(String iconFile, final int actionNum,
            final boolean stroke) {
        JButton theBut = new JButton();
        Icon butIcon = new ImageIcon(iconFile);
        theBut.setIcon(butIcon);

        theBut.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {

                if (stroke) {

                    // JColorChooser is a popup that lets you pick a color

                    strokeColor = JColorChooser.showDialog(null,
                            "Pick a Stroke", Color.BLACK);
                } else {
                                    }
            }
        });

        return theBut;
    }
    public class DrawingBoard extends JComponent {

        private static final long serialVersionUID = -4431176095451940075L;

       // ArrayList<Shape> shapes = new ArrayList<Shape>();
        ArrayList<Color> shapeStroke = new ArrayList<Color>();
        ArrayList<Shape> dottedShape = new ArrayList<Shape>();
        ArrayList<Integer> count = new ArrayList<Integer>();
        ArrayList<NamedShape> shapes = new ArrayList<NamedShape>();
      
      
    public class NamedShape {
    private String name;
    private Shape shape;
    
    public NamedShape( String name, Shape shape ){
        this.name = name;
        this.shape = shape;
    }
    public String getName(){
        return name; 
    }
    public Shape getShape(){ 
        return shape; 
    }
}
        
        Point drawStart, drawEnd;
        // Monitors events on the drawing area of the frame

        public DrawingBoard() {
            

            this.addMouseListener(new MouseAdapter() {

                public void mousePressed(MouseEvent e) {

                    if (currentAction != 1) {

                        // When the mouse is pressed get x & y position

                        drawStart = new Point(e.getX(), e.getY());
                        drawEnd = drawStart;
                        repaint();
                    }
                }
            
                public void mouseReleased(MouseEvent e) {
                    int counts =0;
                    if (currentAction != 1) {
                        Shape aShape = null;
                        String nam = null;
                        
                        if (currentAction == 2) {
                            boolean collision = false;
                            
                            aShape = drawLine(drawStart.x, drawStart.y,
                            e.getX(), e.getY());
                            
                            shapes.add( new NamedShape( "Humpty-Dumpty",
                            aShape ) );
                                                                                    
                            int var = shapes.size();
                            System.out.println(shapes);
                         System.out.println("Array index"+var);                                                 
                            shapeStroke.add(strokeColor);
                            drawStart = null;
                            drawEnd = null;
                            repaint();
                        } else

                            
                        if (currentAction == 3) {
                            boolean collision = false;
                            int collisions =0;
                            aShape = drawEllipse(drawStart.x, drawStart.y,
                             e.getX(), e.getY());
                            
                         
                             String text = (String) JOptionPane.showInputDialog(DrawingBoard, "Enter name of Attribute:");
                            
                            
                            
                            shapes.add( new NamedShape( text,
                            aShape ) );    
                             
                         int var = shapes.size();
                         System.out.println("Array index"+var);                                                    
                            shapeStroke.add(strokeColor);
                            drawStart = null;
                            drawEnd = null;
                            repaint();
                            }
                           // new AttributeForm().setVisible(true);
                        
                            
                           

                    }

                }
            });
            
            this.addMouseMotionListener(new MouseMotionAdapter() {

                public void mouseDragged(MouseEvent e) {

                    // If this is a brush have shapes go on the screen quickly

                    if (currentAction == 1) {

                        int x = e.getX();
                        int y = e.getY();

                        Shape aShape = null;
                        shapes.add( new NamedShape( "Line",
                            aShape ) );

                        shapeStroke.add(strokeColor);

                    }
                    
                    drawEnd = new Point(e.getX(), e.getY());
                    repaint();
                }
            });
        }

        public void paint(Graphics g) {
            // Class used to define the shapes to be drawn

            graphSettings = (Graphics2D) g;
            dotted = (Graphics2D)g;
            

            // Antialiasing cleans up the jagged lines and defines rendering
            // rules

            graphSettings.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                    RenderingHints.VALUE_ANTIALIAS_ON);

            // Defines the line width of the stroke

            graphSettings.setStroke(new BasicStroke(4));
            
            dotted.setRenderingHint(RenderingHints.KEY_ANTIALIASING, 
                                    RenderingHints.VALUE_ANTIALIAS_ON);

            // Iterators created to cycle through strokes and fills
            Iterator<Color> strokeCounter = shapeStroke.iterator();
            for (NamedShape s : shapes) {
 
                // Grabs the next stroke from the color arraylist
                graphSettings.setPaint(strokeCounter.next());

                graphSettings.draw(s.getShape());

            }
            
            for(Shape b : dottedShape)
                        {

                             Stroke dashed = new BasicStroke(3, BasicStroke.CAP_BUTT, 
                                    BasicStroke.JOIN_BEVEL, 0, new float[]{9}, 0);
                             
                             dotted.setStroke(dashed);
                             
                             // Grabs the next stroke from the color arraylist
                        	dotted.setPaint(strokeCounter.next());
                        	
                        	dotted.draw(b);
                        }
                        
            
 

            // Guide shape used for drawing
            if (drawStart != null && drawEnd != null) {
                // Makes the guide shape transparent

                graphSettings.setComposite(AlphaComposite.getInstance(
                        AlphaComposite.SRC_OVER, 0.40f));

                // Make guide shape gray for professional look

                graphSettings.setPaint(Color.LIGHT_GRAY);
                
                
                dotted.setComposite(AlphaComposite.getInstance(
                AlphaComposite.SRC_OVER, 0.40f));
                
                dotted.setPaint(Color.LIGHT_GRAY);

                Shape aShape = null;
                Shape dShape = null;

                if (currentAction == 2) {
                    aShape = drawLine(drawStart.x, drawStart.y, drawEnd.x,
                            drawEnd.y);
                } else

                if (currentAction == 3) {
                    aShape = drawEllipse(drawStart.x, drawStart.y, drawEnd.x,
                            drawEnd.y);
                } 

                graphSettings.draw(aShape);
                
                
            }
        }

 
           private Ellipse2D.Float drawEllipse(int x1, int y1, int x2, int y2) {
            int x = Math.min(x1, x2);
            int y = Math.min(y1, y2);
            int width = Math.abs(x1 - x2);
            int height = Math.abs(y1 - y2);

            return new Ellipse2D.Float(x, y, width, height);
        }

        private Line2D.Float drawLine(int x, int y, int width , int height) {

            return new Line2D.Float(x, y,width, height);
        }
        
           }
    
    }

上面的代码允许用户绘制形状。我的 JComponent 称为 DrawingBoard ，用于绘制形状的 Jpanel 称为 drawPanel ，我的 ArrayList 用于存储形状的是NamedShape

我不太确定在哪里放置方法remove，以便Java也可以识别我的ArrayList和Jpanel。可以请您赐教吗？

这是编辑后的方法:

void removeShape(int index) {
  drawPanel.remove(shapes.remove(index));
}

Answer 1

您可以使用辅助方法来执行此操作，如下所示:

JPanel panelWithShapes ...
List<ShapeComponent> myShapes ...

void removeShape(int index) {
  panelWithShapes.remove(myShapes.remove(index));
}

另一种可能性是从 List 覆盖 remove 并从面板中删除该组件。