Java：按住鼠标时基于2D数组填充图形

所以我有一个JPanel，它由2D数组的内容填充。我有一个鼠标监听器，按下时会改变单元格的颜色。我的问题是，是否有可能让用户将鼠标拖动到一行单元格上，并将其连续着色？我研究过鼠标运动监听器，但这似乎没有帮助

---

有什么想法吗？

您可以将

MouseMotionListener的
mouseDragged（）
方法与
MouseListener的
mousePressed（）
方法结合使用

mousePressed（）
方法将处理简单的单击而不移动，而
mouseDragged（）
将处理任何已完成的拖动。我结合了我为回答您的原始问题而编写的代码，以便更好地阐明每件事的作用，如果您能回答其他问题，我将不胜感激

package stackoverflow.answers;

import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;

import javax.swing.*;

public class JPanelPaint {
    JPanel panel;
    JFrame frame;
    BufferedImage image;

    public JPanelPaint() {
        image = new BufferedImage(50, 50, BufferedImage.TYPE_INT_ARGB);
        for (int i = 0; i < image.getWidth(); i++) {
            for (int j=0; j < image.getHeight(); j++) {
                /* I'm just initializing the image with an arbitrary color (white in this case), you can easily change this. */
                image.setRGB(i, j, new Color((int)(255 ), (int)(255 ), (int)(255 )).getRGB());
            }
        }

        frame = new JFrame("JPanel Paint");
        panel = new JPanel() {
            @Override
            public void paint(Graphics g) {
                super.paint(g);
                Rectangle rect = g.getClipBounds();
                g.setColor(Color.white);
                g.fillRect(rect.x, rect.y, rect.width, rect.height);
                for (int i = 0; i < image.getWidth(); i++) {
                    for (int j=0; j < image.getHeight(); j++) {
                        /* Set the color of the "quadpixel" to that of the original cell on the image. */
                        g.setColor(new Color(image.getRGB(i, j)));
                        g.fillRect(j*4, i*4, 4, 4);
                    }
                }


            }
        };

        panel.addMouseListener(new MouseListener() {

            @Override
            public void mouseClicked(MouseEvent arg0) { }

            @Override
            public void mouseEntered(MouseEvent arg0) { }

            @Override
            public void mouseExited(MouseEvent arg0) { }

            @Override
            public void mousePressed(MouseEvent arg0) {
                /* Y and X are swapped, just a quirk in the JRE */
                /* I'm just setting the pixel with an arbitrary color (black in this case), you can easily change this. */
                image.setRGB(arg0.getY() / 4, arg0.getX() / 4, new Color(0, 0, 0).getRGB());
                panel.repaint();
            }

            @Override
            public void mouseReleased(MouseEvent arg0) { }

        });

        panel.addMouseMotionListener(new MouseMotionListener() {

            @Override
            public void mouseDragged(MouseEvent arg0) {
                /* Y and X are swapped, just a quirk in the JRE */
                /* I'm just setting the pixel with an arbitrary color (black in this case), you can easily change this. */
                image.setRGB(arg0.getY() / 4, arg0.getX() / 4, new Color(0, 0, 0).getRGB());
                panel.repaint();
            }

            @Override
            public void mouseMoved(MouseEvent arg0) { }

        });

        panel.setPreferredSize(new Dimension(200, 200));

        frame.add(panel);
        frame.pack();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);

        panel.repaint();
    }

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

package stackoverflow.answers；
导入java.awt.*；
导入java.awt.event.MouseEvent；
导入java.awt.event.MouseListener；
导入java.awt.event.MouseMotionListener；
导入java.awt.image.buffereImage；
导入javax.swing.*；
公共类JPanelPoint{
JPanel小组；
JFrame框架；
缓冲图像；
公共JPanelPaint（）{
image=新的buffereImage（50，50，buffereImage.TYPE_INT_ARGB）；
对于（int i=0；i
如果扩展JPanel，则不需要鼠标侦听器。只需启用鼠标事件，然后覆盖组件的鼠标事件处理程序。一般逻辑是：

if mouse pressed {
    dragging = true 
    begin drag
}

if mouse dragged and dragging == true {
    process drag
}

if mouse released and dragging == true {
    dragging = false
    finalize drag
}

以下是一个例子：

import java.awt.AWTEvent;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class DragTest {

