Вместо того, чтобы объявлять ползунки в качестве локальных переменных, добавьте их в члены SliderTestFrame, чтобы ваш ActionListener мог обращаться к обоим значениям в той точке, в которой они необходимы:
private JSlider slider1 = new JSlider();
private JSlider slider2 = new JSlider();
public SliderTestFrame()
{
setTitle("SliderTest");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
sliderPanel = new JPanel();
sliderPanel.setLayout(new FlowLayout(FlowLayout.LEFT));
// common listener for all sliders
listener = new ChangeListener()
{
public void stateChanged(ChangeEvent event)
{
// update text field when the slider value changes
textField.setText("" + (slider1.getValue() + slider2.getValue()));
}
};
Удалитьлокальные экземпляры (в рамках метода SliderTestFrame).
Полный код:
package uk.ac.cam.cdi.web;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.util.Dictionary;
import java.util.Hashtable;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.JTextField;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
/**
* @version 1.13 2007-06-12
* @author Cay Horstmann
*/
public class SliderTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
SliderTestFrame frame = new SliderTestFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
/**
* A frame with many sliders and a text field to show slider values.
*/
class SliderTestFrame extends JFrame
{
private JSlider slider1 = new JSlider();
private JSlider slider2 = new JSlider();
public SliderTestFrame()
{
setTitle("SliderTest");
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
sliderPanel = new JPanel();
sliderPanel.setLayout(new FlowLayout(FlowLayout.LEFT));
// common listener for all sliders
listener = new ChangeListener()
{
public void stateChanged(ChangeEvent event)
{
// update text field when the slider value changes
textField.setText("" + (slider1.getValue() + slider2.getValue()));
}
};
// add a slider with alphabetic labels
slider1 = new JSlider();
slider1.setInverted(true);
slider1.setPaintLabels(true);
slider1.setSnapToTicks(true);
slider1.setMajorTickSpacing(20);
slider1.setMinorTickSpacing(20);
Dictionary<Integer, Component> labelTable1 = new Hashtable<Integer, Component>();
labelTable1.put(0, new JLabel("F")); //This should have a value of 0
labelTable1.put(20, new JLabel("E")); //This should have a value of 1000
labelTable1.put(40, new JLabel("D")); //This should have a value of 1250
labelTable1.put(60, new JLabel("C")); //This should have a value of 1500
labelTable1.put(80, new JLabel("B")); //This should have a value of 1750
labelTable1.put(100, new JLabel("A")); //This should have a value of 2000
slider1.setLabelTable(labelTable1);
addSlider(slider1, "Swedish");
// add a slider with alphabetic labels
slider2 = new JSlider();
slider2.setInverted(true);
slider2.setPaintLabels(true);
slider2.setSnapToTicks(true);
slider2.setMajorTickSpacing(20);
slider2.setMinorTickSpacing(20);
Dictionary<Integer, Component> labelTable2 = new Hashtable<Integer, Component>();
labelTable2.put(0, new JLabel("F")); //This should have a value of 0
labelTable2.put(20, new JLabel("E")); //This should have a value of 1000
labelTable2.put(40, new JLabel("D")); //This should have a value of 1250
labelTable2.put(60, new JLabel("C")); //This should have a value of 1500
labelTable2.put(80, new JLabel("B")); //This should have a value of 1750
labelTable2.put(100, new JLabel("A")); //This should have a value of 2000
slider2.setLabelTable(labelTable2);
addSlider(slider2, "PE");
/* ...And about 20 other slides more with the same structure */
textField = new JTextField();
add(sliderPanel, BorderLayout.CENTER); // add the text field that displays the slider value
add(textField, BorderLayout.SOUTH);
}
/*
* Adds a slider to the slider panel and hooks up the listener
* @param s the slider
* @param description the slider description
*/
public void addSlider(JSlider s, String description)
{
s.addChangeListener(listener);
JPanel panel = new JPanel();
panel.add(s);
panel.add(new JLabel(description));
sliderPanel.add(panel);
}
public static final int DEFAULT_WIDTH = 350;
public static final int DEFAULT_HEIGHT = 450;
private JPanel sliderPanel;
private JTextField textField;
private ChangeListener listener;
}