如何将非最终变量传递给匿名内部类? [英] How can I pass a non final variable to an anonymous inner class?

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i传递给匿名内部类以用作SeatingID.你能建议这样做的方法吗?

I have these lines of code. I know you can not pass a non final variable to an inner class but I need to pass the variable i to the anonymous inner class to be used as a seatingID. Can you suggest ways of doing that ?

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);
        }
    });
}

推荐答案

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

The simple way is to create a local final variable and initialize it with the value of the loop variable; e.g.

    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);
            }
         });
    }

这篇关于如何将非最终变量传递给匿名内部类?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！