JTable没有出现在JFrame（Java）上 [英] JTable not showing up on JFrame (Java)
本文介绍了JTable没有出现在JFrame（Java）上的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我遇到了一个问题， JFrame 没有显示添加到它的 JTable 。我已经尝试了 getContentPane（）。add（..），我已经切换到只是添加以保持代码更短。任何帮助都非常感谢！
package com.embah.Accgui;
import java.awt。*;
import javax.swing。*;
公共类accCreator扩展JFrame {
private String [] columnNames = {Username，Password，Members，World};
private Object [] [] data = {{b，b，b，b}，
{e，e，e，e }};
private JTable tbl_Accounts;
private JScrollPane scrollPane;
private JLabel lbl_Account = new JLabel（）;
private JLabel lbl_Username = new JLabel（）;
private JLabel lbl_Password = new JLabel（）;
private JLabel lbl_Homeworld = new JLabel（）;
private JButton btn_Select = new JButton（）;
private JButton btn_Addacc = new JButton（）;
private JButton btn_Delacc = new JButton（）;
private JTextArea txt_Username = new JTextArea（）;
private JTextArea txt_Password = new JTextArea（）;
private JTextArea txt_Homeworld = new JTextArea（）;
private JCheckBox cbox_Members = new JCheckBox（）;
private JCheckBox cbox_RanWrld = new JCheckBox（）;
public accCreator（）{
setLayout（null）;
setupGUI（）;
setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）;
}
void setupGUI（）{
tbl_Accounts = new JTable（data，columnNames）;
tbl_Accounts.setLocation（5,30）;
tbl_Accounts.setPreferredScrollableViewportSize（new Dimension（420,250））;
tbl_Accounts.setFillsViewportHeight（true）;
tbl_Accounts.setVisible（true）;
add（tbl_Accounts）;
scrollPane = new JScrollPane（tbl_Accounts）;
add（scrollPane）;
lbl_Account.setLocation（4,5）;
lbl_Account.setSize（100,20）;
lbl_Account.setText（选择帐户：）;
add（lbl_Account）;
lbl_Username.setLocation（5,285）;
lbl_Username.setSize（70,20）;
lbl_Username.setText（Username：）;
add（lbl_Username）;
lbl_Password.setLocation（5,310）;
lbl_Password.setSize（70,20）;
lbl_Password.setText（密码：）;
add（lbl_Password）;
lbl_Homeworld.setLocation（310,310）;
lbl_Homeworld.setSize（80,20）;
lbl_Homeworld.setText（Home World：）;
add（lbl_Homeworld）;
btn_Select.setLocation（305,5）;
btn_Select.setSize（120,20）;
btn_Select.setText（选择帐户）;
add（btn_Select）;
btn_Addacc.setLocation（300,285）;
btn_Addacc.setSize（60,20）;
btn_Addacc.setText（添加）;
btn_Addacc.addActionListener（new ActionListener（）{
@Override
public void actionPerformed（ActionEvent arg0）{
String worldSel =;
if（cbox_RanWrld.isSelected （））{
worldSel =Random;
} else {
worldSel = txt_Homeworld.getText（）;
}
Object [] row = {txt_Username。 getText（），txt_Password.getText（），cbox_Members.isSelected（），worldSel};
DefaultTableModel model =（DefaultTableModel）tbl_Accounts.getModel（）;
model.addRow（row）;
}
}）;
add（btn_Addacc）;
btn_Delacc.setLocation（365,285）;
btn_Delacc.setSize（60,20）;
btn_Delacc.setText（Del）;
btn_Delacc.addActionListener（new ActionListener（）{
@Override
public void actionPerformed（ActionEvent arg0）{
DefaultTableModel model =（DefaultTableModel）tbl_Accounts.getModel（）;
}
}）;
add（btn_Delacc）;
txt_Username.setLocation（80,285）;
txt_Username.setSize（100,20）;
txt_Username.setText（）;
txt_Username.setRows（5）;
txt_Username.setColumns（5）;
add（txt_Username）;
txt_Password.setLocation（80,310）;
txt_Password.setSize（100,20）;
txt_Password.setText（）;
txt_Password.setRows（5）;
txt_Password.setColumns（5）;
txt_Password.setTabSize（0）;
add（txt_Password）;
txt_Homeworld.setLocation（395,310）;
txt_Homeworld.setSize（30,20）;
txt_Homeworld.setText（82）;
txt_Homeworld.setRows（5）;
txt_Homeworld.setColumns（5）;
txt_Homeworld.setTabSize（0）;
add（txt_Homeworld）;
cbox_Members.setLocation（185,285）;
cbox_Members.setSize（80,20）;
cbox_Members.setText（Members）;
cbox_Members.setSelected（false）;
add（cbox_Members）;
cbox_RanWrld.setLocation（185,310）;
cbox_RanWrld.setSize（115,20）;
cbox_RanWrld.setText（随机世界）;
cbox_RanWrld.setSelected（false）;
add（cbox_RanWrld）;
setTitle（客户经理）;
setSize（440,370）;
setVisible（true）;
setResizable（false）;
}
public static void main（String args []）{
new accCreator（）;
}
}
解决方案
我知道那不是问题，因为其他一切都显示得很好
哦......真的吗？不在我的电脑里......
