Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  
Also in [T Extensions 3](https://developer.android.com/sdkExtensions)

# ObserverCallback

*** ** * ** ***

` public interface ObserverCallback `   
` `

|---|
| android.app.appsearch.observer.ObserverCallback |

<br />

*** ** * ** ***

An interface which apps can implement to subscribe to notifications of changes to AppSearch data.

## Summary

| ### Public methods ||
|---|---|
| ` abstract void` | ` https://developer.android.com/reference/android/app/appsearch/observer/ObserverCallback#onDocumentChanged(android.app.appsearch.observer.DocumentChangeInfo)(https://developer.android.com/reference/android/app/appsearch/observer/DocumentChangeInfo changeInfo) ` Callback to trigger after document changes (documents added, updated or removed). |
| ` abstract void` | ` https://developer.android.com/reference/android/app/appsearch/observer/ObserverCallback#onSchemaChanged(android.app.appsearch.observer.SchemaChangeInfo)(https://developer.android.com/reference/android/app/appsearch/observer/SchemaChangeInfo changeInfo) ` Callback to trigger after schema changes (schema type added, updated or removed). |

## Public methods

### onDocumentChanged

Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  
Also in [T Extensions 3](https://developer.android.com/sdkExtensions)

```
public abstract void onDocumentChanged (DocumentChangeInfo changeInfo)
```

Callback to trigger after document changes (documents added, updated or removed).

<br />

| Parameters ||
|---|---|
| `changeInfo` | `DocumentChangeInfo`: Information about the nature of the change. This value cannot be `null`. <br /> |

### onSchemaChanged

Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)  
Also in [T Extensions 3](https://developer.android.com/sdkExtensions)

```
public abstract void onSchemaChanged (SchemaChangeInfo changeInfo)
```

Callback to trigger after schema changes (schema type added, updated or removed).

<br />

| Parameters ||
|---|---|
| `changeInfo` | `SchemaChangeInfo`: Information about the nature of the change. This value cannot be `null`. <br /> |