问题：
下面是添加额外组合框项的代码，但相应的组合框值不变
柴凌
它没有改变相应的组合框值，为什么它改变的是最新的组合框值，而不是相应的组合框？
当我运行此代码时，单击添加字段两次后，当我更改第一个组合框时，第二个组合框值应该更改而不是第四个组合框，这是错误的，我想要的是取决于第一个组合框选择第二个组合框应该是可选的，如果选择了第三个组合框，那么第四个组合框应该是可选的。
添加字段按钮在窗口中添加额外的组合框，它应该工作的方式是，当添加字段按钮按两次时，我分别选择第一个组合框，第二个组合框应该是可选的，但由于某种原因，第四个组合框变得可选。当你运行上面的代码时，你会更好地理解问题，我在描述中提供了完整的代码，请帮助！
package addextraitem;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JComboBox;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JList;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class ExtraComboBox {
int count = 0;
JComboBox fruits[] = new JComboBox[10];;
JPanel comboPanel;
JFrame guiFrame;
//JComboBox dude1;
String[] valOptions3 = {"&"};
String[] valOptions2 = {"|->", "|=>"};
String[] valOptions1 = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
String[] valOptions0 = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
String[] fruitOptions1 = {"", "Delay1", "Delay2", "Delay3"};
String chosenString;
int numPairs1 = valOptions0.length;
JButton addField;
int count1 = 0;
JComboBox[] ComboBox4 = new JComboBox[numPairs1];
JComboBox[] ComboBox5 = new JComboBox[numPairs1];
JComboBox[] ComboBox6 = new JComboBox[numPairs1];
String[] comborel = {"a", "b", "c", "d", "e"};
JLabel lb;
JComboBox dude;
JTextField handle;
String clockOptions1;
JLabel dudel[] = new JLabel[10];
JComboBox dude1[] = new JComboBox[10];
JComboBox dude2[] = new JComboBox[10];;
//JComboBox dude1[] = new JComboBox[10];
String[] valOptions = {"Unknown", "0", "1"};
String [] s = {"a", "b", "c", "d", "e", "f", "g", "h", "i"};
int cnt = 0;
int i = 0;
JLabel comboLbl;
JLabel lb1;
//Note: Typically the main method will be in a
//separate class. As this is a simple one class
//example it's all in the one class.
public static void main(String[] args) {
new ExtraComboBox();
}
public ExtraComboBox()
{
guiFrame = new JFrame();
//make sure the program exits when the frame closes
guiFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
guiFrame.setTitle("ComboBox GUI");
guiFrame.setSize(350,250);
//This will center the JFrame in the middle of the screen
guiFrame.setLocationRelativeTo(null);
//The first JPanel contains a JLabel and JCombobox
comboPanel = new JPanel();
addField = new JButton("Add Field");
addField.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent event)
{
if (event.getSource() == addField) {
count1++;
comboLbl = new JLabel("Select a relation:");
fruits[count1] = new JComboBox(fruitOptions1);
MyItemListener2 actionListener2 = new MyItemListener2();
fruits[count1].addItemListener(actionListener2);
//System.out.println("HI: " + fruits[count1].getParent());
dude2[count1] = new JComboBox();
System.out.println("ADD FIELDS: " + count1);
comboPanel.add(comboLbl);
comboPanel.add(fruits[count1]);
comboPanel.add(dude2[count1]);
guiFrame.revalidate();
guiFrame.validate();
guiFrame.pack();
guiFrame.repaint();
}
}
});
comboPanel.setLayout(new BoxLayout(comboPanel, BoxLayout.Y_AXIS));
comboPanel.add(addField);
//The JFrame uses the BorderLayout layout manager.
//Put the two JPanels and JButton in different areas.
guiFrame.add(comboPanel, BorderLayout.NORTH);
//make sure the JFrame is visible
guiFrame.setVisible(true);
}
class MyItemListener2 implements ItemListener {
// This method is called only if a new item has been selected.
