我的绘画代码不会停止覆盖我绘制的先前图形。每当我拖动鼠标时，都应该创建一个点并将其保留在此处，因为它会在新位置绘制一个新点。这似乎没有发生，因为在调用paint（）时，它会清除前面的点。我将首先发布完整的代码，然后发布paint（）部分，然后发布Mouse Dragged侦听器。我正在使用NetBeans IDE及其预构建的JForm
1）完整代码
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author User-Pc
*/
import DrawCanvas.*;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.util.Map;
import javax.swing.JColorChooser;
import javax.swing.JPanel;
public class Paint extends javax.swing.JFrame {
/**
* Creates new form Paint
*/
public Color penColor = Color.BLACK, bgColor = Color.WHITE;
public boolean touchState = false, penState = false, eraseState = false;
public int penSize = 5;
public Point mousePoint = new Point();
public Map map;
public class DrawCanvas extends JPanel{
@Override
public void paint(Graphics g)
{
penSize = jSlider1.getValue();
penState = jToggleButton1.isSelected();
eraseState = jToggleButton2.isSelected();
setBackground(bgColor);
g.setColor(penColor);
this.paintComponent(g);
if(touchState){
g.fillOval(mousePoint.x, mousePoint.y, penSize, penSize);
}
}
public void DrawCanvas()
{
addMouseMotionListener(
new MouseMotionAdapter()
{
public void mouseMoved(MouseEvent evt)
{
mousePoint = evt.getPoint();
System.out.println(mousePoint);
}
}
);
}
}
DrawCanvas canvas = new DrawCanvas();
public Paint() {
initComponents();
jPanel2.add(canvas, BorderLayout.CENTER);
canvas.setBounds(canvas.getX() + 1, canvas.getY() + 1, 0, 0);
canvas.setSize(jPanel2.getSize().width - 2, jPanel2.getSize().height - 2);
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
buttonGroup1 = new javax.swing.ButtonGroup();
jPanel1 = new javax.swing.JPanel();
jPanel2 = new javax.swing.JPanel();
jPanel3 = new javax.swing.JPanel();
jLabel1 = new javax.swing.JLabel();
jButton3 = new javax.swing.JButton();
jButton4 = new javax.swing.JButton();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jSlider1 = new javax.swing.JSlider();
jButton5 = new javax.swing.JButton();
jButton6 = new javax.swing.JButton();
jToggleButton1 = new javax.swing.JToggleButton();
jToggleButton2 = new javax.swing.JToggleButton();
jLabel4 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setResizable(false);
jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder("Paint [Reyes, Duazo, Bermudo]"));
jPanel2.setBorder(javax.swing.BorderFactory.createEtchedBorder());
jPanel2.setPreferredSize(new java.awt.Dimension(400, 400));
jPanel2.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
public void mouseDragged(java.awt.event.MouseEvent evt) {
jPanel2MouseDragged(evt);
}
});
javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 396, Short.MAX_VALUE)
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 0, Short.MAX_VALUE)
);
jPanel3.setBorder(javax.swing.BorderFactory.createTitledBorder("Drawing Tools"));
jLabel1.setText("Shapes");
jButton3.setText("Circle");
jButton4.setText("Rectangle");
jLabel2.setText("Custom Parameters");
jLabel3.setText("Pen Thickness");
jSlider1.setMajorTickSpacing(1);
jSlider1.setMaximum(50);
jSlider1.setMinimum(5);
jSlider1.setValue(5);
jSlider1.addChangeListener(new javax.swing.event.ChangeListener() {
public void stateChanged(javax.swing.event.ChangeEvent evt) {
jSlider1StateChanged(evt);
}
});
jButton5.setText("Pen Color");
jButton5.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton5ActionPerformed(evt);
}
});
jButton6.setText("Background Color");
buttonGroup1.add(jToggleButton1);
jToggleButton1.setText("Pen");
buttonGroup1.add(jToggleButton2);
jToggleButton2.setText("Eraser");
jLabel4.setText("5");
javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
jPanel3.setLayout(jPanel3Layout);
jPanel3Layout.setHorizontalGroup(
jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel3Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jSlider1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 220, Short.MAX_VALUE)
.addComponent(jButton5, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton6, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(jPanel3Layout.createSequentialGroup()
.addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jLabel1)
.addComponent(jButton3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton4, javax.swing.GroupLayout.DEFAULT_SIZE, 220, Short.MAX_VALUE)
.addComponent(jLabel2)
.addGroup(jPanel3Layout.createSequentialGroup()
.addGap(10, 10, 10)
.addComponent(jLabel3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jLabel4))
.addComponent(jToggleButton1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jToggleButton2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGap(0, 0, Short.MAX_VALUE)))
.addContainerGap())
);
jPanel3Layout.setVerticalGroup(
jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel3Layout.createSequentialGroup()
.addContainerGap()
.addComponent(jToggleButton1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jToggleButton2)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton4)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel2)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3)
.addComponent(jLabel4))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jSlider1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jButton5)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jButton6)
.addContainerGap(163, Short.MAX_VALUE))
);
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(6, 6, 6)
.addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addContainerGap())
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addContainerGap()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, 466, Short.MAX_VALUE))
.addContainerGap())
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addContainerGap())
);
pack();
}// </editor-fold>
private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {
Color color = JColorChooser.showDialog(Paint.this, "Choose a pen color", penColor);
if(color != null)
penColor = color;
}
private void jSlider1StateChanged(javax.swing.event.ChangeEvent evt) {
jLabel4.setText(Integer.toString(jSlider1.getValue()));
}
private void jPanel2MouseDragged(java.awt.event.MouseEvent evt) {
touchState = true;
mousePoint = evt.getPoint();
System.out.println(mousePoint);
repaint();
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Paint.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Paint.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Paint.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Paint.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(() -> {
new Paint().setVisible(true);
});
}
// Variables declaration - do not modify
private javax.swing.ButtonGroup buttonGroup1;
private javax.swing.JButton jButton3;
private javax.swing.JButton jButton4;
private javax.swing.JButton jButton5;
private javax.swing.JButton jButton6;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JPanel jPanel3;
private javax.swing.JSlider jSlider1;
private javax.swing.JToggleButton jToggleButton1;
private javax.swing.JToggleButton jToggleButton2;
// End of variables declaration
}
2）与绘画有关：
@Override
public void paint(Graphics g)
{
penSize = jSlider1.getValue();
penState = jToggleButton1.isSelected();
eraseState = jToggleButton2.isSelected();
setBackground(bgColor);
g.setColor(penColor);
this.paintComponent(g);
if(touchState){
g.fillOval(mousePoint.x, mousePoint.y, penSize, penSize);
}
}
3）鼠标拖动事件
private void jPanel2MouseDragged(java.awt.event.MouseEvent evt) {
touchState = true;
mousePoint = evt.getPoint();
System.out.println(mousePoint);
repaint();
}
我希望不必使用数据结构来存储每个点的值，然后重新绘制。
答案 0 :(得分：0)
您不会在paint方法重写中调用super的绘画方法，这将阻止进行组件内部管理绘画，包括删除“脏”像素。建议：
paintComponent方法，而不是其paint方法paintComponent(Graphics g)，请在第一行调用super.paintComponent(g)。ArrayList<Point>并将点放置到数组列表中并对其进行遍历。