Button和JSlider僅在我懸停螢屏時出現

有人可以幫助指導我的錯誤在哪里嗎？當我將滑鼠懸停時，按鈕和 JSlider 會出現，這讓我很緊張。當我使用按鈕時很好，但是一旦我添加一個按鈕，JSlider 就會丟失并在我懸停并單擊時出現。

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.ArrayList;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.*;

public class MainDisplay extends JFrame implements MouseMotionListener, 
        MouseListener, ChangeListener, ActionListener{
    
    private Point mousepnt = new Point();
    public static Color penColor = new Color(255,105,180);
    private final JSlider penSize = new JSlider(JSlider.HORIZONTAL, 1, 30, 4);
    public static int pen = 4;
    JButton rbutton = new JButton();
    JButton cbutton = new JButton();
    JButton tbutton = new JButton();
    JButton qbutton = new JButton();
    ImageIcon ricon = new ImageIcon(getClass().getResource("ricon.png"));
    ImageIcon cicon = new ImageIcon(getClass().getResource("cicon.png"));
    ImageIcon ticon = new ImageIcon(getClass().getResource("ticon.png"));
    ImageIcon qicon = new ImageIcon(getClass().getResource("qicon.png"));

    public MainDisplay(){ 
        JPanel toolbar = new JPanel(new FlowLayout(FlowLayout.LEFT));
        JPanel toolbar2 = new JPanel(new FlowLayout(FlowLayout.LEFT));
    JPanel jp = new JPanel();
        jp.addMouseMotionListener(this);
        jp.addMouseListener(this);
        toolbar.add(new Label("Drag mouse to draw"));
        toolbar.add(penSize);
        penSize.addChangeListener(this);
        toolbar2.add(new Label("Choose shape to draw"));
        rbutton = new JButton(ricon);
        rbutton.addActionListener(this);
        rbutton.setMargin(new Insets(1, 2, 1, 2));
        toolbar2.add(rbutton);
        cbutton = new JButton(cicon);
        cbutton.addActionListener(this);
        cbutton.setMargin(new Insets(1, 2, 1, 2));
        toolbar2.add(cbutton);
        tbutton = new JButton(ticon);
        tbutton.addActionListener(this);
        tbutton.setMargin(new Insets(1, 2, 1, 2));
        toolbar2.add(tbutton);
        qbutton = new JButton(qicon);
        qbutton.addActionListener(this);
        qbutton.setMargin(new Insets(1, 2, 1, 2));
        toolbar2.add(qbutton);
    this.add(toolbar,BorderLayout.SOUTH);
        this.add(toolbar2,BorderLayout.NORTH);
        this.add(jp,BorderLayout.CENTER);
        setSize(800,600);
    setVisible(true);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

主班

public class Main {
    public static void main(String[] args){
    MainDisplay md = new MainDisplay();
    }
}

uj5u.com熱心網友回復：

我會做什么：

將 MouseMotionListener 添加到面板：

jp.addMouseMotionListener(new MouseMotionListener() {
            @Override
            public void mouseDragged(MouseEvent e) {
                
            }

            @Override
            public void mouseMoved(MouseEvent e) {
                System.out.println("motion"   e.getPoint());
            }
    });

將 ChangeListener 添加到 penSize：

penSize.addChangeListener(new ChangeListener() {
            @Override
            public void stateChanged(ChangeEvent e) {
                System.out.println("new pensize: "   penSize.getValue());
            }
    });

等等。因此，您已將 lsiteners 添加到組件而不是框架中。

我希望現在對你有所幫助。如果您有任何問題，請發布 Andrew 所寫的最小可重現示例。

斯蒂菲

標籤：爪哇 摇摆 awt

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