Re: [ve-dev] How to add new layout mangers to ve

[Jeffrey Myers <myersj@xxxxxxxxxx>]

Hi Tanul,

The ability to add custom layout managers
is a new feature in VE 1.0 (should work in M1)... so it hasn't been tested
much yet.  Here's some instructions, if they don't work, please let
us know.
Note: right now we only support adding
layout managers with no agument constructors.  Layout managers with
constructors requiring arguments, such as BoxLayout are still handled as
special cases requiring more code.

1)
Assuming you want to add a Swing/AWT
layout manager, in your plugin, create a file  overrides/java/awt/LayoutManager.override
(for SWT this would be overrides/org/eclipse/swt/widgets/Layout.override)

2)
Look at the existing LayoutManager.override
in the same place in the org.eclipse.ve.jfc plugin as a guide.
Copy the top of that override's file,
the xmi tag declaration into your file:

<?xml version="1.0" encoding="UTF-8"?>
<xmi:XMI xmi:version="2.0"
xmlns:xmi="http://www.omg.org/XMI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:org.eclipse.ve.internal.jcm="http:///org/eclipse/ve/internal/jcm.ecore"

    xmlns:org.eclipse.ve.internal.cde.decorators="http:///org/eclipse/ve/internal/cde/decorators.ecore"
    xmlns:org.eclipse.jem.java="java.xmi"
xmlns:ecore="http://www.eclipse.org/emf/2002/Ecore"
    xmlns:event="event.xmi">

Now add an eAnnotation tag to your override:
  <event:AddMany featureName="eAnnotations">

3)
For each layout you want to add, put
in this block of xmi:
        <addedEObjects
xsi:type="ecore:EAnnotation" source="org.eclipse.ve.LayoutInfo">
         
      <details key="org.eclipse.ve.internal.jfc.core.layoutManagerClass"
         
              value="java.awt.BorderLayout"/>
         
      <details key="org.eclipse.ve.internal.jfc.core.layoutManagerDisplayName"
         
              value="BorderLayout"/>
        </addedEObjects>

Replace the "java.awt.BorderLayout"
value with your own custom layout class (fully qualified class name).
Replace the "BorderLayout"
value with the display name you wish to see in the property sheet's cell
editor.

4)
Add the closing tags to the end of your
file:
  </event:AddMany>
</xmi:XMI>

Save your override file.

5)
Next we need to register with beaninfo
to notify it that you've written an override
Open the plugin.xml for your plugin.
Add the following extension within your
plugin.xml:
   <extension
         point="org.eclipse.jem.beaninfo.registrations">
      <registration
         
  container="org.eclipse.jdt.launching.JRE_CONTAINER">
         <override
         
     package="java.awt"
         
     path="overrides/java/awt">
         </override>
      </registration>
   </extension>

Save your plugin.xml.
Launching the VE with your plugin active
should now show your custom layout on the layout property editor for Swing/AWT.
 Selecting it should drop an instance of that class with a no argument
constructor.

6)
To provide visual feedback and the ability
to edit the layout graphically requires quite a lot more work.

First, create an override for your custom
layout class.  If your class is called org.foo.layouts.MyCustomLayout,
you'll need to create the file overrides/org/foo/layouts/MyCustomLayout.override
in your plugin.

In this file add the following xmi:
<?xml version="1.0" encoding="UTF-8"?>
<event:AddMany xmi:version="2.0"
xmlns:xmi="http://www.omg.org/XMI" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:org.eclipse.ve.internal.jcm="http:///org/eclipse/ve/internal/jcm.ecore"
xmlns:ecore="http://www.eclipse.org/emf/2002/Ecore"
    xmlns:codeGenHelpers="platform:/plugin/org.eclipse.ve.java.core/overrides/codegenHelpers.ecore"
    xmlns:event="event.xmi"

    featureName="eAnnotations">
  <addedEObjects xsi:type="org.eclipse.ve.internal.jcm:BeanDecorator">
    <keyedValues xsi:type="ecore:EStringToStringMapEntry"
key="org.eclipse.ve.internal.jfc.core.layoutpolicyfactoryclassnamekey"
        value="org.eclipse.ve.jfc/org.eclipse.ve.internal.jfc.core.BorderLayoutPolicyFactory"/>
  </addedEObjects>
  <addedEObjects xsi:type="codeGenHelpers:CodeGenHelperClass"
source="codegen.CodeGenHelperClass"
     modelled="true"/>
</event:AddMany>

Change the value of "org.eclipse.ve.jfc/org.eclipse.ve.internal.jfc.core.BorderLayoutPolicyFactory"
to
"my.plugin/my.plugin.MyCustomLayoutPolicyFactory"
(replacing with real plugin/layout names of course)

7)
Now create the MyCustomLayoutPolicyFactory
class, extending the org.eclipse.ve.internal.java.visual.ILayoutPolicyFactory
interface.

8)
Back in your plugin.xml, add an override
tag pointing to your custom layout's package.
Look for where you entered:
         <override
         
     package="java.awt"
         
     path="overrides/java/awt">
         </override>
And below that, add:
         <override
         
     package="org.foo.layouts"
         
     path="overrides/org/foo/layouts">
         </override>
(same package and path used in step
6)

9)
Now to actually implement your desired
graphical behavior, you'll need to implement the methods in MyCustomLayoutPolicyFactory.
 Your best bet for getting up to speed on how to accomplish this is
reading through the existing layout edit policies included with the VE
in Swing/AWT and SWT.  The class org.eclipse.ve.internal.jfc.core.FlowLayoutPolicyFactory
would be a good place to start looking.


If you have questions, please ask here
on the dev list or on the VE newsgroup.  If you have feedback or problems
with these instructions please let me know... once we get the bugs shaken
out we'll probably post these instructions as an article in our developer
documentation section.

Good luck,

Jeff Myers
----------------
Eclipse Visual Editor Development
919-254-9130 - T/L 444, HYSA/501/F121
IBM SWG at RTP, 3039 Cornwallis Rd, RTP, NC 27709
Lotus Notes: Jeffrey Myers/Durham/IBM   Internet: myersj@xxxxxxxxxx

tanul sangal <tanulsangal@xxxxxxxxxx> Sent by: ve-dev-admin@xxxxxxxxxxx 05/27/2004 03:02 AM Please respond to ve-dev

To:        ve-dev@xxxxxxxxxxx         cc:                 Subject:        [ve-dev] How to add new layout mangers to ve

Hi,

I have a plugin for ve which is adding some of my custom
components to the ve palette.
Now I want to add some custom layout managers so that they can
behave within the ve in the same way as existing layout
managers.

Kindly provide me with some input on how can this be achieved.

Best Regards
Tanul