java - 在面板上绘制 JTable 行和列

Question

我正在编写一个应用程序，其中我必须在 Canvas 上绘制 JTable 组件。但是经过我的多次尝试还是无法画出一幅完全完美的JTable图。我尝试使用 getCellRect api 使用 JTable 的特定单元格的大小进行绘制，但是当数据很大时无法在 Canvas 上绘制特定单元格。这是示例代码:-

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.*;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.table.*;
import java.util.*;
import java.awt.*;

public class SimpleTableDemo extends JPanel {
    private boolean DEBUG = false;
      private int spacing = 6;
      private Map columnSizes = new HashMap();
      String[] columnNames = {"First Name",
                                "Last Name",
                                "Sport",
                                "# of Years",
                                "Vegetarian"};

        Object[][] data = {
        {"Kathy", "Smith",
         "SnowboardingXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX", new Integer(5), new Boolean(false)},
        {"John", "Doe",
         "Rowing", new Integer(3), new Boolean(true)},
        {"Sue", "Black",
         "Knitting", new Integer(2), new Boolean(false)},
        {"Jane", "White",
         "Speed reading", new Integer(20), new Boolean(true)},
        {"Joe", "Brown",
         "Pool", new Integer(10), new Boolean(false)}
        };

        final JTable table = new JTable(data, columnNames);
        Panel1 panel;

    public SimpleTableDemo() {
        super(new GridLayout(3,0));


        table.setPreferredScrollableViewportSize(new Dimension(500, 70));
        //table.setFillsViewportHeight(true);

        if (DEBUG) {
            table.addMouseListener(new MouseAdapter() {
                public void mouseClicked(MouseEvent e) {
                    printDebugData(table);
                }
            });
        }

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

        //Add the scroll pane to this panel.
        add(scrollPane);

        panel = new Panel1();
        Rectangle rect = table.getCellRect(0,0,true);

        panel.setX(table.getWidth());
        panel.setY(0);
        panel.setWidth(rect.width);
        panel.setHeight(rect.height);
        panel.setStr(table.getModel().getValueAt(0,0).toString());
        panel.setModel(table);

        add(panel);

        final JComboBox jNumberComboBoxSize = new JComboBox();
        jNumberComboBoxSize.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "11", "12", "14", "16", "18", "20", "24", "30", "36", "48", "72" }));
        jNumberComboBoxSize.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
               jNumberComboBoxSizeActionPerformed(jNumberComboBoxSize);
            }
        });

        JPanel panel2 = new JPanel();
        panel2.add(jNumberComboBoxSize);

        add(panel2);
        adjustColumns();

    }

    private void jNumberComboBoxSizeActionPerformed(JComboBox jNumberComboBoxSize)
    {
        int fontSize = Integer.parseInt(jNumberComboBoxSize.getSelectedItem().toString());
        table.setRowHeight(fontSize);
        table.setFont(new Font("Serif", Font.BOLD, fontSize));
        Rectangle rect = table.getCellRect(0,0,true);
        panel.setX(0);
        panel.setY(0);
       // panel.setWidth(rect.width);
        panel.setHeight(rect.height);
        panel.setStr(table.getModel().getValueAt(0,0).toString());
        panel.setModel(table);
        panel.repaint();
        table.revalidate();
    }

    private void printDebugData(JTable table) {
        int numRows = table.getRowCount();
        int numCols = table.getColumnCount();
        javax.swing.table.TableModel model = table.getModel();

        System.out.println("Value of data: ");
        for (int i=0; i < numRows; i++) {
            System.out.print("    row " + i + ":");
            for (int j=0; j < numCols; j++) {
                System.out.print("  " + model.getValueAt(i, j));
            }
            System.out.println();
        }
        System.out.println("--------------------------");
    }

     /*
     *  Adjust the widths of all the columns in the table
     */
    public void adjustColumns()
    {
        TableColumnModel tcm = table.getColumnModel();

        for (int i = 0; i < tcm.getColumnCount(); i++)
        {
            adjustColumn(i);
        }
    }

