[//]: # (title: Modifying Project View Structure)

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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).

This topic describes the [treeStructureProvider](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/tree_structure_provider) sample plugin. 

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

## Register Custom TreeStructure Provider

Add new `com.intellij.treeStructureProvider` extension to the [plugin.xml](https://github.com/JetBrains/intellij-sdk-code-samples/blob/main/tree_structure_provider/src/main/resources/META-INF/plugin.xml)

```java
<extensions defaultExtensionNs="com.intellij">
  <treeStructureProvider implementation="org.intellij.sdk.treeStructureProvider.TextOnlyTreeStructureProvider"/>
</extensions>
```

## Implement Custom TreeStructureProvider

To provide custom Structure View behaviour, implement [`TreeStructureProvider`](upsource:///platform/editor-ui-api/src/com/intellij/ide/projectView/TreeStructureProvider.java) with nodes filtering logic in `modify()` method.
The example below shows how to filter out all the Project View nodes except those which correspond to text files and directories.

```java
```
{src="tree_structure_provider/src/main/java/org/intellij/sdk/treeStructureProvider/TextOnlyTreeStructureProvider.java"}

## Compile and Run the Plugin

See [Code Samples](code_samples.md) on how to set up and run the plugin.

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](text_only.png)