让我们看一下我电脑上显示的实际图形用户界面：
您的计算机中的GUI看起来是否相同？我打赌没有。
但是......为什么我的电脑里看起来像这样？
嗯，如上所述@MadProgrammer的评论，这是因为 setLayout（null）; 行。您可能需要阅读
生成上述图片的代码就是这样：
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridBagConstraints;
import java.awt.GridLayout;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
公共类AccountCreator {
私有JFrame框架;
私人JPanel mainPane;
私人JPanel topPane;
私人JPanel tablePane;
私人JPanel bottomPane;
私人JLabel selectAccountLabel;
private JLabel userNameLabel;
私人JLabel密码标签;
私人JLabel homeWorldLabel;
private JTextField userNameField;
private JTextField homeWorldField;
private JPasswordField passwordField;
私有JCheckBox membersBox;
private JCheckBox randomBox;
私人JButton selectAccountButton;
private JButton addButton;
private JButton deleteButton;
私有JTable表;
私有JScrollPane滚动;
public static void main（String [] args）{
SwingUtilities.invokeLater（new Runnable（）{
@Override
public void run（）{
new AccountCreator（）。createAndShowGui（）;
}
}）;
}
public void createAndShowGui（）{
frame = new JFrame（getClass（）。getSimpleName（））;
int rows = 30;
int cols = 3;
String [] [] data = new String [rows] [cols];
for（int i = 0; i< rows; i ++）{
for（int j = 0; j< cols; j ++）{
data [i] [j] = i + - + j;
}
}
String [] columnNames = {Column1，Column2，Column3};
table = new JTable（data，columnNames）;
scroll = new JScrollPane（table，JScrollPane.VERTICAL_SCROLLBAR_ALWAYS，JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS）;
table.setPreferredScrollableViewportSize（new Dimension（420,250））;
table.setFillsViewportHeight（true）;
selectAccountLabel = new JLabel（选择帐户）;
userNameLabel = new JLabel（Username：）;
passwordLabel = new JLabel（密码：）;
homeWorldLabel =新JLabel（家庭世界）;
selectAccountButton = new JButton（Select Account）;
addButton = new JButton（Add）;
deleteButton = new JButton（Del）;
userNameField = new JTextField（10）;
passwordField = new JPasswordField（10）;
homeWorldField = new JTextField（3）;
membersBox = new JCheckBox（Members）;
randomBox = new JCheckBox（随机世界）;
topPane = new JPanel（）;
topPane.setLayout（new BorderLayout（））;
topPane.add（selectAccountLabel，BorderLayout.WEST）;
topPane.add（selectAccountButton，BorderLayout.EAST）;
tablePane = new JPanel（）;
tablePane.add（scroll）;
bottomPane = new JPanel（）;
bottomPane.setLayout（new GridLayout（0,5,3,3））;
bottomPane.add（userNameLabel）;
bottomPane.add（userNameField）;
bottomPane.add（membersBox）;
bottomPane.add（addButton）;
bottomPane.add（deleteButton）;
bottomPane.add（passwordLabel）;
bottomPane.add（passwordField）;
bottomPane.add（randomBox）;
bottomPane.add（homeWorldLabel）;
bottomPane.add（homeWorldField）;
mainPane = new JPanel（）;
mainPane.setLayout（new BoxLayout（mainPane，BoxLayout.PAGE_AXIS））;
frame.add（topPane，BorderLayout.NORTH）;
frame.add（tablePane，BorderLayout.CENTER）;
frame.add（bottomPane，BorderLayout.SOUTH）;
frame.pack（）;
frame.setVisible（true）;
frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）;
}
}
另外，您可能已经注意到 main（）方法不同，好吧，里面的代码是把程序放在事件调度线程（EDT）。
因此，请务必将其包含在您的未来程序中
I'm having a problem with a JFrame not showing a JTable that is added to it. I've tried getContentPane().add(..), I've switched to just add to keep the code a little shorter. Any help is more than appreciated!
