Java Oracle TableRenderDemo中的单元格/行格式

好的，首先让我说，在几年之后，我将回到编程领域。与此同时，情况发生了很大变化（IDE、OO），我第一次开始用Java编程

我需要构建一个GUI前端，目前正在努力使用JTables、tableModels和Renders

我目前正在通过Oracle TableRenderDemo努力了解它到底在做什么，我有点卡住了

我想我可能会增加这个帖子，但现在

我不明白的是，当第一次运行时，为什么John和Jane的整行都是绿色的，但是当我为他们中的任何一个单击素食者单击框时，只有组合框单元格会改变颜色，而不是整行

请记住，我对所有这些Java东西都是新手，可能需要一个非常简单的解释

非常感谢,

加里

这是密码。。。（谢谢） 包com.novartis.adhoc.view

/*
 * TableRenderDemo.java requires no other files.
 */

import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;

/**
 * TableRenderDemo is just like TableDemo, except that it explicitly initializes
 * column sizes and it uses a combo box as an editor for the Sport column.
 */
public class TableRenderDemo extends JPanel {

    private static final long serialVersionUID = 1L;
    private boolean DEBUG = false;

    public TableRenderDemo() {
        super(new GridLayout(1, 0));

        JTable table = new JTable(new MyTableModel())
        {
            private static final long serialVersionUID = 1L;

            public Component prepareRenderer(TableCellRenderer renderer,
                    int row, int column) {
                Component c = super.prepareRenderer(renderer, row, column);
                int modelRow = convertRowIndexToModel(row);

                // Color row based on a cell value
                if ((Boolean) getModel().getValueAt(modelRow, 4)) {
                    c.setBackground(Color.GREEN);
                } else {
                    c.setBackground(getBackground());
                }
                return c;
            }
        };

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

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

        // Set up column sizes.
        initColumnSizes(table);

        // Fiddle with the Sport column's cell editors/renderers.
        setUpSportColumn(table, table.getColumnModel().getColumn(2));

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

    /*
     * This method picks good column sizes. If all column heads are wider than
     * the column's cells' contents, then you can just use
     * column.sizeWidthToFit().
     */
    private void initColumnSizes(JTable table) {
        MyTableModel model = (MyTableModel) table.getModel();
        TableColumn column = null;
        Component comp = null;
        int headerWidth = 0;
        int cellWidth = 0;
        Object[] longValues = model.longValues;
        TableCellRenderer headerRenderer = table.getTableHeader().getDefaultRenderer();

        for (int i = 0; i < 5; i++) {
            column = table.getColumnModel().getColumn(i);

            comp = headerRenderer.getTableCellRendererComponent(null,
                    column.getHeaderValue(), false, false, 0, 0);
            headerWidth = comp.getPreferredSize().width;

            comp = table.getDefaultRenderer(model.getColumnClass(i))
                    .getTableCellRendererComponent(table, longValues[i], false, false, 0, i);
            cellWidth = comp.getPreferredSize().width;

            if (DEBUG) {
                System.out.println("Initializing width of column " + i + ". "
                        + "headerWidth = " + headerWidth + "; cellWidth = "
                        + cellWidth);
            }

            column.setPreferredWidth(Math.max(headerWidth, cellWidth));
        }
    }

    public void setUpSportColumn(JTable table, TableColumn sportColumn) {
        // Set up the editor for the sport cells.
        JComboBox<String> comboBox = new JComboBox<String>();
        comboBox.addItem("Snowboarding");
        comboBox.addItem("Rowing");
        comboBox.addItem("Knitting");
        comboBox.addItem("Speed reading");
        comboBox.addItem("Pool");
        comboBox.addItem("None of the above");
        sportColumn.setCellEditor(new DefaultCellEditor(comboBox));

        // Set up tool tips for the sport cells.
        DefaultTableCellRenderer renderer = new DefaultTableCellRenderer();
        renderer.setToolTipText("Click for combo box");
        sportColumn.setCellRenderer(renderer);
    }

    class MyTableModel extends AbstractTableModel {

        private static final long serialVersionUID = 1L;
        private String[] columnNames = { "First Name", "Last Name", "Sport",
                "# of Years", "Vegetarian" };
        private Object[][] data = {
                { "Kathy", "Smith", "Snowboarding", 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) } };
        public final Object[] longValues = { "Jane", "Kathy",
                "None of the above", new Integer(20), Boolean.TRUE };

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

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

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

        public Object getValueAt(int row, int col) {
            return data[row][col];
        }

        /*
         * 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<? extends Object> getColumnClass(int c) {
            return getValueAt(0, c).getClass();
        }

        /*
         * 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.
            if (col < 2) {
                return false;
            }
            return true;
        }

        /*
         * Don't need to implement this method unless your table's data can
         * change.
         */
        public void setValueAt(Object value, int row, int col) {
            if (DEBUG) {
                System.out.println("Setting value at " + row + "," + col
                        + " to " + value + " (an instance of "
                        + value.getClass() + ")");
            }

            data[row][col] = value;
            fireTableCellUpdated(row, col);

            if (DEBUG) {
                System.out.println("New value of data:");
                printDebugData();
            }
        }

        private void printDebugData() {
            int numRows = getRowCount();
            int numCols = getColumnCount();

            for (int i = 0; i < numRows; i++) {
                System.out.print("    row " + i + ":");
                for (int j = 0; j < numCols; j++) {
                    System.out.print("  " + data[i][j]);
                }
                System.out.println();
            }
            System.out.println("--------------------------");
        }

    }

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

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

}

谢谢

---

Gary

好的，首先，代码是由一位同事提供给我的（我原以为它就是Oracle网站上的代码），但不是，他一直在玩它

无论如何

我不明白的是，第一次跑步时，为什么整排都是绿色的 对于John和Jane，但当我点击素食者点击框时 其中只有组合框单元格改变颜色，而不是整行

我想我已经找到了发生这种情况的原因-对行中的每个单元格执行以下代码：

if ((Boolean) getModel().getValueAt(modelRow, 4)) {
    c.setBackground(Color.GREEN);
} else {
    c.setBackground(getBackground());

所以，当第一次绘制表格时。。。对于第一列，它检查第4列中的值，如果为“True”，则将第0列（和第1-3列）中的单元格设置为绿色。但是，当第4列中的值更改为“False”时，渲染器没有在第0列（等）中的单元格上运行，因此它不知道再次执行此检查，因此其他列的颜色无法更改

不管怎样，我已经通过

if ((Boolean) getModel().getValueAt(modelRow, 4)) {
    c.setBackground(Color.GREEN);
    repaint();
} else {
    c.setBackground(getBackground());

---

快到了

尝试不同的实现以查看效果。渲染用于渲染多个单元格（通常用于同一列），如果不完全重新配置它们，它们会将状态从一个单元格传递到另一个单元格。发布一个可运行的示例Odd。。。这正是我所希望的，但我不明白为什么当我将“素食者”设置为false时，它会正常工作-代码不会重新绘制，但它会将所有单元格背景设置为白色。实际上，这提出了另一个问题，如果bacground是绿色的，为什么c.setBackground（getBackground（））将其设置为白色？当然getBackground（）返回绿色，而c.setBackground只是再次将其设置为绿色？

if ((Boolean) getModel().getValueAt(modelRow, 4)) {
    c.setBackground(Color.GREEN);
} else {
    c.setBackground(getBackground());

if ((Boolean) getModel().getValueAt(modelRow, 4)) {
    c.setBackground(Color.GREEN);
    repaint();
} else {
    c.setBackground(getBackground());