无法选中复选框-它们是可编辑的！ Java秋千 [英] Check Boxes not able to be Selected -- They are Editable! Java Swing

问题描述

我已经在这个网站上阅读了很多有关此问题的问题，但找不到为什么它仍然无法工作.

I have read so many questions on this website concerning this problem and I cannot find why it is still not working.

问题:

我制作了一个JTable以显示在JScrollPane内部. JTable的构造如下:

I made a JTable to be displayed inside a JScrollPane. The JTable is constructed as follows:

table = new JTable(new DataTableModel());   

如您所见，我使用了名为DataTableModel的自定义AbstractDataModel.现在，当我显示此复选框时，但无法选中它们.您可以在下面看到它们的可编辑性.这是DataTableModel类中的相关代码:(请注意，我用于复选框的列是第一列，索引为0，并且此列中数组中的数据为"null").对于某些

As you can see, I use a custom AbstractDataModel called DataTableModel. Now, when I display this the checkboxes appear, but they are not able to be selected. They are editable as you can see below. Here is the pertinent code in the DataTableModel class: (note that my column for check boxes is the first column, at index 0, and that my data in my array at this column is "null"). For some

public class DataTableModel extends AbstractTableModel
{
    private String[][] data;
    private String[] header =
    { "", "KB Name", "fpGUID" };

    public DataTableModel() throws SQLException
    {
        // ========= CONNECTS TO DB AND PULLS RESULTS ==========

        // GETS RESULTS SET CALLED "rs"

        // populate data array
        int counter = 0;
        while (rs.next())
        {
            //data[counter][0] = "sfsdfsdfs ";
            data[counter][1] = (String) rs.getObject(2);
            data[counter][2] = (String) rs.getObject(4);

            counter++;
        }
        // =====================================================

    }

@Override
public String getValueAt(int rowIndex, int columnIndex)
{
    return data[rowIndex][columnIndex];
}

public boolean isCellEditable(int row, int col)
{
    return col == 0;
}

public Class getColumnClass(int column)
{
    if (column == 0)
    {
        return Boolean.class;
    } else
    {
        return String.class;
    }
}

所以，看来我的getColumnClass()方法很好，那是什么问题呢?可能与我存储表数据的数据"有关.这是数据数组:

So, it seems my getColumnClass() method is fine, so what is the problem? Could it be something with my "data" which I store the data for the table. Here is the data array:

推荐答案

有很多事情可以跳出来...

There are a number of things that jump out...

• (正如已经开始指出的那样)getValueAt似乎被声明为错误.它应该返回Object.想一想.您的期望是第一列将是boolean，因此如何从该方法返回String ...这将导致...
• 您的data数组是String的数组...在这里，再次期望第一个值应为boolean.现在您实际上可以保留它，但是您需要将值从getValueAt方法转换为boolean，然后再次返回setValueAt方法...这将导致...
• 您尚未实现setValueAt，因此无法存储单元格值的更改
• 您还没有实现必需的getRowCount，不是必需的getColumnCount，并且应该实现getColumnName，因为您实际上有一些.

• (As has already begin pointed out) getValueAt appears to be declared wrong. It should be returning Object. Think about it for a second. Your expectation is that the first column will be boolean, so how can you return String from this method...which leads to...
• Your data array is an array of String...where, again, the expectation is that the first value should be boolean. Now you can actually keep this, but you will need to translate the value to boolean from the getValueAt method and back again for the setValueAt method...which leads to...
• You've not implemented setValueAt, so there is no way that the changes to the cell value can be stored
• You're also not implementing getRowCount, which is required, getColumnCount, which is required and you should implement getColumnName, since you actually have some.

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.sql.SQLException;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.AbstractTableModel;

public class TestTableModel02 {

    public static void main(String[] args) {
        new TestTableModel02();
    }

    public TestTableModel02() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new JScrollPane(new JTable(new DataTableModel())));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class DataTableModel extends AbstractTableModel {

        private Object[][] data;
        private String[] header = {"", "KB Name", "fpGUID"};

        public DataTableModel() {//throws SQLException {
            // ========= CONNECTS TO DB AND PULLS RESULTS ==========

            // GETS RESULTS SET CALLED "rs"

            // populate data array
//            int counter = 0;
//            while (rs.next()) {
//                //data[counter][0] = "sfsdfsdfs ";
//                data[counter][1] = (String) rs.getObject(2);
//                data[counter][2] = (String) rs.getObject(4);
//
//                counter++;
//            }
            // =====================================================

            data = new Object[4][3];
            data[0] = new Object[]{false, "Help", "1234"};
            data[1] = new Object[]{false, "On fire", "5648"};
            data[2] = new Object[]{false, "Drowning", "9012"};
            data[3] = new Object[]{false, "Micky Mouse", "3456"};
        }

        @Override
        public Object getValueAt(int rowIndex, int columnIndex) {
            return data[rowIndex][columnIndex];
        }

        @Override
        public boolean isCellEditable(int row, int col) {
            return col == 0;
        }

        @Override
        public Class getColumnClass(int column) {
            if (column == 0) {
                return Boolean.class;
            } else {
                return String.class;
            }
        }

        @Override
        public void setValueAt(Object aValue, int rowIndex, int columnIndex) {
            if (columnIndex == 0) {
                if (aValue instanceof Boolean) {
                    data[rowIndex][columnIndex] = (Boolean)aValue;
                    fireTableCellUpdated(rowIndex, columnIndex);
                }
            }
        }

        @Override
        public int getRowCount() {
            return data.length;
        }

        @Override
        public int getColumnCount() {
            return header.length;
        }

        @Override
        public String getColumnName(int column) {
            return header[column];
        }
    }
}

现在，有很多方法可以解决整个第一列必须是布尔值"问题，但是坦率地说，这样做的代码要少得多.

Now, there are ways you can get around the whole "first column must be boolean" issue, but to be frank, it's much less code to do it this way.

我也强烈建议您查看SwingWorker并使用它进行所有数据加载，否则您可能会发现在开始加载数据时UI会停止运行，这通常是相当不愉快.

I would also, strongly, recommend that you take a look at SwingWorker and do all your data loading using it, otherwise you may find that your UI comes to a grinding halt while the data is begin loaded, which is generally rather unpleasant.

看看...

• Swing中的并发
• 如何使用表

• Concurrency in Swing
• How to use Tables

了解更多详情

这篇关于无法选中复选框-它们是可编辑的！ Java秋千的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！