# NfcAdapter.ReaderCallback

Added in[API level 19](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)

# ReaderCallback

*** ** * ** ***

Kotlin\|[Java](https://developer.android.com/reference/android/nfc/NfcAdapter.ReaderCallback "View this page in Java")  

```
interface ReaderCallback
```

|--------------------------------------------------------------------------------------------------------------------------------|
| [android.nfc.NfcAdapter.ReaderCallback](https://developer.android.com/reference/kotlin/android/nfc/NfcAdapter.ReaderCallback#) |

A callback to be invoked when the system finds a tag while the foreground activity is operating in reader mode.

Register your`ReaderCallback`implementation with[android.nfc.NfcAdapter#enableReaderMode](https://developer.android.com/reference/kotlin/android/nfc/NfcAdapter#enableReaderMode(android.app.Activity,%20android.nfc.NfcAdapter.ReaderCallback,%20kotlin.Int,%20android.os.Bundle))and disable it with[android.nfc.NfcAdapter#disableReaderMode](https://developer.android.com/reference/kotlin/android/nfc/NfcAdapter#disableReaderMode(android.app.Activity)).

## Summary

|                                                                                                                                                      Public methods                                                                                                                                                      ||
|--------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| abstract[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [onTagDiscovered](https://developer.android.com/reference/kotlin/android/nfc/NfcAdapter.ReaderCallback#onTagDiscovered(android.nfc.Tag))`(`tag:` `[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag)!`)` <br /> |

## Public methods

### onTagDiscovered

Added in[API level 19](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)  

```
abstract fun onTagDiscovered(tag: Tag!): Unit
```