我想向 jFrame 上的 jpanel 添加复选框。 UI 是在 netbeans 上制作的，我已经复制了代码以在 eclipse 上使用其功能。 我无法让我的复选框出现在 Jpanel 上。
代码
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JCheckBox;
import javax.swing.border.Border;
public class QueryBuilderUI extends javax.swing.JFrame {
QueryBuilderMethods objQBM = new QueryBuilderMethods();
DefaultComboBoxModel<String> repoModel = new DefaultComboBoxModel<String>();
public QueryBuilderUI() {
getRepositoryListing();
initComponents();
}
private void getRepositoryListing()
{
repoModel = new QueryBuilderMethods().getAllRepositoryName();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jComboBox1 = new javax.swing.JComboBox();
jLabel2 = new javax.swing.JLabel();
jComboBox2 = new javax.swing.JComboBox();
jLabel3 = new javax.swing.JLabel();
jPanel1 = new javax.swing.JPanel();
jTextField1 = new javax.swing.JTextField();
jLabel4 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Choose Repository");
jComboBox1.setModel(repoModel);
jComboBox1.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jComboBox1ItemStateChanged(evt);
}
});
jLabel2.setText("Choose Table");
//jComboBox2.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Item 1", "Item 2", "Item 3", "Item 4" }));
jComboBox2.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jComboBox2ItemStateChanged(evt);
}
});
jLabel3.setText("Choose Columns");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
Border border = BorderFactory.createTitledBorder("Select Columns");
jPanel1.setBorder(border);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 459, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 124, Short.MAX_VALUE)
);
jTextField1.setText("jTextField1");
jLabel4.setText("Generated Query");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1)
.addComponent(jLabel2))
.addGap(57, 57, 57)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 106, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jComboBox2, javax.swing.GroupLayout.PREFERRED_SIZE, 106, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addComponent(jLabel3)
.addComponent(jLabel4)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 412, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(65, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(jComboBox2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addComponent(jLabel3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(44, 44, 44)
.addComponent(jLabel4)
.addGap(18, 18, 18)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(92, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void jComboBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if(evt.getStateChange()== ItemEvent.SELECTED){
Object item = evt.getItem();
DefaultComboBoxModel<String> modelTable = objQBM.getAllTablesForRepo(item.toString());
jComboBox2.setModel(modelTable);
}
}
private void jComboBox2ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if(evt.getStateChange()== ItemEvent.SELECTED){
Object item = evt.getItem();
String RepoName = jComboBox1.getSelectedItem().toString();
List<String> columnNames = objQBM.getAllColumnsForTable(item.toString());
addCheckBox(columnNames);
}
}
private void addCheckBox(List<String> columnNames)
{
int numberCheckBox = columnNames.size();
JCheckBox[] checkBoxList = new JCheckBox[numberCheckBox];
for(int i = 0; i < numberCheckBox; i++) {
checkBoxList[i] = new JCheckBox("hi"+i);
jPanel1.add(checkBoxList[i]);
}
jPanel1.revalidate();
}
public static void main(String args[]) {
// java.awt.EventQueue.invokeLater(new Runnable() {
// public void run() {
new QueryBuilderUI().setVisible(true);
// }
// });
}
// Variables declaration - do not modify
private javax.swing.JComboBox jComboBox1;
private javax.swing.JComboBox jComboBox2;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JPanel jPanel1;
private javax.swing.JTextField jTextField1;
// End of variables declaration
}
用户界面看起来像这样
需要根据 jComboBox2 上的选择动态创建复选框。
最佳答案
您的 jPanel1 JPanel 受到其布局 GroupLayout 的限制，如果没有对难以编写的代码进行大量添加，它不会友好地添加新组件，因为 GroupLayout 不是为了用于手动编码而构建的用于 GUI 构建器编码。我建议您使用对编码器更友好的布局来构建 GUI，或者更好的是，每个使用更简单的布局的嵌套 JPanel 的组合，更有利于添加新组件，然后您的问题将更容易已解决。
如果您愿意，您甚至仍然可以将 GroupLayout 用于 GUI 的主要部分，但不能用于 jPanel1。我建议您考虑使用 GridLayout 或 GridBagLayout 添加 JCheckBoxes 网格。甚至是 FlowLayout。例如，以下代码使用默认的 JPanel 的 FlowLayout:
import java.awt.Dimension;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JCheckBox;
import javax.swing.border.Border;
public class QueryBuilderUI extends javax.swing.JFrame {
protected static final int PREF_W = 400;
protected static final int PREF_H = 200;
QueryBuilderMethods objQBM = new QueryBuilderMethods();
DefaultComboBoxModel<String> repoModel = new DefaultComboBoxModel<String>();
public QueryBuilderUI() {
getRepositoryListing();
initComponents();
}
private void getRepositoryListing() {
repoModel = new QueryBuilderMethods().getAllRepositoryName();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jComboBox1 = new javax.swing.JComboBox();
jLabel2 = new javax.swing.JLabel();
jComboBox2 = new javax.swing.JComboBox();
jLabel3 = new javax.swing.JLabel();
jPanel1 = new javax.swing.JPanel() {
@Override
// !! so the JPanel has some size. This is a shameless kludge *****
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
