---
title: Tree Structure View
---

This tutorial is meant to illustrate how the project tree structure view appearance can be modified programmatically. 
If you need to know more about basic concepts of a project view in IntelliJ-based IDEs, please refer to
[Exploring The Project Structure](https://www.jetbrains.com/idea/help/exploring-the-project-structure.html#d164891e120)
of 
[IntelliJ IDEA Web Help](https://www.jetbrains.com/idea/help/intellij-idea.html).

Series of step below show how to filter out and keep visible only text files and directories in the Project View Panel. 

## Pre-requirements

Create an empty plugin project.
See 
[Creating a Plugin Project](/basics/getting_started/creating_plugin_project.md)
to know how to do it.

## 1. Register Custom TreeStructureView Provider

Add new *treeStructureProvider* extension to the
[plugin.xml](https://github.com/JetBrains/intellij-sdk-docs/blob/master/code_samples/tree_structure_provider/resources/META-INF/plugin.xml)

```java
<extensions defaultExtensionNs="com.intellij">
  <treeStructureProvider implementation="org.jetbrains.tutorials.tree.structure.TextOnlyTreeStructureProvider"/>
</extensions>
```

## 2. Implement Custom TreeStructureProvider

To provide custom Structure View behaviour you need to implement TreeStructureProvider interface.  

```java
public class TextOnlyTreeStructureProvider implements TreeStructureProvider {
    @NotNull
    @Override
    public Collection<AbstractTreeNode> modify(@NotNull AbstractTreeNode parent, @NotNull Collection<AbstractTreeNode> children, ViewSettings settings) {
        return null;
    }

    @Nullable
    @Override
    public Object getData(Collection<AbstractTreeNode> collection, String s) {
        return null;
    }
}
```

## 3. Override modify() method

To implement Tree Structure nodes filtering logic, override modify() method.
The example below shows how to filter out all the Project View nodes except those which correspond text files and directories.

```java
{% include /code_samples/tree_structure_provider/src/org/jetbrains/tutorials/tree/structure/TextOnlyTreeStructureProvider.java %}
```

## 4. Compile and Run the Plugin

Compile and run the code sample from this tutorial.
Refer to 
[Running and Debugging a Plugin](/basics/getting_started/running_and_debugging_a_plugin.md)
section to know how this could be done.

After going through the steps described above you can see only text files and directories belonging to a project in the Project View.

![Text Files](tree_structure_view/img/text_only.png)


Check out 
[plugin source code](https://github.com/JetBrains/intellij-sdk-docs/tree/master/code_samples/tree_structure_provider)
and build the project to see how TreeStructureView provider works in practice.