如何将非最终变量传递给匿名内部类？

问题描述

| 我有这些代码行。我知道您不能将非最终变量传递给内部类，但是我需要将变量“ 0”传递给匿名内部类以用作SeatingID。你能建议这样做的方法吗？

JButton [] seats = new JButton [40]; //creating a pointer to the buttonsArray
for (int i = 0; i < 40; i++)
{
    seats[i] = new JButton();//creating the buttons
    seats[i].setPreferredSize(new Dimension(50,25));//button width
    panel4seating.add(seats[i]);//adding the buttons to the panels

    seats[i].addActionListener(new ActionListener()
    {  //anonymous inner class
        public void actionPerformed(ActionEvent evt)
        {  
            String firstName = (String)JOptionPane.showInputDialog(\"Enter First Name\");
            String lastName = (String)JOptionPane.showInputDialog(\"Enter Last Name\");

            sw101.AddPassenger(firstName,lastName,seatingID);
        }
    });
}

    

解决方法

        一种简单的方法是创建一个局部最终变量，并使用循环变量的值对其进行初始化。例如

    JButton [] seats = new JButton [40]; //creating a pointer to the buttonsArray
    for (int i = 0; i < 40; i++)
    {
        seats[i] = new JButton();//creating the buttons
        seats[i].setPreferredSize(new Dimension(50,25));//button width
        panel4seating.add(seats[i]);//adding the buttons to the panels
        final int ii = i;  // Create a local final variable ...
        seats[i].addActionListener(new ActionListener()
         {  //anonymous inner class
            public void actionPerformed(ActionEvent evt)
            {  
                String firstName = (String)JOptionPane.showInputDialog(\"Enter First Name\");
                String lastName = (String)JOptionPane.showInputDialog(\"Enter Last Name\");

                sw101.AddPassenger(firstName,lastName,ii);
            }
         });
    }

    ,        您不能直接这样做，但可以创建ActionListener的（静态私有）子类，该子类在其构造函数中采用了SeatingID。 然后，而不是

seats[i].addActionListener(new ActionListener() { ... });

你会

seats[i].addActionListener(new MySpecialActionListener(i));

[编辑]实际上，您的代码有很多其他错误，以至于我不确定该建议是否正确。如何展示将要编译的代码。