import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class Main {
public static void main(String[] args) {
final JFrame frame = new JFrame();
final JTextField text = new JTextField(20);
final JSlider slider = new JSlider(0, 100, 0);
slider.addchangelistener(new changelistener(){
@Override
public void stateChanged(ChangeEvent e) {
text.setText(String.valueOf(slider.getValue()));
}
});
text.addKeyListener(new KeyAdapter(){
@Override
public void keyReleased(KeyEvent ke) {
String typed = text.getText();
slider.setValue(0);
if(!typed.matches("\\d+") || typed.length() > 3) {
return;
}
int value = Integer.parseInt(typed);
slider.setValue(value);
}
});
frame.setLayout(new BorderLayout());
frame.add(text, BorderLayout.NORTH);
frame.add(slider, BorderLayout.CENTER);
frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.pack();
}
}
如果要使用浮点数（如标题所示），则可以像下面这样扩展JSlider类：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.text.DecimalFormat;
public class Main {
public static void main(String[] args) {
final DecimalFormat df = new DecimalFormat("0.####");
final JFrame frame = new JFrame();
final JTextField text = new JTextField(20);
final DoubleJSlider slider = new DoubleJSlider(0, 100, 0, 1000);
slider.addchangelistener(new changelistener(){
@Override
public void stateChanged(ChangeEvent e) {
text.setText(df.format(slider.getScaledValue()));
}
});
text.addKeyListener(new KeyAdapter(){
@Override
public void keyReleased(KeyEvent ke) {
String typed = text.getText();
slider.setValue(0);
if(!typed.matches("\\d+(\\.\\d*)?")) {
return;
}
double value = Double.parseDouble(typed)*slider.scale;
slider.setValue((int)value);
}
});
frame.setLayout(new BorderLayout());
frame.add(text, BorderLayout.NORTH);
frame.add(slider, BorderLayout.CENTER);
frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.pack();
}
}
class DoubleJSlider extends JSlider {
final int scale;
public DoubleJSlider(int min, int max, int value, int scale) {
super(min, max, value);
this.scale = scale;
}
public double getScaledValue() {
return ((double)super.getValue()) / this.scale;
}
}
上面的示例表示100步在0到0.1之间的间隔。
602392714
清零编程群