如何将数据插入JTable？

4 回答

• 2

  您必须将JTable添加到其父组件和setVisible（） .

  回复于 2024-04-28T06:58:59+08:00
• 2

  尝试这样的事情，只是为了让它运行 . 请注意，您在pammel方法中删除了 void ，并添加了一个main .

  import javax.swing.*;
  
  class TableDemo { 
      JTable jTable1;
      public static void main( String ... args ) { 
  
         TableDemo tableDemo = new TableDemo();
         tableDemo.pamnel();
  
         JFrame frame = new JFrame();
         frame.add(  new JScrollPane(tableDemo.jTable1) );
         frame.pack();
         frame.setVisible( true );
      }
      public void initComponents(){
      }
      public void pamnel() {
              initComponents();
               String[] columnNames = {"First Name",
                              "Last Name",
                              "Sport",
                              "# of Years",
                              "Vegetarian"};
  
  
  
          Object[][] data = {
              {"Kathy", "Smith",
               "Snowboarding", new Integer(5), new Boolean(false)},
              {"John", "Doe",
               "Rowing", new Integer(3), new Boolean(true)},
              {"Sue", "Black",
               "Knitting", new Integer(2), new Boolean(false)},
              {"Jane", "White",
               "Speed reading", new Integer(20), new Boolean(true)},
              {"Joe", "Brown",
               "Pool", new Integer(10), new Boolean(false)}
          };
  
          jTable1 = new JTable(data, columnNames);                      
  
       }    
  }
  

  

  回复于 2024-04-28T06:58:59+08:00
• 3

  你真的自己编写代码吗？我记得这是来自oracle swing教程 . 无论如何，您还没有将 JTable 添加到组件中 . 请注意以下source

  package components;
  
  /*
   * SimpleTableDemo.java requires no other files.
   */
  
  import javax.swing.JFrame;
  import javax.swing.JPanel;
  import javax.swing.JScrollPane;
  import javax.swing.JTable;
  import java.awt.Dimension;
  import java.awt.GridLayout;
  import java.awt.event.MouseAdapter;
  import java.awt.event.MouseEvent;
  
  public class SimpleTableDemo extends JPanel {
      private boolean DEBUG = false;
  
      public SimpleTableDemo() {
          super(new GridLayout(1,0));
  
          String[] columnNames = {"First Name",
                                  "Last Name",
                                  "Sport",
                                  "# of Years",
                                  "Vegetarian"};
  
          Object[][] data = {
          {"Kathy", "Smith",
           "Snowboarding", new Integer(5), new Boolean(false)},
          {"John", "Doe",
           "Rowing", new Integer(3), new Boolean(true)},
          {"Sue", "Black",
           "Knitting", new Integer(2), new Boolean(false)},
          {"Jane", "White",
           "Speed reading", new Integer(20), new Boolean(true)},
          {"Joe", "Brown",
           "Pool", new Integer(10), new Boolean(false)}
          };
  
          final JTable table = new JTable(data, columnNames);
          table.setPreferredScrollableViewportSize(new Dimension(500, 70));
          table.setFillsViewportHeight(true);
  
          if (DEBUG) {
              table.addMouseListener(new MouseAdapter() {
                  public void mouseClicked(MouseEvent e) {
                      printDebugData(table);
                  }
              });
          }
  
          //Create the scroll pane and add the table to it.
          JScrollPane scrollPane = new JScrollPane(table);
  
          //Add the scroll pane to this panel.
          add(scrollPane);
      }
  
      private void printDebugData(JTable table) {
          int numRows = table.getRowCount();
          int numCols = table.getColumnCount();
          javax.swing.table.TableModel model = table.getModel();
  
          System.out.println("Value of data: ");
          for (int i=0; i < numRows; i++) {
              System.out.print("    row " + i + ":");
              for (int j=0; j < numCols; j++) {
                  System.out.print("  " + model.getValueAt(i, j));
              }
              System.out.println();
          }
          System.out.println("--------------------------");
      }
  
      /**
       * Create the GUI and show it.  For thread safety,
       * this method should be invoked from the
       * event-dispatching thread.
       */
      private static void createAndShowGUI() {
          //Create and set up the window.
          JFrame frame = new JFrame("SimpleTableDemo");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  
          //Create and set up the content pane.
          SimpleTableDemo newContentPane = new SimpleTableDemo();
          newContentPane.setOpaque(true); //content panes must be opaque
          frame.setContentPane(newContentPane);
  
          //Display the window.
          frame.pack();
          frame.setVisible(true);
      }
  
      public static void main(String[] args) {
          //Schedule a job for the event-dispatching thread:
          //creating and showing this application's GUI.
          javax.swing.SwingUtilities.invokeLater(new Runnable() {
              public void run() {
                  createAndShowGUI();
              }
          });
      }
  }
  

  JTable被添加到 SimpleTableDemo 构造函数中的JPanel中 . 然后将JPanel设置为主JFrame中的内容窗格，其作为frame.setVisible（true） . 这发生在 createAndShowGUI 方法中 . 您的代码不显示JTable的原因是因为JTable是一个抽象小部件 . 您需要将抽象窗口小部件添加到组件，例如JFrame（在上面的示例中），以便显示它 .

  回复于 2024-04-28T06:58:59+08:00
• 0

  它的接缝就像新的JTable没有被添加到 pamnel .
  可能在 initComponents() 中添加了另一个未使用数据初始化的实例

  private JTable jTable1 = new JTable();    // empty table
  
  public pamnel() {
      initComponents();
  
      String[] columnNames = ...
      Object[][] data = ...
  
      jTable1 = new JTable(data, columnNames);  // new instance created here
      // nothing happens with that new instance
  }
  
  private void initComponents() {
      ...
      add(jTable1);    // added empty table, not the one created above (constructor)
      ...
  }
  

  add 方法不会向组件添加对变量的引用，它只会添加变量的值 . 因此，如果更改了变量，则组件仍包含先前（旧）值 .
  更改create-add的顺序：

  private JTable jTable1;
  
  public pamnel() {
      initComponents();
  }
  
  private void initComponents() {
      ...
      createTable(); 
      add(jTable1);  
      ...
  }
  
  private void createTable() {
      String[] columnNames = ...
      Object[][] data = ...
  
      jTable1 = new JTable(data, columnNames);
  }
  

  回复于 2024-04-28T06:58:59+08:00