问题
I have this JPanel called CatalogPane, which is of size 800 by 600, which is inside a JTabbedPane inside a JFrame called BookFrame. So inside the CatalogPane, I created a JPanel called bookDisplay which displays a list of books and their details. I want it to be of size 780 by 900, leaving 20px for the scrollbar and taller than the frame so that it can scroll. Then I created a panel of size 800 by 400 because I need to leave some extra space at the bottom for other fields. I tried creating a JScrollPane for bookDisplay and then put it inside the other panel, but somehow the scrollbar appears but can't be used to scroll. I've experimented changing the sizes and scrollpane but I still can't get it to work.
What it looks like: http://prntscr.com/12j0d9
The scrollbar is there but can't work. I'm trying to get the scrollbar to work before I format the layout properly.
CatalogPane:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.io.*;
public class CatalogPane extends JPanel{
//private Order currOrder = new Order();
//ArrayList<Book> bookCatalog = new ArrayList();
GridBagConstraints gbc = new GridBagConstraints();
GridBagLayout gbl = new GridBagLayout();
JPanel bookDisplay = new JPanel();
public CatalogPane()
{
//loadBookCatalog();
this.setPreferredSize(new Dimension(800, 600));
bookDisplay.setPreferredSize(new Dimension(780, 900));
bookDisplay.setLayout(new GridLayout(6, 5));
//bookDisplay.setLayout(gbl);
//gbc.fill = GridBagConstraints.NONE;
//gbc.weightx = 1;
//gbc.weighty = 1;
JLabel bookL = new JLabel("Books");
JLabel hardL = new JLabel("Hardcopy");
JLabel hardQuantL = new JLabel("Quantity");
JLabel eL = new JLabel("EBook");
JLabel eQuantL = new JLabel("Quantity");
bookDisplay.add(bookL);
bookDisplay.add(hardL);
bookDisplay.add(hardQuantL);
bookDisplay.add(eL);
bookDisplay.add(eQuantL);
/*
addComponent(bookL, 0, 0, 1, 1);
addComponent(hardL, 0, 1, 1, 1);
addComponent(hardQuantL, 0, 2, 1, 1);
addComponent(eL, 0, 3, 1, 1);
addComponent(eQuantL, 0, 4, 1, 1);
*/
Iterator<Book> bci = bookCatalog.iterator();
int row = 1;
/*
while(bci.hasNext())
{
Book temp = bci.next();
ImageIcon book1 = new ImageIcon(temp.getImage());
JLabel image = new JLabel(temp.getTitle(), book1, JLabel.CENTER);
image.setVerticalTextPosition(JLabel.TOP);
image.setHorizontalTextPosition(JLabel.CENTER);
String[] quant = {"1", "2", "3", "4", "5"};
JLabel hardP = new JLabel("$" + temp.getHardPrice());
JLabel eP = new JLabel("$" + temp.getEPrice());
JComboBox jbc1 = new JComboBox(quant);
JComboBox jbc2 = new JComboBox(quant);
jbc1.setSelectedIndex(0);
jbc2.setSelectedIndex(0);
/*
addComponent(b1temp, row, 0, 1, 1);
addComponent(hardP, row, 1, 1, 1);
addComponent(jbc1, row, 2, 1, 1);
addComponent(eP, row, 3, 1, 1);
addComponent(jbc2, row, 4, 1, 1);
row++;
bookDisplay.add(image);
bookDisplay.add(new JLabel("$" + temp.getHardPrice()));
bookDisplay.add(jbc1);
bookDisplay.add(new JLabel("$" + temp.getEPrice()));
bookDisplay.add(jbc2);
*/
for(int i=0;i<5;i++)
{
String[] quant = {"1", "2", "3", "4", "5"};
JComboBox jbc1 = new JComboBox(quant);
JComboBox jbc2 = new JComboBox(quant);
jbc1.setSelectedIndex(0);
jbc2.setSelectedIndex(0);
JLabel image = new JLabel("image");
bookDisplay.add(image);
bookDisplay.add(new JLabel("$" + 20));
bookDisplay.add(jbc1);
bookDisplay.add(new JLabel("$" + 15));
bookDisplay.add(jbc2);
}
JScrollPane vertical = new JScrollPane(bookDisplay);
//JPanel testP = new JPanel();
//testP.setPreferredSize(new Dimension(800, 400));