    /*
     *  Adjust the width of the specified column in the table
     */
    public void adjustColumn(final int column)
    {
        TableColumn tableColumn = table.getColumnModel().getColumn(column);

        if (! tableColumn.getResizable()) return;

        int columnHeaderWidth = getColumnHeaderWidth( column );
        int columnDataWidth   = getColumnDataWidth( column );
        int preferredWidth    = Math.max(columnHeaderWidth, columnDataWidth);
        panel.setWidth(preferredWidth);
        updateTableColumn(column, preferredWidth);
    }

    /*
     *  Calculated the width based on the column name
     */
    private int getColumnHeaderWidth(int column)
    {
        TableColumn tableColumn = table.getColumnModel().getColumn(column);
        Object value = tableColumn.getHeaderValue();
        TableCellRenderer renderer = tableColumn.getHeaderRenderer();

        if (renderer == null)
        {
            renderer = table.getTableHeader().getDefaultRenderer();
        }

        Component c = renderer.getTableCellRendererComponent(table, value, false, false, -1, column);
        return c.getPreferredSize().width;
    }

    /*
     *  Calculate the width based on the widest cell renderer for the
     *  given column.
     */
    private int getColumnDataWidth(int column)
    {
        int preferredWidth = 0;
        int maxWidth = table.getColumnModel().getColumn(column).getMaxWidth();

        for (int row = 0; row < table.getRowCount(); row++)
        {
            preferredWidth = Math.max(preferredWidth, getCellDataWidth(row, column));

            //  We've exceeded the maximum width, no need to check other rows

            if (preferredWidth >= maxWidth)
                break;
        }

        return preferredWidth;
    }

    /*
     *  Get the preferred width for the specified cell
     */
    private int getCellDataWidth(int row, int column)
    {
        //  Inovke the renderer for the cell to calculate the preferred width

        TableCellRenderer cellRenderer = table.getCellRenderer(row, column);
        Component c = table.prepareRenderer(cellRenderer, row, column);
        int width = c.getPreferredSize().width + table.getIntercellSpacing().width;

        return width;
    }

    /*
     *  Update the TableColumn with the newly calculated width
     */
    private void updateTableColumn(int column, int width)
    {
        final TableColumn tableColumn = table.getColumnModel().getColumn(column);

        if (! tableColumn.getResizable()) return;

        width += spacing;

        //  Don't shrink the column width

        width = Math.max(width, tableColumn.getPreferredWidth());


        columnSizes.put(tableColumn, new Integer(tableColumn.getWidth()));
        table.getTableHeader().setResizingColumn(tableColumn);
        tableColumn.setWidth(width);
    }

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

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

class Panel1 extends JPanel
{
    int x;
    int y;
    int width;
    int height;
    String str;
    JTable model;

    public void setModel(JTable model)
    {
       this.model = model;
    }

    public void setX(int x)
    {
        this.x = x;
    }

    public void setY(int y)
    {
        this.y = y;
    }

    public void setWidth(int w)
    {
        this.width = w;
    }

    public void setHeight(int h)
    {
        this.height = h;
    }

    public void setStr(String s)
    {
        this.str = s;
    }

    public void paint(Graphics g)
    {
        super.paint(g);
        int initX= 0;
        for(int row=0;row < 5; ++row)
        {
            initX = x;
            for (int col=0;col < 5;++col)
            {
                g.drawRect(x,y,width,height);
                g.drawString(model.getModel().getValueAt(row,col).toString(),x + 10,y + 10);
                x = x + width;
            }
            x = initX;
            y = y + height;

        }

    }
};

