Example text in JTextField

Question

I am looking for a way to put example text into a swing JTextField and have it grayed out. The example text should then disappear as soon as any thing is entered into that t

Answer 1

The Text Prompt class provides the required functionality without using a custom JTextField.

It allows you to specify a prompt that is displayed when the text field is empty. As soon as you type text the prompt is removed.

The prompt is actually a JLabel so you can customize the font, foreground etc..:

JTextField tf7 = new JTextField(10);
TextPrompt tp7 = new TextPrompt("First Name", tf7);
tp7.setForeground( Color.RED );

Answer 2

private JLabel l;

JPromptTextField(String prompt) {
    l = new JLabel(prompt, SwingConstants.CENTER);
    l.setForeground(Color.GRAY);
}

@Override
protected void paintComponent(Graphics g) {
    super.paintComponent(g);

    if (this.getText().length() == 0) {
        // Reshape the label if needed, then paint

        final Rectangle mine = this.getBounds();
        final Rectangle its = l.getBounds(); 
        boolean resized = (mine.width != its.width) || (mine.height != its.height);
        boolean moved = (mine.x != its.x) || (mine.y != its.y);
        if (resized || moved)
            l.setBounds(mine);

        l.paint(g);
    }
}

Answer 3

How about initialize the text field with default text and give it a focus listener such that when focus is gained, if the text .equals the default text, call selectAll() on the JTextField.

Answer 4

You can't do that with a plain text field, but you can put a disabled JLabel on top of the JTextField and hide it if the text field gets the focus.

Answer 5

If you can use external librairies, the Swing components from Jide software have what you are looking for; it's called LabeledTextField (javadoc) and it's part of the JIDE Common Layer (Open Source Project) - which is free. It's doing what mklhmnn suggested.

Answer 6

Rather than overriding, put a value in the field and add a KeyListener that would remove the value when a key stroke is registered. Maybe also have it change the foreground.

You could wrap this up into your own custom JTextField class that would take the default text in a constructor.