如何将数据插入JTable？

我写这段代码用于在表格中显示字符串。

但它没有显示，也没有效果。

什么是problrem？

public 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); } 

编辑：我在面板上添加Jtable。

在主面板中添加一个jframe。

  JFrame frame = new JFrame(); frame.add(new pamnel()); frame.setVisible(true); frame.setSize(600, 600); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

显示该表但未显示数据。 表的行和列是空的！

Answer 1

您必须将JTable添加到其父组件和setVisible（）。

Answer 2

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。 请注意以下来源

 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。

Answer 3

尝试这样的事情，只是为了让它运行。 请注意，您删除了pammel方法中的void ，并添加了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); } } 

Answer 4

它的接缝就像新的JTable没有添加到pamnel 。
可能在initComponents()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); }