Custom JTooltip

Okay, this is going to be quick as I am a little short on time lately. This blog entry was motivated by me trying to create a custom JTooltip. I didn’t want custom borders or colors, as described in Swing Hacks. I actually wanted to add some components to the JTooltip, so that users could interact with it and provide input. After reading the relevant part of swing’s source code, I set out googling for ideas. It turned out to be quite difficult to find any interesting/simple ideas. Hence, this blog post.

In the end, what we need to do is to subclass JTooltip. This subclass should build and layout the desired components. Then an instance of this class has to be returned by the component that will own the tooltip. An example follows:

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JToolTip;

public class CustomTooltipSample extends JFrame {
    private CustomLabel m_label;

    public CustomTooltipSample() {
        setTitle("Custom tooltip sample");
        setSize(300, 200);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        m_label = new CustomLabel("My Label");
        m_label.setToolTipText("Yo, I am a tooltip with components!"); // activate tooltips for this component
        add(m_label);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override public void run() {
                JFrame frame = new CustomTooltipSample();
                frame.setVisible(true);
            }
        });
    }

    private static class CustomLabel extends JLabel {
        private CustomTooltip m_tooltip;

        public CustomLabel(String text) {
            super(text);
        }

        @Override public JToolTip createToolTip() {
            if (m_tooltip == null) {
                m_tooltip = new CustomTooltip();
                m_tooltip.setComponent(this);
            }
            return m_tooltip;
        }
    }

    private static class CustomTooltip extends JToolTip {
        private JLabel m_label;
        private JButton m_button;
        private JPanel m_panel;

        public CustomTooltip() {
            super();
            m_label = new JLabel();
            m_button = new JButton("See, I am a button!");
            m_panel = new JPanel(new BorderLayout());
            m_panel.add(BorderLayout.CENTER, m_label);
            m_panel.add(BorderLayout.SOUTH, m_button);
            setLayout(new BorderLayout());
            add(m_panel);
        }

        @Override public Dimension getPreferredSize() {
            return m_panel.getPreferredSize();
        }

        @Override public void setTipText(String tipText) {
            if (tipText != null && !tipText.isEmpty()) {
                m_label.setText(tipText);
            } else {
                super.setTipText(tipText);
            }
        }
    }
}

That’s it. Now you can use your creativity to customize the tooltip. Happy coding!

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