希望是一个简单的问题。
来自 http://download.oracle.com/docs/cd/E17409_01/javase/tutorial/uiswing/components/combobox.html 上的示例在“提供自定义渲染器”部分,我可以制作一个 JComboBox,如
Picture 3 - Text 3
-------------------
Picture 1 - Text 1
Picture 2 - Text 2
Picture 3 - Text 3
Picture 4 - Text 4
Picture 5 - Text 5
其中Picture 3 - Text 3
为当前选中项。
是否可以自定义标签?比如
Text 3
-------------------
Picture 1 - Text 1
Picture 2 - Text 2
Picture 3 - Text 3
Picture 4 - Text 4
Picture 5 - Text 5
组合框处于最小化状态时不显示图像。
我以前使用过 JButton/未修饰的弹出 JFrame 来模拟这个,但我想知道是否可以使用纯 JComboBox
谢谢
最佳答案
Is it possible to have a custom label? Such as...
是的。同一个渲染器用于渲染下拉列表和组合框中的选定项。当“渲染器索引”为-1 时,选择的值为渲染器,因此您可以根据需要自定义渲染。像这样的东西:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.plaf.basic.*;
public class ComboBoxItemIcon extends JFrame
{
public ComboBoxItemIcon()
{
Vector model = new Vector();
model.addElement( new Item(new ImageIcon("copy16.gif"), "copy" ) );
model.addElement( new Item(new ImageIcon("add16.gif"), "add" ) );
model.addElement( new Item(new ImageIcon("about16.gif"), "about" ) );
JComboBox comboBox;
comboBox = new JComboBox( model );
comboBox.setRenderer( new ItemRenderer() );
getContentPane().add(comboBox, BorderLayout.SOUTH );
}
class ItemRenderer extends BasicComboBoxRenderer
{
public Component getListCellRendererComponent(
JList list, Object value, int index,
boolean isSelected, boolean cellHasFocus)
{
super.getListCellRendererComponent(list, value, index,
isSelected, cellHasFocus);
Item item = (Item)value;
if (index == -1)
{
setText( item.getText() );
setIcon( null );
}
else
{
setText( item.getText() );
setIcon( item.getIcon() );
}
return this;
}
}
class Item
{
private Icon icon;
private String text;
public Item(Icon icon, String text)
{
this.icon = icon;
this.text = text;
}
public Icon getIcon()
{
return icon;
}
public String getText()
{
return text;
}
}
public static void main(String[] args)
{
JFrame frame = new ComboBoxItemIcon();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.pack();
frame.setVisible( true );
}
}
关于java - 自定义 JComboBox 顶部标签,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3339176/