java - 将 JSliders 给出的两个数字相加

Question

假设我们想将用户用两个 JSlider 指定的两个数字 (0 <= n <= 20) 相加并打印出来。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存 0 (首先它们用 0 初始化)，代码如下:

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x,y 都为零时，您仅打印一次x+y，这是在您移动 slider 之前。 您可以在 Handler 或 Handler1 中添加 System.out.println(x + y);，然后如果您移动 slider ，它将显示总和。