如何在Eclipse插件开发中禁用/启用视图工具栏菜单/操作

Question

I have view that extends ViewPart . In this view, I want to add toolbar menu.

What I know, we can add toolbar menu by using ActionContributionItem or Action , and add it to ToolBarMenu from createPartControl method in ViewPart .

But what I don't know is this: How can we disable/enable the toolbar menu programmatically?

So basically, I want to add Play , Stop , and Pause button to toolbar view. So at first, the Play button is on enabled mode, and the others are disabled. When I pressed Play button, it is disabled, and others will be enabled.

For more details, what I want to achieve is something like the following image.

In the red circle are disabled button, and in the blue circle are enabled button.

Answer 1

Instead of using Actions, have a look at Eclipse commands (they are the replacement for actions and function in a cleaner way): http://help.eclipse.org/indigo/topic/org.eclipse.platform.doc.isv/guide/workbench_cmd.htm

You will see in the documentation that you can enable and disable a command and all places where it's used will properly update their state automatically.

Answer 2

There is another approach which I found by stumbling upon on google. This approach is using ISourceProvider to provide variable state. So we can provide the state of enablement/disablement of command in that class (that implementing ISourceProvider). Here is the detail link http://eclipse-tips.com/tutorials/1-actions-vs-commands?showall=1

Answer 3

Try this..

1: Implement your actions. ex: PlayAction, StopAction.

Public class StartAction extends Action {

@Override
public void run() {
    //actual code run here
}

@Override
public boolean isEnabled() {
    //This is the initial value, Check for your respective criteria and return the appropriate value.
    return false;
}

@Override
public String getText() {
    return "Play";
}
}

2: Register your view part(Player view part)

Public class Playerview extends ViewPart
    {

 @Override
public void createPartControl(Composite parent) {

 //your player UI code here.


    //Listener registration. This is very important for enabling and disabling the tool bar level buttons
     addListenerObject(this);


    //Attach selection changed listener to the object where you want to perform the action based on the selection type. ex; viewer
    viewer.addselectionchanged(new SelectionChangedListener())  



      }
        }

    //selection changed

    private class SelectionChangedListener implements ISelectionChangedListener        {

    @Override
    public void selectionChanged(SelectionChangedEvent event) {
        ISelection selection = Viewer.getSelection();
        if (selection != null && selection instanceof StructuredSelection) {
            Object firstElement = ((StructuredSelection)selection).getFirstElement();

            //here you can handle the enable or disable based on your selection. that could be your viewer selection or toolbar.
            if (playaction.isEnabled()) { //once clicked on play, stop  should be enabled.
                stopaction.setEnabled(true); //Do required actions here.
                playaction.setEnabled (false);  //do

            }

        }

    }

    }

Hope this would help you.