如何将背景图像添加到JComboBox？

Question

我问here如何正确添加背景图片的JComboBox，但没有看到答案，所以我想，我应该对这两个问题分开......

所以。如何将JComboBox文本字段和JComboBox弹出式面板的背景图像正确添加？

UPD： 一些对你的代码）

当前代码：

// ... Renderer 

public class CBoxListCellRenderer implements ListCellRenderer { 

    ImagePanel panel; 
    JLabel label = new JLabel(); 

    public CBoxListCellRenderer(Image img) {panel = new ImagePanel(img);} 

    public void setImage(Image img) {panel.setImage(img);} 

    @Override 
    public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { 
      label.setText(value.toString()); 
      panel.add(label); 
      return panel; 
    } 
} 

// ... ImagePanel 

public class ImagePanel extends JPanel { 

    private BufferedImage img; 

    public ImagePanel(String img) { 
     setImage(img); 
    } 

    public void setImage(String img) 
    { 
     try { 
      this.img = ImageIO.read(this.getClass().getResource(img)); 
     } catch (IOException ex) { 
      ex.printStackTrace(); 
     } 
     Dimension size = new Dimension(this.img.getWidth(), this.img.getHeight()); 
     setSize(size); 
    } 

    @Override 
    public void paintComponent(Graphics g) { 
     g.drawImage(img, 0, 0, getWidth(), getHeight(), 0, 0, img.getWidth(), img.getHeight(), this); 
    } 
} 

// ... Colorizing arrow 

class ColorArrowUI extends BasicComboBoxUI { 

    public static ComboBoxUI createUI(JComponent c) { 
     return new ColorArrowUI(); 
    } 

    @Override protected JButton createArrowButton() { 
      return new BasicArrowButton(
       BasicArrowButton.SOUTH, 
       Color.cyan, Color.magenta, 
       Color.yellow, Color.blue); 
    } 
} 

// ... Creating object 

combo_language = new JComboBox(new DefaultComboBoxModel(new String[] { "English", "日本語", "Русский" })); 
combo_language.setBorder(null); 
combo_language.setRenderer(new CBoxListCellRenderer(new ImageIcon(getClass().getResource("/Images/form.png")).getImage())); 
combo_language.setUI(new ColorArrowUI()); 


// ... Putting JComboBox to JFrame 

Answer 1

这里有一个自定义ListCellRenderer的例子。我返回一个JPanel，它已经绘制了一个图像，然后添加了一个保存列表对象值的JLabel。它有改进的空间，但它只是你能做的一个例子。

import java.awt.*; 
import java.awt.image.BufferedImage; 
import java.io.IOException; 
import javax.imageio.ImageIO; 
import javax.swing.*; 

public class TestCBoxListCellRenderer { 

    public TestCBoxListCellRenderer() { 
     String[] list = {"Hello World 1", "Hello World 2", "Hello World 3"}; 
     JComboBox box = new JComboBox(list); 
     box.setRenderer(new CBoxListCellRenderer()); 

     JOptionPane.showMessageDialog(null, box, "Check out this Renderer", JOptionPane.PLAIN_MESSAGE); 
    } 

    public static void main(String[] args) { 
     new TestCBoxListCellRenderer(); 
    } 

    class BackGroundPanel extends JPanel { 

     BufferedImage img = null; 

     public BackGroundPanel() { 
      try { 
       img = ImageIO.read(TestCBoxListCellRenderer.class.getResource("/res/leafcell.png")); 
      } catch (IOException ex) { 
       ex.printStackTrace(); 
      } 
     } 
     @Override 
     protected void paintComponent(Graphics g) { 
      super.paintComponent(g); 
      g.drawImage(img, 0, 0, getWidth(), getHeight(), 
        0, 0, img.getWidth(), img.getHeight(), this); 
     } 
    } 

    private class CBoxListCellRenderer implements ListCellRenderer { 

     final BackGroundPanel panel = new BackGroundPanel(); 
     JLabel label = new JLabel(); 

     @Override 
     public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { 

      label.setText(value.toString()); 
      panel.add(label); 

      return panel; 
     } 
    } 
} 

您可能需要添加一个细线边框或它的选择时，它给你做一些事情。使用getListCellRendererComponent方法中的变量根据您的喜好进行渲染

Answer 2

尝试使用ListCellRenderer喜欢这里描述： http://docs.oracle.com/javase/tutorial/uiswing/components/combobox.html#renderer