[SOLVED] [newbie] java.lang.String cannot be cast to javax.swing.Icon

[jon80]

Any idea what the problem is here?

ToolBarFrame.java
package homenetwork.bkr.training;

import javax.swing.*;

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

@SuppressWarnings("serial")
public class ToolBarFrame extends JFrame {

	public ToolBarFrame()
	{
		setTitle("Toolbar test");
		setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
		
		//add a panel for color change
		panel = new JPanel();
		add(panel, BorderLayout.CENTER);
		
		//set up actions
		Action blueAction = new ColorAction("Blue", new ImageIcon("C:\\icons\\blue-ball.png"), Color.BLUE);
		Action yellowAction = new ColorAction("Yellow", new ImageIcon("C:\\icons\\yellow-ball.png"), Color.YELLOW);
		Action redAction = new ColorAction("Red", new ImageIcon("C:\\icons\\red-ball.png"), Color.RED);
		Action exitAction = new AbstractAction("Exit", new ImageIcon("C:\\icons\\exit.png"))
			{
				public void actionPerformed(ActionEvent event)
				{
					System.exit(0);
				}
			};
				

			exitAction.putValue(Action.SHORT_DESCRIPTION, "Exit");
		
		//populate tool bar
		JToolBar bar = new JToolBar();
		bar.add(blueAction);
		bar.add(yellowAction);
		bar.add(redAction);
		bar.addSeparator();
		bar.add(exitAction);
		add(bar, BorderLayout.NORTH);
		
		//populate menu
		JMenu menu = new JMenu("Color");
		menu.add(yellowAction);
		menu.add(blueAction);
		menu.add(redAction);
		menu.add(exitAction);
		JMenuBar menuBar = new JMenuBar();
		menuBar.add(menu);
		setJMenuBar(menuBar);
		
	}
	
	public class ColorAction extends AbstractAction {
		
		public ColorAction (String name, ImageIcon icon, Color c)
		{
			putValue(Action.NAME, name);
			putValue(Action.SMALL_ICON, name);
			putValue(Action.SHORT_DESCRIPTION, name);
			putValue("Color", c);
		}
		
		public void actionPerformed(ActionEvent event)
		{
			Color c = (Color) getValue("Color");
			panel.setBackground(c);
		}

	}
	
	public static final int DEFAULT_WIDTH = 300;
	public static final int DEFAULT_HEIGHT = 200;
	
	private JPanel panel;
}


Test.java
package homenetwork.bkr.training;
import java.awt.*;

import javax.swing.JFrame;

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable()
		{
			public void run()
			{
				ToolBarFrame frame = new ToolBarFrame();
				frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
				frame.setVisible(true);
			}
		});

	}

}

Output:
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to javax.swing.Icon
at javax.swing.AbstractButton.setIconFromAction(Unkno wn Source)
at javax.swing.AbstractButton.configurePropertiesFrom Action(Unknown Source)
at javax.swing.AbstractButton.setAction(Unknown Source)
at javax.swing.JToolBar.add(Unknown Source)
at homenetwork.bkr.training.ToolBarFrame.<init>(ToolB arFrame.java:37)
at homenetwork.bkr.training.Test$1.run(Test.java:16)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(U nknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

[OrangeDog]

Yes, a String cannot be cast to an Icon. I think you probably meant to use icon somewhere in your action's constructor.

[jon80]

Well I think I'm passing an ImageIcon:

Action blueAction = new ColorAction("Blue", new ImageIcon("C:\\icons\\blue-ball.png"), Color.BLUE);

...

public ColorAction (String name, ImageIcon icon, Color c)

[hardwired]

putValue(Action.SMALL_ICON, name);

is better

putValue(Action.SMALL_ICON, icon);

[jon80]

Did you mean...?

Action blueAction = new ColorAction("Blue", new ImageIcon("C:\\icons\\blue-ball.png"), Color.BLUE);
		blueAction.putValue(Action.SHORT_DESCRIPTION, "Blue");
		Action yellowAction = new ColorAction("Yellow", new ImageIcon("C:\\icons\\yellow-ball.png"), Color.YELLOW);
		yellowAction.putValue(Action.SHORT_DESCRIPTION, "Yellow");
		Action redAction = new ColorAction("Red", new ImageIcon("C:\\icons\\red-ball.png"), Color.RED);
		redAction.putValue(Action.SHORT_DESCRIPTION, "Red");
		Action exitAction = new AbstractAction("Exit", new ImageIcon("C:\\icons\\exit.png"))
			{
				public void actionPerformed(ActionEvent event)
				{
					System.exit(0);
				}
			};
				

			exitAction.putValue(Action.SHORT_DESCRIPTION, "Exit");

It still loads the error which starts at:

...
bar.add(blueAction);
...

[jon80]

Umm...Sorry I didn't get it straight away, thanks for spotting that

Any idea how to make the path to the image relative to the application itself when it is compiled.

In the meantime I would like to have the images stored in the project directory of the application itself?

[hardwired]

Any idea how to make the path to the image relative to the application itself when it is compiled
Yes. See How to Use Icons for a discussion of this subject and especially the section Loading Images Using getResource.
Using ImageIcon is an older method of loading images. One drawback of using it is that it doesn't give any feedback if it could not find the file, could not recognize the image format, of if the image data is corrupted or unreadable.
The newer way to load images is shown here Reading/Loading an Image.
In the meantime I would like to have the images stored in the project directory of the application itself
Okay.
About the image path in your code —

C:\\icons\\blue-ball.png

the double back slashes are for ms only. Use a single forward slash for java/all platforms.
You can move the icons folder into your project directory and use the path

icons/blue-ball.png