问题
I'm making a grapher by using eclipse and windowbuilder that gets an mathematical expression from the user(for example ADD(MUL(X,Y),Z) ) and at one point asks the user to designate one of its variables as time . then the user will be asked to choose the starting point and the range of that variable. then the program will show a frame (and a panel) that has a jslider and a play button .when the user clicks the button the program should start drawing the expression . It should look like a Gapminder chart .
I have checked other questions about updating jsliders but they are usually about a music player slider or a slider that just changes with time(without the graphing part).
my question is specifically about the updating of slider( the intervals can be 1 ) but it would be great if you could also guide how can I make that playable slider that it could also be used for the graphing part.
this the code so far:
package progGUI;
import java.awt.BorderLayout;
public class CanvasFrame extends JFrame {
private JPanel contentPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
CanvasFrame frame = new CanvasFrame();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public CanvasFrame() {
setTitle("Graph");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 700, 542);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
JSlider slider = new JSlider();
slider.setPaintLabels(true);
slider.setMinorTickSpacing(1);
slider.setMajorTickSpacing(5);
slider.setPaintTicks(true);
JLabel lblEnteredExpression = new JLabel("Entered Expression");
JLabel lblVaraibles = new JLabel("Variables");
JFormattedTextField formattedTextField = new JFormattedTextField();
JFormattedTextField formattedTextField_1 = new JFormattedTextField();
JPanel panel = new JPanel();
panel.setBackground(Color.WHITE);
JButton btnNewButton = new JButton("Play");
GroupLayout gl_contentPane = new GroupLayout(contentPane);
gl_contentPane.setHorizontalGroup(
gl_contentPane.createParallelGroup(Alignment.LEADING)
.addGroup(gl_contentPane.createSequentialGroup()
.addContainerGap()
.addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
.addGroup(gl_contentPane.createSequentialGroup()
.addComponent(panel, GroupLayout.PREFERRED_SIZE, 453, GroupLayout.PREFERRED_SIZE)
.addPreferredGap(ComponentPlacement.RELATED, 51, Short.MAX_VALUE)
.addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
.addComponent(lblEnteredExpression, Alignment.TRAILING)
.addComponent(lblVaraibles)
.addComponent(formattedTextField, GroupLayout.PREFERRED_SIZE, 119, GroupLayout.PREFERRED_SIZE)
.addComponent(formattedTextField_1, GroupLayout.PREFERRED_SIZE, 123, GroupLayout.PREFERRED_SIZE))
.addGap(57))
.addGroup(gl_contentPane.createSequentialGroup()
.addComponent(btnNewButton, GroupLayout.PREFERRED_SIZE, 87, GroupLayout.PREFERRED_SIZE)
.addPreferredGap(ComponentPlacement.RELATED)
.addComponent(slider, GroupLayout.PREFERRED_SIZE, 454, GroupLayout.PREFERRED_SIZE)
.addContainerGap())))
);
gl_contentPane.setVerticalGroup(
gl_contentPane.createParallelGroup(Alignment.TRAILING)
.addGroup(gl_contentPane.createSequentialGroup()
.addGap(18)
.addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
.addGroup(gl_contentPane.createSequentialGroup()
.addComponent(lblEnteredExpression)
.addPreferredGap(ComponentPlacement.RELATED)
.addComponent(formattedTextField_1, GroupLayout.PREFERRED_SIZE, 22, GroupLayout.PREFERRED_SIZE)
.addPreferredGap(ComponentPlacement.UNRELATED)
.addComponent(lblVaraibles)
.addPreferredGap(ComponentPlacement.RELATED)
.addComponent(formattedTextField, GroupLayout.PREFERRED_SIZE, 20, GroupLayout.PREFERRED_SIZE))
.addComponent(panel, GroupLayout.PREFERRED_SIZE, 350, GroupLayout.PREFERRED_SIZE))
.addGroup(gl_contentPane.createParallelGroup(Alignment.LEADING)
.addGroup(gl_contentPane.createSequentialGroup()
.addGap(31)
.addComponent(btnNewButton))
.addGroup(gl_contentPane.createSequentialGroup()
.addGap(18)
.addComponent(slider, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)))
.addGap(402))
);
contentPane.setLayout(gl_contentPane);
}
}
回答1:
User a javax.swing.Timer to schedule a periodical call back, which updates the JSlider's value. Use a ChangeListener attached to the JSlider to drive the graph, for example...
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.JTextField;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private Timer timer;
private JSlider slider;
private JButton button;
private JTextField field;
public TestPane() {
slider = new JSlider();
field = new JTextField(4);
button = new JButton(">");
add(slider);
add(button);
add(field);
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
field.setText(Integer.toString(slider.getValue()));
}
});
slider.setValue(0);
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if (timer.isRunning()) {
stopTheClock();
} else {
startTheClock();
}
}
});
timer = new Timer(500, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
int value = slider.getValue() + 1;
if (value >= slider.getMaximum()) {
stopTheClock();
} else {
slider.setValue(value);
}
}
});
}
protected void startTheClock() {
slider.setValue(0);
timer.start();
button.setText("[]");
}
protected void stopTheClock() {
timer.stop();
button.setText(">");
}
}
}
See How to use Swing Timers and How to Use Sliders for more details
来源：https://stackoverflow.com/questions/28472409/making-a-playable-jslider-in-java