將ActionListener添加到JRadioButton和JComboBox

Question

所以我要在這里實現的是，如果選擇了第一個組合框的第一個單選按鈕和第一個選項，那么我想顯示該類別下的食物，如果它是第一個組合框的第一個單選按鈕和第二個選項然后是該類別下的其他食物。 我的單選按鈕部分工作正常，但無法同時使用下拉部分。 行rb1.isSelected（）&& cmbItems [0] .isSelected（）給了我錯誤。 請幫助我克服錯誤。 這是我的代碼：

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class Tryout extends JFrame  implements ActionListener {

        private static final long serialVersionUID = 1L;

        private JTabbedPane tabbedPane = new JTabbedPane();
        private JPanel inputpanel;
        private JPanel searchpanel;
        public JButton submit;
        public JRadioButton rb1, rb2;
        public JComboBox <String> cmb;
        public String cmbItems [] ={"North Indian","South Indian","East Indian", "West Indian"};
        JFrame frame=new JFrame("Get selected JRadioButton");  

        public Tryout() {           
                inputpanel = createPage1();
                searchpanel = createPage2();
                tabbedPane.addTab("Input Form", inputpanel);
                tabbedPane.addTab("Search Form", searchpanel);
                this.add(tabbedPane, BorderLayout.CENTER);           
        }

        public JPanel createPage1() {           
            String cmbItems2 [] ={"European","Asian","American"};          
            JPanel panel = new JPanel();
            panel.setLayout(new GridBagLayout());
            GridBagConstraints c = new GridBagConstraints();
            //Column1
            c.anchor = GridBagConstraints.LINE_START;
            c.weightx = 0.5;
            c.weighty = 0.5;
            JLabel region = new JLabel("Enter Region");      
            c.gridx = 0;
            c.gridy = 0;
            panel.add(region, c);
            JLabel subregion = new JLabel("Enter Sub-Region");
            c.gridx = 0;
            c.gridy = 1;
            panel.add(subregion, c);
            //Column2
            c.anchor = GridBagConstraints.LINE_START;
            ButtonGroup bg = new ButtonGroup();
            rb1 = new JRadioButton("Indian"); 
            c.gridx = 1;
            c.gridy = 0;
            bg.add(rb1);
            panel.add(rb1, c);
            cmb = new JComboBox<String>(cmbItems);
            c.gridx = 1;
            c.gridy = 1;   
            panel.add(cmb, c);        
            //Column3
            c.anchor = GridBagConstraints.LINE_START;
            rb2 = new JRadioButton("International");
            c.gridx = 2;
            c.gridy = 0;           
            bg.add(rb2);
            panel.add(rb2, c);          
            JComboBox<String> cmb2 = new JComboBox<String>(cmbItems2);
            c.gridx = 2;
            c.gridy = 1;      
            cmb2.setEnabled(false);
            panel.add(cmb2, c); 
            submit = new JButton("Submit");
            c.weighty = 10;
            c.anchor = GridBagConstraints.FIRST_LINE_START;
            c.gridx = 1;
            c.gridy = 2;
            panel.add(submit, c);
            submit.addActionListener(this);           
            return panel;            
        }

        public void actionPerformed(ActionEvent e) {
            if(e.getSource()==submit) {
                if(rb1.isSelected() && cmbItems[0].isSelected()) {
                    JOptionPane.showMessageDialog(frame,"You select : "+rb1.getText());
                }
                else if(rb2.isSelected()) {
                    JOptionPane.showMessageDialog(frame,"You select : "+rb2.getText());
                }               
            }           
        }

        public JPanel createPage2() {           
                JPanel panel = new JPanel();
                panel.setLayout(new GridBagLayout());
                GridBagConstraints c = new GridBagConstraints();
                c.fill = GridBagConstraints.RELATIVE;
                JTextField field = new JTextField(20);
                panel.add(field);
                JButton search = new JButton("SEARCH");
                panel.add(search);
                return panel;
        }

        public static void main(String args[]) {
                SwingUtilities.invokeLater(new Runnable() {
                        @Override
                        public void run() {
                                Tryout ex = new Tryout();
                                ex.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                                ex.setSize(500,500);
                                ex.setVisible(true);
                        }
                });
        }       
}

Answer 1

cmbItems是一個字符串數組，因此自然不會對其是否被“選中”一無所知。 您想問問組合框本身，所選項目是什么，所以您應該說

if(rb1.isSelected() && cmb.getSelectedIndex() == 0) {
    JOptionPane.showMessageDialog(frame,"You select : "+rb1.getText());
}