---

我修改了这段代码以重绘具有字体大小和边框的列单元格。我想绘制所有这些表格自定义，请看一下并提出一些建议。

谢谢

SimpleTableDemo.java

   package com.swing.data;


import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.HashMap;
import java.util.Map;

import javax.swing.BorderFactory;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;

public class SimpleTableDemo extends JPanel 
{
    private boolean DEBUG = false;
    private int spacing = 6;
    private Map columnSizes = new HashMap();
    String[] columnNames = {"First Name","Last Name","Sport","# of Years","Vegetarian"};

    Object[][] data = 
        {
            {"Kathy", "Smith","SnowboardingXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX", new Integer(5), new Boolean(false)},
            {"John", "Doe","Rowing", new Integer(3), new Boolean(true)},
            {"Sue", "Black","Knitting", new Integer(2), new Boolean(false)},
            {"Jane", "White","Speed reading", new Integer(20), new Boolean(true)},
            {"Joe", "Brown","Pool", new Integer(10), new Boolean(false)}
        };

    JTable table = new JTable(data, columnNames);
    Panel1 panel;

    public SimpleTableDemo() 
    {
        super(new GridLayout(3,0));      
        table.setPreferredScrollableViewportSize(new Dimension(500, 70));
        if (DEBUG) 
        {
            table.addMouseListener(new MouseAdapter() {
                public void mouseClicked(MouseEvent e) {
                    printDebugData(table);
                }
            });
        }
        //Create the scroll pane and add the table to it.
        JScrollPane scrollPane = new JScrollPane(table);


        //Add the scroll pane to this panel.
        add(scrollPane);

        panel = new Panel1();
//      Rectangle rect = table.getCellRect(0,0,true);
//
// 
//      panel.setX(table.getWidth());
//
//      panel.setY(0);
//      panel.setWidth(rect.width);
//      panel.setHeight(rect.height);
//      panel.setStr(table.getModel().getValueAt(0,0).toString());

        panel.setModel(table);

        add(panel);

        final JComboBox jNumberComboBoxSize = new JComboBox();
        jNumberComboBoxSize.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "11", "12", "14", "16", "18", "20", "24", "30", "36", "48", "72" }));
        jNumberComboBoxSize.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
               jNumberComboBoxSizeActionPerformed(jNumberComboBoxSize);
            }
        });

        JPanel panel2 = new JPanel();
        panel2.add(jNumberComboBoxSize);

        add(panel2);
        adjustColumns();
    }

    private void jNumberComboBoxSizeActionPerformed(JComboBox jNumberComboBoxSize)
    {
        int fontSize = Integer.parseInt(jNumberComboBoxSize.getSelectedItem().toString());
        table.setRowHeight(fontSize);
        setBorder(new Font("Serif", Font.BOLD, fontSize));
        table.setFont(new Font("Serif", Font.BOLD, fontSize));
        panel.setFont(new Font("Serif", Font.BOLD, fontSize));
        Rectangle rect = table.getCellRect(0,0,true);
        panel.setX(0);
        panel.setY(0);
        panel.setHeight(rect.height);
        panel.setStr(table.getModel().getValueAt(0,0).toString());
        panel.setModel(table);
        panel.repaint();
        table.revalidate();
    }

    public void setBorder(Font f)
    {
        BorderCellRenderer cellRenderer = new BorderCellRenderer();
        cellRenderer.setColumnBorder(BorderFactory.createLineBorder(Color.BLACK, 2)); 
        cellRenderer.setFont(f);
        table.getColumnModel().getColumn(0).setCellRenderer(cellRenderer);
        table.getColumnModel().getColumn(1).setCellRenderer(cellRenderer);

    }
    private void printDebugData(JTable table) 
    {
        int numRows = table.getRowCount();
        int numCols = table.getColumnCount();
        javax.swing.table.TableModel model = table.getModel();

        System.out.println("Value of data: ");
        for (int i=0; i < numRows; i++) 
        {
            System.out.print("    row " + i + ":");
            for (int j=0; j < numCols; j++) 
            {
                System.out.print("  " + model.getValueAt(i, j));
            }
            System.out.println();
        }
        System.out.println("--------------------------");
    }

