仅当JTable适合视口时才启用JTable的自动调整大小

Question

我需要在JScrollPane中创建一个带有可调整大小的列的JTable(当用户增加列宽时 - 出现水平滚动条).为此,我有用table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);.此外,当视口宽度足以包含整个表格时 - 列应该拉伸以填充视口宽度.为了实现这一点,我有getScrollableTracksViewportWidth()JTable类的覆盖方法如下:

@Override
public boolean getScrollableTracksViewportWidth() {
    return getPreferredSize().width < getParent().getWidth();
}

这种方法很有效,除了一件事:当我第一次尝试调整列的大小时,它返回自己的宽度以开始位置.如果我快速调整列大小并释放鼠标表继续工作正常.那么,这种行为的原因是什么？为什么表尝试调整大小,即使getScrollableTracksViewportWidth()返回false？或者,也许,你可以提出更好的解决方案来实现这样的调整大小模式？

贝娄是上述问题的简单工作示例:

import javax.swing.*;

public class TestTable {
    private static Object[][] data = new Object[][] {
            { "a", "b", "c" },
            { "d", "e", "f" }
    };
    private static Object[] colNames = new Object[] { "1", "2", "3" };

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JTable table = new JTable(data, colNames) {
                    @Override
                    public boolean getScrollableTracksViewportWidth() {
                        return getPreferredSize().width < getParent().getWidth();
                    }
                };
                table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);

                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setVisible(true);
            }
        });
    }
}

Answer 1

doLayout()当水平滚动条不可见时,当你试图增加列的大小时似乎默认逻辑不起作用,所以我摆脱了默认逻辑并且只是接受了列的宽度而没有尝试调整它.

import javax.swing.*;
import javax.swing.table.*;

public class TestTable {
    private static Object[][] data = new Object[][] {
            { "a", "b", "c" },
            { "d", "e", "f" }
    };
    private static Object[] colNames = new Object[] { "1", "2", "3" };

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JTable table = new JTable(data, colNames)
                {
                    @Override
                    public boolean getScrollableTracksViewportWidth()
                    {
                        return getPreferredSize().width < getParent().getWidth();
                    }

                    @Override
                    public void doLayout()
                    {
                        TableColumn resizingColumn = null;

                        if (tableHeader != null)
                            resizingColumn = tableHeader.getResizingColumn();

                        //  Viewport size changed. May need to increase columns widths

                        if (resizingColumn == null)
                        {
                            setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
                            super.doLayout();
                        }

                        //  Specific column resized. Reset preferred widths

                        else
                        {
                            TableColumnModel tcm = getColumnModel();

                            for (int i = 0; i < tcm.getColumnCount(); i++)
                            {
                                TableColumn tc = tcm.getColumn(i);
                                tc.setPreferredWidth( tc.getWidth() );
                            }

                            // Columns don't fill the viewport, invoke default layout

                            if (tcm.getTotalColumnWidth() < getParent().getWidth())
                                setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
                                super.doLayout();
                        }

                        setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
                    }

                };
                table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);

                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setVisible(true);
            }
        });
    }
}

编辑使用AUTO_RESIZE_ALL_COLUMNS.