好的，首先让我说我在几年之后回到编程。事情发生了很大的变化（IDE，OO），我开始用Java首次编程。
我需要构建一个GUI前端，目前正在努力使用JTables，tableModels和Renderers。
我目前正在通过Oracle TableRenderDemo努力了解它正在做什么，并且有点卡住了。
我怀疑我可能会加入这篇文章，但现在......
我不明白的是，第一次运行时，为什么John和Jane的整行都是绿色的，但当我点击其中任何一个的Vegetarian clickBox时，只有comboBox单元改变颜色而不是整行？
请记住，我对所有这些Java内容都很陌生，可能需要用非常简单的术语解释。
非常感谢，
加里
这是代码......（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();
}
});
}
}
好的，所以我真的想添加到帖子而不是编辑原文，但我无法弄清楚如何做到（此刻感觉真的很厚）。无论如何我现在正在看以下部分...
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;
}
所以我正确地假设标题与表格的其余部分有不同的渲染器吗？
另外，我没有得到headerRenderer.getTableCellRendererComponent的参数... table = null，row = 0，column = 0.这里发生了什么？
另外，如果column.getHeaderValue（）返回列i标题中的对象，为什么我们不能只说：
comp = column.getHeaderValue();
headerWidth = comp.getPreferredSize().width;
谢谢，
加里
答案 0 :(得分：0)
好的，首先是代码由同事提供给我（我认为这是Oracle网站上的确切代码），但不，他一直在玩它。
...总之
我不明白的是，第一次运行时，为什么整行是绿色的 对于约翰和简，但是当我点击素食clickBox时 他们只有comboBox单元改变颜色而不是整行？
我想我已经弄明白为什么会发生这种情况 - 对该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());
因此，当第一列绘制表时...它会检查第4列中的值，如果它是'True'，它会将第0列中的单元格设置为绿色（和第1-3列）。但是，当第4列中的值更改为“False”时，渲染器未在第0列（等）中的单元格上运行，因此它不知道再次执行此检查，因此颜色不能更改其他列。
无论如何，我已经解决了这个......
if ((Boolean) getModel().getValueAt(modelRow, 4)) {
c.setBackground(Color.GREEN);
repaint();
} else {
c.setBackground(getBackground());
去那儿！