我想在JTable中添加JScrollPane并希望它：
JList的行为与此完全相同，顺便说一下。但我发现没有简单的方法可以同时使用JTable完成所有目标。完成第一个的简单方法是禁用自动调整大小，但这会阻止第二个发生。我想出了一个非常hacky的解决方案，它将一个组件监听器添加到JScrollPane的父容器中，并在调整该容器大小时调整表的大小。但是，我必须在resize方法中添加一些“软糖因子”（参见4x注释），用小像素量来改变我的高度/宽度检查，因为我猜想有些固有的不准确性。如果没有这些软糖因素，滚动条会显得太快（在需要它们之前），或者即使滚动条存在，长表格单元格的末端也会被切断。关于这些hacky软糖因素最糟糕的部分是，如果你改变了GUI的外观和感觉，那么整个解决方案就会彻底停止工作（即软糖因素需要改变）。这显然远非理想。
必须有一种更清洁的方法来实现这一目标。有人可以帮忙吗？运行附加的代码并拖动整个框架的大小以查看表更新。这段代码使用的金属外观和感觉似乎适用于我的Windows 7机器，并选择了软糖因子，但如果它在另一个操作系统上不能干净利用，我也不会感到惊讶。
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.ScrollPaneConstants;
import javax.swing.UIManager;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;
public class JTableScrollTest {
private JFrame frame;
private JPanel panel;
private DefaultTableModel tableModel;
private JTable table;
private JScrollPane scrollPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
try {
UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
} catch (Throwable e) {
e.printStackTrace();
}
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
JTableScrollTest window = new JTableScrollTest();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public JTableScrollTest() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel = new JPanel();
frame.getContentPane().add(panel, BorderLayout.CENTER);
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
scrollPane = new JScrollPane();
panel.add(scrollPane);
tableModel = new DefaultTableModel(new Object[]{"Stuff"},0);
tableModel.addRow(new Object[]{"reeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeally long string"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"a"});
tableModel.addRow(new Object[]{"LAST ITEM"});
table = new JTable(tableModel);
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
scrollPane.setViewportView(table);
resizeTable();
panel.addComponentListener(new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent evt) {
resizeTable();
}
});
}
public void resizeTable() {
int width = 0;
int height = 0;
for (int row = 0; row < table.getRowCount(); row++) {
TableCellRenderer renderer = table.getCellRenderer(row, 0);
Component comp = table.prepareRenderer(renderer, row, 0);
width = Math.max (comp.getPreferredSize().width, width);
height += comp.getPreferredSize().height;
}
if (width > panel.getWidth() - 2) { // fudge factor
width += 4; // fudge factor
scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
} else {
width = panel.getWidth();
scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
}
if (height > panel.getHeight() + 4) { // fudge factor
height -= 26; // fudge factor
scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
} else {
height = panel.getHeight();
scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER);
}
table.setPreferredSize(new Dimension(width, height));
}
}
答案 0 :(得分：2)
我有同样的问题。该表只是使列更大或更小，而不是显示滚动条。通过反复试验，我提到的黑客是ComponentListener，您附加到ScrollPane。
一旦滚动窗格小于表格的首选大小，诀窍是关闭表格的自动调整大小。请注意，您不应直接设置表的首选大小。单独留下来自动计算。如果您需要更大或更小的某些列，请通过列模型设置其宽度（例如table.getColumnModel().getColumn(0).setMaxWidth(25)）。
此类还包括另一个TableModelListener，它在将列添加到表中时执行相同的逻辑。
public final class ScrollingTableFix implements ComponentListener {
private final JTable table;
public ScrollingTableFix(JTable table, JScrollPane scrollPane) {
assert table != null;
this.table = table;
table.getModel().addTableModelListener(new ColumnAddFix(table, scrollPane));
}
public void componentHidden(final ComponentEvent event) {}
public void componentMoved(final ComponentEvent event) {}
public void componentResized(final ComponentEvent event) {
// turn off resize and let the scroll bar appear once the component is smaller than the table
if (event.getComponent().getWidth() < table.getPreferredSize().getWidth()) {
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
}
// otherwise resize new columns in the table
else {
table.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
}
}
public void componentShown(final ComponentEvent event) {}
// similar behavior is needed when columns are added to the table
private static final class ColumnAddFix implements TableModelListener {
private final JTable table;
private final JScrollPane scrollPane;
ColumnAddFix(JTable table, JScrollPane scrollPane) {
this.table = table;
this.scrollPane = scrollPane;
}
@Override
public void tableChanged(TableModelEvent e) {
if (e.getFirstRow() == TableModelEvent.HEADER_ROW) {
if (scrollPane.getViewport().getWidth() < table.getPreferredSize().getWidth()) {
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
}
else {
table.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
}
}
}
}
}
要使用它，只需将所有内容连接起来：
JTable table = new JTable();
JScrollPane scroller = new JScrollPane(table);
scroller.addComponentListener(new ScrollingTableFix(table, scroller));