Creating a custom JButton in Java

Question

Is there a way to create a JButton with your own button graphic and not just with an image inside the button?

If not, is there another way to create a custom JButton in java?

Answer 1

When I was first learning Java we had to make Yahtzee and I thought it would be cool to create custom Swing components and containers instead of just drawing everything on one JPanel. The benefit of extending Swing components, of course, is to have the ability to add support for keyboard shortcuts and other accessibility features that you can't do just by having a paint() method print a pretty picture. It may not be done the best way however, but it may be a good starting point for you.

Edit 8/6 - If it wasn't apparent from the images, each Die is a button you can click. This will move it to the DiceContainer below. Looking at the source code you can see that each Die button is drawn dynamically, based on its value.

Here are the basic steps:

1. Create a class that extends JComponent
2. Call parent constructor super() in your constructors
3. Make sure you class implements MouseListener

4. Put this in the constructor:

   enableInputMethods(true);    addMouseListener(this); 

5. Override these methods:

   public Dimension getPreferredSize()   public Dimension getMinimumSize()   public Dimension getMaximumSize() 

6. Override this method:

   public void paintComponent(Graphics g) 

The amount of space you have to work with when drawing your button is defined by getPreferredSize(), assuming getMinimumSize() and getMaximumSize() return the same value. I haven't experimented too much with this but, depending on the layout you use for your GUI your button could look completely different.

And finally, the source code. In case I missed anything.

Answer 2

Yes, this is possible. One of the main pros for using Swing is the ease with which the abstract controls can be created and manipulates.

Here is a quick and dirty way to extend the existing JButton class to draw a circle to the right of the text.

package test;  import java.awt.Color; import java.awt.Container; import java.awt.Dimension; import java.awt.FlowLayout; import java.awt.Graphics;  import javax.swing.JButton; import javax.swing.JFrame;  public class MyButton extends JButton {      private static final long serialVersionUID = 1L;      private Color circleColor = Color.BLACK;      public MyButton(String label) {         super(label);     }      @Override     protected void paintComponent(Graphics g) {         super.paintComponent(g);          Dimension originalSize = super.getPreferredSize();         int gap = (int) (originalSize.height * 0.2);         int x = originalSize.width + gap;         int y = gap;         int diameter = originalSize.height - (gap * 2);          g.setColor(circleColor);         g.fillOval(x, y, diameter, diameter);     }      @Override     public Dimension getPreferredSize() {         Dimension size = super.getPreferredSize();         size.width += size.height;         return size;     }      /*Test the button*/     public static void main(String[] args) {         MyButton button = new MyButton("Hello, World!");          JFrame frame = new JFrame();         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);         frame.setSize(400, 400);          Container contentPane = frame.getContentPane();         contentPane.setLayout(new FlowLayout());         contentPane.add(button);          frame.setVisible(true);     }  } 

Note that by overriding paintComponent that the contents of the button can be changed, but that the border is painted by the paintBorder method. The getPreferredSize method also needs to be managed in order to dynamically support changes to the content. Care needs to be taken when measuring font metrics and image dimensions.

For creating a control that you can rely on, the above code is not the correct approach. Dimensions and colours are dynamic in Swing and are dependent on the look and feel being used. Even the default Metal look has changed across JRE versions. It would be better to implement AbstractButton and conform to the guidelines set out by the Swing API. A good starting point is to look at the javax.swing.LookAndFeel and javax.swing.UIManager classes.

http://docs.oracle.com/javase/8/docs/api/javax/swing/LookAndFeel.html

http://docs.oracle.com/javase/8/docs/api/javax/swing/UIManager.html

Understanding the anatomy of LookAndFeel is useful for writing controls: Creating a Custom Look and Feel