Java Swing-单击形状以更改其颜色

Question

I need to make a Java Swing application that displays a rectangle on screen and if it is being clicked, it should change its color to black if it's white or white if it's black. The problem is that it is a class that needs to extend JComponent and override paintComponent. I got everything done except the clicking part. For some reason I cannot make it so that it only changes colors when it is clicked. It also changes colors when the background apart from it is being clicked.

Here is the code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;


public class RectangleC extends JComponent implements MouseListener{
    private int width, height;
    private Color color;

    public RectangleC(int w, int h, Color c){
        width = w;
        height = h;
        color = c;
        this.addMouseListener(this);
    }

    @Override
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        g.setColor(color);
        g.fillRect(0, 0, width, height);
    }

    @Override
    public void mousePressed(MouseEvent e){
        if(this.contains(e.getPoint())){
            if(color == Color.WHITE) {
                color = Color.BLACK;
            }
            else {
                color = Color.WHITE;
            }
        }
        repaint();
    }

    public void mouseClicked(MouseEvent e){};
    public void mouseReleased(MouseEvent e){};
    public void mouseEntered(MouseEvent e){};
    public void mouseExited(MouseEvent e){};

    public static void main(String args[]){
        JFrame frame = new JFrame("Rectangle Component");
        RectangleC rectangle2 = new RectangleC(300, 500, Color.BLACK);
        frame.add(rectangle2);
        frame.setSize(600,600);;
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

I cannot seem to get it working using the e.getPoint() method. I also tried using coordinates and e.getX() and e.getY() and that works as long as the shape is in its default position. However, if the shape is being moved to the center, it does no longer work.

Here is the method that I tried:

    @Override
public void mousePressed(MouseEvent e)
{
    int currentX = e.getX();
    int currentY = e.getY();
    if(currentX > this.getX() && currentX < this.getX() + width && currentY > this.getY() && currentY < this.getY() + height ){        
        if(color != Color.WHITE)
            color = Color.WHITE;
        else
            color = Color.black;
    }
    repaint();
}

How can I make it so that it only changes colors when it is clicked? I am really out of ideas and I could not find any way to do this.

Answer 1

Ok, so it seems the code shared above is fine with a small issue that you are taking x and y of the component instead of the Rectangle painted on Component while comparing in mousePressed . So what you can do is create two functions to return x and y of rectangle and then use those functions where ever you need to check the coordinates of rectangle.

Please find the updated code below:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;


public class RectangleC extends JComponent implements MouseListener{
    private int width, height;
    int x,y;
    private Color color;

    public RectangleC(int w, int h, Color c){
        width = w;
        height = h;

        //Given x and y some default position. This can be changed as required
        x = 20;
        y = 20;

        color = c;
        this.addMouseListener(this);
    }

    @Override
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        g.setColor(color);
        g.fillRect(x, y, width, height);
    }

    @Override
    public void mousePressed(MouseEvent e)
    {
        int currentX = e.getX();
        int currentY = e.getY();
        if(currentX > this.getRectX() && currentX < this.getRectX() + width && currentY > this.getRectY() && currentY < this.getRectY() + height ){        
            if(color != Color.WHITE)
                color = Color.WHITE;
            else
                color = Color.black;
        }
        repaint();
    }

    // Function to return rectangle coordinate
    private int getRectX() {
        return this.getX()+x;
    }


    private int getRectY() {
        return this.getY()+y;
    }
public void mouseClicked(MouseEvent e){};
    public void mouseReleased(MouseEvent e){};
    public void mouseEntered(MouseEvent e){};
    public void mouseExited(MouseEvent e){};

    public static void main(String args[]){
        JFrame frame = new JFrame("Rectangle Component");
        RectangleC rectangle2 = new RectangleC(300, 500, Color.BLACK);
        frame.add(rectangle2);
        frame.setSize(600,600);;
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}