Extend JComponent to create custom Component - Java Swing

Java examples for Swing:JComponent

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Description

Extend JComponent to create custom Component

Demo Code

import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import javax.swing.JComponent;
import javax.swing.BorderFactory;
import java.awt.BasicStroke;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.Color;
import java.awt.geom.Line2D;

/* XMarksTheSpot is used by ComponentDisplayer. */
class XMarksTheSpot extends JComponent {
    Dimension preferredSize = null;

    public XMarksTheSpot() {
        setOpaque(true);//  w  w  w  .j  a  va2 s  .  c o m

        //Set the border using either a MatteBorder (standard, used in 
        //Exercise 1) or a StripeBorder (custom, used in Exercise 3).
        //You can find the exercises here:
        //  http://docs.oracle.com/javase/javatutorials/tutorial/uiswing/QandE/questions-ch6.html
        setBorder(BorderFactory.createMatteBorder(5, 5, 5, 5, Color.BLACK));
        //setBorder(new StripeBorder());
    }

    protected void paintComponent(Graphics g) {
        if (isOpaque()) {
            g.setColor(getBackground());
            g.fillRect(0, 0, getWidth(), getHeight());
            g.setColor(getForeground());
        }

        Graphics2D g2 = (Graphics2D) g;
        Insets insets = getInsets();
        g2.setStroke(new BasicStroke(5.0f));
        g2.draw(new Line2D.Double(insets.left, insets.top, getWidth()
                - insets.right, getHeight() - insets.bottom));
        g2.draw(new Line2D.Double(insets.left, getHeight() - insets.bottom,
                getWidth() - insets.right, insets.top));
    }

    public Dimension getPreferredSize() {
        if (preferredSize == null) {
            return new Dimension(250, 100);
        } else {
            return super.getPreferredSize();
        }
    }

    public void setPreferredSize(Dimension newPrefSize) {
        preferredSize = newPrefSize;
        super.setPreferredSize(newPrefSize);
    }
}
/* 
 * ComponentDisplayer.java requires the following files:
 *   XMarksTheSpot.java
 */
//Note: This program doesn't create its GUI in invokeAndWait.  Since it does
//no event handling, that's almost certainly OK.
public class ComponentDisplayer {
    public static void main(String[] args) {
        JFrame f = new JFrame("ComponentDisplayer");

        JPanel p = new JPanel(new BorderLayout());
        p.add(new XMarksTheSpot(), BorderLayout.CENTER);

        f.setContentPane(p);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.pack();
        f.setVisible(true);
    }
}

/*
 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

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