    // example JPanel. click and drag on it to create lines.
    static class DragPanel extends JPanel {

        private static final long serialVersionUID = 1L;

        static class Line {
            int x1, y1, x2, y2;
        }

        private final List<Line> lines = new ArrayList<Line>();
        private Line draggedLine; // null if not dragging

        public DragPanel() {

            // enable mouse event processing even if no listeners are registered
            enableEvents(AWTEvent.MOUSE_EVENT_MASK | AWTEvent.MOUSE_MOTION_EVENT_MASK);

        }

        @Override
        public void paintComponent(Graphics g) {

            super.paintComponent(g);
            g.setColor(Color.BLACK);
            g.fillRect(0, 0, getWidth(), getHeight());
            // draw saved lines
            g.setColor(Color.WHITE);
            for (Line line : lines)
                g.drawLine(line.x1, line.y1, line.x2, line.y2);
            // draw currently active line if there is one
            if (draggedLine != null) {
                g.setColor(Color.RED);
                g.drawLine(draggedLine.x1, draggedLine.y1, draggedLine.x2, draggedLine.y2);
            }

        }

        // does the work; since motion and press/release are all MouseEvent,
        // we can just direct MouseEvents here from the event handler overrides
        // and handle based on event ID.
        private void handleMouseEvent(MouseEvent e) {

            if (e.getID() == MouseEvent.MOUSE_PRESSED && e.getButton() == MouseEvent.BUTTON1) {
                // begin drag by initializing a new Line at mouse position
                if (draggedLine == null) {
                    draggedLine = new Line();
                    draggedLine.x1 = draggedLine.x2 = e.getX();
                    draggedLine.y1 = draggedLine.y2 = e.getY();
                    e.consume();
                }
            } else if (e.getID() == MouseEvent.MOUSE_DRAGGED) {
                // if drag in progress, update line endpoint
                if (draggedLine != null) {
                    draggedLine.x2 = e.getX();
                    draggedLine.y2 = e.getY();
                    e.consume();
                }
            } else if (e.getID() == MouseEvent.MOUSE_RELEASED && e.getButton() == MouseEvent.BUTTON1) {
                // if drag in progress, accept new line and end drag
                if (draggedLine != null) {
                    draggedLine.x2 = e.getX();
                    draggedLine.y2 = e.getY();
                    lines.add(draggedLine);
                    draggedLine = null;
                    e.consume();
                }
            }

            if (e.isConsumed())
                repaint();

        }

        @Override
        public void processMouseMotionEvent(MouseEvent e) {
            handleMouseEvent(e); // pass to our handler, may consume event
            super.processMouseMotionEvent(e); // in case there are registered listeners
        }

        @Override
        public void processMouseEvent(MouseEvent e) {
            handleMouseEvent(e); // pass to our handler, may consume event
            super.processMouseEvent(e); // in case there are registered listeners
        }

    }

    public static final void main(String[] args) {

        JFrame frame = new JFrame("Panel Drag Example");
        frame.getContentPane().add(new DragPanel());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(640, 480);
        frame.setVisible(true);

    }

}

import java.awt.AWTEvent；
导入java.awt.Color；
导入java.awt.Graphics；
导入java.awt.event.MouseEvent；
导入java.util.ArrayList；
导入java.util.List；
导入javax.swing.JFrame；
导入javax.swing.JPanel；
公共类绘图测试{
//示例JPanel。单击并拖动它以创建线条。
静态类DragPanel扩展了JPanel{
私有静态最终长serialVersionUID=1L；
静态类线{
int-x1，y1，x2，y2；
}
私有最终列表行=新的ArrayList（）；
私有行draggedLine；//如果不拖动，则为null
公共绘图板（）{
//即使未注册侦听器，也启用鼠标事件处理
enableEvents（awteEvent.MOUSE_EVENT_MASK | awteEvent.MOUSE_MOTION_EVENT_MASK）；
}
@凌驾
公共组件（图形g）{
超级组件（g）；
g、 设置颜色（颜色为黑色）；
g、 fillRect（0,0，getWidth（），getHeight（））；
//绘制保存的线
g、 setColor（Color.WHITE）；
用于（行：行）
g、 抽绳（线x1、线y1、线x2、线y2）；
//绘制当前活动线（如果有）
if（DragedLine！=null）{
g、 setColor（Color.RED）；
g、 抽绳（draggedLine.x1、draggedLine.y1、draggedLine.x2、draggedLine.y2）；
}
}
//动作和按下/释放都是MouseEvent，
//我们可以通过事件处理程序覆盖将MouseEvents定向到这里
//和基于事件ID的句柄。
私有无效handleMouseEvent（MouseeEvent e）{