所以我有4个类，在我的绘图程序中，我正在尝试将滚动条添加到画布，以便我可以滚动，当我制作我的缓冲图像时，它设置为桌面的大小，但JFrame是只有我认为700左右的像素，所以你扩展或调整大小仍然在画布上。但我无法弄清楚如何将JScrollPane添加到缓冲的图像，以便我可以滚动。
// 主要 //
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
public class Main
{
public static int choice;
public static void main(String[] args)
{
Board.getInstance();
}
}
// // FRAME
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseListener;
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
/**
*
* @author Calvin Moss
*/
public class Board extends JFrame implements ActionListener
{
public static Board inst;
Board()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container c = getContentPane();
c.add(Menu.getInstance(), BorderLayout.NORTH);
getContentPane().add(Drawing.getInstance(), BorderLayout.CENTER);
Drawing.getInstance().add(new JScrollPane());
setSize(1200, 800);
setBackground(Color.WHITE);
setVisible(true);
JMenuBar menuBar = new JMenuBar();
setJMenuBar(menuBar);
JMenu help = new JMenu("Help");
menuBar.add(help);
JMenuItem about = new JMenuItem("About");
help.add(about);
about.addActionListener(this);
}
public static Board getInstance()
{
if(inst == null)
inst = new Board();
return inst;
}
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("About"))
{
JFrame about = new JFrame("About");
about.setSize(300, 300);
JButton picture = new JButton(new ImageIcon("C:/Users/TehRobot/Desktop/Logo.png"));
about.add(picture);
about.setVisible(true);
}
}
}
// MENUPANEL //
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.ButtonGroup;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.border.TitledBorder;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.event.*;
import java.awt.image.BufferedImage;
/**
*
* @author Calvin Moss
*/
public class Menu extends JPanel implements MouseListener, ActionListener{
public static Color bgColor = null;
public static int stroke = 0;
public static Menu instance;
private JButton clear;
private JButton line;
private JButton color;
private JButton erase;
private JButton pen;
public static boolean once = true;
public static BufferedImage buf = new BufferedImage(50,25,2);
public static Graphics2D gr = buf.createGraphics();
public static BufferedImage buf2 = new BufferedImage(50,25,2);
public static Graphics2D gr2 = buf2.createGraphics();
public static BufferedImage buf3 = new BufferedImage(50,25,2);
public static Graphics2D gr3 = buf3.createGraphics();
public static BufferedImage buf1 = new BufferedImage(50,25,2);
public static Graphics2D gr1 = buf1.createGraphics();
Menu()
{
setBackground(Color.GRAY);
TitledBorder titledBorder = BorderFactory.createTitledBorder("Toolbox");
setBorder(titledBorder);
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception e) {
// If Nimbus is not available, you can set the GUI to another look and feel.
}
;
clear = new JButton("Clear");
clear.setActionCommand("Clear");
clear.addActionListener(this);
pen = new JButton("Pen");
pen.setActionCommand("Pen");
pen.addActionListener(this);
erase = new JButton("Erase");
erase.setActionCommand("e");
erase.addActionListener(this);
color = new JButton("Color");
color.setActionCommand("Color");
color.addActionListener(this);
ImageIcon ir2 = new ImageIcon(buf3);
JButton emptyR = new JButton(ir2);
emptyR.addActionListener(this);
emptyR.setActionCommand("ER");
ImageIcon ir1 = new ImageIcon(buf2);
JButton emptyO = new JButton(ir1);
emptyO.addActionListener(this);
emptyO.setActionCommand("EO");
ImageIcon ir = new ImageIcon(buf);
JButton fillR = new JButton(ir);
fillR.addActionListener(this);
fillR.setActionCommand("FR");
