[英]Add to JList and select element?
我需要一些帮助才能将元素添加到JList以及如何选择元素连事件。
这是我的JList:
DefaultListModel model = new DefaultListModel();
JList list = new JList(model);
list.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
JScrollPane listScroller = new JScrollPane(list);
listScroller.setPreferredSize(new Dimension(430, 80));
这是我的动作监听器的一部分,它处理不同的按钮。 我要在这里使用model.add(“ Name”); bot我在Eclipse中看到红色下划线!
public void actionPerformed(ActionEvent event){
// New customer
if(event.getSource() == buttonNewCustomer && statusButtonNewCustomer)
{
String name = textInputName.getText();
String number = textInputPersonalNumber.getText();
boolean checkCustomerExist = customHandler.findCustomer(name, number);
if(!checkCustomerExist) // If not true add new customer
{
customHandler.addCustomer(name, number); // Call method to add name
setTitle(title + "Kund: " + name); // Set new title
model.addElement(name);
}
}
}
然后,我会为您提供一些帮助,如何选择JList中的元素? 我应该对类或FrameHandler对象使用实现ActionListener吗? 谢谢!
编辑:我无法解决的主要问题是JList在construcor内部,当我使用model.add(“ name”);时, 在构造函数内部,它可以工作,但是当我想在构造函数之外添加一些东西时,它不起作用? 我已经阅读了几次本教程,但是找不到任何帮助。
编辑2:completet代码。 可能是一些超出范围的问题?
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class GUI4EX extends JFrame implements ActionListener{
private JButton buttonNewCustomer, buttonTerminate, buttonAddNewName, buttonAddNewSavingsAccount, buttonAddNewCreditAccount;
private JLabel textLabelName, textLabelPersonalNumber, textLabelNewName;
private JTextField textInputName, textInputPersonalNumber, textInputNewName;
private JPanel panelNewCustomer, panelQuit, panelNewAccount, panelChangeName, panelSelectCustomer;
private boolean statusButtonNewCustomer = true;
private boolean statusButton2 = true;
private boolean statusButtonAddNewName = true;
private String title = "Bank ";
// Create a customHandler object
CustomHandler customHandler = new CustomHandler();
// Main method to start program
public static void main(String[] args){
GUI4EX frame = new GUI4EX();
frame.setVisible(true);
frame.setDefaultCloseOperation(3);
}
// Cunstructor
public GUI4EX(){
// Create window
setTitle(title);
setSize(450,500);
setLocation(400,100);
setResizable(false);
// Set layout to boxlayout
Container container = getContentPane( );
setLayout(new BoxLayout(container, BoxLayout.Y_AXIS));
DefaultListModel model = new DefaultListModel();
JList list = new JList(model);
list.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
JScrollPane listScroller = new JScrollPane(list);
listScroller.setPreferredSize(new Dimension(430, 80));
model.addElement("test");
model.addElement("test");
model.addElement("test");
model.addElement("test");
model.addElement("test");
model.addElement("test");
// Create jpanels
panelNewCustomer = new JPanel();
panelQuit = new JPanel();
panelNewAccount = new JPanel();
panelChangeName = new JPanel();
panelSelectCustomer = new JPanel();
// Create and add components - buttons
buttonNewCustomer = new JButton("OK");
buttonTerminate = new JButton("Avsluta");
buttonAddNewName = new JButton("OK");
buttonAddNewSavingsAccount = new JButton("Sparkonto");
buttonAddNewCreditAccount = new JButton("Kreditkonto");
// Create and add components - labels
textLabelName = new JLabel("Namn");
textLabelPersonalNumber = new JLabel("Personnummer");
textLabelNewName = new JLabel("Nytt namn");
//add(textLabel1);
// Create and add components - textfields
textInputName = new JTextField("");
textInputPersonalNumber = new JTextField("");
textInputName.setColumns(10);
textInputPersonalNumber.setColumns(10);
textInputNewName = new JTextField();
textInputNewName.setColumns(20);
// Add components to panel new customer
panelNewCustomer.add(textLabelName);
panelNewCustomer.add(textInputName);
panelNewCustomer.add(textLabelPersonalNumber);
panelNewCustomer.add(textInputPersonalNumber);
panelNewCustomer.add(buttonNewCustomer);
// Add components to panel to select customer
panelSelectCustomer.add(listScroller);
