从JComboBox获取值时出错

Question

I created a JComboBox and I want to get the value from it. Here is the code that I wrote:

        final JComboBox jc = new JComboBox();
        jc.addItem("ARR");
        jc.addItem("SRR");

        myPanel.add(jc, gbc);
        String pat_order;

        jc.addItemListener(new ItemListener() {
            public void itemStateChanged(ItemEvent ie) {
                String order = (String) jc.getSelectedItem();
                pat_order = order;
            }
        });

and the problem is that I got an error: "local variable pat_order is accessed from whitin inner class; needs to be declared final" and when I put final in pat_order declaration, get another error: "cannot assign a value to a final variable pat_order". Sorry I'm totally beginner in Java GUI. Thanks in advance.

Answer 1

Here is your program, it is working fine, I don know why are you getting the error, even after you made the pat_Order final(Private) , I am just using the static method for pat_Order. To show that, you have selected things from the combo box, I added, dialogbox , which shows the thing, that you selected ,,. :) if you have any further question, about my program, feel free to ask me, import java.awt.event.ItemListener;

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;


public class comboBoxProblem  extends JFrame{

static JPanel myPanel  = new JPanel();
static String pat_order;
public static void main(String [] args)
    {
        new comboBoxProblem().show(); 

    }
public comboBoxProblem()
    {
        setTitle("Combo");
        setResizable(false);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        getContentPane().setLayout(new GridBagLayout());


        GridBagConstraints gbc = new GridBagConstraints();
        myPanel.setLayout(new GridBagLayout());
        myPanel.setBorder(BorderFactory.createTitledBorder("Button's"));

        final JComboBox jc = new JComboBox(); 
        jc.addItem("ARR");
        jc.addItem("SRR");

        gbc.gridx = 0;
        gbc.gridy = 1;
        jc.addItemListener(new ItemListener() 
            {
                public void itemStateChanged(ItemEvent ie)
                    {
                        String order = (String) jc.getSelectedItem();
                        pat_order = order;
                        JOptionPane.showConfirmDialog(null, pat_order, " Message Dialog Box", JOptionPane.DEFAULT_OPTION    );
                    }
            });

        myPanel.add(jc, gbc);


        gbc.gridx = 1;
        gbc.gridy = 0;

        getContentPane().add(myPanel, gbc);



pack();
 } 

 }