[news.eclipse.platform.swt] Re: TabItem visibility

[Nik Bhattacharya <nik_bhat@xxxxxxxxx>]

Whoops...a little bug in the last program.  calling setControl after the 
tabItem was recreated was throwing an exception with message "widget has 
wrong parent".  Here is the updated snippet.  Sorry.

---------------------------------------------------------
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.TabFolder;
import org.eclipse.swt.widgets.TabItem;

public class CompositeTester extends Composite {

    private TabFolder tabFolder;
    private static final String SHOW = "Show TabItemOne";
    private static final String HIDE = "Hide TabItemOne";
    private TabItem tabItemTwo;
    private TabItem tabItemOne;
    private boolean show = true;

    public CompositeTester(Composite parent, int style) {
        super(parent, style);
        setLayout(new FillLayout());

        tabFolder = new TabFolder(this, SWT.NONE);

        createTabitemOne();

        createTabItemTwo();

        final Composite composite = new Composite(this, SWT.NONE);
        composite.setLayout(new FillLayout());

        final Button hideButton = new Button(composite, SWT.NONE);
        hideButton.addSelectionListener(new SelectionAdapter() {

            public void widgetSelected(SelectionEvent e) {
                if(show)
                {
                    tabItemOne.dispose();
                    hideButton.setText(SHOW);
                    show = false;
                }
                else
                {
                    createTabitemOne();
                    hideButton.setText(HIDE);
                    show = true;
                }
            }
        });
        hideButton.setText(HIDE);


        //
    }

    private void createTabItemTwo() {
        tabItemTwo = new TabItem(tabFolder, SWT.NONE);
        tabItemTwo.setText("TabItemTwo");
    }

    private void createTabitemOne() {
        tabItemOne = new TabItem(tabFolder, SWT.NONE);
        tabItemOne.setText("TabItemOne");
    }

    @Override
    public void dispose() {
        super.dispose();
    }

    @Override
    protected void checkSubclass() {
        // Disable the check that prevents subclassing of SWT components
    }

    public static void main (String [] args) {
        Display display = new Display();
        Shell shell = new Shell (display);
        shell.setLayout(new FillLayout());
        CompositeTester tester = new CompositeTester(shell, SWT.CENTER);
        shell.open ();
        while (!shell.isDisposed ()) {
            if (!display.readAndDispatch ()) display.sleep ();
        }
        display.dispose ();
    }

}

Nik Bhattacharya wrote:
> Below is the snippet I came up with based on Grant's response (not exact 
> though as I am passing in the tabFolder on recreation of the tabItem, 
> and not doing the setControl as he mentioned).  Whats the reason that 
> visibility is not a behavior available on org.eclipse.swt.widgets.Item 
> just like it is on Control?
>
> Disposing/recreating seems unnecessary to me for something like toggling 
> visibility.
>
> Nik
>
> --------------------------------------------------------------
> import org.eclipse.swt.SWT;
> import org.eclipse.swt.events.SelectionAdapter;
> import org.eclipse.swt.events.SelectionEvent;
> import org.eclipse.swt.layout.FillLayout;
> import org.eclipse.swt.widgets.Button;
> import org.eclipse.swt.widgets.Composite;
> import org.eclipse.swt.widgets.Display;
> import org.eclipse.swt.widgets.Shell;
> import org.eclipse.swt.widgets.TabFolder;
> import org.eclipse.swt.widgets.TabItem;
>
> public class CompositeTester extends Composite {
>
>     private TabFolder tabFolder;
>     private static final String SHOW = "Show TabItemOne";
>     private static final String HIDE = "Hide TabItemOne";
>     private TabItem tabItemTwo;
>     private TabItem tabItemOne;
>     private boolean show = true;
>
>     public CompositeTester(Composite parent, int style) {
>         super(parent, style);
>         setLayout(new FillLayout());
>
>         tabFolder = new TabFolder(this, SWT.NONE);
>
>         createTabitemOne();
>
>         createTabItemTwo();
>
>         final Composite composite = new Composite(this, SWT.NONE);
>         composite.setLayout(new FillLayout());
>
>         final Button hideButton = new Button(composite, SWT.NONE);
>         hideButton.addSelectionListener(new SelectionAdapter() {
>
>             public void widgetSelected(SelectionEvent e) {
>                 if(show)
>                 {
>                     tabItemOne.dispose();
>                     hideButton.setText(SHOW);
>                     show = false;
>                 }
>                 else
>                 {
>                     createTabitemOne();
>                     tabItemOne.setControl(tabFolder);
>                     hideButton.setText(HIDE);
>                     show = true;
>                 }
>             }
>         });
>         hideButton.setText(HIDE);
>        
>        
>         //
>     }
>
>     private void createTabItemTwo() {
>         tabItemTwo = new TabItem(tabFolder, SWT.NONE);
>         tabItemTwo.setText("TabItemTwo");
>     }
>
>     private void createTabitemOne() {
>         tabItemOne = new TabItem(tabFolder, SWT.NONE);
>         tabItemOne.setText("TabItemOne");
>     }
>
>     @Override
>     public void dispose() {
>         super.dispose();
>     }
>
>     @Override
>     protected void checkSubclass() {
>         // Disable the check that prevents subclassing of SWT components
>     }
>     
>     public static void main (String [] args) {
>         Display display = new Display();
>         Shell shell = new Shell (display);
>         shell.setLayout(new FillLayout());
>         CompositeTester tester = new CompositeTester(shell, SWT.CENTER);
>         shell.open ();
>         while (!shell.isDisposed ()) {
>             if (!display.readAndDispatch ()) display.sleep ();
>         }
>         display.dispose ();
>     }
>
> }
>
> Grant Gayed wrote:
> > Hi Frank,
> >
> > TabItems cannot be hidden, they can only be created and disposed.  So you
> > can "hide" it by disposing and later re-creating the tab.  You will 
> > not have
> > to re-create all of the tab's controls in this scenario since they're
> > parented on the TabFolder, you can just use
> > myRecreatedTabItem.setControl(theCompositeThatHoldsTheSetOfControlsThatWereO 
> >
> > nThePreviousInstanceOfThisTab).
> >
> > Grant
> >
> >
> > "frank Buloup" <buloup@xxxxxxxxxxxxxxxx> wrote in message
> > news:ekjhdq$3f8$1@xxxxxxxxxxxxxxxxxxxx
> > > Hello,
> > >
> > > Do you know how to set the visibility of a TabItem in a TabFolder ?
> > >
> > > thanks a lot,
> > > regards,
> > > frank