两个JComboBox。第一个不会改变第二个

Question

我希望我的应用程序能够选择1000个预设。

所以我有了这样的想法，1000个预设分为10组，每组100个预设。

我想使用两个JCombobox，第一个是银行列表(从10个中选择1)。第二个将有100个预设。

在第一个银行中选择一个银行后，它不会刷新第二个银行中的预设列表。

方法GetXML.setBankFromBankCombo()正在更改变量bank。(GetXML是一个读取XML文件的类)。从打印System.out.println()可以看出，但我不知道为什么JCombo中的预设没有改变。

为了使代码更加清晰，我将银行和预设的数量限制为3项。

屏幕截图1屏幕截图2

类FrameCombo:

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.event.*;
public class FrameCombo extends JPanel {
private Presets comboPresets;
private JComboBox comboBank;
private int activeBank;
public FrameCombo() {
activeBank = 1;
setPreferredSize(new Dimension(410, 200));

/**
* Bank Combo
*
*/
String[] banks = {
"Bank 0",
"Bank 1",
"Bank 2"
};

comboBank = new JComboBox(banks);
comboBank.setEditable(true);
comboBank.setPreferredSize(new Dimension(180, 30));
comboBank.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JComboBox cb = (JComboBox) e.getSource();
activeBank = cb.getSelectedIndex();
comboPresets.setBank(activeBank);
System.out.println("FrameCombo.activeBank = " + activeBank);
}
});
JPanel bankPanel = new JPanel();
bankPanel.setPreferredSize(new Dimension(180, 100));
bankPanel.add(new JLabel("Banks"));
bankPanel.add(comboBank);
add(bankPanel);


/**
* Presets Combo
*
*/
comboPresets = new Presets();
comboPresets.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
//presets do something
}
});
JPanel presetPanel = new JPanel();
presetPanel.setPreferredSize(new Dimension(180, 110));
presetPanel.add(new JLabel("Presets"));
presetPanel.add(comboPresets);
add(presetPanel);
}
public void setBank(int value) {
activeBank = value;
}
public int getBank() {
return activeBank;
}
public static void main(String[] args) {
final String title = " Frame Combo";
System.out.println(title);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame(title);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new FrameCombo());
frame.setResizable(false);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}

class预设：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class Presets extends JPanel
implements ActionListener {
private int bank;
private int value;
private int[] ctrlIdx = new int[3];
private int controller;
private ChangeEvent changeEvent = null;
private EventListenerList listenerList = new EventListenerList();
private GetXMLPresets dane;
private String[][] patern;
private String[] itemName;
public MainWindow model = new MainWindow();
JComboBox item;
public Presets() {

dane = new GetXML(bank);
patern = dane.ct; // controllers
itemName = dane.lb; // name
System.out.println("Presets() " + bank);
JComboBox item = new JComboBox(itemName);
item.setSelectedIndex(0);
item.addActionListener(this);
item.setPreferredSize(new Dimension(180, 30));
add(item);
setPreferredSize(new Dimension(210, 40));
}
public void setValue(int c, int v) {
controller = c;
value = v;
ctrlIdx[controller] = value;
repaint();
fireChangeEvent();
}
public int getController() {
return controller;
}
public int getValue(int c) {
int w = (int) ctrlIdx[c];
return (int) w;
}
public void setBank(int value) {
bank = value;
dane.setBankFromBankCombo(bank);
repaint();
fireChangeEvent();
}
public int getBank() {
return bank;
}
public void actionPerformed(ActionEvent e) {
JComboBox cb = (JComboBox) e.getSource();
String item = (String) cb.getSelectedItem();
int indeks = cb.getSelectedIndex();
for (int i = 0; i < itemName.length; i++) {
for (int j = 0; j < patern[i].length; j++) {
model.setController(j, Integer.parseInt(patern[indeks][j]));
setValue(j, Integer.parseInt(patern[indeks][j]));
}
}
}
public void addChangeListener(ChangeListener cl) {
listenerList.add(ChangeListener.class, cl);
}
public void removeChangeListener(ChangeListener cl) {
listenerList.remove(ChangeListener.class, cl);
}
protected void fireChangeEvent() {
Object[] listeners = listenerList.getListenerList();
for (int i = listeners.length - 2; i >= 0; i -= 2) {
if (listeners[i] == ChangeListener.class) {
if (changeEvent == null) {
changeEvent = new ChangeEvent(this);
}
((ChangeListener) listeners[i + 1]).stateChanged(changeEvent);
}
}
}
}

classGetXML：

import java.io.*;
import javax.swing.*;
import javax.xml.xpath.*;
import org.w3c.dom.*;
import org.xml.sax.InputSource;
public class GetXML extends JPanel {
private int numpresets;
public String[] lb = new String[3];
public String[][] ct = new String[3][3];
private int bank;
public GetXML(int a) {
bank = a;
try {
XPathFactory factory = XPathFactory.newInstance();
XPath xPath = factory.newXPath();
NodeList patches = (NodeList) xPath.evaluate("/bank/patch",
new InputSource(new FileReader(new File("patches/presets" + bank + ".xml").getAbsolutePath())),
XPathConstants.NODESET);
setNumPresets(patches.getLength());
String[] labels = new String[numpresets];
String[][] ctrl = new String[numpresets][3];
for (int i = 0; i < numpresets; i++) {
Element patch = (Element) patches.item(i);
String controllerName = xPath.evaluate("controllers/name/text()", patch);
for (int j = 0; j < 3; j++) {
ctrl[i][j] = xPath.evaluate("controllers/c" + Integer.toString(j + 1) + "/text()", patch);
ct[i][j] = ctrl[i][j];
}
labels[i] = controllerName;
lb[i] = labels[i];
}
} catch (FileNotFoundException fnfe) {
System.out.println("FileNotFoundException " + fnfe);
fnfe.printStackTrace();
} catch (IOException ioe) {
System.out.println("IOException " + ioe);
} catch (Exception eio) {
System.out.println("eio " + eio);
}
}
public void setBank(String[] b) {
lb = b;
}
public String[] getBank() {
return lb;
}
public void setPreset(String[][] c) {
ct = c;
}
public String[][] getPreset() {
return ct;
}
public void setNumPresets(int a) {
numpresets = a;
}
public int getNumPresets() {
return numpresets;
}
public void setBankFromBankCombo(int id) {
System.out.println("GetXMLPresets.setIDFromBankCombo() " + id);
bank = id;

}
}

和一个XML文件的示例Preset0.XML

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<bank bid="0">
<patch pid="1">
<controllers>
<name>bank 0: preset 1</name>
<c1>55</c1>
<c2>3</c2>
<c3>24</c3>
</controllers>
</patch>
<patch pid="2">
<controllers>
<name>bank 0: preset 2</name>
<c1>33</c1>
<c2>1</c2>
<c3>45</c3>
</controllers>
</patch>
<patch pid="3">
<controllers>
<name>bank 0: preset 3</name>
<c1>43</c1>
<c2>23</c2>
<c3>39</c3>   
</controllers>
</patch>
</bank>

Answer 1

很简单，您没有更改Preset的组合框的内容，这意味着虽然数据已经加载，但它还没有应用于组合框模型，因此组合框不知道它有新的数据要显示。

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