将 JSliders 给出的两个数字相加

Question

假设我们要将用户指定的两个数字 (0 <= n <= 20) 添加到两个 JSlider 中并打印出来。问题是当我将 JSliders 的值分配给 x 和 y 变量时，它们只是不保存新值并保持 0（起初它们用 0 初始化），这里是代码：

import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import java.awt.*;

public class GUIJframe extends JFrame {

    private JPanel jp1 = new JPanel();
    private JTextField jtf = new JTextField();
    private JTextField jtf2 = new JTextField();
    private JSlider js1 = new JSlider(0,20);
    private JSlider js2 = new JSlider(0,20);
    private int x = 0;
    private int y = 0;

    public GUIJframe () {

        setSize(400,400);
        setLocation(200,200);
        setLayout(new GridLayout(5,1));
        add(js1);
        add(jtf);
        add(js2);
        add(jtf2);
        Handler h = new Handler();
        Handler2 h2 = new Handler2();
        js1.addChangeListener(h);
        js2.addChangeListener(h2);
        setVisible(true);
        System.out.println(x + y);

    }

    private class Handler implements ChangeListener {
        @Override
        public void stateChanged(ChangeEvent e) {
            JSlider js = (JSlider) e.getSource();

            jtf.setText( "" + js.getValue() );
            x = js.getValue();
        }
    }
    private class Handler2 implements ChangeListener {
        @Override
        public void stateChanged(ChangeEvent e) {
            JSlider js = (JSlider) e.getSource();

            jtf2.setText( "" + js.getValue() );
            y = js.getValue();
        }
    }
}

Answer 1

当两个 x,y 都为零时，您只打印一次 x+y，甚至在您移动滑块之前。您可以在 Handler 或 Handler1 中添加 System.out.println(x + y); 然后如果您移动滑块它将显示总和。

Answer 2

如果您想在移动 JSlider 时打印 x 和 y 的总和，请移动您的 System.out.println(x+y);

进入更改侦听器方法

下面是代码：-

import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import java.awt.*;

public class GUIJframe extends JFrame {

    private JPanel jp1 = new JPanel();
    private JTextField jtf = new JTextField();
    private JTextField jtf2 = new JTextField();
    private JSlider js1 = new JSlider(0,20);
    private JSlider js2 = new JSlider(0,20);
    private int x = 0;
    private int y = 0;

    public GUIJframe () {

        setSize(400,400);
        setLocation(200,200);
        setLayout(new GridLayout(5,1));
        add(js1);
        add(jtf);
        add(js2);
        add(jtf2);
        Handler h = new Handler();
        Handler2 h2 = new Handler2();
        js1.addChangeListener(h);
        js2.addChangeListener(h2);
        setVisible(true);
        //dont use print statement here

    }

    private class Handler implements ChangeListener {
        @Override
        public void stateChanged(ChangeEvent e) {
            JSlider js = (JSlider) e.getSource();

            jtf.setText( "" + js.getValue() );
            x = js.getValue();
            System.out.println(x + y);//use it here
        }
    }
    private class Handler2 implements ChangeListener {
        @Override
        public void stateChanged(ChangeEvent e) {
            JSlider js = (JSlider) e.getSource();

            jtf2.setText( "" + js.getValue() );
            y = js.getValue();
            System.out.println(x + y);//and here also
        }
    }
}

将 JSliders 给出的两个数字相加

adding two numbers given by JSliders

java

add

jslider