ControlListenerExample.java Source code

Introduction

Here is the source code for ControlListenerExample.java

Source

//Send questions, comments, bug reports, etc. to the authors:

//Rob Warner (rwarner@interspatial.com)
//Robert Harris (rbrt_harris@yahoo.com)

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * This class demonstrates ControlListeners
 */
public class ControlListenerExample {
    /**
     * Runs the application
     */
    public void run() {
        Display display = new Display();
        Shell shell = new Shell(display);
        Image image = new Image(display, "java2s.gif");
        createContents(shell, image);
        shell.pack();
        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }
        if (image != null)
            image.dispose();
        display.dispose();
    }

    /**
     * Creates the main window's contents
     * 
     * @param shell the main window
     * @param image the image
     */
    private void createContents(Shell shell, Image image) {
        shell.setLayout(new GridLayout());

        // Create a label to hold the image
        Label label = new Label(shell, SWT.NONE);
        label.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_BEGINNING));
        label.setImage(image);
        shell.setData(label);

        // Add the listener
        shell.addControlListener(new ControlAdapter() {
            public void controlResized(ControlEvent event) {
                // Get the event source (the shell)
                Shell shell = (Shell) event.getSource();

                // Get the source's data (the label)
                Label label = (Label) shell.getData();

                // Determine how big the shell should be to fit the image
                Rectangle rect = shell.getClientArea();
                ImageData data = label.getImage().getImageData();

                // If the shell is too small, hide the image
                if (rect.width < data.width || rect.height < data.height) {
                    shell.setText("Too small.");
                    label.setText("I'm melting!");
                } else {
                    // He fits!
                    shell.setText("Happy Guy Fits!");
                    label.setImage(label.getImage());
                }
            }
        });
    }

    /**
     * Application entry point
     * 
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new ControlListenerExample().run();
    }
}