};
jTextField1 = new javax.swing.JTextField();
jLabel4 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Choose Repository");
jComboBox1.setModel(repoModel);
jComboBox1.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jComboBox1ItemStateChanged(evt);
}
});
jLabel2.setText("Choose Table");
// jComboBox2.setModel(new javax.swing.DefaultComboBoxModel(new String[] {
// "Item 1", "Item 2", "Item 3", "Item 4" }));
jComboBox2.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jComboBox2ItemStateChanged(evt);
}
});
jLabel3.setText("Choose Columns");
// *************** Note Changes Below ****************
// !! javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(
// !! jPanel1);
// !! jPanel1.setLayout(jPanel1Layout);
// !! jPanel1 now uses JPanel's default FlowLayout
Border border = BorderFactory.createTitledBorder("Select Columns");
jPanel1.setBorder(border);
jTextField1.setText("jTextField1");
jLabel4.setText("Generated Query");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(
getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(layout
.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(
layout.createSequentialGroup()
.addContainerGap()
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(
layout.createSequentialGroup()
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(
jLabel1)
.addComponent(
jLabel2))
.addGap(57, 57, 57)
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(
jComboBox1,
javax.swing.GroupLayout.PREFERRED_SIZE,
106,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(
jComboBox2,
javax.swing.GroupLayout.PREFERRED_SIZE,
106,
javax.swing.GroupLayout.PREFERRED_SIZE)))
.addComponent(jLabel3)
.addComponent(jLabel4)
.addComponent(
jPanel1,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(
jTextField1,
javax.swing.GroupLayout.PREFERRED_SIZE,
412,
javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(65, Short.MAX_VALUE)));
layout.setVerticalGroup(layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.LEADING).addGroup(
layout.createSequentialGroup()
.addGap(18, 18, 18)
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jComboBox1,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(
layout.createParallelGroup(
javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(jComboBox2,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addComponent(jLabel3)
.addPreferredGap(
javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jPanel1,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(44, 44, 44)
.addComponent(jLabel4)
.addGap(18, 18, 18)
.addComponent(jTextField1,
javax.swing.GroupLayout.PREFERRED_SIZE,
javax.swing.GroupLayout.DEFAULT_SIZE,
javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(92, Short.MAX_VALUE)));
pack();
}// </editor-fold>
private void jComboBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if (evt.getStateChange() == ItemEvent.SELECTED) {
Object item = evt.getItem();
DefaultComboBoxModel<String> modelTable = objQBM
.getAllTablesForRepo(item.toString());
jComboBox2.setModel(modelTable);
}
}
private void jComboBox2ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if (evt.getStateChange() == ItemEvent.SELECTED) {
Object item = evt.getItem();
String RepoName = jComboBox1.getSelectedItem().toString();
List<String> columnNames = objQBM.getAllColumnsForTable(item
.toString());
addCheckBox(columnNames);
}
}
private void addCheckBox(List<String> columnNames) {
int numberCheckBox = columnNames.size();
JCheckBox[] checkBoxList = new JCheckBox[numberCheckBox];
System.out.println("numberCheckBox = " + numberCheckBox);
for (int i = 0; i < numberCheckBox; i++) {
checkBoxList[i] = new JCheckBox("hi" + i);
jPanel1.add(checkBoxList[i]);
}
jPanel1.revalidate();
jPanel1.repaint();
System.out.println("check boxes added");
}
public static void main(String args[]) {
// java.awt.EventQueue.invokeLater(new Runnable() {
// public void run() {
new QueryBuilderUI().setVisible(true);
// }
// });
}
// Variables declaration - do not modify
private javax.swing.JComboBox jComboBox1;
private javax.swing.JComboBox jComboBox2;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JPanel jPanel1;
private javax.swing.JTextField jTextField1;
// End of variables declaration
}
// mock code added so that the above code will compile and run
// because you didn't give us this code
class QueryBuilderMethods {
public DefaultComboBoxModel<String> getAllRepositoryName() {
DefaultComboBoxModel<String> cModel = new DefaultComboBoxModel<>();
for (String item : new String[] { "one", "two", "three", "four", "five" }) {
cModel.addElement(item);
}
return cModel;
}
public List<String> getAllColumnsForTable(String string) {
List<String> columns = new ArrayList<>();
for (String item : new String[] { "col 1", "col 2", "col 3", "col 4" }) {
columns.add(item);
}
return columns;
}
public DefaultComboBoxModel<String> getAllTablesForRepo(String string) {
DefaultComboBoxModel<String> cModel = new DefaultComboBoxModel<>();
for (String item : new String[] { "repo one", "repo two", "repo three",
"repo four", "repo five" }) {
cModel.addElement(item);
}
return cModel;
}
}
关于java - 无法将动态创建的复选框添加到 jPanel，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31579126/