JTable列宽仅在两个请求后发生变化

时间:2013-03-18 21:18:57

标签: java swing user-interface jtable preferredsize

在我的应用程序中,我有一个两列表,它将在程序的生命周期中动态填充。我有一个名为updateTableWidths的方法,在调用时,执行以下操作:

  • 使第一列与适合单元格内容所需的宽度相同
  • 使第二列尽可能宽,以适应单元格内容
  • 如果整个表格比其容器宽,则启用水平滚动条
  • 否则,让最后一列拉伸以填充容器

它似乎工作得很好,但是出于一些非常奇怪的原因,它需要被称为两次(但仅在某些情况下,即当表宽度增长而不是缩小时)。下面的SSCCE说明了我的困境。

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;

@SuppressWarnings("serial")
public class TableResizeTest extends JComponent {

    private JFrame frame;
    private JScrollPane scrollPane;
    private DefaultTableModel tableModel;
    private JTable table;
    private JPanel panel;

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Throwable e) {
            e.printStackTrace();
        }
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    TableResizeTest window = new TableResizeTest();
                    window.frame.setVisible(true);
                    window.frame.requestFocusInWindow();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public TableResizeTest() {
        initialize();
    }

    private void initialize() {
        frame = new JFrame("Test");
        frame.setBounds(300, 300, 200, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        tableModel = new DefaultTableModel(new Object[]{"Col_1", "Col_2"},0);

        table = new JTable(tableModel);
        table.setAutoResizeMode(JTable.AUTO_RESIZE_LAST_COLUMN);
        table.setAlignmentY(Component.TOP_ALIGNMENT);
        table.setAlignmentX(Component.LEFT_ALIGNMENT);
        table.setBorder(new EmptyBorder(0, 0, 0, 0));
        table.setFillsViewportHeight(true);
        table.setTableHeader(null);
        table.setEnabled(false);
        table.getColumnModel().setColumnMargin(0);
        frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.Y_AXIS));

        panel = new JPanel();
        frame.getContentPane().add(panel);
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));

        JButton btnFillTableShort = new JButton("Fill table short");
        btnFillTableShort.setAlignmentX(Component.CENTER_ALIGNMENT);
        panel.add(btnFillTableShort);

        JButton btnFillTableLong = new JButton("Fill table long");
        btnFillTableLong.setAlignmentX(Component.CENTER_ALIGNMENT);
        panel.add(btnFillTableLong);

        JButton btnUpdateTableWidths = new JButton("Update table widths");
        btnUpdateTableWidths.setAlignmentX(Component.CENTER_ALIGNMENT);
        panel.add(btnUpdateTableWidths);
        btnUpdateTableWidths.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                updateTableWidths();
            }
        });
        btnFillTableLong.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                fillTableLong();
            }
        });
        btnFillTableShort.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                fillTableShort();
            }
        });
        scrollPane = new JScrollPane(table);
        scrollPane.setPreferredSize(new Dimension(200, 100));
        scrollPane.setMaximumSize(new Dimension(32767, 100));
        frame.getContentPane().add(scrollPane);
        scrollPane.setAlignmentY(Component.TOP_ALIGNMENT);
        scrollPane.setBorder(new LineBorder(new Color(0, 0, 0)));

        frame.pack();
    }

    public void fillTableShort() {
        tableModel.setRowCount(0);
        tableModel.addRow(new Object[]{"short", "short"});
    }

    public void fillTableLong() {
        tableModel.setRowCount(0);
        tableModel.addRow(new Object[]{"looooooooooooooooooooong", "looooooooooooooooooooong"});
    }

    public void updateTableWidths() {
        int col_1_width = 0;
        for (int row = 0; row < table.getRowCount(); row++) {
            TableCellRenderer renderer = table.getCellRenderer(row, 0);
            Component comp = table.prepareRenderer(renderer, row, 0);
            col_1_width = Math.max (comp.getPreferredSize().width, col_1_width);
        }
        col_1_width += table.getIntercellSpacing().width;
        col_1_width += 10;
        table.getColumn("Col_1").setMinWidth(col_1_width);
        table.getColumn("Col_1").setMaxWidth(col_1_width);
        System.out.println("col_1_width was set to " + col_1_width);

