IntelliJ Platform SDK DevGuide

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File View Providers

A file view provider (FileViewProvider) manages access to multiple PSI trees within a single file.

For example, a JSPX page has a separate PSI tree for the Java code in it (PsiJavaFile), a separate tree for the XML code (XmlFile), and a separate tree for JSP as a whole (JspFile).

Each of the PSI trees covers the entire contents of the file and contains special “outer language elements” in the places where contents in a different language can be found.

A FileViewProvider instance corresponds to a single VirtualFile, a single Document, and can retrieve multiple PsiFile instances.

How do I get a FileViewProvider?

  • From a VirtualFile: PsiManager.getInstance(project).findViewProvider()
  • From a PsiFile: psiFile.getViewProvider()

What can I do with a FileViewProvider?

  • To get the set of all languages for which PSI trees exist in a file: fileViewProvider.getLanguages()
  • To get the PSI tree for a particular language: fileViewProvider.getPsi(language). For example, to get the PSI tree for XML, use fileViewProvider.getPsi(XMLLanguage.INSTANCE).
  • To find an element of a particular language at the specified offset in the file: fileViewProvider.findElementAt(offset, language)

How do I extend the FileViewProvider?

To create a file type that has multiple interspersing trees for different languages, a plugin must contain an extension to the com.intellij.fileType.fileViewProviderFactory extension point.

Implement FileViewProviderFactory and return your FileViewProvider implementation from createFileViewProvider() method.

Register as follows in plugin.xml:

<extensions defaultExtensionNs="com.intellij"> <fileType.fileViewProviderFactory filetype="%file_type%" implementationClass="com.plugin.MyFileViewProviderFactory" /> </extensions>

Where %file_type% refers to the type of the file being created (for example, “JFS”).

Last modified: 21 September 2020