17. 89. 4. SWT provides two kinds of event listening mechanism: typed and untyped.
A typed listener can be used to listen for only one particular typed event.
For example, SelectionListener is a typed listener for event SelectionEvent.
Untyped event listeners offer a generic, low-level mechanism to listen for events.
public class GenericEventUntyped { public static void main(String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new GridLayout());
Button button = new Button(shell, SWT.NONE);
button.setText("Click and check the console");
button.addSelectionListener(new SelectionListener() { public void widgetSelected(SelectionEvent arg0) {
System.out.println("widgetSelected");
}
public void widgetDefaultSelected(SelectionEvent arg0) {
System.out.println("widgetDefaultSelected");
}
});
shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) {
display.sleep();
}
}
}
}