我有两种形式。第一个是通过使用jslider来决定按钮的数量。第二种形式是根据jslider值显示jbuttons。当我单击jbutton2时，第二个窗体显示并显示按钮。它工作得很好。但是，我想在第二个窗体上创建jbutton，而不是在第一个窗体中单击jbutton2。 相反，当我更改jslider时，它应该在运行时在第二个窗体上创建jbuttons，并且一旦我更改jslider，它应该在第二个窗体上再次创建该量的按钮，并根据jslider值刷新第二个窗体按钮编号。 我试过revalidate（）;, repaint（）;但他们不工作，他们不刷新第二种形式。
那么，当第一个表单上的jslider发生变化时，如何刷新第二个表单？请帮忙.....
编辑：我使用默认的netbeans Jframe ....
/ * *要更改此模板，请选择“工具”|模板 *并在编辑器中打开模板。 * /
public class NewJFrame7 extends javax.swing.JFrame {
/**
* Creates new form NewJFrame7
*/
public NewJFrame7() {
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() {
jSlider1 = new javax.swing.JSlider();
jButton2 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jSlider1.setMajorTickSpacing(2);
jSlider1.setMaximum(20);
jSlider1.setMinimum(1);
jSlider1.setPaintLabels(true);
jSlider1.setPaintTicks(true);
jSlider1.setToolTipText("");
jSlider1.addChangeListener(new javax.swing.event.ChangeListener() {
public void stateChanged(javax.swing.event.ChangeEvent evt) {
jSlider1StateChanged(evt);
}
});
jButton2.setText("jButton2");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(29, 29, 29)
.addComponent(jSlider1, javax.swing.GroupLayout.PREFERRED_SIZE, 295, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(273, Short.MAX_VALUE))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(262, 262, 262)
.addComponent(jButton2)
.addContainerGap(262, Short.MAX_VALUE)))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(87, 87, 87)
.addComponent(jSlider1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(168, Short.MAX_VALUE))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(138, 138, 138)
.addComponent(jButton2)
.addContainerGap(139, Short.MAX_VALUE)))
);
pack();
}// </editor-fold>
private void jSlider1StateChanged(javax.swing.event.ChangeEvent evt) {
// TODO add your handling code here:
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
form2 = true;
new NewJFrame8().setVisible(true);
}
/**
* @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(NewJFrame7.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame7.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame7.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame7.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 NewJFrame7().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton2;
private javax.swing.JSlider jSlider1;
// End of variables declaration
}
2.form
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
public class NewJFrame8 extends javax.swing.JFrame {
/**
* Creates new form NewJFrame8
*/
public NewJFrame8() {
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() {
jPanel1 = new javax.swing.JPanel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
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(371, Short.MAX_VALUE)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(19, 19, 19))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(48, 48, 48)
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(242, 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(NewJFrame8.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame8.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame8.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame8.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 NewJFrame8().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JPanel jPanel1;
// End of variables declaration
}
答案 0 :(得分：3)
放置它们的一个布局约束（BorderLayout.CENTER），以及要在其中显示的一个组件。 （向托尔金道歉。）
答案 1 :(得分：2)
请查看此示例程序，这是您所需要的。 revalidate()和repaint()就是为此而努力的。
import java.awt.*;
import javax.swing.event.*;
import javax.swing.*;
public class SliderExample
{
private JSlider slider;
private static final int MIN_BUTTONS = 2;
private static final int SOME_BUTTONS = 4;
private static final int MAX_BUTTONS = 6;
private void createAndDisplayGUI()
{
ButtonPanel bp = new ButtonPanel();
JFrame frame = new JFrame("JSlider Example : ");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationByPlatform(true);
JPanel contentPane = new JPanel();
slider = new JSlider(JSlider.HORIZONTAL, MIN_BUTTONS, MAX_BUTTONS
, SOME_BUTTONS);
slider.addChangeListener(new ChangeListener()
{
public void stateChanged(ChangeEvent ce)
{
int value = (int) slider.getValue();
ButtonPanel.panel.removeAll();
for (int i = 0; i < value; i++)
{
ButtonPanel.panel.add(new JButton("JButton " + i));
}
ButtonPanel.panel.revalidate();
ButtonPanel.panel.repaint();
}
});
contentPane.add(slider);
frame.getContentPane().add(contentPane);
frame.pack();
frame.setVisible(true);
frame.requestFocusInWindow();
}
public static void main(String... args)
{
Runnable runnable = new Runnable()
{
public void run()
{
new SliderExample().createAndDisplayGUI();
}
};
SwingUtilities.invokeLater(runnable);
}
}
class ButtonPanel extends JFrame
{
public static JPanel panel;
public ButtonPanel()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationByPlatform(true);
panel = new JPanel();
panel.setLayout(new GridLayout(0, 2));
getContentPane().add(panel);
setSize(300, 300);
setVisible(true);
}
}
答案 2 :(得分：1)
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
import javax.swing.*;
public class SliderExample
{
private JSlider slider;
private static final int MIN_BUTTONS = 2;
private static final int SOME_BUTTONS = 4;
private static final int MAX_BUTTONS = 6;
private JButton[] buttonArray;
private ActionListener actionButton = new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
JButton button = (JButton) ae.getSource();
System.out.println(button.getText());
}
};
private void createAndDisplayGUI()
{
ButtonPanel bp = new ButtonPanel();
JFrame frame = new JFrame("JSlider Example : ");
frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
frame.setLocationByPlatform(true);
JPanel contentPane = new JPanel();
slider = new JSlider(JSlider.HORIZONTAL, MIN_BUTTONS, MAX_BUTTONS
, SOME_BUTTONS);
slider.addChangeListener(new ChangeListener()
{
public void stateChanged(ChangeEvent ce)
{
int value = (int) slider.getValue();
ButtonPanel.panel.removeAll();
buttonArray = new JButton[value];
for (int i = 0; i < value; i++)
{
buttonArray[i] = new JButton(String.valueOf(i));
buttonArray[i].addActionListener(actionButton);
ButtonPanel.panel.add(buttonArray[i]);
}
ButtonPanel.panel.revalidate();
ButtonPanel.panel.repaint();
}
});
contentPane.add(slider);
frame.getContentPane().add(contentPane);
frame.pack();
frame.setVisible(true);
frame.requestFocusInWindow();
}
public static void main(String... args)
{
Runnable runnable = new Runnable()
{
public void run()
{
new SliderExample().createAndDisplayGUI();
}
};
SwingUtilities.invokeLater(runnable);
}
}
class ButtonPanel extends JFrame
{
public static JPanel panel;
public ButtonPanel()
{
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationByPlatform(true);
panel = new JPanel();
panel.setLayout(new GridLayout(0, 2));
getContentPane().add(panel);
setSize(300, 300);
setVisible(true);
}
}
对于你的陈述this.buttonArray[i].addActionListener(this);，原因是为什么这不起作用，是因为你在anonymous class new ChangeListener()的对象里面，它没有任何名为{ {1}}在其自身内部，它是buttonArray[i]类的实例变量，因此要么放置SliderExample类的对象，要么引用您的代码，然后使用SliderExample初始化数组的类，就像你编写Object NewFrame8内的JButton[] buttonArray = new JButton[120];内部一样，所以使用NewFrame8的对象而不是this来引用buttonArray[i]这个东西。