     /*
     *  Adjust the widths of all the columns in the table
     */
    public void adjustColumns()
    {
        TableColumnModel tcm = table.getColumnModel();

        for (int i = 0; i < tcm.getColumnCount(); i++)
        {
            adjustColumn(i);
        }
    }

    /*
     *  Adjust the width of the specified column in the table
     */
    public void adjustColumn(int column)
    {
        TableColumn tableColumn = table.getColumnModel().getColumn(column);

        if (! tableColumn.getResizable()) return;

        int columnHeaderWidth = getColumnHeaderWidth( column );
        int columnDataWidth   = getColumnDataWidth( column );
        int preferredWidth    = Math.max(columnHeaderWidth, columnDataWidth);
        panel.setWidth(preferredWidth);
        updateTableColumn(column, preferredWidth);
    }

    /*
     *  Calculated the width based on the column name
     */
    private int getColumnHeaderWidth(int column)
    {
        TableColumn tableColumn = table.getColumnModel().getColumn(column);
        Object value = tableColumn.getHeaderValue();
        TableCellRenderer renderer = tableColumn.getHeaderRenderer();

        if (renderer == null)
        {
            renderer = table.getTableHeader().getDefaultRenderer();
        }

        Component c = renderer.getTableCellRendererComponent(table, value, false, false, -1, column);
        return c.getPreferredSize().width;
    }

    /*
     *  Calculate the width based on the widest cell renderer for the
     *  given column.
     */
    private int getColumnDataWidth(int column)
    {
        int preferredWidth = 0;
        int maxWidth = table.getColumnModel().getColumn(column).getMaxWidth();

        for (int row = 0; row < table.getRowCount(); row++)
        {
            preferredWidth = Math.max(preferredWidth, getCellDataWidth(row, column));

            if (preferredWidth >= maxWidth)
                break;
        }

        return preferredWidth;
    }

    /*
     *  Get the preferred width for the specified cell
     */
    private int getCellDataWidth(int row, int column)
    {
        //  Inovke the renderer for the cell to calculate the preferred width

        TableCellRenderer cellRenderer = table.getCellRenderer(row, column);
        Component c = table.prepareRenderer(cellRenderer, row, column);
        int width = c.getPreferredSize().width + table.getIntercellSpacing().width;

        return width;
    }

    /*
     *  Update the TableColumn with the newly calculated width
     */
    private void updateTableColumn(int column, int width)
    {
        final TableColumn tableColumn = table.getColumnModel().getColumn(column);

        if (! tableColumn.getResizable()) return;

        width += spacing;

        //  Don't shrink the column width

        width = Math.max(width, tableColumn.getPreferredWidth());


        columnSizes.put(tableColumn, new Integer(tableColumn.getWidth()));
        table.getTableHeader().setResizingColumn(tableColumn);
        tableColumn.setWidth(width);
    }

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

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

**Panel1.java**

    package com.swing.data;

import java.awt.Font;
import java.awt.Graphics;
import java.awt.Rectangle;

import javax.swing.JPanel;
import javax.swing.JTable;


class Panel1 extends JPanel
{
    int x;
    int y;
    int width;
    int height;
    String str;
    JTable model;
    Font font;

    public Font getFont() {
        return font;
    }
    public void setFont(Font font) {
        this.font = font;
    }
    public void setModel(JTable model)
    {
       this.model = model;
    }
    public JTable getModel()
    {
        return model;
    }

