如何創建可滾動的JTable

Question

我真的不知道我在做什么錯。 我嘗試遵循其他人的代碼，但似乎無法理解如何向JTable添加滾動條

這是我到目前為止的內容：

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Vector;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JButton;
import javax.swing.LayoutStyle.ComponentPlacement;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;
import javax.swing.table.TableModel;
import javax.swing.JTextArea;
import javax.swing.JTable;
import javax.swing.JTextPane;
import javax.swing.border.BevelBorder;

public class TBB_SQLBuilder {

    private JFrame frame;
    private JTable table;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    TBB_SQLBuilder window = new TBB_SQLBuilder();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public TBB_SQLBuilder() {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 950, 900);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JTextArea textArea = new JTextArea();

        JButton button = new JButton("New button");

        table = new JTable();

        table.setBorder(new BevelBorder(BevelBorder.LOWERED, null, null, null, null));
        new JScrollPane(table, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);

        GroupLayout groupLayout = new GroupLayout(frame.getContentPane());
        groupLayout.setHorizontalGroup(
            groupLayout.createParallelGroup(Alignment.TRAILING)
                .addGroup(Alignment.LEADING, groupLayout.createSequentialGroup()
                    .addContainerGap()
                    .addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
                        .addComponent(table, GroupLayout.DEFAULT_SIZE, 938, Short.MAX_VALUE)
                        .addGroup(groupLayout.createSequentialGroup()
                            .addComponent(textArea, GroupLayout.PREFERRED_SIZE, 289, GroupLayout.PREFERRED_SIZE)
                            .addPreferredGap(ComponentPlacement.RELATED)
                            .addComponent(button)))
                    .addContainerGap())
        );
        groupLayout.setVerticalGroup(
            groupLayout.createParallelGroup(Alignment.LEADING)
                .addGroup(groupLayout.createSequentialGroup()
                    .addContainerGap()
                    .addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
                        .addComponent(textArea, GroupLayout.PREFERRED_SIZE, 77, GroupLayout.PREFERRED_SIZE)
                        .addComponent(button))
                    .addPreferredGap(ComponentPlacement.RELATED)
                    .addComponent(table, GroupLayout.PREFERRED_SIZE, 176, GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(613, Short.MAX_VALUE))
        );
        frame.getContentPane().setLayout(groupLayout);
        frame.add(new JScrollPane(table));


        button.addActionListener(new ActionListener(){
               public void actionPerformed(ActionEvent ae){
                  String getValue = textArea.getText();
                  String connectDB = "jdbc:ucanaccess:///Users/sebastianzeki/Documents/PhysJava/My.mdb;";
                    Connection conn;
                    try {
                        conn = DriverManager.getConnection(connectDB);
                        Statement st =conn.createStatement();
                        ResultSet rsHNum = st.executeQuery(getValue);

                         table.setModel(buildTableModel(rsHNum));  
                            ((DefaultTableModel)table.getModel()).fireTableDataChanged(); // show changes 

                    } catch (SQLException e) {
                        e.printStackTrace();
                    }                 
               }
            }); 
    }
    public static DefaultTableModel buildTableModel(ResultSet rs1)
            throws SQLException {
        ResultSetMetaData metaData = rs1.getMetaData();

        // names of columns
        Vector<String> columnNames = new Vector<String>();
        int columnCount = metaData.getColumnCount();
        for (int column = 1; column <= columnCount; column++) {
            columnNames.add(metaData.getColumnName(column));
        }

        // data of the table
        Vector<Vector<Object>> data = new Vector<Vector<Object>>();

        while (rs1.next()) {
            Vector<Object> vector = new Vector<Object>();
            for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
                vector.add(rs1.getObject(columnIndex));

                System.out.println(rs1.getObject(columnIndex));
            }
            data.add(vector);
        }
        return new DefaultTableModel(data, columnNames);
    }

Answer 1

盡管您正在使用JScrollPane放置表格，但實際上並沒有將滾動窗格添加到GroupLayout 。 相反，您將其添加到JFrame -這是您的第一個錯誤。

因此，您應該首先創建滾動窗格，然后在其中添加表； 然后將滾動窗格添加到GroupLayout ，如下所示

JScrollPane scrollPane = new JScrollPane(table);
// Force the scrollbars to always be displayed
scrollPane.setHorizontalScrollBarPolicy(
    JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scrollPane.setVerticalScrollBarPolicy(
    JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); 


GroupLayout groupLayout = new GroupLayout(frame.getContentPane());
groupLayout.setHorizontalGroup(
    groupLayout.createParallelGroup(Alignment.TRAILING)
    .addGroup(Alignment.LEADING, groupLayout.createSequentialGroup()
      .addContainerGap()
      .addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
        .addComponent(scrollPane, GroupLayout.DEFAULT_SIZE, 938, Short.MAX_VALUE)

因此，無論您在哪里執行addComponent(table都應該使用addComponent(scrollPane 。現在，讓我們看兩行。在創建滾動窗格之后。

scrollPane.setHorizontalScrollBarPolicy(
    JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scrollPane.setVerticalScrollBarPolicy(
    JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); 

這些將為您提供所需的精美外觀。 滾動條（禁用），即使沒有滾動內容。

Answer 2

只需創建JScrollPane並將表添加到值中即可...請參見下面的示例。

public class MainView extends JFrame{

private JPanel mainPanel;
private JTable table;
private DefaultTableModel model_table;
private JScrollPane scroll_table;

public static void main(String[] args) {
    MainView main = new MainView();
    main.setVisible(true);
}   
public MainView() {
    mainPanel = new JPanel(null);
    setSize(500, 500);

    table = new JTable();
    model_table = new DefaultTableModel();
    model_table.addColumn("1");
    model_table.addColumn("2");
    model_table.addColumn("3");
    model_table.addColumn("4");
    table.setModel(model_table);

    for(int i=0;i<10;i++){                             // add value to table
           Vector<String> r  = new Vector<String>();
            r.addElement("a");
            r.addElement("b");
            r.addElement("c");
            r.addElement("d");
            model_table.addRow(r);
    } 

    scroll_table = new JScrollPane(table);            // add table to scroll panel
    scroll_table.setBounds(5, 10, 300, 150);
    scroll_table.setVisible(true);
    mainPanel.add(scroll_table);

    this.add(mainPanel);
  }
}