Question

我有两个JFrame，第一个用于使用JTable显示SQL表，第二个用于更新SQL表上的数据。在第一帧，有一个用于显示第二帧的按钮，它有单选按钮。但是，我无法将其设置为true。我想要发生的是根据我从Label中获得的值来将单选按钮设置为true，其中Label的值来自数据库。这就是我所做的：

第一个JFRAME：

private void btnUpdateActionPerformed(java.awt.event.ActionEvent evt) {
 String hours = null;
  try
    {
        DbUpdate up = new DbUpdate();

        // To connect on SQL and get the JTable's value
        int get = (int)jTable2.getModel().getValueAt(jTable2.getSelectedRow(), 0);
        String query= "SELECT * FROM roominfo WHERE CustomerNo = '"+get+"' " ;

        String url = "jdbc:mysql://localhost:3306/adve"; 
        Connection conn = DriverManager.getConnection(url,"root","sa"); 
        Statement st = conn.createStatement();
        rs = st.executeQuery(query);

        while(rs.next())
        {
        hours= rs.getString("Hours"); // This is where I can get the value for hours and to be passed on a label
        }
         up.jLabel12.setText(hours); //I set on a Jlabel for the next frame
        }
        catch(SQLException e){
    JOptionPane.showMessageDialog(null, "Please select a record to update");
    }

}

第二个JFRAME：

  public void set(){ //THIS SUPPOSE TO SET THE BUTTONS BASED ON THE VALUE OF THE LABEL
if (jLabel12.getText().equals("12-Hours")) { // if 12-Hours, Rdn12 should be true or selected
   Rdn12.isSelected();
   Rdn12.setSelected(true);
   Rdn24.setSelected(false);
 }
 else if (jLabel12.getText().equals("24-Hours")) { // if 24-Hours, Rdn24 should be true or selected
   Rdn12.setSelected(false);
   Rdn24.setSelected(true);
 }    
  jTextField1.setEditable(false);
  jLabel20.setVisible(false);

}

但是，仍然无法选择单选按钮。我究竟做错了什么？有什么建议？请帮忙。

Answer 1

更新：我不知道，我是否完全明白你的问题。这个应用程序是你想要的吗？

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.ListSelectionModel;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.table.DefaultTableModel;

public class DatabaseRadioButtons extends JFrame {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new DatabaseRadioButtons().setVisible(true);
            }
        });
    }

    JTable table = new JTable();
    JButton showSecondFrame = new JButton("Show second frame");
    SecondFrame secondFrame = new SecondFrame();

    public DatabaseRadioButtons() {

        table.setModel(new DefaultTableModel(new Object[][] {
                new Object[] { "first", "entry" },
                new Object[] { "second", "entry" } }, new Object[] { "column",
                "names" }));
        ListSelectionModel selectionModel = table.getSelectionModel();
        selectionModel.addListSelectionListener(new ListSelectionListener() {

            @Override
            public void valueChanged(ListSelectionEvent e) {
                if (e.getValueIsAdjusting())
                    return; // ignore this event, if we expect another event
                            // right after this one

                int selectedRow = table.getSelectedRow();
                refreshRadioButtonsAccordingToDatabaseValues(selectedRow);
            }
        });

        showSecondFrame.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                SwingUtilities.invokeLater(new Runnable() {

                    @Override
                    public void run() {
                        secondFrame.setVisible(true);
                    }
                });
            }
        });

        JPanel panel = new JPanel(new BorderLayout());
        panel.add(new JScrollPane(table), BorderLayout.CENTER);
        panel.add(showSecondFrame, BorderLayout.SOUTH);
        setContentPane(panel);
        setSize(400, 300);
        setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);

    }

    protected void refreshRadioButtonsAccordingToDatabaseValues(int selectedRow) {

        String databaseValue;

        // put you database SELECT here, instead of this fixed value
        System.out.println("Make Database select for row " + selectedRow);
        databaseValue = selectedRow == 0 ? "12-Hours" : "24-Hours";

        // Choose what to do, according to database values
        if (databaseValue.equals("12-Hours")) {

            // you can change the fields of the second frame directly in here
            secondFrame.Rdn12.isSelected();
            secondFrame.Rdn12.setSelected(true);
            secondFrame.Rdn24.setSelected(false);
        } else if (databaseValue.equals("24-Hours")) {
            secondFrame.Rdn12.setSelected(false);
            secondFrame.Rdn24.setSelected(true);
        }
    }

}

class SecondFrame extends JFrame {

    JRadioButton Rdn12 = new JRadioButton("Radio 12");
    JRadioButton Rdn24 = new JRadioButton("Radio 24");

    public SecondFrame() {
        setSize(400, 300);
        setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        setLocation(100, 100);
        JPanel panel = new JPanel(new GridLayout(10, 1));
        panel.add(Rdn12);
        panel.add(Rdn24);
        setContentPane(panel);
    }
}

您可以在第二帧中更改标签的值，但不一定非必要。正如我的示例所示，您可以在第一帧的代码中更改第二帧的复选框。

更新refreshRadioButtonsAccordingToDatabaseValues()方法以从数据库中读取实际数据。

Answer 2

你应该这样做：

private void btnUpdateActionPerformed(java.awt.event.ActionEvent evt) {  
String hours = null;
 try
    {
        DbUpdate up = new DbUpdate();

        int get = (int)jTable2.getModel().getValueAt(jTable2.getSelectedRow(), 0);
        String query= "SELECT * FROM roominfo WHERE CustomerNo = '"+get+"' " ;

        String url = "jdbc:mysql://localhost:3306/adv"; 
        Connection conn = DriverManager.getConnection(url,"root","sa"); 
        Statement st = conn.createStatement();
        rs = st.executeQuery(query);


        while(rs.next())
        {
         hours= rs.getString("Hours");
}
 if (hours.equals("12-Hours")) {
        // you can change the fields of the second frame directly in here
        up.Rdn12.isSelected();
        up.Rdn12.setSelected(true);
        up.Rdn24.setSelected(false);

    } else if (hours.equals("24-Hours")) {
        up.Rdn24.isSelected();
        up.Rdn12.setSelected(false);
        up.Rdn24.setSelected(true);
    }

    }
    catch(Exception e){
    JOptionPane.showMessageDialog(null, "Please select a record to update");
    }


}

基于JLabel将JRadioButton设置为true

2 个答案: