Java swing-使用按钮更改包含图标的标签的颜色

Question

I am trying to change the color of an icon using 3 different JButtons, each for a different color.

The icon is a circle that starts out as red default. When the user clicks the button called "blue" the circle changes color to blue, same idea for "green".

To update this icon color, i am supposed to use the repaint() method.

Here is my method to create the red circle icon.

import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;


public class ColorIcon implements Icon
{
private int width;
private Color color;
private ChangeColor c;


public ColorIcon(int aWidth, ChangeColor c)
{
this.c = c;
width = aWidth;
color = Color.RED;
}

public int getIconWidth()
{
return width;
}

public int getIconHeight()
{
return width / 2;
}

public void setColor(Color c)
{
color = c;
}

public void paintIcon(Component c, Graphics g, int x, int y)
{

color = c.color;
Graphics2D g2 = (Graphics2D) g;
Ellipse2D.Double ellipse = new Ellipse2D.Double(x,y, width, width);
g2.setColor( color );
g2.fill( ellipse );
}
}

And here is the class i use to test it. This class is the one with the event handler that creates the buttons that when pressed should change the color of the icon.

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class TestColorIcon{

public java.awt.Color color = java.awt.Color.RED;

public Component createComponents()
{ 
JButton buttonRed = new JButton("Red");
JButton buttonBlue = new JButton("Blue");
JButton buttonGreen = new JButton("Green");

final ColorIcon icon = new ColorIcon( 20);
final JLabel label = new JLabel( icon );

JPanel panel = new JPanel();
panel.setLayout( new GridLayout(0, 3) );
panel.add( buttonRed );
panel.add( buttonBlue );
panel.add( buttonGreen );
panel.add( label );

buttonRed.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
color = Color.RED;
label.repaint();
}
});

buttonBlue.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
color = Color.BLUE;
label.repaint();
}
});

buttonGreen.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
color = Color.GREEN;
label.repaint();
}
});

return panel;
}


public static void main(String[] args)
{    

JFrame frame = new JFrame();
ChangeColor changeColor = new ChangeColor(); 
Component content = changeColor.createComponents();
frame.getContentPane().add( content );
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.show();
}
}

When I run this, i get an error saying compiler cannot resolve class ColorIcon. I am not sure how to fix this error and get the desired output.

The code has gotten a bit long so i am unable to pinpoint the exact reason for the error, so any help is appreciated.

Answer 1

You never seem to change the color of the ColorIcon itself

buttonRed.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        color = Color.RED;
        label.repaint();
    }
});

Instead, make sure you are applying the color to the icon as well.

buttonRed.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        color = Color.RED;
        icon.setColor(color);
        label.repaint();
    }
});

Icon should not be relying on any other information other then what it's provide for itself, so instead of trying to get the color from yet another source, simply use the support that the ColorIcon already has

Answer 2

When I run this, i get an error saying compiler cannot resolve class ColorIcon.

Your constructor of the ColorIcon class is

public ColorIcon(int aWidth, ChangeColor c)

It expects one int and one ChnageColor arguments.

And you are calling it with wrong parameters.

final ColorIcon icon = new ColorIcon(20);