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如何防止将 JLabel 拖到 JDesktopPane 边界之外？

我做过一个应用，里面有一个JLabel放在JDesktopPane里面，JLabel可以拖到任何地方，但是拖的时候问题是JLabel可以拖到JDesktopPane的边界外吗？谁能告诉我如何防止这种情况？

并且

在应用程序中，任何人都可以告诉我如何通过双击来编辑 JLabel 文本值。目前我已经通过JOptionPane.showInputDialog()完成了，我们可以通过双击来编辑 JLabel 的文本并以任何其他方式编辑它而不是使用JOptionPane.showInputDialog

我的代码是这个

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

public class Testing extends javax.swing.JFrame {
private int clicX = 0,clicX1 = 0;
private int clicY = 0,clicY1 = 0;
private boolean drag = false,drag1 = false;

    public Testing() {
        initComponents();
        headlabel.setVisible(false);
        footlabel.setVisible(false);
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">

//自动生成的代码

    private void initComponents() {
            head = new javax.swing.JCheckBox();
            jDesktopPane1 = new javax.swing.JDesktopPane();
            headlabel = new javax.swing.JLabel();
            footlabel = new javax.swing.JLabel();
            foot = new javax.swing.JCheckBox();
            setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
            head.setText("Head");
            head.addActionListener(new java.awt.event.ActionListener() {
                public void actionPerformed(java.awt.event.ActionEvent evt) {
                    headActionPerformed(evt);
                }
            });       jDesktopPane1.setBackground(javax.swing.UIManager.getDefaults().getColor("Button.background"));
            headlabel.setBackground(new java.awt.Color(255, 255, 255));
            headlabel.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
            headlabel.setForeground(new java.awt.Color(255, 255, 255));
            headlabel.setText("Heading");
            headlabel.addMouseListener(new java.awt.event.MouseAdapter() {
                public void mouseClicked(java.awt.event.MouseEvent evt) {
                    headlabelMouseClicked(evt);
                }
                public void mousePressed(java.awt.event.MouseEvent evt) {
                    headlabelMousePressed(evt);
                }
                public void mouseReleased(java.awt.event.MouseEvent evt) {
                    headlabelMouseReleased(evt);
                }
            });
            headlabel.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
                public void mouseDragged(java.awt.event.MouseEvent evt) {
                    headlabelMouseDragged(evt);
                }
            });
            headlabel.setBounds(80, 20, 100, 20);
            jDesktopPane1.add(headlabel, javax.swing.JLayeredPane.DEFAULT_LAYER);

            footlabel.setBackground(new java.awt.Color(255, 255, 255));
            footlabel.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
            footlabel.setForeground(new java.awt.Color(255, 255, 255));
            footlabel.setText("Foot");
            footlabel.addMouseListener(new java.awt.event.MouseAdapter() {
                public void mouseClicked(java.awt.event.MouseEvent evt) {
                    footlabelMouseClicked(evt);
                }
                public void mousePressed(java.awt.event.MouseEvent evt) {
                    footlabelMousePressed(evt);
                }
                public void mouseReleased(java.awt.event.MouseEvent evt) {
                    footlabelMouseReleased(evt);
                }
            });
            footlabel.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
                public void mouseDragged(java.awt.event.MouseEvent evt) {
                    footlabelMouseDragged(evt);
                }
            });
            footlabel.setBounds(100, 280, 100, 20);
            jDesktopPane1.add(footlabel, javax.swing.JLayeredPane.DEFAULT_LAYER);

            foot.setText("Foot");
            foot.addActionListener(new java.awt.event.ActionListener() {
                public void actionPerformed(java.awt.event.ActionEvent evt) {
                    footActionPerformed(evt);
                }
            });

            javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
            getContentPane().setLayout(layout);
            layout.setHorizontalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                    .addContainerGap()
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addComponent(head, javax.swing.GroupLayout.PREFERRED_SIZE, 81, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addComponent(foot, javax.swing.GroupLayout.PREFERRED_SIZE, 81, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 52, Short.MAX_VALUE)
                    .addComponent(jDesktopPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 264, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap())
            );
            layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                            .addComponent(jDesktopPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 305, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGroup(layout.createSequentialGroup()
                            .addGap(52, 52, 52)
                            .addComponent(head)
                            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                            .addComponent(foot)
                            .addGap(0, 0, Short.MAX_VALUE)))
                    .addContainerGap())
            );

            pack();
}// </editor-fold>

// 函数定义

 private void headlabelMouseClicked(java.awt.event.MouseEvent evt) {                                       
            if (evt.getClickCount() == 2) {
            String str = JOptionPane.showInputDialog(null, "Enter text : ", "Enter text", 1);


             Point location = headlabel.getLocation();

             headlabel.setLocation(location);
             headlabel.setText(str);
            }

    }                                      



    private void headlabelMouseReleased(java.awt.event.MouseEvent evt) {                                        
                // drag = false;
    }                                       


    private void headlabelMousePressed(java.awt.event.MouseEvent evt) {                                       
                drag = true;
                if (evt.getSource() == headlabel) {
                }
                if (evt.getSource() == headlabel) {
                clicX = evt.getX();
                clicY = evt.getY();
                }
    }                                      


    private void headlabelMouseDragged(java.awt.event.MouseEvent evt) {                                       
                if (evt.getSource() == headlabel) {

                javax.swing.JComponent jc = (javax.swing.JComponent)evt.getSource();
                jc.setLocation(jc.getX()+evt.getX()-clicX, jc.getY()+evt.getY()-clicY);