public void itemStateChanged(ItemEvent evt) {
JComboBox cb = (JComboBox) evt.getSource();
Object item = evt.getItem();
if (evt.getStateChange() == ItemEvent.SELECTED) {
// Item was just selected
System.out.println("COUNTER: " + count1);
System.out.println(evt.getItem());
dude2[count1].removeAllItems();
if(evt.getItem() == "Delay1") {
System.out.println(valOptions1.length);
for(int i = 0; i < valOptions1.length; i++) {
dude2[count1].addItem(valOptions1[i]); //dude1 = new JComboBox(valOptions1);
System.out.println(valOptions1[i]);
}
}
else if(evt.getItem() == "Delay2") {
System.out.println(valOptions2.length);
for(int j = 0; j < valOptions2.length; j++) {
System.out.println(valOptions2[j]);
dude2[count1].addItem(valOptions2[j]); //dude1 = new JComboBox(valOptions1);
}
}
else if(evt.getItem() == "Delay3") {
System.out.println(valOptions3.length);
for(int j = 0; j < valOptions3.length; j++) {
System.out.println(valOptions3[j]);
dude2[count1].addItem(valOptions3[j]); //dude1 = new JComboBox(valOptions1);
}
}
} else if (evt.getStateChange() == ItemEvent.DESELECTED) {
// Item is no longer selected
}
}
}
}
共有1个答案
松和泰
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class ExtraComboBox {
private int maxFields = 4; // The max number of fields allowed in the dialog
JComboBox fruits[] = new JComboBox[maxFields];
JPanel comboPanel;
JFrame guiFrame;
String[] valOptions3 = { "&" };
String[] valOptions2 = { "|->", "|=>" };
String[] valOptions1 = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
String[] valOptions0 = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" };
String[] fruitOptions1 = { "", "Delay1", "Delay2", "Delay3" };
JButton addField;
int count1 = 0;
JLabel dudel[] = new JLabel[maxFields];
JComboBox dude2[] = new JComboBox[maxFields];
String[] valOptions = { "Unknown", "0", "1" };
String[] s = { "a", "b", "c", "d", "e", "f", "g", "h", "i" };
private JLabel comboLbl;
public static void main(String[] args) {
new ExtraComboBox();
}
public ExtraComboBox() {
guiFrame = new JFrame();
// make sure the program exits when the frame closes
guiFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
guiFrame.setTitle("ComboBox GUI");
guiFrame.setSize(350, 350);
// The first JPanel contains a JLabel and JCombobox
comboPanel = new JPanel();
addField = new JButton("Add Field");
addField.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
if (event.getSource().equals(addField)) {
if (count1 < maxFields) {
comboLbl = new JLabel("Select a relation:");
fruits[count1] = new JComboBox<String>(fruitOptions1);
MyItemListener2 actionListener2 = new MyItemListener2(count1);
fruits[count1].addItemListener(actionListener2);
// System.out.println("HI: " + fruits[count1].getParent());
dude2[count1] = new JComboBox<String>();
System.out.println("ADD FIELDS: " + count1);
comboPanel.add(comboLbl);
comboPanel.add(fruits[count1]);
comboPanel.add(dude2[count1]);
guiFrame.validate();
guiFrame.repaint();
count1++;
} else {
System.out.println("You reached the maximum of 4 fields.");
}
}
}
});
comboPanel.setLayout(new BoxLayout(comboPanel, BoxLayout.Y_AXIS));
comboPanel.add(addField);
// The JFrame uses the BorderLayout layout manager.
// Put the two JPanels and JButton in different areas.
guiFrame.add(comboPanel, BorderLayout.NORTH);
// make sure the JFrame is visible
guiFrame.setVisible(true);
}
class MyItemListener2 implements ItemListener {
private int index;
public MyItemListener2(int pIndex) {
super();
index = pIndex;
}
// This method is called only if a new item has been selected.
public void itemStateChanged(ItemEvent evt) {
if (evt.getStateChange() == ItemEvent.SELECTED) {
// Item was just selected
System.out.println("COUNTER: " + index);
System.out.println(evt.getItem());
dude2[index].removeAllItems();
switch ((String) evt.getItem()) {
case "Delay1":
for (int i = 0; i < valOptions1.length; i++) {
dude2[index].addItem(valOptions1[i]); // dude1 = new JComboBox(valOptions1);
System.out.println(valOptions1[i]);
}
break;
case "Delay2":
for (int j = 0; j < valOptions2.length; j++) {
System.out.println(valOptions2[j]);
dude2[index].addItem(valOptions2[j]); // dude1 = new JComboBox(valOptions1);
}
break;
case "Delay3":
for (int j = 0; j < valOptions3.length; j++) {
System.out.println(valOptions3[j]);
dude2[index].addItem(valOptions3[j]); // dude1 = new JComboBox(valOptions1);
}
}
}
}
}
}
我想这解决了你的要求。我删除了所有未使用的代码，但保留了所有变量名。请以任何阅读代码的人都知道变量的用途的方式选择变量的名称。
很明显，您不了解java或任何其他高级编程语言。我建议您在尝试编程花哨的东西之前先学习基础知识。
我希望这对你有帮助
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