package com.embah.Accgui;
import java.awt.*;
import javax.swing.*;
public class accCreator extends JFrame {
private String[] columnNames = {"Username", "Password", "Members", "World"};
private Object[][] data = {{"b", "b", "b", "b"},
{ "e", "e", "e", "e"}};
private JTable tbl_Accounts;
private JScrollPane scrollPane;
private JLabel lbl_Account = new JLabel();
private JLabel lbl_Username = new JLabel();
private JLabel lbl_Password = new JLabel();
private JLabel lbl_Homeworld = new JLabel();
private JButton btn_Select = new JButton();
private JButton btn_Addacc = new JButton();
private JButton btn_Delacc = new JButton();
private JTextArea txt_Username = new JTextArea();
private JTextArea txt_Password = new JTextArea();
private JTextArea txt_Homeworld = new JTextArea();
private JCheckBox cbox_Members = new JCheckBox();
private JCheckBox cbox_RanWrld = new JCheckBox();
public accCreator() {
setLayout(null);
setupGUI();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
void setupGUI() {
tbl_Accounts = new JTable(data, columnNames);
tbl_Accounts.setLocation(5, 30);
tbl_Accounts.setPreferredScrollableViewportSize(new Dimension(420, 250));
tbl_Accounts.setFillsViewportHeight(true);
tbl_Accounts.setVisible(true);
add(tbl_Accounts);
scrollPane = new JScrollPane(tbl_Accounts);
add(scrollPane);
lbl_Account.setLocation(4, 5);
lbl_Account.setSize(100, 20);
lbl_Account.setText("Select Account:");
add(lbl_Account);
lbl_Username.setLocation(5, 285);
lbl_Username.setSize(70, 20);
lbl_Username.setText("Username:");
add(lbl_Username);
lbl_Password.setLocation(5, 310);
lbl_Password.setSize(70, 20);
lbl_Password.setText("Password:");
add(lbl_Password);
lbl_Homeworld.setLocation(310, 310);
lbl_Homeworld.setSize(80, 20);
lbl_Homeworld.setText("Home World:");
add(lbl_Homeworld);
btn_Select.setLocation(305, 5);
btn_Select.setSize(120, 20);
btn_Select.setText("Select Account");
add(btn_Select);
btn_Addacc.setLocation(300, 285);
btn_Addacc.setSize(60, 20);
btn_Addacc.setText("Add");
btn_Addacc.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent arg0) {
String worldSel = "";
if(cbox_RanWrld.isSelected()){
worldSel = "Random";
} else {
worldSel = txt_Homeworld.getText();
}
Object[] row = {txt_Username.getText(), txt_Password.getText(), cbox_Members.isSelected(), worldSel};
DefaultTableModel model = (DefaultTableModel) tbl_Accounts.getModel();
model.addRow(row);
}
});
add(btn_Addacc);
btn_Delacc.setLocation(365, 285);
btn_Delacc.setSize(60, 20);
btn_Delacc.setText("Del");
btn_Delacc.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent arg0) {
DefaultTableModel model = (DefaultTableModel) tbl_Accounts.getModel();
}
});
add(btn_Delacc);
txt_Username.setLocation(80, 285);
txt_Username.setSize(100, 20);
txt_Username.setText("");
txt_Username.setRows(5);
txt_Username.setColumns(5);
add(txt_Username);
txt_Password.setLocation(80, 310);
txt_Password.setSize(100, 20);
txt_Password.setText("");
txt_Password.setRows(5);
txt_Password.setColumns(5);
txt_Password.setTabSize(0);
add(txt_Password);
txt_Homeworld.setLocation(395, 310);
txt_Homeworld.setSize(30, 20);
txt_Homeworld.setText("82");
txt_Homeworld.setRows(5);
txt_Homeworld.setColumns(5);
txt_Homeworld.setTabSize(0);
add(txt_Homeworld);
cbox_Members.setLocation(185, 285);
cbox_Members.setSize(80, 20);
cbox_Members.setText("Members");
cbox_Members.setSelected(false);
add(cbox_Members);
cbox_RanWrld.setLocation(185, 310);
cbox_RanWrld.setSize(115, 20);
cbox_RanWrld.setText("Random World");
cbox_RanWrld.setSelected(false);
add(cbox_RanWrld);
setTitle("Account Manager");
setSize(440, 370);
setVisible(true);
setResizable(false);
}
public static void main(String args[]) {
new accCreator();
}
}
解决方案
I know thats not the problem tho because everything else shows up just fine
Oh... really? Not in my computer...