        int col_2_width = 0;
        for (int row = 0; row < table.getRowCount(); row++) {
            TableCellRenderer renderer = table.getCellRenderer(row, 1);
            Component comp = table.prepareRenderer(renderer, row, 1);
            col_2_width = Math.max (comp.getPreferredSize().width, col_2_width);
        }
        col_2_width += table.getIntercellSpacing().width;
        int tableWidth = col_2_width + col_1_width;
        if (scrollPane.getVerticalScrollBar().isVisible()) {
            tableWidth += scrollPane.getVerticalScrollBar().getWidth();
        }
        if (tableWidth > scrollPane.getWidth()) {
            table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
            System.out.println("Auto resize was set to AUTO_RESIZE_OFF");
        } else {
            table.setAutoResizeMode(JTable.AUTO_RESIZE_LAST_COLUMN);
            col_2_width = scrollPane.getWidth() + col_1_width;
            System.out.println("Auto resize was set to AUTO_RESIZE_LAST COLUMN");
        }
        table.getColumn("Col_2").setPreferredWidth(col_2_width);
        table.getColumn("Col_2").setMinWidth(col_2_width);
        System.out.println("col_2_width was set to " + col_2_width + "\n");
    }
}

以下是重现行为可以遵循的一系列步骤:

1)启动应用

2)点击“填表短”

按钮

enter image description here

3)单击“更新表格宽度”按钮(在这种情况下只需单击一次)

enter image description here

4)点击“长桌填充”按钮

enter image description here

5)单击“更新表格宽度”按钮(第一次点击)

enter image description here

6)单击“更新表格宽度”按钮(第二次点击)

enter image description here

第二次点击后,它会正确显示。我有一些打印到控制台的调试信息,对于第一次和第二次点击,该方法似乎做了完全相同的事情:

col_1_width was set to 152
Auto resize was set to AUTO_RESIZE_OFF
col_2_width was set to 142

因为在第一次运行期间发生了某些变化,第二次发生了一些明显的差异。正如我之前提到的,这只发生在表列增长而不是缩小时。

我真的很难过。有什么想法吗?

2 个答案:

答案 0 :(得分:4)

您可能需要为第一列指定首选大小,以便与滚动一起正常工作。尝试添加以下行:

table.getColumn("Col_1").setPreferredWidth(col_1_width);

Col_1方法中处理updateTableWidths计算的块中。它解决了发布的SSCCE中的问题。

编辑:

setPreferredWidth中的maxWidth和minWidth存在依赖关系。以下是setPreferredWidth的代码。所以订单可能很重要。

public void setPreferredWidth(int preferredWidth) {
    int old = this.preferredWidth;
    this.preferredWidth = Math.min(Math.max(preferredWidth, minWidth), maxWidth);
    firePropertyChange("preferredWidth", old, this.preferredWidth);
}

同时探索setMaxWidth表示它也可以设置首选宽度:

public void setMaxWidth(int maxWidth) {
    int old = this.maxWidth;
    this.maxWidth = Math.max(minWidth, maxWidth);
    if (width > this.maxWidth) {
        setWidth(this.maxWidth);
    }
    if (preferredWidth > this.maxWidth) {
        setPreferredWidth(this.maxWidth);
    }
    firePropertyChange("maxWidth", old, this.maxWidth);
}

答案 1 :(得分:3)

尝试添加TableColumn#setWidth和/或TableColumn#setPreferredWidth

table.getColumn("Col_1").setWidth(col_1_width);
table.getColumn("Col_1").setPreferredWidth(col_1_width);

//...///

table.getColumn("Col_2").setWidth(col_2_width);
table.getColumn("Col_2").setPreferredWidth(col_2_width);