Using an icon image for a GUI

Question

I have created the following code for a school project, a "password protector", just for fun, really. However, the problem I have is that the icon image does not appear, but instead the default java "coffee cup".

import javax.swing.*;

import java.awt.*;
import java.awt.event.*;

public class UserInterfaceGUI extends JFrame
{
    private static final long serialVersionUID = 1;
    private JLabel userNameInfo; // ... more unimportant vars.

    public UserInterfaceGUI()
    {
        this.setLayout(new FlowLayout());
        userNameInfo = new JLabel("Enter Username:"); // ... more unimportant var. declartions

        this.add(userNameInfo); // ... more unimportant ".add"s

        event e = new event();
        submit.addActionListener(e);
    }

    public static void main(String[] args)
    {
        //This icon has a problem \/
        ImageIcon img = new ImageIcon("[File Location hidden for privacy]/icon.ico");

        UserInterfaceGUI gui = new UserInterfaceGUI();
        gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        gui.setSize(400, 140);
        gui.setIconImage(img.getImage());
        gui.setTitle("Password Protector");
        gui.setVisible(true);
    }
}

Can someone tell me why this just shows the java coffee cup at the bottom of the screen and on the bar at the top of the window?

Not sure if java can read an ".ico" file. Try using a .jpg or .gif image. — camickr, Apr 08 '15 at 15:35
Are you sure your ImageIcon is fully initialized (error on path?) @camickr you're right , see http://stackoverflow.com/questions/12185768/does-swing-support-ico-files — alias_boubou, Apr 08 '15 at 15:36
This is not going to solve your problem, but consider using [`setIconImages`](http://docs.oracle.com/javase/8/docs/api/java/awt/Window.html#setIconImages-java.util.List-) instead, which allows to define images of different resolutions — Robin, Apr 08 '15 at 15:44
Let me know the file is resource or in a folder out of project? Also the file you use must be smaller than "32*32" i think.. — crAlexander, Apr 08 '15 at 15:57
@crAlexander *"Also the file you use must be smaller than "32*32" i think."* [Think again](http://stackoverflow.com/questions/18224184/sizes-of-frame-icons-used-in-swing). The icon size on some Windows machines reaches at least 40x40. — Andrew Thompson, Apr 09 '15 at 08:29

score 3 · Accepted Answer · edited May 23 '17 at 11:43

There are two likely problems here:

Java is unlikely to support .ico files. The only types that can be relied on are GIF, PNG & JPEG.

For all types supported on any specific JRE, use ImageIO.getReaderFileSuffixes() (but seriously, for app. icons stick to the 3 types with guaranteed support).
The code is trying to load an application resource as a file, when it will likely be (or become) an embedded-resource that should be accessed by URL. See the embedded resource info. page for tips on how to form the URL.

Using an icon image for a GUI

1 Answers1