# Observer

Artifact: [androidx.lifecycle:lifecycle-livedata-core](https://developer.android.com/jetpack/androidx/releases/lifecycle) [View Source](https://cs.android.com/search?q=file:androidx/lifecycle/Observer.kt+class:androidx.lifecycle.Observer) Added in [2.0.0](https://developer.android.com/jetpack/androidx/releases/lifecycle#2.0.0)

*** ** * ** ***


```
public fun interface Observer<T extends Object>
```

<br />

*** ** * ** ***

A simple callback that can receive from `https://developer.android.com/reference/androidx/lifecycle/LiveData`.

| See also |
|---|---|
| `https://developer.android.com/reference/androidx/lifecycle/LiveData` | LiveData - for a usage description. |

## Summary

| ### Public methods |
|---|---|
| `abstract void` | `https://developer.android.com/reference/androidx/lifecycle/Observer#onChanged(kotlin.Any)(@https://developer.android.com/reference/androidx/annotation/NonNull T value)` Called when the data is changed to `https://developer.android.com/reference/androidx/lifecycle/Observer#onChanged(kotlin.Any)`. |

## Public methods

### onChanged

Added in [2.0.0](https://developer.android.com/jetpack/androidx/releases/lifecycle#2.0.0)

```
abstract void onChanged(@NonNull T value)
```

Called when the data is changed to `https://developer.android.com/reference/androidx/lifecycle/Observer#onChanged(kotlin.Any)`.