问题
I am trying to set an icon to a JLabel from a folder of images whenever an item is selected from a JComboBox. The name of items in the JComboBox and name of the images in the folder are same. So whenever an item is selected from the JComboBox, the corresponding image with the same name should be set as an icon to the JLabel. I am trying to do something like this.
private void cmb_movieselectPopupMenuWillBecomeInvisible(javax.swing.event.PopupMenuEvent evt){
updateLabel(cmb_moviename.getSelectedItem().toString());
}
protected void updateLabel(String name) {
ImageIcon icon = createImageIcon(\"C:\\\\Users\\\\xerof_000\\\\Pictures\\\\tmspictures\\\\\" + name + \".jpg\");
if(icon != null){
Image img = icon.getImage();
Image newimg = img.getScaledInstance(lbl_pic.getWidth(), lbl_pic.getHeight(), java.awt.Image.SCALE_SMOOTH);
icon = new ImageIcon(newimg);
lbl_pic.setIcon(icon);
lbl_pic.setText(null);
}
else{
lbl_pic.setText(\"Image not found\");
lbl_pic.setIcon(null);
}
}
protected static ImageIcon createImageIcon(String path) {
URL imgURL;
imgURL = NowShowing.class.getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL);
} else {
return null;
}
}
I thought the problem is in \"C:\\Users\\xerof_000\\Pictures\\tmspictures\\\" I tried using \"C:/Users/xerof_000/Pictures/tmspictures/\" but even that did not work. And whatever I do it only shows \"Image not found\" on the JLabel.
回答1:
This is my directory structure :
packageexample
|
-------------------------------------------
| | |
build(folder) src(folder) manifest.txt
| |
swing(package) ComboExample.java
|
imagetest(subpackage)
|
ComboExample.class + related .class files
This is the content of the ComboExample.java file :
package swing.imagetest;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import javax.swing.*;
public class ComboExample {
private String[] data = new String[]{
"geek0",
"geek1",
"geek2",
"geek3",
"geek4"
};
private String MESSAGE = "No Image to display yet...";
private JLabel imageLabel;
private JComboBox cBox;
private ActionListener comboActions =
new ActionListener() {
@Override
public void actionPerformed(ActionEvent ae) {
JComboBox combo = (JComboBox) ae.getSource();
ImageIcon image = new ImageIcon(
getClass().getResource(
"/" + combo.getSelectedItem() + ".gif"));
if (image != null) {
imageLabel.setIcon(image);
imageLabel.setText("");
} else {
imageLabel.setText(MESSAGE);
}
}
};
private void displayGUI() {
JFrame frame = new JFrame("Combo Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
imageLabel = new JLabel(MESSAGE, JLabel.CENTER);
cBox = new JComboBox(data);
cBox.addActionListener(comboActions);
contentPane.add(imageLabel);
contentPane.add(cBox);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new ComboExample().displayGUI();
}
});
}
}
NOW THE COMPILATION :
To compile I did this :
Gagandeep Bali@LAPTOP ~/c/Mine/JAVA/J2SE/src/packageexample
$ javac -d build src/*.java
Contents of Manifest File :
JAR File creation :
Gagandeep Bali@LAPTOP ~/c/Mine/JAVA/J2SE/src/packageexample
$ cd build
Gagandeep Bali@LAPTOP ~/c/Mine/JAVA/J2SE/src/packageexample/build
$ jar -cfm imagecombo.jar ../manifest.txt *
Now take this JAR File to any location having these images (
, 
, 
, 
and 
), and run the JAR File, and see the results :-)
回答2:
As discussed in How to Use Icons, the getResource() method expects to find the image in your program's JAR file. You'll need to move the image into your project. IconDemo is a complete example.
回答3:
Since you use jLabel, you can simple use HTML tags, just begin the label text with < html > and use HTML tags in the label as u want, in tour case : < img src=filepth\imagefile.jpg > U can use this to replace : ). With smile icon.
回答4:
/*
Create an Image File whose size is 700 x 472 (pixels) in any image editor.
Here Image was created using MS - Paint.
Make sure that the Image File and the main file are in the same folder.
The size of the JFrame should be set to 700 x 472 (pixels) in the program.
Set the JLabel's IconImage.
Add the JLabel to the JFrame.
Set JFrame properties.
Display JFrame.
------------------------------------------------------------------------------
label.setIcon(getClass().getResources(String name));
label.setIcon(new ImageIcon(String file));
These 2 methods, don't always work with us.
So, we create a method "getImageIcon(File f)" that returns a new ImageIcon Object,
everytime a new File Object is passed to it.
*/
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.Image;
import javax.imageio.ImageIO;
import java.io.File;
import java.io.IOException;
import javax.swing.ImageIcon;
import static javax.swing.WindowConstants.*;
public class ImageDemo
{
JFrame frame = new JFrame(); //initialized
JLabel label = new JLabel(); //initialized
JButton button = new JButton(); //initialized
ImageIcon ii; //not initialized
public void displayImage()
{
//Layout Type: Null Layout.
label.setIcon(getImageIcon(new File("print.png")));
button.setBounds(150,150,358,66);
//Note that sizes of the Image and Button are same.
button.setIcon(getImageIcon(new File("Button.png")));
label.add(button);
//add the button to the label
frame.add(label);
frame.setBounds(300, 50, 700, 472);
//(300 x 50 = HorizontalAlignment x VerticalAlignment)
//(700 x 472 = Width x Height)
frame.setTitle("Image Demo");
frame.setDefaultCloseOperation(EXIT_ON_CLOSE); //WindowConstants.EXIT_ON_CLOSE
frame.setVisible(true);
}
public ImageIcon getImageIcon(File f)
{
try
{
Image im = ImageIO.read(f);
ii = new ImageIcon(im);
}
catch(IOException i)
{
i.printStackTrace();
}
finally
{
return ii;
}
}
public static void main(String[] args)
{
ImageDemo id = new ImageDemo();
id.displayImage();
}
}
来源：https://stackoverflow.com/questions/15182329/how-to-set-icon-to-a-jlabel-from-an-image-from-a-folder