Question

我想为JCombobox中的行/条目设置字体颜色，每行都是唯一的。所以基本上当你点击下拉箭头时，你应该会看到几行不同的颜色，我想根据它们的属性自己指定颜色。我应该怎么做呢？谢谢！

Answer 1

您需要创建一个自定义ListCellRenderer：

class Renderer extends JLabel implements ListCellRenderer {

并实现此方法：

public Component getListCellRendererComponent(JList list, Object value,
            int index, boolean isSelected, boolean cellHasFocus) {
        // Get the selected index. (The index param isn't
        // always valid, so just use the value.)

        if (isSelected) {
            setBackground(list.getSelectionBackground());
            setForeground(list.getSelectionForeground());
        } else {
            setBackground(list.getBackground());
            setForeground(list.getForeground());
        }

        // Display the text
        String text = (String) value;
        setText(text);

        // Get the source

然后，根据您的来源，使用this.setForeground（颜色）设置文本的颜色。最后，

return this;

}

Answer 2

您可能需要为JComboBox提供自定义渲染器，请查看Sun的教程：

http://java.sun.com/docs/books/tutorial/uiswing/components/combobox.html#renderer

（很抱歉没有链接，因为我是新会员而无法发布链接）

Answer 3

您可以使用ListCellRenderer。你需要为此编写自定义类。以下是基于索引设置前景的完整代码（以避免重复）。您还可以为此设置自定义选择背景和背景。请参阅代码中的注释。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
class ListCellRendererDemo2 extends JFrame
{
Hashtable<Integer,Color> table;
JComboBox<String> c;

    public ListCellRendererDemo2()
    {
        createAndShowGUI();
    }

    private void createAndShowGUI()
    {
        setTitle("JComboBox Demo");
        setLayout(new FlowLayout());
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        table=new Hashtable<Integer,Color>();
        table.put(1,Color.RED);
        table.put(2,Color.BLUE);
        table.put(3,Color.GREEN);
        table.put(4,Color.GRAY);


        c=new JComboBox<String>();
        c.addItem("Item 1");
        c.addItem("Item 2");
        c.addItem("Item 3");
        c.addItem("Item 4");
        c.addItem("Item 5");
        c.addItem("Item 6");
        c.addItem("Item 7");
        c.addItem("Item 8");

        c.setRenderer(new MyListCellRenderer(table));

        add(c);
        setSize(400,400);
        setVisible(true);
    }

    public static void main(String args[])
    {
        SwingUtilities.invokeLater(new Runnable(){
            public void run()
            {
                new ListCellRendererDemo2();
            }
        });
    }
}
class MyListCellRenderer extends DefaultListCellRenderer
{
Hashtable<Integer,Color> table;

    public MyListCellRenderer(Hashtable<Integer,Color> table)
    {
        this.table=table;

        // Set opaque for the background to be visible
        setOpaque(true);
    }

    public Component getListCellRendererComponent(JList jc,Object val,int idx,boolean isSelected,boolean cellHasFocus)
    {
        // Set text (mandatory)
        setText(val.toString());

        // Set the foreground according to the selected index
        setForeground(table.get(idx));

            // Set your custom selection background, background
            // Or you can get them as parameters as you got the table
            if(isSelected) setBackground(Color.LIGHT_GRAY);
            else setBackground(Color.WHITE);

    return this;
    }
}

如何为JCombobox中的线条制作独特的字体颜色？

3 个答案: