Java Netbeans,空的DefaultListModel
为什么我的列表是空的 从输出中,我可以看到myList的大小不正确,但消息的大小正确 输出:Java Netbeans,空的DefaultListModel,java,swing,user-interface,netbeans,jlist,Java,Swing,User Interface,Netbeans,Jlist,为什么我的列表是空的 从输出中,我可以看到myList的大小不正确,但消息的大小正确 输出: Apr 23, 2012 4:28:42 PM net.bounceme.dur.nntp.MessagesJFrame <init> INFO: messages 11 Apr 23, 2012 4:28:42 PM net.bounceme.dur.nntp.MessagesJFrame <init> INFO: myList 0 2012年4月23日下午4:28:42 n
Apr 23, 2012 4:28:42 PM net.bounceme.dur.nntp.MessagesJFrame <init>
INFO: messages 11
Apr 23, 2012 4:28:42 PM net.bounceme.dur.nntp.MessagesJFrame <init>
INFO: myList 0
2012年4月23日下午4:28:42 net.bounceme.dur.nntp.MessagesJFrame
信息:留言11
2012年4月23日下午4:28:42 net.bounceme.dur.nntp.MessagesJFrame
信息:myList 0
消息框架:
package net.bounceme.dur.nntp;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.mail.Message;
import javax.swing.DefaultListModel;
public class MessagesJFrame extends javax.swing.JFrame {
private static final long serialVersionUID = 1L;
private static final Logger LOG = Logger.getLogger(MessagesJFrame.class.getName());
DefaultListModel<Message> myList = new DefaultListModel<Message>();
public MessagesJFrame() {
initComponents();
EnumNNTP nntp = EnumNNTP.INSTANCE;
List messages = null;
try {
messages = nntp.getMessages(false);
} catch (Exception ex) {
LOG.severe("didn't get messages");
}
myList.copyInto(messages.toArray());
LOG.log(Level.INFO, "messages {0}", messages.size());
LOG.log(Level.INFO, "myList {0}", myList.size());
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jScrollPane2 = new javax.swing.JScrollPane();
jList1 = new javax.swing.JList();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jList1.setModel(myList);
jScrollPane2.setViewportView(jList1);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(13, Short.MAX_VALUE)
.addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(129, 129, 129))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(158, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/*
* Set the Nimbus look and feel
*/
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/*
* If Nimbus (introduced in Java SE 6) is not available, stay with the
* default look and feel. For details see
* http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/*
* Create and display the form
*/
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new MessagesJFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JList jList1;
private javax.swing.JScrollPane jScrollPane2;
// End of variables declaration
}
package net.bounceme.dur.nntp;
导入java.util.List;
导入java.util.logging.Level;
导入java.util.logging.Logger;
导入javax.mail.Message;
导入javax.swing.DefaultListModel;
公共类MessagesJFrame扩展了javax.swing.JFrame{
私有静态最终长serialVersionUID=1L;
私有静态最终记录器LOG=Logger.getLogger(MessagesJFrame.class.getName());
DefaultListModel myList=新的DefaultListModel();
公共消息框架(){
初始化组件();
EnumNNTP nntp=EnumNNTP.INSTANCE;
列表消息=null;
试一试{
messages=nntp.getMessages(false);
}捕获(例外情况除外){
LOG.severy(“没有收到消息”);
}
myList.copyInto(messages.toArray());
LOG.LOG(Level.INFO,“messages{0}”,messages.size());
LOG.LOG(Level.INFO,“myList{0}”,myList.size());
}
/**
*从构造函数中调用此方法来初始化表单。
*警告:不要修改此代码。此方法的内容始终为
*由表单编辑器重新生成。
*/
@抑制警告(“未选中”)
//
私有组件(){
jScrollPane2=newjavax.swing.JScrollPane();
jList1=newjavax.swing.JList();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jList1.setModel(myList);
jScrollPane2.setViewportView(jList1);
javax.swing.GroupLayout=newjavax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(布局);
layout.setHorizontalGroup(
createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING,layout.createSequentialGroup()
.addContainerGap(13,简称最大值)
.addComponent(jScrollPane2,javax.swing.GroupLayout.PREFERRED\u SIZE,javax.swing.GroupLayout.DEFAULT\u SIZE,javax.swing.GroupLayout.PREFERRED\u SIZE)
.addGap(129、129、129))
);
layout.setVerticalGroup(
createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane2,javax.swing.GroupLayout.PREFERRED\u SIZE,javax.swing.GroupLayout.DEFAULT\u SIZE,javax.swing.GroupLayout.PREFERRED\u SIZE)
.addContainerGap(158,简称最大值))
);
包装();
}//
/**
*@param指定命令行参数
*/
公共静态void main(字符串参数[]){
/*
*设置Nimbus的外观和感觉
*/
//
/*
*如果Nimbus(在JavaSE6中引入)不可用,请使用
*默认外观。有关详细信息,请参阅
* http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
试一试{
for(javax.swing.UIManager.LookAndFeelInfo:javax.swing.UIManager.getInstalledLookAndFeels()){
if(“Nimbus”.equals(info.getName())){
setLookAndFeel(info.getClassName());
打破
}
}
}捕获(ClassNotFoundException ex){
getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE,null,ex);
}catch(实例化异常){
getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE,null,ex);
}捕获(非法访问例外){
getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE,null,ex);
}catch(javax.swing.UnsupportedLookAndFeelException ex){
getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE,null,ex);
}
//
/*
*创建并显示表单
*/
invokeLater(new Runnable()){
公开募捐{
新MessagesJFrame().setVisible(true);
}
});
}
//变量声明-不修改
私有javax.swing.JList jList1;
私有javax.swing.JScrollPane-jScrollPane2;
//变量结束声明
}
您将模型添加到JList的何处?为了使JList能够使用和显示模型保存的数据,必须通过JList的构造函数或其setModel(…)
方法将模型添加到JList中。你有没有通过考试?如果没有,这是您应该首先查看的地方,因为它将解释如何使用JLists,然后是一些
编辑1DefaultListModel
copyInto(…)
方法的作用与您认为的相反。它将数据从模型复制到数组中
根据API:
将此列表的组件复制到指定的数组中
在最狭义的意义上,以下代码填充模型: 固定方法:
public MessagesJFrame() {
initComponents();
EnumNNTP nntp = EnumNNTP.INSTANCE;
List<Message> messages = null;
try {
messages = nntp.getMessages(false);
} catch (Exception ex) {
LOG.severe("didn't get messages");
}
for (Message m : messages) {
myList.addElement(m);
}
LOG.log(Level.INFO, "messages {0}", messages.size());
LOG.log(Level.INFO, "myList {0}", myList.size());
}
public MessagesJFrame(){
初始化组件();
EnumNNTP nntp=EnumNNTP.INSTANCE;
列表消息=null;
试一试{
messages=nntp.getMessages(false);
}捕获(例外情况除外){
LOG.severy(“没有收到消息”);
}
用于(消息m:消息){
myList.addElement(m);
}
LOG.LOG(Level.INFO,“messages{0}”,messages.size());
LOG.LOG(Level.INFO,“myList{0}”,myList.size());
}
但是,myList.copyInto(messages.toArray())有什么问题