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Sync Horizontal Scrolling across two tables [message #1050796]

Sat, 27 April 2013 19:32

Wojtek

Messages: 47
Registered: August 2011

Member

I have the following code:

((Scrollable) baseTable).getHorizontalBar().addSelectionListener( new
SelectionAdapter()
{
@Override
public void widgetSelected( SelectionEvent event )
{
((Scrollable) totalsTable).getHorizontalBar().setSelection(
((Scrollable) baseTable).getHorizontalBar().getSelection() );
}
} );

This does a nice job in moving the scroll bars in sync, BUT it does not
actually move the contents of the totalsTable.

Is there an event I have to trigger to get the contents to also scroll?

--
Wojtek :-)

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Re: Sync Horizontal Scrolling across two tables [message #1053306 is a reply to message #1050796]

Fri, 03 May 2013 18:12

Wojtek

Messages: 47
Registered: August 2011

Member

Wojtek wrote :
> I have the following code:
>
> ((Scrollable) baseTable).getHorizontalBar().addSelectionListener( new
> SelectionAdapter()
> {
> @Override
> public void widgetSelected( SelectionEvent event )
> {
> ((Scrollable) totalsTable).getHorizontalBar().setSelection(
> ((Scrollable) baseTable).getHorizontalBar().getSelection() );
> }
> } );
>
> This does a nice job in moving the scroll bars in sync, BUT it does not
> actually move the contents of the totalsTable.
>
> Is there an event I have to trigger to get the contents to also scroll?

I placed the totalsTable inside a composite, then did a:

((Scrollable) composite).getHorizontalBar().setSelection(((Scrollable)
baseTable).getHorizontalBar().getSelection() );

Thinking that I could scroll the composite which would take the table
with it, and thus sync the horizontal movement.

But, alas, no. So it seems that the
getHorizontalBar().setSelection(int) will move the scroll bar, but will
NOT move the contents.

I cannot believe this is a defined behavior. There MUST be a way to
scroll the contents when the bar selection is changed by the program.

Otherwise why does the the method setSelection(int) even exist?

--
Wojtek :-)

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Re: Sync Horizontal Scrolling across two tables [message #1053388 is a reply to message #1050796]

Sat, 04 May 2013 23:00

Wojtek

Messages: 47
Registered: August 2011

Member

So there is no solution to this? setSelection(int) is a useless method
put only there as a counter to getSelection()?

Should I open a high priority bug for this non-behavior?

BTW a Google search will bring up lots of people who also tried to make
this work, and failed.

--
Wojtek :-)

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Re: Sync Horizontal Scrolling across two tables [message #1053396 is a reply to message #1053388]

Sun, 05 May 2013 04:00

David Wegener

Messages: 1445
Registered: July 2009

Senior Member

On 05/04/2013 06:00 PM, Wojtek wrote:
> So there is no solution to this? setSelection(int) is a useless method
> put only there as a counter to getSelection()?
>
> Should I open a high priority bug for this non-behavior?
>
> BTW a Google search will bring up lots of people who also tried to make
> this work, and failed.
>
Have you tried using the setOrigin method on the Scrollable instead of
setSelection? That method is documented to set point to be displayed in
the top left corner of the Scrollable. This appears to also set the the
scrollbar positions.

Here is an example that might help:

http://www.java2s.com/Code/Java/SWT-JFace-Eclipse/CreatetwoScrolledCompositesthatscrollintandem.htm

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Re: Sync Horizontal Scrolling across two tables [message #1053651 is a reply to message #1053396]

Tue, 07 May 2013 07:18

Wojtek

Messages: 47
Registered: August 2011

Member

David Wegener wrote :
> On 05/04/2013 06:00 PM, Wojtek wrote:
>> So there is no solution to this? setSelection(int) is a useless method
>> put only there as a counter to getSelection()?
>>
>> Should I open a high priority bug for this non-behavior?
>>
>> BTW a Google search will bring up lots of people who also tried to make
>> this work, and failed.
>>
> Have you tried using the setOrigin method on the Scrollable instead of
> setSelection? That method is documented to set point to be displayed in the
> top left corner of the Scrollable. This appears to also set the the
> scrollbar positions.
>
> Here is an example that might help:
>
> http://www.java2s.com/Code/Java/SWT-JFace-Eclipse/CreatetwoScrolledCompositesthatscrollintandem.htm

Interesting, but it did not work.

I think the problem with using a ScrolledComposite is that it is not
linked to the table columns. When I size a middle column so that the
right column is moved off the window, then a horizontal bar appears. If
I move the horizontal bar then the right column is moved into view and
the left column moves off the window. The table does not move, just its
contents (columns).

The table does not actually grow horizontally. So changing the origin
would create a blank area to the right (or left) of the table, because
I must move the entire table to mimic a bar movement.

Then there are funky issues with making the table show in the first
place as ScrolledComposite does not use FormLayout so the table has
nothing to attach to. It took me a while to figure out why my table was
invisible. It wasn't, it was just sized to 1x1 pixels. Which also means
that I must write code to resize the table whenever the shell is sized.

--
Wojtek :-)

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