Where do I need to put the UI initialization code in an IntelliJ Idea plugin?

Question

I want to create a plugin for IntelliJ Idea, which puts a little button into the status bar.

AFAIK the code for this must look like this:

final StatusBar statusBar = WindowManager.getInstance().getStatusBar(project);
final StatusBarWidget widget = new WordCounterWidget();
statusBar.addWidget(widget);

WordCounterWidget is the button I want to place into the status bar.

I tried to put it

• into an action that is called, when I select a particular menu item and
• into the constructor of a project service .

None of this brought the expected result -- the button is not shown.

Is the above code for inserting a button (or anything else that can display text and is clickable) correct? If yes, where should I put it so that it's executed whenever a project is opened, re-opened, or created (the status bar widget should be visible all the time when there is a project open in Idea)?

The code is here .

Update 1: Tried to change the code of WordCounterServiceImpl to

public class WordCounterServiceImpl implements WordCounterService {
    private final Project project;
    public WordCounterServiceImpl(final Project project) {
        this.project = project;
    }

    @Override
    public void projectOpened() {
        final StatusBar statusBar = WindowManager.getInstance().getStatusBar(project);
        final StatusBarWidget widget = new WordCounterWidget();
        statusBar.addWidget(widget);
    }
}

The button is still not shown.

Answer 1

com.intellij.openapi.components.ProjectComponent#projectOpened

请参阅： https ： //www.jetbrains.org/intellij/sdk/docs/basics/plugin_structure/plugin_components.html