Let's have a picture of your actual GUI shown in my PC:
Does the GUI looks the same in your computer? I bet no.
But... why does it looks like that in my PC?
Well, as stated above in the comments by @MadProgrammer this is because of the setLayout(null); line. You might want to read Null layout is evil and Why is it frowned upon to use a null layout in Java Swing? for more information.
Now, that being said, you should also want to read and learn how to use the various layout managers that will let you create complex GUIs.
In your code you never set the location / bounds for scrollPane, and the size of it, so the component has a default size of 0, 0.
But... I think it's better to show you how you can get a really similar GUI (I'm in a hurry so I didn't make an even more similar GUI). You can copy-paste my code and see the same output (with slight differences because of the OS maybe) but text won't be cropped.
The code that produces the above image is this one:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridBagConstraints;
import java.awt.GridLayout;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class AccountCreator {
private JFrame frame;
private JPanel mainPane;
private JPanel topPane;
private JPanel tablePane;
private JPanel bottomPane;
private JLabel selectAccountLabel;
private JLabel userNameLabel;
private JLabel passwordLabel;
private JLabel homeWorldLabel;
private JTextField userNameField;
private JTextField homeWorldField;
private JPasswordField passwordField;
private JCheckBox membersBox;
private JCheckBox randomBox;
private JButton selectAccountButton;
private JButton addButton;
private JButton deleteButton;
private JTable table;
private JScrollPane scroll;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new AccountCreator().createAndShowGui();
}
});
}
public void createAndShowGui() {
frame = new JFrame(getClass().getSimpleName());
int rows = 30;
int cols = 3;
String[][] data = new String[rows][cols];
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
data[i][j] = i + "-" + j;
}
}
String[] columnNames = { "Column1", "Column2", "Column3" };
table = new JTable(data, columnNames);
scroll = new JScrollPane(table, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
table.setPreferredScrollableViewportSize(new Dimension(420, 250));
table.setFillsViewportHeight(true);
selectAccountLabel = new JLabel("Select Account");
userNameLabel = new JLabel("Username: ");
passwordLabel = new JLabel("Password: ");
homeWorldLabel = new JLabel("Home world");
selectAccountButton = new JButton("Select Account");
addButton = new JButton("Add");
deleteButton = new JButton("Del");
userNameField = new JTextField(10);
passwordField = new JPasswordField(10);
homeWorldField = new JTextField(3);
membersBox = new JCheckBox("Members");
randomBox = new JCheckBox("Random world");
topPane = new JPanel();
topPane.setLayout(new BorderLayout());
topPane.add(selectAccountLabel, BorderLayout.WEST);
topPane.add(selectAccountButton, BorderLayout.EAST);
tablePane = new JPanel();
tablePane.add(scroll);
bottomPane = new JPanel();
bottomPane.setLayout(new GridLayout(0, 5, 3, 3));
bottomPane.add(userNameLabel);
bottomPane.add(userNameField);
bottomPane.add(membersBox);
bottomPane.add(addButton);
bottomPane.add(deleteButton);
bottomPane.add(passwordLabel);
bottomPane.add(passwordField);
bottomPane.add(randomBox);
bottomPane.add(homeWorldLabel);
bottomPane.add(homeWorldField);
mainPane = new JPanel();
mainPane.setLayout(new BoxLayout(mainPane, BoxLayout.PAGE_AXIS));
frame.add(topPane, BorderLayout.NORTH);
frame.add(tablePane, BorderLayout.CENTER);
frame.add(bottomPane, BorderLayout.SOUTH);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
Also, you might have noticed that the main() method is different, well, the code inside it is placing the program on the Event Dispatch Thread (EDT).
So, be sure to include it in your future programs
这篇关于JTable没有出现在JFrame（Java）上的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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