Netbeans ImageIcon not displaying

问题

I am using the NetBeans GUIBuilder to make a JPanel Form. I added a JLabel and used NetBeans' interface to give it an icon from an external image (.png). The path is verified and the image shows up on the GUIBuilder screen. It even shows up when I click the "Preview Design" button. It DOES NOT show up when I RUN the project. The rest of the GUI appears as it should. Do any of you know why this happening and/or how to fix it?

A lot of you have been asking for an SSCCE. Since the code is generated by the NetBeans Form Builder, I have instead included the steps I took to make the JLabel. The areas of focus are circled in red.

1. Drag and drop a JLabel into the Form Builder.

   

2. Open up the JLabel's properties menu. Enter the empty string ("") for the text field. Click the ellipsis next to icon.

   

3. Select External Image and click the ellipsis.

   

4. Select the image of choice. In my case it's a .png.

   

5. Notice that the image appears in the icon preview.

   

6. Close the icon menu and the properties menu, and notice that the image appears as the JLabel's icon on the Form Builder.

   

Thank you for accepting an unorthodox SSCCE and thank you in advance for your help.

回答1:

I found out the hard way that relying on Netbeans GUI builder to do everything for you is a mistake.

Just create an icon fetching class like the one below, put the icons in it's package, and use "Custom code" instead of "Image chooser". Sure the icons will not be visible inside NB. But if they show up when the app is running, who cares about that.

package com.example.resource.icons;

import javax.swing.ImageIcon;

public class IconFetch {

    private static IconFetch instance;

    private IconFetch(){
    }

    public static IconFetch getInstance() {
        if (instance == null)
            instance = new IconFetch();
        return instance;
    }

    public ImageIcon getIcon(String iconName) {
        java.net.URL imgUrl = getClass().getResource(iconName);
        if (imgUrl != null) {
            return new ImageIcon(imgUrl);
        } else {
            throw new IllegalArgumentException("This icon file does not exist");
        }
    }

    public static final String MINESWEEPER_ONE = "one.png";
}

Usage:

IconFetch.getInstance().getIcon(IconFetch.MINESWEEPER_ONE);

If the icon still doesn't show up after trying this, then something might be wrong with the way you layed out components in your form (the label is there but you can't see it).

Hope this helps even though it's a long shot.

回答2:

I had the same problem, and predi's solution wasn't working either. Then I created a package instead of a folder, and added the images there, and it works now.

来源：https://stackoverflow.com/questions/10876742/netbeans-imageicon-not-displaying