// Add components to panel new name
panelChangeName.add(textLabelNewName);
panelChangeName.add(textInputNewName);
panelChangeName.add(buttonAddNewName);
// Add components to panel new accounts
panelNewAccount.add(buttonAddNewSavingsAccount);
panelNewAccount.add(buttonAddNewCreditAccount);
// Add components to panel quit
panelQuit.add(buttonTerminate);
// Set borders to jpanels
panelNewCustomer.setBorder(BorderFactory.createTitledBorder("Skapa ny kund"));
panelChangeName.setBorder(BorderFactory.createTitledBorder("Ändra namn"));
panelNewAccount.setBorder(BorderFactory.createTitledBorder("Skapa nytt konto"));
panelQuit.setBorder(BorderFactory.createTitledBorder("Avsluta programmet"));
panelSelectCustomer.setBorder(BorderFactory.createTitledBorder("Välj kund"));
// Add panels to window
add(panelNewCustomer);
add(panelSelectCustomer);
add(panelChangeName);
add(panelNewAccount);
add(panelQuit);
// Listener
// FrameHandler handler = new FrameHandler();
// Add listener to components
//button1.addActionListener(handler);
buttonNewCustomer.addActionListener(this);
buttonAddNewName.addActionListener(this);
buttonAddNewSavingsAccount.addActionListener(this);
buttonAddNewCreditAccount.addActionListener(this);
buttonTerminate.addActionListener(this);
}
//private class FrameHandler implements ActionListener{
public void actionPerformed(ActionEvent event){
// New customer
if(event.getSource() == buttonNewCustomer && statusButtonNewCustomer)
{
String name = textInputName.getText();
String number = textInputPersonalNumber.getText();
boolean checkCustomerExist = customHandler.findCustomer(name, number); // Check if customer exist
if(!checkCustomerExist) // If not true add new customer
{
customHandler.addCustomer(name, number); // Call method to add name
setTitle(title + "Kund: " + name); // Set new title
model.addElement("name");
}
}
// Change name
if(event.getSource() == buttonAddNewName && statusButtonAddNewName)
{
String newName = textInputNewName.getText();
customHandler.changeName(newName); // call method to change name
setTitle(title + "Kund: " + newName);
}
// Create new savings account
if(event.getSource() == buttonAddNewSavingsAccount)
{
customHandler.CreateNewSavingsAccount();
}
// Create new credit account
if(event.getSource() == buttonAddNewCreditAccount)
{
customHandler.CreateNewCreditAccount();
}
// Terminate program
if(event.getSource()==buttonTerminate && statusButton2)
{
System.exit(3);
}
}
//}
}
你很幸运,我心情很好。 这是一个非常基本的示例,与您提供的代码匹配。 在文本字段中输入内容,点击输入按钮,然后查看列表。
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JTextField;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class AddToJListDemo {
private static JFrame createGUI(){
JFrame frame = new JFrame( );
final DefaultListModel model = new DefaultListModel();
JList list = new JList( model );
final JTextField input = new JTextField( 10 );
input.addActionListener( new ActionListener() {
public void actionPerformed( ActionEvent aActionEvent ) {
String text = input.getText();
if ( text.length() > 0 ) {
model.addElement( text );
input.setText( "" );
}
}
} );
frame.add( list, BorderLayout.CENTER );
frame.add( input, BorderLayout.SOUTH );
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
return frame;
}
public static void main( String[] args ) {
EventQueue.invokeLater( new Runnable() {
public void run() {
JFrame frame = createGUI();
frame.setSize( 200,200 );
frame.setVisible( true );
}
} );
}
}
编辑
根据您的完整代码,必须使列表成为GUI4EX
类中的一个字段,类似于buttonNewCustomer
字段
public class GUI4EX extends JFrame implements ActionListener{
//... all other field
DefaultListModel model;
//constructor
public GUI4EX(){
//all other code
//DefaultListModel model = new DefaultListModel(); instantiate the field instead
model = new DefaultListModel();
JList list = new JList(model);
//rest of your code
}
}
这将确保您可以在actionPerformed
方法中访问model
。 但是,如果您不能弄清楚这个基本知识,则不应该创建GUI,而应阅读基本的Java语法和OO原理。
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