Rimondini il 08:28, 14 apr 2008

2008-04-14T08:28:33Z

Rimondini: ha spostato Programmazione:Java/Event Interface implementation a Programmazione:Java/Eclipse RCP/Event Interface implementation

2008-04-14T08:06:44Z

ha spostato Programmazione:Java/Event Interface implementation a Programmazione:Java/Eclipse RCP/Event Interface implementation

Rimondini il 11:56, 31 ott 2007

2007-10-31T11:56:14Z

Nuova pagina

=How to implement Event Interface=

This article use '''org.eclipse.swt.widgets.Listener''' interface as example....but it's valid for all interface

==Bad Practice==
<code java>
public class TestEventImpl {
Shell shell;
Button bt;

public void create() {
shell = new Shell(PlatformUI.getWorkbench().getDisplay());

Composite c = new Composite(shell, SWT.BORDER);

bt = new Button(c, SWT.PUSH);
bt.setText("Push ME");
bt.addListener(SWT.Selection, new Listener() {
public void handleEvent(Event event) {
// Do something
}
});

shell.addListener(SWT.Dispose, new Listener() {
public void handleEvent(Event event) {
// I can't remove listener...I don't have reference....
}
});
shell.open();
}
}
</code>

==Not Bad Practice but...==
<code java>
public class TestEventImpl {
Listener bt_listener, shell_listener;
Shell shell;
Button bt;

public void create() {
shell = new Shell(PlatformUI.getWorkbench().getDisplay());

Composite c = new Composite(shell, SWT.BORDER);

bt = new Button(c, SWT.PUSH);
bt.setText("Push ME");
bt_listener = new Listener() {
public void handleEvent(Event event) {
// Do something
}
}
bt.addListener(SWT.Selection, bt_listener);

shell_listener = new Listener() {
public void handleEvent(Event event) {
TestEventImpl parent = (TestEventImpl)event.widget.getData("ClassParent");
parent.bt.removeListener(bt_listener);
parent.shell.removeListener(shell_listener);
}
}
shell.addListener(SWT.Dispose, shell_listener);
shell.setData("ClassParent", this); // must save a class reference
shell.open();
}
}
</code>

==Best Practice ==
<code java>
public class TestEventImpl implements Listener {
Shell shell;
Button bt;

public void create() {
shell = new Shell(PlatformUI.getWorkbench().getDisplay());

Composite c = new Composite(shell, SWT.BORDER);

bt = new Button(c, SWT.PUSH);
bt.setText("Push ME");
bt.addListener(SWT.Selection, this);

shell.addListener(SWT.Dispose, this);
shell.open();
}

public void handleEvent(Event event) {
switch(event.type) {
case SWT.Selection:
if(event.widget == bt) {
// Do something
}
break;
case SWT.Dispose:
if(event.widget == shell) {
bt.removeListener(this);
shell.removeListener(this);
}
break;
}
}
}
</code>

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Programmazione:Java/Eclipse RCP/Event Interface implementation - Cronologia

Rimondini il 08:28, 14 apr 2008

Rimondini: ha spostato Programmazione:Java/Event Interface implementation a Programmazione:Java/Eclipse RCP/Event Interface implementation

Rimondini il 11:56, 31 ott 2007