ImageIcon io = new ImageIcon(buf1);
JButton fillO = new JButton(io);
fillO.addActionListener(this);
fillO.setActionCommand("FO");
line = new JButton("Line");
line.setActionCommand("L");
line.addActionListener(this);
JButton button6 = new JButton("Line");
button6.addActionListener(this);
JRadioButton thin = new JRadioButton("Thin Line");
thin.addActionListener(this);
JRadioButton medium = new JRadioButton("Medium Line");
medium.addActionListener(this);
JRadioButton thick = new JRadioButton("Thick Line");
thick.addActionListener(this);
ButtonGroup lineOption = new ButtonGroup( );
lineOption.add(thin);
lineOption.add(medium);
lineOption.add(thick);
add(clear);
add(erase);
add(color);
add(pen);
add(line);
add(thin);
add(medium);
add(thick);
add(emptyR);
add(emptyO);
add(fillR);
add(fillO);
buttonGraphics();
once = false;
}
public static Menu getInstance()
{
if(instance == null)
instance = new Menu();
return instance;
}
public static void buttonGraphics()
{
if (once == true)
{
gr.setColor(Color.RED);
gr1.setColor(Color.RED);
gr2.setColor(Color.RED);
gr3.setColor(Color.RED);
}else
gr3.setColor(bgColor);
gr3.drawRect(0, 0, 48, 23);
gr2.setColor(bgColor);
gr2.drawOval(0, 0, 47, 23);
gr.setColor(bgColor);
gr.fillRect(0, 0, 50, 23);
gr1.setColor(bgColor);
gr1.fillOval(0, 0, 50, 25);
}
public void actionPerformed(ActionEvent e)
{
if(e.getActionCommand().equals("Clear"))
{
Drawing.getInstance().clear();
repaint();
}
if (e.getActionCommand().equals("e"))
{
Main.choice = 8;
Drawing.getInstance().draw();
}
if (e.getActionCommand().equals("Color"))
{
bgColor = JColorChooser.showDialog(this,"Choose Background Color", getBackground());
gr.setColor(bgColor);
gr1.setColor(bgColor);
gr2.setColor(bgColor);
gr3.setColor(bgColor);
Main.choice = 7;
buttonGraphics();
repaint();
Drawing.getInstance().draw();
}
if (e.getActionCommand().equals("L"))
{
Drawing.getInstance().FoE = 2;
Main.choice = 1;
repaint();
}
if (e.getActionCommand().equals("FR"))
{
Drawing.getInstance().FoE = 2;
Main.choice = 2;
repaint();
}
if (e.getActionCommand().equals("EO"))
{
Drawing.getInstance().FoE = 2;
Main.choice = 3;
repaint();
}
if (e.getActionCommand().equals("FO"))
{
Drawing.getInstance().FoE = 2;
Main.choice = 4;
repaint();
}
if(e.getActionCommand().equals("ER"))
{
Drawing.getInstance().FoE = 2;
Main.choice = 5;
repaint();
}
if (e.getActionCommand().equals("Thin Line"))
{
stroke = 0;
Drawing.getInstance().eraserHeight = 5;
Drawing.getInstance().eraserWidth = 5;
}
if (e.getActionCommand().equals("Medium Line"))
{
stroke = 1;
Drawing.getInstance().eraserHeight = 15;
Drawing.getInstance().eraserWidth = 15;
}
if (e.getActionCommand().equals("Thick Line"))
{
stroke = 2;
Drawing.getInstance().eraserHeight = 25;
Drawing.getInstance().eraserWidth = 25;
}
if(e.getActionCommand().equals("Pen"))
{
Main.choice = 10;
Drawing.getInstance().draw();
}
}
public void mouseClicked(MouseEvent e){}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mousePressed(MouseEvent e){}
public void mouseReleased(MouseEvent e){}
}
// 绘制帆布面板 //
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Toolkit;
import javax.swing.JColorChooser;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import java.awt.event.*;
import java.awt.image.BufferedImage;
/**
*
* @author Calvin Moss
*/
public class Drawing extends JPanel implements MouseListener, ActionListener, MouseMotionListener
{
public int x1, x2 ,y1, y2;
public static Drawing instance;
public int FoE;
public int eraserWidth = 15;
public int eraserHeight = 15;
BufferedImage grid;
static Graphics2D gc;
