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GridBagLayout and changin

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  GridBagLayout and changin "Daniel Pitts" <daniel.pitts@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "Chris Smith" <chris.smith@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "Knute Johnson" <knute.johnson@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "Tom Hawtin" <tom.hawtin@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
      Re: GridBagLayout and cha "Daniel Pitts" <daniel.pitts@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "SadRed" <sadred@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
      Re: GridBagLayout and cha "Daniel Pitts" <daniel.pitts@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "SadRed" <sadred@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "Brandon McCombs" <brandon.mccombs@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
      Re: GridBagLayout and cha "Daniel Pitts" <daniel.pitts@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "Ian Wilson" <ian.wilson@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
      Re: GridBagLayout and cha "Daniel Pitts" <daniel.pitts@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "Larry Barowski" <larry.barowski@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000
    Re: GridBagLayout and cha "Larry Barowski" <larry.barowski@THRWHITE.remove-dii-this> - 2011-04-27 15:32 +0000

#1288 — GridBagLayout and changin

  To: comp.lang.java.gui,comp.l

Say I have the following code:

JPanel myPanel = new JPanel(new GridBagLayout());
GridBagConstraints constaints = getConstraints();
myPanel.add(new JLabel("Hello world"), constaints);

And then later (as a result of an Event), I do something like
constraints.gridx = 3;
myPanel.revalidate();

Will this have the expected effect, or do I need to remove the old
label, and re-add it with the new constraints?

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#1289 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
Daniel Pitts <googlegroupie@coloraura.com> wrote:
> 
> Say I have the following code:
> 
> JPanel myPanel = new JPanel(new GridBagLayout());
> GridBagConstraints constaints = getConstraints();
> myPanel.add(new JLabel("Hello world"), constaints);
> 
> And then later (as a result of an Event), I do something like
> constraints.gridx = 3;
> myPanel.revalidate();
> 
> Will this have the expected effect, or do I need to remove the old
> label, and re-add it with the new constraints?

The latter.  The GridBagLayout class makes a copy of the layout 
constraints when the device is added.  In fact, it's fairly common to 
create just one GridBagConstraints object, and use it to add a large 
number of components by just changing the few properties that differ 
each time.

-- 
Chris Smith

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#1290 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
Daniel Pitts wrote:
> Say I have the following code:
> 
> JPanel myPanel = new JPanel(new GridBagLayout());
> GridBagConstraints constaints = getConstraints();

What class does the method getConstraints() belong to?

> myPanel.add(new JLabel("Hello world"), constaints);
> 
> And then later (as a result of an Event), I do something like
> constraints.gridx = 3;
> myPanel.revalidate();
> 
> Will this have the expected effect, or do I need to remove the old
> label, and re-add it with the new constraints?
> 

No.  You will have to re-add it.

-- 

Knute Johnson
email s/nospam/knute/

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#1291 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
Daniel Pitts wrote:
> Say I have the following code:
> 
> JPanel myPanel = new JPanel(new GridBagLayout());
> GridBagConstraints constaints = getConstraints();
> myPanel.add(new JLabel("Hello world"), constaints);
> 
> And then later (as a result of an Event), I do something like
> constraints.gridx = 3;
> myPanel.revalidate();
> 
> Will this have the expected effect, or do I need to remove the old
> label, and re-add it with the new constraints?

It wont have any affect. The constraints object is cloned. Indeed it is 
normal to use one constraints object to add many components.

To change the constraints for a component, just call 
LayoutManager[2].addLayoutComponent.

Tom Hawtin

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#1292 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
On Mar 25, 3:57 pm, Tom Hawtin <use...@tackline.plus.com> wrote:
> Daniel Pitts wrote:
> > Say I have the following code:
>
> > JPanel myPanel = new JPanel(new GridBagLayout());
> > GridBagConstraints constaints = getConstraints();
> > myPanel.add(new JLabel("Hello world"), constaints);
>
> > And then later (as a result of an Event), I do something like
> > constraints.gridx = 3;
> > myPanel.revalidate();
>
> > Will this have the expected effect, or do I need to remove the old
> > label, and re-add it with the new constraints?
>
> It wont have any affect. The constraints object is cloned. Indeed it is
> normal to use one constraints object to add many components.
>
> To change the constraints for a component, just call
> LayoutManager[2].addLayoutComponent.
>
> Tom Hawtin

Thanks to everyone who replied.
I should have RTFM. Actually, its RTFA, isn't it?

