Resizing JButtons and other components according to text

Question

How do you resize a JButton at runtime so it adapts to the text given by setSize? I've done some searching and this is the code I've come up with so far. Could this be turned into a utility method?

FontMetrics metrics = getFontMetrics( font );
int width = metrics.stringWidth( string );

P.S: No layout manager is being used.

Answer 1

You need to use setPreferredSize() on the component. Then, to resize it, call setBounds().

I would probably subclass the button, and override the setText(String text) method to include the resizing code.

@Override
public void setText(String arg0) {
    super.setText(arg0);
    FontMetrics metrics = getFontMetrics(getFont()); 
    int width = metrics.stringWidth( getText() );
    int height = metrics.getHeight();
    Dimension newDimension =  new Dimension(width+40,height+10);
    setPreferredSize(newDimension);
    setBounds(new Rectangle(
                   getLocation(), getPreferredSize()));
}

---

For testing, I did this in the constructor of my new JButton subclass:

public ResizeToTextButton(String txt){
    super(txt);
    addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent arg0) {
            setText(JOptionPane.showInputDialog("Text"));
        }
    });
}

So, whenever I clicked on the button I could change the text and see if it resized properly.

Answer 2

I had the same problem, even when using a layout manager (BorderLayout). But in my case a simple call to layoutContainer() of the associated layout manager and then a repaint() on the JFrame was sufficient for changing the width of the button.

button1.setText("New Label that differs in width");
// button1 is inside the container horizontalBox
horizontalBox.getLayout().layoutContainer(horizontalBox);
repaint(); // on the containing JFrame