                }
    }                                      


    private void headActionPerformed(java.awt.event.ActionEvent evt) {                                     
             if (head.isSelected()) {
                    headlabel.setVisible(true);
                } else {
                    headlabel.setVisible(false);
                }
    }                                    


    private void footlabelMouseClicked(java.awt.event.MouseEvent evt) {                                       
               if (evt.getClickCount() == 2) {
            String str = JOptionPane.showInputDialog(null, "Enter text : ", "Enter text", 1);


             Point location = footlabel.getLocation();

             footlabel.setLocation(location);
             footlabel.setText(str);
            }
    }                                      


    private void footlabelMousePressed(java.awt.event.MouseEvent evt) {                                       
                 drag1 = true;
                if (evt.getSource() == footlabel) {
                }
                if (evt.getSource() == footlabel) {
                clicX1 = evt.getX();
                clicY1 = evt.getY();
                }
    }                                      


    private void footlabelMouseReleased(java.awt.event.MouseEvent evt) {                                        
                // TODO add your handling code here:
    }                                       


    private void footlabelMouseDragged(java.awt.event.MouseEvent evt) {                                       
               if (evt.getSource() == footlabel) {

                javax.swing.JComponent jc = (javax.swing.JComponent)evt.getSource();
                jc.setLocation(jc.getX()+evt.getX()-clicX1, jc.getY()+evt.getY()-clicY1);
                }
    }                                      


    private void footActionPerformed(java.awt.event.ActionEvent evt) {                                     
               if (foot.isSelected()) {
                    footlabel.setVisible(true);
                } else {
                    footlabel.setVisible(false);
                }
    }                                    


    public static void main(String args[]) 
    {
                try {
                    for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                        if ("Nimbus".equals(info.getName())) {
                            javax.swing.UIManager.setLookAndFeel(info.getClassName());
                            break;
                        }
                    }
                } catch (ClassNotFoundException ex) {
                    java.util.logging.Logger.getLogger(Testing.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
                } catch (InstantiationException ex) {
                    java.util.logging.Logger.getLogger(Testing.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
                } catch (IllegalAccessException ex) {
                    java.util.logging.Logger.getLogger(Testing.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
                } catch (javax.swing.UnsupportedLookAndFeelException ex) {
                    java.util.logging.Logger.getLogger(Testing.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
                }

                java.awt.EventQueue.invokeLater(new Runnable() {

                    public void run() {
                        new Testing().setVisible(true);
                    }
                });
            }
            // Variables declaration - do not modify
            private javax.swing.JCheckBox foot;
            private javax.swing.JLabel footlabel;
            private javax.swing.JCheckBox head;
            private javax.swing.JLabel headlabel;
            private javax.swing.JDesktopPane jDesktopPane1;
            // End of variables declaration
        }
4

1 回答 1

2

基本思想是防止组件超出其父边界。因此，在更改标签位置时，在鼠标侦听器/拖动器中，您应该验证标签的边界是否保持在标签父级的边界内。如果不是，那么您应该“修复”边界，以便标签保持在其父组件的边界内。

这是一个示例（它不使用 JDesktopPane，但解决方案应该类似）。它缺少一些小的调整，但基本上效果很好：

import java.awt.Component;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;

public class TestLimitedDrag {

    public static class MouseDragger extends MouseAdapter {
        private Point startPoint;
        private Component draggedObject;

        @Override
        public void mousePressed(MouseEvent e) {
            draggedObject = (Component) e.getSource();
            startPoint = SwingUtilities.convertPoint(draggedObject, e.getPoint(), draggedObject.getParent());
        }

        @Override
        public void mouseDragged(MouseEvent e) {
            Point location = SwingUtilities.convertPoint(draggedObject, e.getPoint(), draggedObject.getParent());
            if (draggedObject.getParent().getBounds().contains(location)) {
                Point newLocation = draggedObject.getLocation();
                newLocation.translate(location.x - startPoint.x, location.y - startPoint.y);
                newLocation.x = Math.max(newLocation.x, 0);
                newLocation.x = Math.min(newLocation.x, draggedObject.getParent().getWidth() - draggedObject.getWidth());
                newLocation.y = Math.max(newLocation.y, 0);
                newLocation.y = Math.min(newLocation.y, draggedObject.getParent().getHeight() - draggedObject.getHeight());
                draggedObject.setLocation(newLocation);
                startPoint = location;
            }
        }

        @Override
        public void mouseReleased(MouseEvent e) {
            startPoint = null;
            draggedObject = null;
        }

        public void makeDraggable(Component component) {
            component.addMouseListener(this);
            component.addMouseMotionListener(this);
        }

    }

    private void initUI() {
        JFrame frame = new JFrame(TestLimitedDrag.class.getSimpleName());
        frame.setLayout(null);
        MouseDragger dragger = new MouseDragger();
        JLabel labelToDrag = new JLabel("Drag me");
        dragger.makeDraggable(labelToDrag);
        frame.add(labelToDrag);
        labelToDrag.setSize(labelToDrag.getPreferredSize());
        labelToDrag.setLocation(50, 50);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 300);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new TestLimitedDrag().initUI();
            }
        });
    }

}
于 2012-11-16T09:39:25.000 回答