java jlabel 单击/拖动

Question

当您单击并拖动它时，蓝色标签会移动。这可行，但 x/y 位置然后以一种有趣的方式跳跃。

代码如下:

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

@SuppressWarnings("serial")
public class test extends JFrame implements MouseListener, MouseMotionListener {

private JPanel panel = new JPanel(null);    
private JLabel label1 = new JLabel();
private JLabel label2 = new JLabel();
private int mouseX = 200;
private int mouseY = 100;
private boolean drag = false;

public test() {
    this.add(panel);
    panel.setBackground(Color.WHITE);

    panel.add(label1);
    label1.setOpaque(true); 
    label1.setBackground(Color.BLUE);
    label1.setBounds(mouseX, mouseY, 100, 50);
    label1.addMouseMotionListener(this);
    label1.addMouseListener(this);

    panel.add(label2);
    label2.setOpaque(true); 
    label2.setBackground(Color.RED);
    label2.setBounds(mouseX + 200, mouseY, 100, 50);
    label2.addMouseMotionListener(this);
    label2.addMouseListener(this);
}

@Override
public void mousePressed(MouseEvent e) {
    if (e.getSource() == label1) {
        drag = true;
    } 
}

@Override
public void mouseReleased(MouseEvent e) {
    drag = false;
}

@Override
public void mouseDragged(MouseEvent e) {
    if (drag == true) {
        mouseX = e.getX();
        mouseY = e.getY();
        label1.setBounds(mouseX, mouseY, 100, 50);
    }
}

public void mouseMoved(MouseEvent e) {}
public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mouseClicked(MouseEvent e) {}

public static void main(String[] args) {
    test frame = new test();
    frame.setVisible(true);
    frame.setSize(600, 400);
    frame.setResizable(false);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

Answer 1

只需将其放在您的 MouseDragged 方法中:

public void mouseDragged(MouseEvent e) 
{
    if (drag == true) 
    {
        JComponent jc = (JComponent)e.getSource();
        jc.setLocation(jc.getX()+e.getX(), jc.getY()+e.getY());
    }
}