# DownloadHelper.Callback

Artifact: [androidx.media3:media3-exoplayer](https://developer.android.com/jetpack/androidx/releases/media3) [View Source](https://cs.android.com/search?q=file:androidx/media3/exoplayer/offline/DownloadHelper.java+class:androidx.media3.exoplayer.offline.DownloadHelper.Callback)

*** ** * ** ***


```
public interface DownloadHelper.Callback
```

<br />

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A callback to be notified when the `https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper` is prepared.

## Summary

| ### Public methods |
|---|---|
| `abstract void` | `https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper.Callback#onPrepareError(androidx.media3.exoplayer.offline.DownloadHelper,java.io.IOException)(https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper helper, https://developer.android.com/reference/java/io/IOException.html e)` Called when preparation fails. |
| `abstract void` | `https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper.Callback#onPrepared(androidx.media3.exoplayer.offline.DownloadHelper,boolean)(https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper helper, boolean tracksInfoAvailable)` Called when preparation completes. |

## Public methods

### onPrepareError

```
abstract void onPrepareError(DownloadHelper helper, IOException e)
```

Called when preparation fails.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper helper` | The reporting `https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper`. |
| `https://developer.android.com/reference/java/io/IOException.html e` | The error. |

### onPrepared

```
abstract void onPrepared(DownloadHelper helper, boolean tracksInfoAvailable)
```

Called when preparation completes.

| Parameters |
|---|---|
| `https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper helper` | The reporting `https://developer.android.com/reference/androidx/media3/exoplayer/offline/DownloadHelper`. |
| `boolean tracksInfoAvailable` | Whether tracks information is available. |