Extending Breadcrumbs


I'd like to extend the editor Breadcrumbs, specifically to add the file name as the first "crumb" before any symbols.  Where should I look to start out?

Alexandr Evstigneev

You may start right here com.intellij.ui.breadcrumbs.BreadcrumbsProvider


Thanks for the info @Alexander.

Unfortunately despite my best efforts I can't seen to figure out how this API is supposed to work.

Can you provide an explanation or example?


It looks as though I would need to provide a subclass of FileBreadcrumbsCollector to a VirtualFile, Editor or EditorWindow, but there doesn't seem to be a way to do that.


Okayyyyy update. Using the IntelliJ Community source I tracked this down to (in the case of the Java language) simply subclassing 'JavaBreadcrumbsInfoProvider', overriding 'acceptElement()' to accept everything the superclass accepts, plus 'PsiFile', and updating 'java/java-impl/src/META-INF/JavaPlugin.xml' to reference the new class. Works perfectly.


Some questions:


How do I get this to work in a plugin? It looks like Extensions may be the way to go. I experimented with adding this to my plugin.xml:

<extensions defaultExtensionNs="com.intellij">
<breadcrumbsInfoProvider implementation="JavaFilenameBreadcrumbsInfoProvider" />

...and defining a class of 'JavaFilenameBreadcrumbsInfoProvider' in my plugin.

Am I heading down the right path?


I can't see JavaBreadcrumbsInfoProvider from within my plugin. This means I need to inherit from 'BreadcrumbsProvider', provide 'private static final Language[] ourLanguages' myself, and I can't rely on the superclass's implementation of 'acceptElement()'. Fine. However, in re-creating JavaFilenameBreadcrumbsInfoProvider's acceptElement() I need visibility to 'PsiMember' and 'PsiLambdaExpression' which apparently I can't have in a plugin. Am I missing something here? How can I use these missing classes in my plugin?


What might be a good approach for adding more languages? I only really care about making this work for C/C++ with CLion, but I'd like to make this plugin available to others in other environments if possible.


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