Java：链接 JSlider 和 JTextfield 以获得浮点值
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/1548606/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Java: link JSlider and JTextfield for float value
提问by clamp
what is the best and easiest way to link a JSlider and a JTextField so that if one changes, the other gets updated too, but there is no recursive loop?
链接 JSlider 和 JTextField 的最佳和最简单的方法是什么，以便如果一个更改，另一个也会更新，但没有递归循环？
thanks!
谢谢！
回答by Bart Kiers
Here's a quick and dirty demo:
这是一个快速而肮脏的演示：
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();
}
}
EDIT
编辑
And if you want to use floats (as the title suggests), you could extends the JSlider class like this:
如果你想使用浮点数（正如标题所暗示的那样），你可以像这样扩展 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;
}
}
The example above denotes the interval between 0 and 0.1 in 100 steps.
上面的例子表示 0 到 0.1 之间的间隔，以 100 步为单位。
This (again) is just a quick and dirty example, but might help you on your way.
这（再次）只是一个快速而肮脏的例子，但可能会对您有所帮助。
