我想在面板中添加一个图像和描述，但只要我在组合框中选择一年，描述就会出现在列表中，问题是图像没有显示在面板的下半部分。我想我的代码有些不对劲。有人可以帮我解决这个问题吗？
这是我到目前为止所尝试的：
public class Main extends JApplet
{
private String[] description;
private JList list = new JList();
private DefaultListModel defaultListModel = new DefaultListModel();
private JComboBox c = new JComboBox();
private JButton b = new JButton("Ok");
private ImageIcon image;
public void init()
{
try
{
description = new String[22];
description[0] = "1990";
description[1] = "1991";
description[2] = "1992";
description[3] = "1993";
description[4] = "1994";
description[5] = "1995";
description[6] = "1996";
description[7] = "1997";
description[8] = "1998";
description[9] = "1999";
description[10] = "2000";
description[11] = "2001";
description[12] = "2002";
description[13] = "2003";
description[14] = "2004";
description[15] = "2005";
description[16] = "2006";
description[17] = "2007";
description[18] = "2008";
description[19] = "2009";
description[20] = "2010";
description[21] = "2011";
description[22] = "2012";
}
catch (ArrayIndexOutOfBoundsException e)
{
e.printStackTrace();
}
c = new JComboBox(description);
list = new JList(defaultListModel);
list.setBorder(BorderFactory.createLineBorder(Color.black, 1));
b.setText("<html><b><u>Click</click></b></html>");
list.setFont(new Font("Garamond", Font.BOLD, 17));
list.setForeground(Color.BLUE);
JLabel label = new JLabel(image);
JPanel down = new JPanel();
down.setBorder(BorderFactory.createEmptyBorder(100, 100, 100, 100));
down.add(label);
JPanel panel = new JPanel();
panel.add(c);
panel.add(b);
Container cp = getContentPane();
cp.add(list, BorderLayout.CENTER);
cp.add(panel, BorderLayout.NORTH);
cp.add(down, BorderLayout.SOUTH);
this.setVisible(true);
b.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent
event)
{
int select;
select = c.getSelectedIndex();
defaultListModel.clear();
if (select == 0)
{
defaultListModel.addElement("the year of 1990");
image = new ImageIcon("chicken.gif");
}
}
});
}
答案 0 :(得分：3)
我用它来调整我的ImageIcon：
if (select == 0)
{
defaultListModel.addElement("the year of 1990");
image = new ImageIcon("chicken.gif")
label.setIcon(new ImageIcon(getScaledImage(image.getImage(), 32, 32))))
}
....
/**
* Resizes an image using a Graphics2D object backed by a BufferedImage.
* @param srcImg - source image to scale
* @param w - desired width
* @param h - desired height
* @return - the new resized image
*/
private Image getScaledImage(Image srcImg, int w, int h){
BufferedImage resizedImg = new BufferedImage(w, h, BufferedImage.TRANSLUCENT);
Graphics2D g2 = resizedImg.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2.drawImage(srcImg, 0, 0, w, h, null);
g2.dispose();
return resizedImg;
}
答案 1 :(得分：2)
首先，您在init()方法的开头有一个错误，这与您的实际问题无关。你有一个包含22个字符串的数组，并且你试图将一个值分配给第23个索引，这是错误的，除非你放弃它，否则你会收到错误。
对于您的实际问题，更改图像的值不会更改/更新标签。请尝试使用actionPerformed()方法中的代码段，但是您需要将标签设为最终变量或全局变量。
if (select == 0)
{
try
{
label.setIcon(new ImageIcon(ImageIO.read(new File("chicken.gif"))));
} catch (IOException e) {
e.printStackTrace();
}
}
答案 2 :(得分：2)
您的代码中有很多错误。
String Array描述的大小为22，您要为索引22添加一个值，这将导致ArrayIndexOutOfBoundsException。JLabel时，它将不会显示任何内容，如预期的那样。PAGE_START，PAGE_END，LINE_START，LINE_END和CENTER。但是你使用的是NORTH，EAST，WEST，SOUTH方法，这是旧的。在这里，我稍微修改了你的代码，看看，你的图像现在是否来了。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Main extends JApplet
{
private String[] description;
private JList list = new JList();
private DefaultListModel defaultListModel = new DefaultListModel();
private JComboBox c = new JComboBox();
private JButton b = new JButton("Ok");
private ImageIcon image;
private Icon infoIcon = UIManager.getIcon("OptionPane.informationIcon");
public void init()
{
try
{
description = new String[22];
description[0] = "1990";
description[1] = "1991";
description[2] = "1992";
description[3] = "1993";
description[4] = "1994";
description[5] = "1995";
description[6] = "1996";
description[7] = "1997";
description[8] = "1998";
description[9] = "1999";
description[10] = "2000";
description[11] = "2001";
description[12] = "2002";
description[13] = "2003";
description[14] = "2004";
description[15] = "2005";
description[16] = "2006";
description[17] = "2007";
description[18] = "2008";
description[19] = "2009";
description[20] = "2010";
description[21] = "2011";
//description[22] = "2012";
}
catch (ArrayIndexOutOfBoundsException e)
{
e.printStackTrace();
}
c = new JComboBox(description);
list = new JList(defaultListModel);
list.setBorder(BorderFactory.createLineBorder(Color.black, 1));
b.setText("<html><b><u>Click</click></b></html>");
list.setFont(new Font("Garamond", Font.BOLD, 17));
list.setForeground(Color.BLUE);
final JLabel label = new JLabel(image);
JPanel down = new JPanel();
down.setBorder(BorderFactory.createEmptyBorder(100, 100, 100, 100));
down.add(label);
JPanel panel = new JPanel();
panel.add(c);
panel.add(b);
Container cp = getContentPane();
cp.add(list, BorderLayout.CENTER);
cp.add(panel, BorderLayout.PAGE_START);
cp.add(down, BorderLayout.PAGE_END);
this.setVisible(true);
b.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent
event)
{
int select;
select = c.getSelectedIndex();
defaultListModel.clear();
if (select == 0)
{
defaultListModel.addElement("the year of 1990");
label.setIcon(infoIcon);
}
else
{
label.setIcon(null);
}
}
});
}
}
使用带有ImageIO的{{1}}访问图片的更好方法，因为图片是URL，因此通过Application Resource而不是URL访问图片更为明智我的这篇文章中显示了File：Access Images via ImageIO