//JScrollPane vertical = new JScrollPane(testP);
//testP.add(bookDisplay);
vertical.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
JPanel testP = new JPanel();
testP.setPreferredSize(new Dimension(800, 400));
testP.add(vertical);
add(testP);
}
public void addComponent(Component c, int row, int col, int hei, int wid)
{
gbc.gridx = col;
gbc.gridy = row;
gbc.gridwidth = wid;
gbc.gridheight = hei;
gbl.setConstraints(c, gbc);
bookDisplay.add(c);
}
public Order getCurrOrder()
{
return currOrder;
}
private void loadBookCatalog()
{
try
{
String[] str = new String[8];
Scanner sc = new Scanner(new File("bookcat.txt"));
double temp1, temp2;
while(sc.hasNextLine())
{
str = sc.nextLine().split(";");
temp1 = Double.parseDouble(str[3]);
temp2 = Double.parseDouble(str[4]);
Book temp = new Book(temp1, temp2, str[0], str[1], str[2], str[5]);
bookCatalog.add(temp);
}
}
catch(IOException e)
{
System.out.println("File not found!");
}
}
}
BookFrame:
public class BookFrame extends JFrame{
JButton closeButton;
CatalogPane cp;
//IntroPane ip;
public BookFrame(String name)
{
super(name);
this.setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e)
{
JOptionPane.showMessageDialog(JOptionPane.getFrameForComponent(new IntroPane()),
"Thank you for visiting Groovy Book Company.", "Message",
JOptionPane.INFORMATION_MESSAGE, new ImageIcon("coffee.jpg"));
System.exit(0);
}
});
//ip = new IntroPane();
cp = new CatalogPane();
JTabbedPane jtp = new JTabbedPane();
jtp.setPreferredSize(new Dimension(800, 600));
//jtp.addTab("Intro", ip);
jtp.addTab("Catalog", cp);
add(jtp);
pack();
setVisible(true);
}
}
回答1:
I'd look at JTable, which handles scrolling and rendering as shown here and below. This example shows how to render images and currency. Start by adding a third column for quantity of type Integer. This related example illustrates using a JComboBox editor.
import java.awt.Dimension;
import java.awt.EventQueue;
import java.text.NumberFormat;
import javax.swing.Icon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
/**
* @see https://stackoverflow.com/a/16264880/230513
*/
public class Test {
public static final Icon ICON = UIManager.getIcon("html.pendingImage");
private JPanel createPanel() {
JPanel panel = new JPanel();
DefaultTableModel model = new DefaultTableModel() {
@Override
public Class<?> getColumnClass(int col) {
if (col == 0) {
return Icon.class;
} else {
return Double.class;
}
}
};
model.setColumnIdentifiers(new Object[]{"Book", "Cost"});
for (int i = 0; i < 42; i++) {
model.addRow(new Object[]{ICON, Double.valueOf(i)});
}
JTable table = new JTable(model);
table.setDefaultRenderer(Double.class, new DefaultTableCellRenderer() {
@Override
protected void setValue(Object value) {
NumberFormat format = NumberFormat.getCurrencyInstance();
setText((value == null) ? "" : format.format(value));
}
});
table.setRowHeight(ICON.getIconHeight());
panel.add(new JScrollPane(table) {
@Override
public Dimension getPreferredSize() {
return new Dimension(320, 240);
}
});
return panel;
}
private void display() {
JFrame f = new JFrame("Test");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JTabbedPane jtp = new JTabbedPane();
jtp.addTab("Test1", createPanel());
jtp.addTab("Test2", createPanel());
f.add(jtp);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new Test().display();
}
});
}
}
来源：https://stackoverflow.com/questions/16263678/jscrollpane-inside-jpanel-inside-a-jtabbedpane-is-not-scrolling