我正在用Java创建一个简单的信使（仅用于学习目的），我想要一个朋友标签，左侧是朋友列表，右侧是与朋友的消息，你单击，但每当我尝试在选项卡中添加JSplitPane时，它都不会显示。我做了完全相同的代码（除了我只做了JSplitPane的东西及其组件，而不是其他标签和菜单等。
我的所有代码
package Client;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.Box;
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.JRadioButtonMenuItem;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTabbedPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.ListSelectionModel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class ClientMain extends JFrame {
int WIDTH = 640;
int HEIGHT = 480;
JTabbedPane tabbedPane;
JMenuBar topMenuBar;
JMenu userMenu, helpMenu, settingsMenu;
JRadioButtonMenuItem menuItem;
JPanel mainPanel, friendsPanel, groupsPanel, testPanel;
JLabel title;
JScrollPane consoleScrollPane, friendChatScrollPane, friendListScrollPane;
JSplitPane friendsSplitPane;
JTextArea friendChatArea, testArea;
JTextField friendChatField, testField;
JList friendList;
Box box;
DefaultListModel friends;
public ClientMain() {
super("Messenger Client");
//Networking();
/** MAIN PANEL **/
title = new JLabel("Client!");
title.setFont(new Font("Impact", Font.PLAIN, 32));
mainPanel = new JPanel();
mainPanel.setLayout(null);
mainPanel.add(title);
/** TEST PANEL **/
groupsPanel = new JPanel();
groupsPanel.setLayout(null);
/** FRIENDS PANEL **/
friendsPanel = new JPanel();
friendsPanel.setLayout(null);
friends = new DefaultListModel();
//method here that retrieves users' friends from the server and adds them to the friends DefaultListModel
friends.addElement("Person1");
friends.addElement("Person2");
friendList = new JList(friends);
friendList.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
friendList.setLayoutOrientation(JList.VERTICAL_WRAP);
friendList.setVisibleRowCount(3);
friendList.setSize(50, 50);
friendChatArea = new JTextArea();
friendChatArea.setSize(50, 50);
friendChatArea.setFont(new Font("", Font.PLAIN, 13 + 1/2));
friendChatArea.append("TEST");
Dimension minimumSize = new Dimension(100, 50);
friendListScrollPane = new JScrollPane(friendList);
friendListScrollPane.setMinimumSize(minimumSize);
friendChatScrollPane = new JScrollPane(friendChatArea);
friendChatScrollPane.setMinimumSize(minimumSize);
friendsSplitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, friendListScrollPane, friendChatScrollPane);
friendsSplitPane.setOneTouchExpandable(false);
friendsSplitPane.setDividerLocation(50);
friendsPanel.add(friendsSplitPane);
/** TEST PANEL **/
testPanel = new JPanel();
testPanel.setLayout(null);
testArea = new JTextArea();
testArea.setFont(new Font("", Font.PLAIN, 13 + 1/2));
testArea.setBounds(0, 0, WIDTH, HEIGHT - 100);
testArea.setEditable(false);
testArea.setLineWrap(true);
testField = new JTextField(20);
testField.setBounds(0, 380, 640, 25);
//testField.setLocation(0, HEIGHT - 50);
testField.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ClientNet net = new ClientNet();
String input = null;
input = testField.getText();
testArea.append(input);
testField.setText("");
if(input.equalsIgnoreCase("/sendmessage")) {
testArea.append("\n Input who you would like to send the message to:");
input = null;
if(input.equalsIgnoreCase("Hello")) {
net.userEntry = input;
}
}
}
});
testPanel.add(testArea);
testPanel.add(testField);
/** SET UP **/
tabbedPane = new JTabbedPane();
tabbedPane.add(mainPanel, "Main");
tabbedPane.add(friendsPanel, "Friends");
tabbedPane.add(groupsPanel, "Groups");
tabbedPane.add(testPanel, "Test");
topMenuBar = new JMenuBar();
userMenu = new JMenu("User");
settingsMenu = new JMenu("Settings");
helpMenu = new JMenu("Help");
menuItem = new JRadioButtonMenuItem("Something here");
userMenu.add(menuItem);
topMenuBar.add(userMenu, "User");
topMenuBar.add(settingsMenu, "Settings");
topMenuBar.add(helpMenu, "Help");
add(topMenuBar);
add(tabbedPane);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch(UnsupportedLookAndFeelException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
ClientMain frame = new ClientMain();
Insets insets = frame.getInsets();
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.setSize(frame.WIDTH, frame.HEIGHT);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setResizable(false);
frame.setJMenuBar(frame.topMenuBar);
}
public void Networking() {
ClientNet net;
try {
net = new ClientNet();
net.start();
} catch(Exception e) {
e.printStackTrace();
}
}
public void createMenuBar() {
topMenuBar = new JMenuBar();
userMenu = new JMenu("User");
settingsMenu = new JMenu("Settings");
helpMenu = new JMenu("Help");
menuItem = new JRadioButtonMenuItem("MenuItem");
menuItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
}
});
topMenuBar.add(userMenu, "User");
topMenuBar.add(settingsMenu, "Settings");
topMenuBar.add(helpMenu, "Help");
}
public void createSplitPane() {
friendListScrollPane = new JScrollPane();
friendListScrollPane.add(new JLabel("Hello"));
friendChatArea = new JTextArea();
friendChatArea.setBounds(0, 150, HEIGHT, HEIGHT);
friendChatArea.setFont(new Font("", Font.PLAIN, 13 + 1/2));
Dimension minimumSize = new Dimension(WIDTH/2 , HEIGHT);
friendListScrollPane.setMinimumSize(minimumSize);
//friendsSplitPane.setLeftComponent()
friendsSplitPane.add(friendChatArea);
friendsSplitPane.setRightComponent(friendChatScrollPane);
}
}
特定的JSplitPane代码（上面代码的一部分）
friendsPanel = new JPanel();
friendsPanel.setLayout(null);
friends = new DefaultListModel();
//method here that retrieves users' friends from the server and adds them to the friends DefaultListModel
friends.addElement("Person1");
friends.addElement("Person2");
friendList = new JList(friends);
friendList.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
friendList.setLayoutOrientation(JList.VERTICAL_WRAP);
friendList.setVisibleRowCount(3);
friendList.setSize(50, 50);
friendChatArea = new JTextArea();
friendChatArea.setSize(50, 50);
friendChatArea.setFont(new Font("", Font.PLAIN, 13 + 1/2));
friendChatArea.append("TEST");
Dimension minimumSize = new Dimension(100, 50);
friendListScrollPane = new JScrollPane(friendList);
friendListScrollPane.setMinimumSize(minimumSize);
friendChatScrollPane = new JScrollPane(friendChatArea);
friendChatScrollPane.setMinimumSize(minimumSize);
friendsSplitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, friendListScrollPane, friendChatScrollPane);
friendsSplitPane.setOneTouchExpandable(false);
friendsSplitPane.setDividerLocation(50);
friendsPanel.add(friendsSplitPane);
答案 0 :(得分：2)
friendsPanel.setLayout(null);
您的friendsPanel具有空布局，并且您要将拆分窗格添加为：
friendsPanel.add(friendsSplitPane);
要将component添加到具有null布局的容器（friendsPanel），您必须使用component.setBounds()方法指定要添加的组件的边界。但是，为什么甚至使用null布局呢？不要使用它。堆栈溢出的回转族已经从页面到页面的建议。尝试使用Swing开发人员为我们创建的布局管理器之一，努力日复一日浪费时间，以节省我们自己的时间。
开始学习：Lesson: Laying Out Components Within a Container。让我们为节省时间付出一些努力，我们只是为了找到答案而花费的时间：uhh! where is my component!?!