Drawing()
{
setBackground(Color.RED);
addMouseListener(this);
}
public static Drawing getInstance()
{
if(instance == null)
instance = new Drawing();
return instance;
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
if(grid == null)
{
Toolkit toolkit = Toolkit.getDefaultToolkit ();
Dimension dim = toolkit.getScreenSize();
grid = (BufferedImage)(this.createImage(dim.width,dim.height));
gc = grid.createGraphics();
gc.setColor(Color.RED);
BufferedImage grid;
Graphics2D gc;
}
g2.drawImage(grid, null, 0, 0);
}
public void draw()
{
Graphics2D g = (Graphics2D)getGraphics();
int w = x2 - x1;
if (w<0)
w = w *(-1);
int h = y2-y1;
if (h<0)
h= h*(-1);
gc.setColor(Menu.bgColor);
switch(Main.choice)
{
case 1:
{
removeMouseMotionListener(instance);
if (Menu.stroke == 0)
gc.setStroke(new BasicStroke (1));
if (Menu.stroke == 1)
gc.setStroke(new BasicStroke (3));
if (Menu.stroke == 2)
gc.setStroke(new BasicStroke (6));
gc.drawLine(x1, y1, x2, y2);
repaint();
break;
}
case 2:
{
removeMouseMotionListener(instance);
check();
gc.drawRect(x1, y1, w, h);
gc.fillRect(x1, y1, w, h);
repaint();
break;
}
case 3:
{
removeMouseMotionListener(instance);
check();
gc.drawOval(x1, y1, w, h);
repaint();
break;
}
case 4:
{
removeMouseMotionListener(instance);
check();
gc.drawOval(x1, y1, w, h);
gc.fillOval(x1, y1, w, h);
repaint();
break;
}
case 5:
{
removeMouseMotionListener(instance);
check();
gc.drawRect(x1, y1, w, h);
repaint();
break;
}
case 6:
{
removeMouseMotionListener(instance);
repaint();
Color temp = gc.getColor();
gc.setColor(Color.WHITE);
gc.fillRect(0, 0, getWidth(), getHeight());
gc.setColor(temp);
repaint();
break;
}
case 7:
{
removeMouseMotionListener(instance);
gc.setColor(Menu.bgColor);
break;
}
case 8:
{
FoE = 0;
addMouseMotionListener(instance);
break;
}
case 10:
{
FoE = 1;
addMouseMotionListener(instance);
break;
}
}
}
public void check()
{
if (Menu.stroke == 0)
gc.setStroke(new BasicStroke (1));
if (Menu.stroke == 1)
gc.setStroke(new BasicStroke (3));
if (Menu.stroke == 2)
gc.setStroke(new BasicStroke (6));
if (x1 > x2)
{
int z = 0;
z = x1;
x1 = x2;
x2 =z;
}
if (y1 > y2)
{
int z = 0;
z = y1;
y1 = y2;
y2 = z;
}
}
public void clear()
{
repaint();
Color temp = gc.getColor();
gc.setColor(Color.WHITE);
gc.fillRect(0, 0, getWidth(), getHeight());
gc.setColor(temp);
repaint();
}
public void mouseExited(MouseEvent e){ }
public void mouseEntered(MouseEvent e){}
public void mouseClicked(MouseEvent e){
}
public void mousePressed(MouseEvent evt)
{
x1 = evt.getX();
y1= evt.getY();
}
public void mouseReleased(MouseEvent evt)
{
x2 = evt.getX();
y2 = evt.getY();
removeMouseMotionListener(instance);
draw();
}
public void mouseDragged(MouseEvent me)
{
check();
if (FoE == 0)
{
Color c = gc.getColor();
gc.setColor(Color.WHITE);
gc.drawOval(me.getX(), me.getY(), eraserWidth, eraserHeight);
gc.fillOval(me.getX(), me.getY(), eraserWidth, eraserHeight);
gc.setColor(c);
repaint();
}
else if (FoE == 1)
{
gc.setColor(gc.getColor());
gc.drawOval(me.getX(), me.getY(), eraserWidth, eraserHeight);
gc.fillOval(me.getX(), me.getY(), eraserWidth, eraserHeight);
repaint();
}
else
{
}
}
public void mouseMoved(MouseEvent arg0)
{
}
public void actionPerformed(ActionEvent arg0) {
}
}
答案 0 :(得分：4)
我尚未测试您的代码，但您似乎正在尝试向JPanel添加JScrollPane（绘图）。如果应该将JPanel添加到JScrollPane，然后将JScrollPane添加到框架的内容窗格，则应该是另一种方式：
JScrollPane scrollPane = new JScrollPane(Drawing.getInstance());
getContentPane().add(scrollPane, BorderLayout.CENTER);
答案 1 :(得分：3)
您需要覆盖Drawing类的getPreferredSize（）方法以返回BufferedImages的大小。
仅当添加到滚动窗格的组件的首选大小大于滚动窗格的大小时，才会显示滚动条。