Question

添加＆＃34;复选框编辑器＆＃34;的最佳方法是什么？对于JTable？到目前为止，我有一个使用自定义AbstractTableModel的JTable，它使用两个数据集合：一个是为每行添加复选框的HashMap，带有＆＃34; false＆＃34;值。第二个集合框架是带有Integers的简单ArrayList。 AbstractTableModel还具有从ArrayList和AbstractTableModel中删除所选行的自定义方法。问题是，如果我＆＃34;检查＆＃34;表中的chceckBox，选中的值保持在同一行。我认为问题在于重写setValueAt。我的代码：

package checkboxeditor;

import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.HashMap;
import javax.swing.JButton;

public class CheckBoxEditor extends JPanel {

    public CheckBoxEditor() {
        super(new BorderLayout());

        MyTableModel myTableModel = new MyTableModel();
        JTable table = new JTable(myTableModel);
        table.setFillsViewportHeight(true);

        JButton deleteBtn = new JButton("Delete selected rows");
        deleteBtn.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent ae) {
                int rowCount = table.getRowCount();
                for (int i = rowCount - 1; i >= 0; i--) {
                    boolean checked = (boolean) table.getValueAt(i, 0);
                    if (checked) {
                        myTableModel.removeRow((int) table.getValueAt(i, 1));
                    }
                }
            }
        });
        add(deleteBtn, BorderLayout.PAGE_START);

        //Create the scroll pane and add the table to it.
        JScrollPane scrollPane = new JScrollPane(table);

        //Add the scroll pane to this panel.
        add(scrollPane, BorderLayout.CENTER);
    }

    class MyTableModel extends AbstractTableModel {

        // column names
        private String[] columnNames = {"#", "Number"};
        // check boxes
        HashMap<Integer, Boolean> checkBoxes = new HashMap();
        // data
        ArrayList<Integer> data = new ArrayList();

        public MyTableModel() {
            for (Integer i = 1; i < 6; i++) {
                data.add(i);
            }

        }

        public void removeRow(Integer numberToDelete) {
            int index = data.indexOf(numberToDelete);
            data.remove(numberToDelete);
            fireTableRowsDeleted(index, index);
        }

        public int getColumnCount() {
            return columnNames.length;
        }

        public int getRowCount() {
            return data.size();
        }

        public String getColumnName(int col) {
            return columnNames[col];
        }

        public Object getValueAt(int row, int col) {
            switch (col) {
                case 0:
                    Object value = checkBoxes.get(row);
                    return (value == null) ? false : value;
                case 1:
                    return data.get(row);
                default:
                    return "";
            }
        }

        /*
         * JTable uses this method to determine the default renderer/
         * editor for each cell.  If we didn't implement this method,
         * then the last column would contain text ("true"/"false"),
         * rather than a check box.
         */
        public Class getColumnClass(int col) {
            switch (col) {
                case 0:
                    return Boolean.class;
                default:
                    return Integer.class;
            }
        }

        /*
         * Don't need to implement this method unless your table's
         * editable.
         */
        public boolean isCellEditable(int row, int col) {
            //Note that the data/cell address is constant,
            //no matter where the cell appears onscreen.
            return (col == 0);
        }

        /*
         * Don't need to implement this method unless your table's
         * data can change.
         */
        public void setValueAt(Object value, int row, int col) {
            if (col == 0) {
                checkBoxes.put(row, (boolean) value);
            }
        }

    }

    /**
     * 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("TableDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        CheckBoxEditor newContentPane = new CheckBoxEditor();
        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();
            }
        });
    }
}

Answer 1

一个是HashMap，为每个行复选框添加“false”值。第二个集合框架是带有整数的简单ArrayList

不需要两个数据结构或创建自定义TableModel。

您可以使用DefaultTableModel。 DefaultTableModel允许您在每行中存储任何类型的Object。您需要做的就是覆盖模型的getColumnClass(...)方法以返回正确的类，表格将为列选择合适的渲染器/编辑器。类似的东西：

String[] columnNames = {"#", "Number"};
DefaultTableModel model = new DefaultTableModel(columnNames, 0)
{
    //  Returning the Class of each column will allow different
    //  renderers and editors to be used based on Class

    public Class getColumnClass(int column)
    {
        return column == 0 ? Boolean.class : Integer.class;
    }
};

JTable table = new JTable(model);

然后，您可以通过执行以下操作向表中添加数据：

for (Integer i = 1; i < 6; i++) 
{
    Object[] row = {Boolean.FALSE, i};
    model.addRow( row);
}

DefaultTableModel已经支持从模型中删除行的方法。

＆＃34; Checkbox编辑器＆＃34;对于JTable

1 个答案: