java - 仅使用 mousePressed、mouseReleased 和 mouseDragged 选择自定义 JTable 中的多行

Question

我在自定义 JTable 类中选择和取消选择行时遇到问题。

我的自定义类扩展了 JTable 并实现了 MouseListener 和 MouseMotionListener。当我按下一行时，我希望该行被选中；如果按下未选定的行，我希望取消选择它；用于选择和取消选择行的代码当前位于重写的changeSelection 方法中。

import javax.swing.*;
import javax.swing.table.TableModel;
import java.awt.event.*;

public class SelectFRCTable extends JTable implements MouseListener, MouseMotionListener {

  private boolean isPressed;
  private boolean isReleased;
  private boolean isDragged;

  public SelectFRCTable(TableModel model) {
    //Register for mouse events on the table.
    this.setModel(model);
    addMouseListener(this);
    addMouseMotionListener(this);
  }

  public void mousePressed(MouseEvent e) {
    System.out.println("Mouse Pressed: " + e.getClickCount());
    isPressed = true;
    isReleased = false;
  }

  public void mouseReleased(MouseEvent e) {
    System.out.println("Mouse Released: " + e.getClickCount());
    isPressed = false;
    isDragged = false;
    isReleased = true;
  }

  public void mouseEntered(MouseEvent e) {}

  public void mouseExited(MouseEvent e) {}

  public void mouseClicked(MouseEvent e) {
    System.out.println("Mouse Clicked: " + e.getClickCount());
  }

  public void mouseDragged(MouseEvent e) {
    System.out.println("Mouse Dragged: " + e.getClickCount());
    isDragged = true;
  }

  public void mouseMoved(MouseEvent e) {}

  @Override
  public void changeSelection(int rowIndex, int columnIndex, boolean toggle, boolean extend) {
    ListSelectionModel selectionModel = getSelectionModel();
    boolean selected = selectionModel.isSelectedIndex(rowIndex);

    if (selected) {
      selectionModel.removeSelectionInterval(rowIndex, rowIndex);
      getValueAt(rowIndex, columnIndex);
    } else if (!selected) {
      selectionModel.addSelectionInterval(rowIndex, rowIndex);
    }
  }
}

import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;
import java.awt.*;
import java.util.Vector;

public class TableExample extends JFrame{

  public TableExample() {
    JFrame frame = new JFrame("Custom JTable Example");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(925,700);
    frame.setLayout(new GridBagLayout());

    // Create a table with all the events
    Vector<String> columns = new Vector<String>();
    Vector<Vector<String>> rows = new Vector<Vector<String>>();
    columns.add("Column 1");

    // Get information about each event and store it in a vector to eventually be loaded into a
    // table model.
    for (int i=0; i<30; i++) {
      String info = "Hello World";
      Vector<String> data = new Vector<String>();
      data.add(info);
      rows.add(data);
    }

    // Create table model and configure it so that none of the cells are editable.
    TableModel model = new DefaultTableModel(rows, columns) {
      public Class getColumnClass(int column) {
        Class returnValue;
        if ((column >= 0) && (column < getColumnCount())) {
          returnValue = getValueAt(0, column).getClass();
        } else {
          returnValue = Object.class;
        }
        return returnValue;
      }
      public boolean isCellEditable(int row, int column) {
        return false; //This causes all cells to be not editable
      }
    };

    // Create custom table
    SelectFRCTable table = new SelectFRCTable(model);

    // Add the table to a scrollable pane
    JScrollPane scrollPane = new JScrollPane(table);
    add(scrollPane, BorderLayout.CENTER);

    pack();
    setVisible(true);
  }
}

当前代码在一定程度上有效。如果用户按下该行，则选择该行；如果用户再次按下该行，则取消选择选定的行。然而，如果用户按下一行并选择它，然后在选择它后继续按住鼠标左键并移动光标，则该行会被取消选择，然后再次选择，然后再次取消选择，依此类推，直到用户释放鼠标左键。

这是当前条件用于执行changeSelection 方法中的if/else-if 语句的结果。我尝试了各种其他条件，这些条件也使用全局 boolean 变量 isPressed、isReleased 和 isDragged 的​​组合，但到目前为止我还没有找到有效的解决方案。

有人有什么想法吗？

非常感谢任何帮助，提前致谢。

Answer 1

我找到了解决最初问题的方法，该解决方案也适用于启用拖动的情况:

import javax.swing.*;
import javax.swing.table.TableModel;
import java.awt.event.*;

public class SelectFRCTable extends JTable implements MouseListener, MouseMotionListener {

  private boolean selectionDetermined;
  private boolean isSelecting;
  private boolean isDeselecting;

  public SelectFRCTable(TableModel model) {
    //Register for mouse events on the table.
    this.setModel(model);
    addMouseListener(this);
    addMouseMotionListener(this);
  }

  public void mousePressed(MouseEvent e) {}

  public void mouseReleased(MouseEvent e) {
    selectionDetermined = false;
    isSelecting = false;
    isDeselecting = false;
  }

  public void mouseEntered(MouseEvent e) {}

  public void mouseExited(MouseEvent e) {}

  public void mouseClicked(MouseEvent e) {}

  public void mouseDragged(MouseEvent e) {}

  public void mouseMoved(MouseEvent e) {}

  @Override
  public void changeSelection(int rowIndex, int columnIndex, boolean toggle, boolean extend) {
    ListSelectionModel selectionModel = getSelectionModel();
    boolean selected = selectionModel.isSelectedIndex(rowIndex);

    if (selected && !selectionDetermined) {
      selectionDetermined = true;
      isSelecting = false;
      isDeselecting = true;
    } else if (!selected && !selectionDetermined) {
      selectionDetermined = true;
      isSelecting = true;
      isDeselecting = false;
    }

    if (isSelecting && !selected) {
      selectionModel.addSelectionInterval(rowIndex, rowIndex);
    } else if (isDeselecting && selected) {
      selectionModel.removeSelectionInterval(rowIndex, rowIndex);
    }
  }
}

释放鼠标时会设置标志，并且这些标志在 ChangeSelection() 方法中用作 if\else-if 语句的条件。