我正在构建一个程序，该程序将显示从JComboBox中选择名称后的点数，在“获得的总分数”和“我不知道除了使用System.out.println("");之外怎么做但我希望它在程序内部显示在“获得总积分：”字样旁边的pointsEarned JTextField中，而不是在我的编译器框中。
以下是我的代码：
import java.awt.*;
import javax.swing.event.PopupMenuEvent;
import javax.swing.event.PopupMenuListener;
import javax.swing.*;
import java.awt.event.*;
public class UserHistory extends JPanel {
private JLabel jcomp1;
private JComboBox userList;
private JLabel jcomp5;
private JTextField pointsEarned;
private JLabel jcomp7;
private JList choresCompleted;
public UserHistory() {
//construct preComponents
ManageUsersGUI list = new ManageUsersGUI();
String[] userListItems = new String[list.users.size()];
String[] choresCompletedItems = {"Item 1", "Item 2", "Item 3"};
//construct components
jcomp1 = new JLabel ("User History");
userList = new JComboBox(userListItems);
userList.addPopupMenuListener(new PopupMenuListener() {
@Override
public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
userList.removeAllItems();
for (User user: list.users) {
userList.addItem(user.getUserName());
}
}
@Override
public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
}
@Override
public void popupMenuCanceled(PopupMenuEvent e) {
}
});
jcomp5 = new JLabel ("Total points earned: ");
pointsEarned = new JTextField ();
userList.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
myBox(e);
}
});
jcomp7 = new JLabel ("List of chores completed: ");
choresCompleted = new JList (choresCompletedItems);
//set components properties
userList.setToolTipText ("Select a user");
//adjust size and set layout
setPreferredSize (new Dimension (465, 343));
setLayout (null);
//add components
add (jcomp1);
add (userList);
add (jcomp5);
add (pointsEarned);
add (jcomp7);
add (choresCompleted);
//set component bounds (only needed by Absolute Positioning)
jcomp1.setBounds (120, 20, 70, 25);
userList.setBounds (210, 20, 100, 25);
jcomp5.setBounds (125, 105, 140, 25);
pointsEarned.setBounds (245, 105, 100, 25);
jcomp7.setBounds (95, 140, 160, 25);
choresCompleted.setBounds (245, 145, 100, 75);
}
protected void myBox(ActionEvent e) {
if(userList.getSelectedItem() != null) {
//System.out.println(User.getPoints());
}
}
public static void main (String[] args) {
JFrame frame = new JFrame ("UserHistory");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new UserHistory());
frame.pack();
frame.setVisible (true);
ManageUsersGUI.manageUsers();
}
}
这是我的用户类：
public class User {
private String userName;
private int points = 0;
public User(String userName) {
this.userName = userName;
}
public User() {
userName = "";
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getUserName() {
return userName;
}
public void addPoints(int chorePoints) {
points += chorePoints;
}
public int getPoints() {
return points;
}
public String toString() {
return userName + "\n";
}
}
这是我的ManageUsersGUI类：
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import javax.swing.JCheckBox;
public class ManageUsersGUI extends JPanel {
public static ArrayList<User> users = new ArrayList<>();
private final JLabel addNewUserLabel;
private final JTextField addNewUserTextField;
private final JLabel deleteUsersLabel;
private final JButton addButton;
private final JButton deleteButton;
private final JPanel namePanel;
/**
*
*/
public ManageUsersGUI() {
//construct components
addNewUserLabel = new JLabel ("Add new User here:");
addNewUserTextField = new JTextField (0);
deleteUsersLabel = new JLabel ("Select which User(s) you would like to delete:");
addButton = new JButton ("Add");
deleteButton = new JButton ("Delete");
namePanel = new JPanel();
namePanel.setLayout(new BoxLayout(namePanel, BoxLayout.Y_AXIS));
//set components properties
addNewUserTextField.setToolTipText ("Enter name and click on Add button.");
addButton.setToolTipText ("Click here to Add new user.");
deleteButton.setToolTipText ("Click here to delete User(s) selected.");
//adjust size and set layout
setPreferredSize (new Dimension (580, 485));
setLayout (null);
//add components
add (addNewUserLabel);
add (addNewUserTextField);
add (deleteUsersLabel);
add (namePanel);
add (addButton);
add (deleteButton);
//set component bounds (only needed by Absolute Positioning)
addNewUserLabel.setBounds (85, 130, 120, 25);
addNewUserTextField.setBounds (235, 130, 125, 25);
deleteUsersLabel.setBounds (135, 225, 281, 25);
addButton.setBounds (385, 130, 100, 25);
namePanel.setBounds(225, 270, 140, 0);
deleteButton.setBounds (230, 335, 100, 25);
addButton.addActionListener(new AddButtonListener());
deleteButton.addActionListener(new DeleteButtonListener());
}
/**
*
* @return
*/
public ArrayList<User> getUser() {
return users;
}
private class AddButtonListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
String text = addNewUserTextField.getText();
users.add(new User(text));
// Display the changes.
