Question

所以我想在这里实现的是，如果第一个单选按钮和第一个组合框中的第一个选项被选中，那么我想显示该类别下的食物，如果它是第一个单选按钮和第二个选项来自第一个组合框，然后是该类别下的其他一些食物。我让radiobutton部件工作正常，但无法随身携带下拉部件。行rb1.isSelected（）＆amp;＆amp; cmbItems [0] .isSelected（）给我错误。请帮我克服错误。这是我的代码：

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是一个字符串数组，所以很自然它不知道它是否被“选中”。你想问组合框本身选择的项目是什么，所以你应该说

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

将ActionListener添加到JRadioButton＆amp;的JComboBox

1 个答案: