迭代列表，但它只显示最后一项 [英] Iterating through List but it only shows last item
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问题描述
我想要实现的是有一个 JLabel 来显示 List 中的多个项目。
What I am trying to achieve is have one JLabel to display multiple items from a List.
我已经将列表定义如下，但是当我测试代码时，我的方法遍历列表，点击一下按钮后，只显示最后一项在列表中完成！。
I have defined the list as below but when I test the code my method to iterate through the list, after a button click, only shows the last item in the list which is "DONE!".
我试图在每个按钮点击一个 JLabel后完成在列表中显示仅下一个项目 。
I am trying to accomplish displaying only the next item in the list after each button click on one JLabel.
public class ScoutGUI extends javax.swing.JFrame {
/**
* Creates new form ScoutGUI
*/
List<String> strings = Arrays.asList("Do you mind Clutter in Room?", "Do you mind alarm clocks?","Do you mind loud visitors?","Can you sleep with lights on?","Do you mind noise past Midnight?",
"Do you consider yourself as an introvert?", "Do you consider yourself as an extrovert?","Do you like to go to parties?","Do you drink alcoholic beverages?(21+)", "DONE!");
ArrayList<Student> obj = new ArrayList<>();
String name , email , gender , major , year , language , building ;
int id , i;
public ScoutGUI() {
initComponents();
}
public ScoutGUI(int a) {
i = a;
initComponents();
}
/**
* 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() {
panel1 = new java.awt.Panel();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jButton1.setFont(new java.awt.Font("Courier", 0, 13)); // NOI18N
jButton1.setText("NO");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setFont(new java.awt.Font("Courier", 0, 13)); // NOI18N
jButton2.setText("YES");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
jLabel1.setFont(new java.awt.Font("Courier New", 1, 18)); // NOI18N
jLabel1.setBorder(javax.swing.BorderFactory.createMatteBorder(1, 1, 1, 1, new java.awt.Color(204, 255, 153)));
javax.swing.GroupLayout panel1Layout = new javax.swing.GroupLayout(panel1);
panel1.setLayout(panel1Layout);
panel1Layout.setHorizontalGroup(
panel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(panel1Layout.createSequentialGroup()
.addGap(71, 71, 71)
.addComponent(jButton1)
.addGap(94, 94, 94)
.addComponent(jButton2)
.addContainerGap(129, Short.MAX_VALUE))
.addGroup(panel1Layout.createSequentialGroup()
.addContainerGap()
.addComponent(jLabel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addContainerGap())
);
panel1Layout.setVerticalGroup(
panel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(panel1Layout.createSequentialGroup()
.addGap(26, 26, 26)
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 159, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addGroup(panel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2))
.addContainerGap(68, Short.MAX_VALUE))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(panel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(panel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
//skip and never
buttonpressActionPerformed();
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
//match and update
buttonpressActionPerformed();
}
private void buttonpressActionPerformed() {
// int i = 0;
Iterator<String> iterator = strings.iterator();
//for (String strin : strings)
while (iterator.hasNext())
{
//if (jButton2.isSelected() || jButton1.isSelected())
//{
jLabel1.setText(iterator.next());
//}
}
}
/**
* @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(ScoutGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(ScoutGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(ScoutGUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(ScoutGUI.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 ScoutGUI().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JLabel jLabel1;
private java.awt.Panel panel1;
// End of variables declaration
}
推荐答案
您当前的代码总是覆盖JPanel中的当前文本，并且它的速度非常快，您没有看到它。不是使用Iterator，而是通过定义每次按下增加的int变量来获取列表中的下一个项目。
index 变量在此示例中是一个公共int：
Your current code always overrides the current text in the JPanel, and it does that so fast, that you don't see it. Instead of using the Iterator, get the next item in the list by defining an int variable that gets incremented every press.
The index variable is a public int in this example:
jLabel1.setText(strings.get(index));
if (index < strings.size()-1)
index++;
没有循环，这是您方法中所需的一切。
No loops, that's everything needed in your method.
这篇关于迭代列表，但它只显示最后一项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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