JOptionPane.showMessageDialog(null, text + " has been added.");
JCheckBox nameCheckBox = new JCheckBox();
nameCheckBox.setText(addNewUserTextField.getText());
namePanel.add(nameCheckBox);
namePanel.setBounds(225, 270, 140, namePanel.getHeight() + 25);
deleteButton.setBounds(230, deleteButton.getY() + 25, 100, 25);
JFrame frame = (JFrame) getRootPane().getParent();
frame.setSize(frame.getWidth(), frame.getHeight() + 25);
frame.pack();
}
}
private class DeleteButtonListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
for(Component component : namePanel.getComponents()) {
if(component instanceof JCheckBox) {
if(((JCheckBox)component).isSelected())
namePanel.remove(component);
}
}
namePanel.revalidate();
namePanel.repaint();
}
}
public static void main (String[] args) {
JFrame frame = new JFrame ("AddUsersPanel");
frame.setTitle("Manage Users");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new ManageUsersGUI());
frame.pack();
frame.setVisible (true);
}
// in ManageUsersGUI
public static void manageUsers() {
JFrame frame = new JFrame ("AddUsersPanel1");
frame.setTitle("Manage Users");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new ManageUsersGUI());
frame.pack();
frame.setVisible (true);
}
}
答案 0 :(得分：1)
您似乎有JTextField，pointsEarned，这似乎是您要用来打印值的内容。
如果您查看JavaDocs for JTextField，您会发现setText方法需要String
因此，问题确实变成了，＆＃34;如何将int转换为String？＆＃34;。那么有很多方法......
Integer.toString String.valueOf NumberFormat.getNumberInstance "" + intValue 您将使用哪个将取决于您想要实现的目标。
protected void myBox(ActionEvent e) {
Object obj = userList.getSelectedItem();
if(obj != null) {
if (obj instanceof User) {
User user = (User)obj;
pointsEarned.setText(NumberFormat.getNumberInstance().format(user.getPoints())
}
}
}
因此，在花了一些时间编写代码之后，似乎已经出现了许多问题。
首先，static
public class ManageUsersGUI extends JPanel {
public static ArrayList<User> users = new ArrayList<>();
static不是跨对象通信机制，此信息应在需要时传递给ManageUsersGUI的实例，或者应生成并返回列表，具体取决于您要实现的目标。
其次，您只使用用户名填充JComboBox，虽然这可以完成并且有办法管理它，但只需添加User对象就可以了。直接，这就解决了当两个具有相同名称的用户被添加到列表时会发生什么的问题
for (User user: list.users) {
userList.addItem(user);
}
您还应该让泛型用户定义您的例外...
private JComboBox<User> userList;
这意味着addItem只接受User的实例，getSelectedItem将返回User而不是Object
JComboBox应该从List填充，而不是当弹出窗口可见时，您会发现用户体验更好。
您也应该使用模态对话框，从用户那里收集少量信息，从长远来看，这将使您的代码更易于管理
看看：
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