GridBagLayout.setConstraints is what I need to use. :-)

Cheers,
Daniel.

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#1293 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
On Mar 26, 7:07 am, "Daniel Pitts" <googlegrou...@coloraura.com>
wrote:
> Say I have the following code:
>
> JPanel myPanel = new JPanel(new GridBagLayout());
> GridBagConstraints constaints = getConstraints();
> myPanel.add(new JLabel("Hello world"), constaints);
>
> And then later (as a result of an Event), I do something like
> constraints.gridx = 3;
> myPanel.revalidate();
>
> Will this have the expected effect, or do I need to remove the old
> label, and re-add it with the new constraints?

You could try it yourself.

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#1294 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
On Mar 25, 5:14 pm, "SadRed" <cardinal_r...@yahoo.co.jp> wrote:
> On Mar 26, 7:07 am, "Daniel Pitts" <googlegrou...@coloraura.com>
> wrote:
>
> > Say I have the following code:
>
> > JPanel myPanel = new JPanel(new GridBagLayout());
> > GridBagConstraints constaints = getConstraints();
> > myPanel.add(new JLabel("Hello world"), constaints);
>
> > And then later (as a result of an Event), I do something like
> > constraints.gridx = 3;
> > myPanel.revalidate();
>
> > Will this have the expected effect, or do I need to remove the old
> > label, and re-add it with the new constraints?
>
> You could try it yourself.

I could, but that might have only proved that sometimes it works. I
was asking if it would always work...  As I discovered, it won't ever
work, but there is a different way to do it that will always work.

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#1295 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
On Mar 26, 7:07 am, "Daniel Pitts" <googlegrou...@coloraura.com>
wrote:
> Say I have the following code:
>
> JPanel myPanel = new JPanel(new GridBagLayout());
> GridBagConstraints constaints = getConstraints();
> myPanel.add(new JLabel("Hello world"), constaints);
>
> And then later (as a result of an Event), I do something like
> constraints.gridx = 3;
> myPanel.revalidate();
>
> Will this have the expected effect, or do I need to remove the old
> label, and re-add it with the new constraints?

Why don't you try it yourself?

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#1296 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
Daniel Pitts wrote:
> Say I have the following code:
> 
> JPanel myPanel = new JPanel(new GridBagLayout());
> GridBagConstraints constaints = getConstraints();
> myPanel.add(new JLabel("Hello world"), constaints);
> 
> And then later (as a result of an Event), I do something like
> constraints.gridx = 3;
> myPanel.revalidate();
> 
> Will this have the expected effect, or do I need to remove the old
> label, and re-add it with the new constraints?
> 

You will have to remove it and re-add it. How is Java to know which 
Object is supposed to have the new constraint if you don't re-add the 
Object with that constraint? It could assume to apply that new 
constraint property to the only Object in a JPanel if there is only one 
in it but that wouldn't work for more than 1 Object in container and it 
isn't a good way to do it anyway. It is bad design to need to 
relocate/resize an Object after an event occurs. You should rethink how 
you are presenting the interface to the user because the user should not 
normally see new things appear when they do something; all the Objects 
in the GUI should be visible, their sizes unchanging, and the unused 
ones disabled until they are needed (with the enabling trigger being 
your event).

As it is now, the line:
myPanel.add(new JLabel("Hello world"), constaints);

isn't going to do much because you aren't defining what your constraints 
are although some of the properties do have default values. The default 
for gridx is 'relative' which may not be what you want initially.