    public void setX(int x)
    {
        this.x = x;
    }

    public void setY(int y)
    {
        this.y = y;
    }

    public void setWidth(int w)
    {
        this.width = w;
    }

    public void setHeight(int h)
    {
        this.height = h;
    }

    public void setStr(String s)
    {
        this.str = s;
    }

    public void paint(Graphics g)
    {
        super.paint(g);
//      int initX= 0;
//      for(int row=0;row < 5; ++row)
//      {
//          initX = x;
//          for (int col=0;col < 5;++col)
//          {
//              g.drawRect(x,y,width,height);
//              String str = model.getModel().getValueAt(row, col).toString();
//              int xloc =  (x+10);
//              int yloc = y +10;
////                System.out.println("xloc : "+xloc);
////                System.out.println("yloc : "+yloc);
////                System.out.println("width : "+width);
////                System.out.println("height : "+height);
////                System.out.println("str : "+str);
//              
//              g.drawString(model.getModel().getValueAt(row,col).toString(),x + 10,y + 10);
//              x = x + width;
//          }
//            x = initX;
//          y = y + height;
// 
//      }

        System.out.println("Inside paint() >>>>>>>>>>>>>>>>>>>>>");

        JTable table = getModel();
        int columnCount = table.getModel().getColumnCount();
        int rowCount = table.getModel().getRowCount();
        int yLoc = 10;
        int rowHeight = 0 ;
        int columnWidth  = 0 ;
        g.setFont(font);
        for(int r = 0 ; r < rowCount; r++)
        {
            int xLoc = 0 ;
            for(int c= 0 ; c< columnCount; c++)
            {
                Rectangle rect = table.getCellRect(r, c, true);
                columnWidth = rect.width;
                rowHeight = rect.height;
                g.drawRect(xLoc, yLoc, columnWidth, rowHeight);
                String displayString = table.getValueAt(r, c).toString(); 
                System.out.println("displayString ::"+displayString);
                g.drawString(displayString, xLoc+5, yLoc+15);
                xLoc+= columnWidth; 
            }
            yLoc+= rowHeight;
        }
    }
}

**BorderCellRenderer.java**
package com.swing.data;

import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.border.*;

/**
 * @version 1.0 03/06/99
 */
public class BorderCellRenderer extends JLabel
    implements TableCellRenderer {
  protected Border noFocusBorder; 
  protected Border columnBorder; 
  protected Font font;

  public Font getFont() {
    return font;
}

public void setFont(Font font) {
    this.font = font;
}

public BorderCellRenderer() {
    noFocusBorder = new EmptyBorder(1, 2, 1, 2);
    setOpaque(true);
  }

  public Component getTableCellRendererComponent(JTable table, Object value,
                 boolean isSelected, boolean hasFocus, int row, int column) {
      setText((value == null) ? "" : value.toString());
      setBorder(columnBorder);
      setFont(font);
    return this;
  }

  public void setColumnBorder(Border border) {
    columnBorder = border;
  }

  public Border getColumnBorder() {
    return columnBorder;
  }
}

请建议重绘适当的 JTable 字体和边框。

Answer 1

有几个问题很明显:

1. 您似乎是在使用现有 JTable 的几何结构创建自己的 TableView ；这些尺寸可能在 pack() 之后才有效。

2. 您遍历 adjustColumns 中的列，但只有最后一列的宽度在 panel 中设置，然后变成表格中看到的恒定宽度。

3. 与使用 flyweight rendering 的 JTable 本身相比，您的实现的扩展性较差，图文并茂here .

4. 当调整框架大小时，您的面板消失；您应该显式调用 repaint，监听 TableModel，或者使用 JTable 本身。

5. 从 Java 5 开始，autoboxing允许以下内容；比较:

   {"John", "Doe", "Rowing", new Integer(3), new Boolean(true)}
   {"John", "Doe", "Rowing", 3, true}
   

6. 不要替换内容面板； add() 您的面板；比较:

   frame.setContentPane(newContentPane);
   frame.add(newContentPane);
   

7. 您对 GridLayout(3,0) 的使用表明存在误解；要在一列中获取任意数量的行，请使用 GridLayout(0, 1)。

8. 在扩展 JPanel 时，请注意“Swing 程序应该覆盖 paintComponent() 而不是覆盖 paint();”另见 Painting in AWT and Swing: The Paint Methods .