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Menu Contributions/Radio Button Command
You can create a command with a required parameter. The parameter will be passed during every execution.
Command Definition
You want to create a command that will be executed with a paramter. The parameter in this example matches which of the radio buttons is selected.
<command categoryId="org.eclipse.ui.category.help" defaultHandler="z.ex.dropdown.internal.RadioHandler" id="z.ex.dropdown.radio" name="Radio Example"> <commandParameter id="z.ex.dropdown.radio.info" name="Radio Name" optional="false"> </commandParameter> </command>
Handler
The handler will receive the parameter. It can then update its model (in my example my model is a local variable, but that might not be appropriate in command that can have multiple handlers).
package com.example.handlers.internal; import java.util.Map; import org.eclipse.core.commands.AbstractHandler; import org.eclipse.core.commands.ExecutionEvent; import org.eclipse.core.commands.ExecutionException; import org.eclipse.ui.commands.ICommandService; import org.eclipse.ui.commands.IElementUpdater; import org.eclipse.ui.handlers.HandlerUtil; import org.eclipse.ui.menus.UIElement; public class RadioHandler extends AbstractHandler implements IElementUpdater { private static final String PARM_INFO = "z.ex.dropdown.radio.info"; private String fCurrentValue; public Object execute(ExecutionEvent event) throws ExecutionException { String parm = event.getParameter(PARM_INFO); if (parm.equals(fCurrentValue)) { return null; // in theory, we're already in the correct state } // do whatever having "parm" active implies fCurrentValue = parm; // update our radio button states ... get the service from // a place that's most appropriate ICommandService service = (ICommandService) HandlerUtil .getActiveWorkbenchWindowChecked(event).getService( ICommandService.class); service.refreshElements(event.getCommand().getId(), null); return null; } public void updateElement(UIElement element, Map parameters) { String parm = (String) parameters.get(PARM_INFO); if (parm != null) { if (fCurrentValue != null && fCurrentValue.equals(parm)) { element.setChecked(true); } else { element.setChecked(false); } } } }
Menu Contribution
Then you add menu contributions with the specific parameters that you want:
<menuContribution locationURI="menu:help?after=additions"> <separator name="z.ex.dropdown.menu.separator1" visible="true"> </separator> <command commandId="z.ex.dropdown.radio" id="z.ex.dropdown.menu.radio1" label="Moe" style="radio"> <parameter name="z.ex.dropdown.radio.info" value="Moe"> </parameter> </command> <command commandId="z.ex.dropdown.radio" id="z.ex.dropdown.menu.radio2" label="Larry" style="radio"> <parameter name="z.ex.dropdown.radio.info" value="Larry"> </parameter> </command> <command commandId="z.ex.dropdown.radio" id="z.ex.dropdown.menu.radio3" label="Curly" style="radio"> <parameter name="z.ex.dropdown.radio.info" value="Curly"> </parameter> </command> <separator name="z.ex.dropdown.menu.separator2" visible="true"> </separator> </menuContribution> </extension>
Initializing the Handler
It may happen that your radio menu contributions are not initialized the first time the menu is displayed. This is because at this time, your Handler might not yet have been instantiated (this is due to Eclipse's lazy loading policy). If this is the case, you can enforce the instantiation of your Handler within the Activator of your plug-in. Just add the following code to the start(BundleContext) method:
UIJob job = new UIJob("InitCommandsWorkaround") { @Override public IStatus runInUIThread(@SuppressWarnings("unused") IProgressMonitor monitor) { ICommandService commandService = (ICommandService) PlatformUI .getWorkbench().getActiveWorkbenchWindow().getService( ICommandService.class); Command command = commandService.getCommand("z.ex.dropdown.radio"); command.isEnabled(); return new Status(IStatus.OK, "my.plugin.id", "Init commands workaround performed succesfully"); } }; job.schedule();