Question

在这个例子中，我试图在我的GUI中添加一个表，然后动态地向其添加行（以显示进度）。我不明白的是为什么所有的行都会立刻出现。我的意思是，表格的变化，不是吗？有人可以给我一个解释吗？

import java.awt.Component;

public class Main {
  public static void main(String[] args) {
    // Show GUI
    java.awt.EventQueue.invokeLater(new Runnable() {
      public void run() {
        GUI gui = new GUI();
        gui.setVisible(true);

        DefaultTableModel model = new DefaultTableModel(
          new String[] { "Column 1", "Column 2" }, 0);
        JTable table = new JTable(model);

        gui.add(table);
        gui.validate();

        for (int i = 0; i < 10; i++) {
          System.out.println("Row " + i);
          model
            .addRow(new String[] { "Row", String.valueOf(i) });
          // model.fireTableDataChanged();

          try {
            Thread.sleep(250);
          } catch (InterruptedException e) {
            e.printStackTrace();
          }

        }
      }
    });
  }
}

class GUI extends JFrame {
  private static final long serialVersionUID = 1L;

  public GUI() {
    setTitle("GUI");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 350, 100);
    setLocationRelativeTo(null);

    JPanel cp = new JPanel();
    cp.setBorder(new EmptyBorder(10, 10, 10, 10));
    setContentPane(cp);
  }
}

Answer 1

重申Kleopatra：不要睡觉EDT

您可以使用this answer

中的javax.swing.Timer

enter image description here

修改

我也不想弄乱你的代码太多（只是因为它看起来很奇怪）但我改变了一点来添加Timer

import java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.Timer; import javax.swing.border.EmptyBorder; import javax.swing.table.DefaultTableModel; public class Main { static JTable table; static GUI gui; static Processor p = null; public static void main(String[] args) { // Show GUI java.awt.EventQueue.invokeLater(new Runnable() { public void run() { gui = new GUI(); p = new Processor() { @Override public void execute() { final JTable table = new JTable(p.getTableModel()); final JScrollPane scrollPane = new JScrollPane(table); gui.getContentPane().add(scrollPane, BorderLayout.CENTER); gui.setLocationRelativeTo(null); gui.setVisible(true); Timer timer = new Timer(100, new ActionListener(){ public void actionPerformed(ActionEvent e) { p.processRow(); table.scrollRectToVisible(table.getCellRect(table.getRowCount() - 1, 0, true)); } }); timer.start(); } }; p.execute(); } }); } } class GUI extends JFrame { private static final long serialVersionUID = 1L; public GUI() { setTitle("GUI"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setBounds(100, 100, 350, 400); JPanel contentPane = new JPanel(); contentPane.setBorder(new EmptyBorder(10, 10, 10, 10)); contentPane.setLayout(new BorderLayout(0, 0)); setContentPane(contentPane); } } interface Callback { void execute(); } abstract class Processor implements Callback { private final String[] cols = {"COL", "COL", "COL", "COL", "COL"}; private DefaultTableModel tableModel; int numRows; int numCols; int a, b, c, d, e; Processor() { a = 1; b = 2; c = 3; d = 4; e = 4; numRows = 1000; tableModel = new DefaultTableModel(cols, numCols); } public DefaultTableModel getTableModel() { return tableModel; } public void processRow() { tableModel.addRow(new Object[]{a, b, c, d, e}); a++; b++; c++; d++; e++; } }

Answer 2

正如kleopatra和peeskillet指出的那样，我最初的例子遭遇了一个愚蠢的错误。值得注意的是，peeskillet和我正在采用不同的方法。在我的示例中，列旨在表示可能花费未知时间且实际上可能失败的连接尝试（或多或少）（在这种情况下，只有在这种情况下，下一列才会起作用等等））。因此，对我来说，一次添加行是没有意义的（这可能是因为我的例子对peeskillet来说看起来很奇怪）。我已经使用SwingWorker解决了这个任务。正如kleopatra所指出的，还有另一个错误，现在已经修复了。这是我的代码：

package SwingWorkerExampleCopy;

import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingWorker;
import javax.swing.border.EmptyBorder;
import javax.swing.table.DefaultTableModel;
import java.awt.BorderLayout;

public class SwingWorkerExampleCopy {
  public static void main(String[] args) {
    // Show GUI
    java.awt.EventQueue.invokeLater(new Runnable() {
      @Override
      public void run() {
        GUI gui = new GUI();

        DefaultTableModel tableModel = new DefaultTableModel();

        // Use a SwingWorker
        Worker worker = new Worker(tableModel);
        worker.execute();

        JTable table = new JTable(tableModel);
        table.setEnabled(false);
        // table.setTableHeader(null);

        JScrollPane scrollPane = new JScrollPane(table);
        gui.getContentPane()
          .add(scrollPane, BorderLayout.CENTER);

      }
    });
  }
}

class GUI extends JFrame {
  private static final long serialVersionUID = 1L;

  public GUI() {
    setTitle("GUI");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 350, 400);
    setLocationRelativeTo(null);
    setVisible(true);

    JPanel contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(10, 10, 10, 10));
    contentPane.setLayout(new BorderLayout(0, 0));

    setContentPane(contentPane);
  }
}

class Worker extends SwingWorker<DefaultTableModel, Object[]> {

  private final static int  numRows = 10;
  private final static int  numCols = 10;

  private DefaultTableModel model;

  Worker(DefaultTableModel model) {
    this.model = model;
    model.setColumnCount(numCols);
  }

  @Override
  protected DefaultTableModel doInBackground() throws Exception {
    // Add row
    for (int row = 0; row < numRows; row++) {
      // Build columns
      for (int col = 0; col < numCols; col++) {
        if (col == 0) {
          publish(new Object[] { new String("Row " + row), row,
            col });
        } else {
          // Simulate a slow source
          Thread
            .sleep(new Random().nextInt((250 - 50) + 1) + 50);

          Boolean isSuccessful = false;

          // Simulate a return value
          if (new Random().nextBoolean()) {
            isSuccessful = true;
          }

          publish(new Object[] {
            new String((isSuccessful == true ? "x" : "o")), row,
            col });

          if (isSuccessful == true) {
            break;
          }
        }
      }
    }

    return model;
  }

  @Override
  protected void process(List<Object[]> chunks) {
    for (Object[] chunk : chunks) {
      // chunk[0]: cell value
      // chunk[1]: number
      // chunk[2]: column
      if ((int) chunk[2] == 0) {
        Object[] row = new Object[numCols];
        row[0] = (Object) chunk[0];
        model.addRow(row);
      } else {
        model.setValueAt((Object) chunk[0], (int) chunk[1],
          (int) chunk[2]);
      }
    }
  }
}

Answer 3

因为在您的代码运行时，没有其他事件（例如重绘事件）可以执行 - 您将阻止事件线程，直到您完成。

您可以直接调用重绘，但在代码运行时，UI仍然无法响应输入。您最好在单独的工作线程中运行循环，并在需要时使用invokeLater或invokeAndWait来执行UI的更新。

动态地向JTable添加行 - 为什么它们一次出现？

3 个答案: