[英]JComboBox having different color in every item failed
截图: http://i.stack.imgur.com/EgfZs.png
以下是我消化并尝试错误后的代码 Dr.Google 显示:
public class ColorCode{
private Color color;
private String alias;
...
}
public class ElectronicColorCode extends JFrame implements ActionListener{
private JComboBox[] selections = new JComboBox[4];
...
public ElectronicColorCode(){
for(int i=0; i<selections.length; i++){
selections[i] = new JComboBox();
for(int j=0; j<tolColorSets.length; j++)
selections[i].addItem(new ComboBoxRenderer(colorSets[j]));
}
selections[i].addActionListener(this);
...
}
}
class ComboBoxRenderer extends JLabel implements ListCellRenderer{
private ColorCode colorCode;
public ComboBoxRenderer(ColorCode colorCode){
super();
this.colorCode = colorCode;
setBackground(colorCode.getColor());
setText(colorCode.getAlias());
System.out.println(colorCode.getAlias());
}
public Component getListCellRendererComponent(JList list, Object obj, int row, boolean isSelected, boolean hasFocus){
return this;
}
}
您不会将渲染器添加为组合框的项目。 渲染器用于渲染存储在 model 中的 Object。 如果需要,可以将自定义 object 添加到 model 中,其中包含要在渲染器中显示的文本和背景颜色。
这是一个简单的例子,展示了如何做到这一点。 您显然需要自定义代码来存储和呈现背景颜色而不是 id。
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.plaf.basic.*;
public class ComboBoxItem2 extends JFrame implements ActionListener
{
public ComboBoxItem2()
{
Vector model = new Vector();
model.addElement( new Item(1, "car" ) );
model.addElement( new Item(2, "plane" ) );
model.addElement( new Item(4, "boat" ) );
model.addElement( new Item(3, "train" ) );
JComboBox comboBox = new JComboBox( model );
comboBox.setRenderer( new ItemRenderer() );
comboBox.addActionListener( this );
getContentPane().add(comboBox, BorderLayout.SOUTH );
}
public void actionPerformed(ActionEvent e)
{
JComboBox comboBox = (JComboBox)e.getSource();
Item item = (Item)comboBox.getSelectedItem();
System.out.println( item.getId() + " : " + item.getDescription() );
}
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;
setText( item.getDescription().toUpperCase() );
return this;
}
}
class Item
{
private int id;
private String description;
public Item(int id, String description)
{
this.id = id;
this.description = description;
}
public int getId()
{
return id;
}
public String getDescription()
{
return description;
}
public String toString()
{
return description;
}
}
public static void main(String[] args)
{
JFrame frame = new ComboBoxItem2();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.pack();
frame.setVisible( true );
}
}
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