动作侦听器无法处理按钮，除非我右键单击它

Question

我有一个我无法解决的问题。 按钮 B1 和 B2 完美运行，但是当我尝试在 B3 上实现操作侦听器时（与我添加到按钮 1 和 2 的方式完全相同），它不起作用。我被难住了。我从字面上复制并粘贴了我为 b1 实现 b2 和 b3 的方式，但它不起作用！！这很奇怪，因为它只有在我单击 B3 然后右键单击它时才有效，但我应该单击 B3（命名边缘）并在任何地方左键单击以使消息出现。

B1 将出现

一个矩形，B2 将出现椭圆，右键单击形状将删除它。

   import java.awt.BorderLayout;
   import java.awt.Color;
   import java.awt.Graphics;
   import java.awt.Graphics2D;
   import java.awt.GridBagConstraints;
   import java.awt.GridBagLayout;
   import java.awt.Insets;
   import java.awt.Rectangle;
   import java.awt.Shape;
   import java.awt.event.ActionEvent;
   import java.awt.event.ActionListener;
   import java.awt.event.MouseEvent;
   import java.awt.event.MouseListener;
   import java.awt.geom.Ellipse2D;
   import java.awt.geom.Line2D;
   import java.awt.geom.Point2D;
   import java.util.ArrayList;
   import javax.swing.JButton;
   import javax.swing.JFrame;
   import javax.swing.JOptionPane;
   import javax.swing.JPanel;
   import javax.swing.JTextField;
   import javax.swing.SwingUtilities;
    public class Tutorial extends JPanel
{
    /**
 * 
 */
private static final long serialVersionUID = 1L;
    public static void storeShape(Shape shape){
        shapes.add(shape);
    }
    public static void removeShape(int index){
        shapes.remove(index);
    }
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g; 
        if(shape != null) 
    for ( Shape shape1 : shapes){
        g2.draw(shape1);
    }
    }
     private static ArrayList<Shape> shapes = new ArrayList<Shape>();
     private Object lastbuttonpressed;
     static Shape shape;
    public static void main (String[] args){
        Tutorial t = new Tutorial();
        JFrame f = new JFrame();
        f.setTitle("Tutorial");
        f.setSize(600, 400);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(t);
        JPanel p = new JPanel(new GridBagLayout());

        JButton b1 = new JButton("Rectangle");
        JButton b2 = new JButton("Ellipse");
        JButton b3 = new JButton("Edge");
        JButton b4 = new JButton("Label");
        GridBagConstraints gbc2 = new GridBagConstraints();
        gbc2.insets = new Insets(5,5,5,5);
        gbc2.gridx = 0;
        gbc2.gridy = 0;
        p.add(b1,gbc2);
        gbc2.gridx = 1;
        gbc2.gridy = 0;
        p.add(b2,gbc2) ;
        gbc2.gridx = 2;
        gbc2.gridy = 0;
        p.add(b3,gbc2);
        gbc2.gridx = 0;
        gbc2.gridy = 1;
        p.add(b4,gbc2);
        f.add(p, BorderLayout.NORTH);
        JTextField textField = new JTextField(" text field");
        gbc2.gridx = 1;
        gbc2.gridy = 1;
        p.add(textField, gbc2);

        b1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                t.lastbuttonpressed = e.getSource();
            }
        });
        b2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                t.lastbuttonpressed = e.getSource();
            }
        });
        b3.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                t.lastbuttonpressed = e.getSource();
            }
        });
        f.addMouseListener(new MouseListener() {
            @Override
            public void mouseReleased(MouseEvent e) {
                // TODO Auto-generated method stub
            }
            @Override
            public void mousePressed(MouseEvent e) {
                if (SwingUtilities.isLeftMouseButton(e)){
                if (t.lastbuttonpressed == b1){

                    shape = new Rectangle(e.getX()-50,e.getY()-120,100,50);
                    storeShape(shape);
                    t.repaint();
                }
                else if ( t.lastbuttonpressed == b2){
                    shape = new Ellipse2D.Double(e.getX()-50,e.getY()-120,100,50);  
                    storeShape(shape);
                    t.repaint();
                }
            }
                else if (t.lastbuttonpressed == b3){
                    JOptionPane.showMessageDialog(null, "button 3");
                    t.repaint();
                }
                else if (SwingUtilities.isRightMouseButton(e)){
                    for (int i=0; i<shapes.size(); i++){
                    if (shapes.get(i).contains(e.getX()-50,e.getY()-100)){
                shapes.remove(i);
                t.repaint();
                    }
            }
                }
            }
            @Override
            public void mouseExited(MouseEvent e) {
                // TODO Auto-generated method stub
            }
            @Override
            public void mouseEntered(MouseEvent e) {
                // TODO Auto-generated method stub  
            }
            @Override
            public void mouseClicked(MouseEvent e) {

            }
        });
        f.setVisible(true);
    }

}

Answer 1

您的格式有点偏离，很难阅读。看起来您正在检查正在按下的 b3：

否则如果（t.lastbutton按下== b3）{

在此之外，如果检查：

if （SwingUtilities.isLeftMouseButton（e））{