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#1297 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
On Mar 25, 10:28 pm, Brandon McCombs <n...@none.com> wrote:
> Daniel Pitts wrote:
> > Say I have the following code:
>
> > JPanel myPanel = new JPanel(new GridBagLayout());
> > GridBagConstraints constaints = getConstraints();
> > myPanel.add(new JLabel("Hello world"), constaints);
>
> > And then later (as a result of an Event), I do something like
> > constraints.gridx = 3;
> > myPanel.revalidate();
>
> > Will this have the expected effect, or do I need to remove the old
> > label, and re-add it with the new constraints?
>
> You will have to remove it and re-add it. How is Java to know which
> Object is supposed to have the new constraint if you don't re-add the
> Object with that constraint? It could assume to apply that new
> constraint property to the only Object in a JPanel if there is only one
> in it but that wouldn't work for more than 1 Object in container and it
> isn't a good way to do it anyway. It is bad design to need to
> relocate/resize an Object after an event occurs. You should rethink how
> you are presenting the interface to the user because the user should not
> normally see new things appear when they do something; all the Objects
> in the GUI should be visible, their sizes unchanging, and the unused
> ones disabled until they are needed (with the enabling trigger being
> your event).
Actually, I have four objects which would only trade places, and they
are similar enough that the change shouldn't bother users.  Have you
ever played a game on Yahoo games?  notice when you sit at a table,
your side becomes the southern most side.   I'm basically emulating
that effect.

It is easier to move the components around than to change which model
each component is looking at.  Either way, the effect would be the
same.

>
> As it is now, the line:
> myPanel.add(new JLabel("Hello world"), constaints);
>
> isn't going to do much because you aren't defining what your constraints
> are although some of the properties do have default values. The default
> for gridx is 'relative' which may not be what you want initially.

Hmm, I don't see how you think that my constraints object is unset. I
simply didn't copy the code that implemented getConstraints();

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#1298 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
Daniel Pitts wrote:
> Say I have the following code:

OK, I shall ...

> 
> JPanel myPanel = new JPanel(new GridBagLayout());
> GridBagConstraints constaints = getConstraints();
> myPanel.add(new JLabel("Hello world"), constaints);
> 
> And then later (as a result of an Event), I do something like
> constraints.gridx = 3;
> myPanel.revalidate();
> 
> Will this have the expected effect, or do I need to remove the old
> label, and re-add it with the new constraints?
> 

Others have given the answer you were seeking. However I can't help 
noticing that the code you quoted can never have the expected effect 
since constaints != constraints :-)

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#1302 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
On Mar 26, 2:46 am, Ian Wilson <scoblo...@infotop.co.uk> wrote:
> Daniel Pitts wrote:
> > Say I have the following code:
>
> OK, I shall ...
>
>
>
> > JPanel myPanel = new JPanel(new GridBagLayout());
> > GridBagConstraints constaints = getConstraints();
> > myPanel.add(new JLabel("Hello world"), constaints);
>
> > And then later (as a result of an Event), I do something like
> > constraints.gridx = 3;
> > myPanel.revalidate();
>
> > Will this have the expected effect, or do I need to remove the old
> > label, and re-add it with the new constraints?
>
> Others have given the answer you were seeking. However I can't help
> noticing that the code you quoted can never have the expected effect
> since constaints != constraints :-)

Did I surround that code with an sscce tag? I don't think so. :-)

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#1300 — Re: GridBagLayout and cha

  To: comp.lang.java.gui

"Daniel Pitts" <googlegroupie@coloraura.com> wrote in message 
news:1174860473.305833.284620@n76g2000hsh.googlegroups.com...
>
> Say I have the following code:
>
> JPanel myPanel = new JPanel(new GridBagLayout());
> GridBagConstraints constaints = getConstraints();
> myPanel.add(new JLabel("Hello world"), constaints);
>
> And then later (as a result of an Event), I do something like
> constraints.gridx = 3;
> myPanel.revalidate();
>
> Will this have the expected effect, or do I need to remove the old
> label, and re-add it with the new constraints?

It will have no effect. Normally you change the (single) constraints
object between adding components. There is no need to create
multiple constraints objects. To change after creation, I assume you
can use GridBagLayout.setConstraints(). You could use
GridBagLayout.getConstraints(), make the change, then use
setConstraints() to avoid storing the constraints object.

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#1301 — Re: GridBagLayout and cha

  To: comp.lang.java.gui
Oops, the OP was to cljp and cljg with followups to cljg, so
I didn't see the answers already here.

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