# TagTechnology Added in[API level 10](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) # TagTechnology *** ** * ** *** Kotlin\|[Java](https://developer.android.com/reference/android/nfc/tech/TagTechnology "View this page in Java") ``` interface TagTechnology : Closeable ``` |------------------------------------------------------------------------------------------------------------------| | [android.nfc.tech.TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#) | 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| Known Direct Subclasses [IsoDep](https://developer.android.com/reference/kotlin/android/nfc/tech/IsoDep),[MifareClassic](https://developer.android.com/reference/kotlin/android/nfc/tech/MifareClassic),[MifareUltralight](https://developer.android.com/reference/kotlin/android/nfc/tech/MifareUltralight),[Ndef](https://developer.android.com/reference/kotlin/android/nfc/tech/Ndef),[NdefFormatable](https://developer.android.com/reference/kotlin/android/nfc/tech/NdefFormatable),[NfcA](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcA),[NfcB](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcB),[NfcBarcode](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcBarcode),[NfcF](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcF),[NfcV](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcV) |------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------| | [IsoDep](https://developer.android.com/reference/kotlin/android/nfc/tech/IsoDep) | Provides access to ISO-DEP (ISO 14443-4) properties and I/O operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | [MifareClassic](https://developer.android.com/reference/kotlin/android/nfc/tech/MifareClassic) | Provides access to MIFARE Classic properties and I/O operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | [MifareUltralight](https://developer.android.com/reference/kotlin/android/nfc/tech/MifareUltralight) | Provides access to MIFARE Ultralight properties and I/O operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | [Ndef](https://developer.android.com/reference/kotlin/android/nfc/tech/Ndef) | Provides access to NDEF content and operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | [NdefFormatable](https://developer.android.com/reference/kotlin/android/nfc/tech/NdefFormatable) | Provide access to NDEF format operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | [NfcA](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcA) | Provides access to NFC-A (ISO 14443-3A) properties and I/O operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | [NfcB](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcB) | Provides access to NFC-B (ISO 14443-3B) properties and I/O operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | [NfcBarcode](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcBarcode) | Provides access to tags containing just a barcode. | | [NfcF](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcF) | Provides access to NFC-F (JIS 6319-4) properties and I/O operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | [NfcV](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcV) | Provides access to NFC-V (ISO 15693) properties and I/O operations on a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#). | | is an interface to a technology in a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#) Obtain a[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)implementation by calling the static method`get()`on the implementation class. NFC tags are based on a number of independently developed technologies and offer a wide range of capabilities. The[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)implementations provide access to these different technologies and capabilities. Some sub-classes map to technology specification (for example[NfcA](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcA),[IsoDep](https://developer.android.com/reference/kotlin/android/nfc/tech/IsoDep), others map to pseudo-technologies or capabilities (for example[Ndef](https://developer.android.com/reference/kotlin/android/nfc/tech/Ndef),[NdefFormatable](https://developer.android.com/reference/kotlin/android/nfc/tech/NdefFormatable)). It is mandatory for all Android NFC devices to provide the following[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)implementations. - [NfcA](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcA)(also known as ISO 14443-3A) - [NfcB](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcB)(also known as ISO 14443-3B) - [NfcF](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcF)(also known as JIS 6319-4) - [NfcV](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcV)(also known as ISO 15693) - [IsoDep](https://developer.android.com/reference/kotlin/android/nfc/tech/IsoDep) - [Ndef](https://developer.android.com/reference/kotlin/android/nfc/tech/Ndef)on NFC Forum Type 1, Type 2, Type 3 or Type 4 compliant tags It is optional for Android NFC devices to provide the following[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)implementations. If it is not provided, the Android device will never enumerate that class via[Tag.getTechList](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#getTechList()). - [MifareClassic](https://developer.android.com/reference/kotlin/android/nfc/tech/MifareClassic) - [MifareUltralight](https://developer.android.com/reference/kotlin/android/nfc/tech/MifareUltralight) - [NfcBarcode](https://developer.android.com/reference/kotlin/android/nfc/tech/NfcBarcode) - [NdefFormatable](https://developer.android.com/reference/kotlin/android/nfc/tech/NdefFormatable)must only be enumerated on tags for which this Android device is capable of formatting. Proprietary knowledge is often required to format a tag to make it NDEF compatible. [TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)implementations provide methods that fall into two classes:*cached getters* and*I/O operations*. #### Cached getters These methods (usually prefixed by`get`or`is`) return properties of the tag, as determined at discovery time. These methods will never block or cause RF activity, and do not require[connect](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#connect())to have been called. They also never update, for example if a property is changed by an I/O operation with a tag then the cached getter will still return the result from tag discovery time. #### I/O operations I/O operations may require RF activity, and may block. They have the following semantics. - [connect](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#connect())must be called before using any other I/O operation. - close must be called after completing I/O operations with a[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#), and it will cancel all other blocked I/O operations on other threads (including[connect](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#connect())with[IOException](https://developer.android.com/reference/kotlin/java/io/IOException.html#). - Only one[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)can be connected at a time. Other calls to[connect](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#connect())will return[IOException](https://developer.android.com/reference/kotlin/java/io/IOException.html#). - I/O operations may block, and should never be called on the main application thread. **Note:** Methods that perform I/O operations require the[android.Manifest.permission#NFC](https://developer.android.com/reference/kotlin/android/Manifest.permission.html#NFC:kotlin.String)permission. ## Summary | Public methods || |--------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | abstract[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [close](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#close())`()` Disable I/O operations to the tag from this[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)object, and release resources. | | abstract[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [connect](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#connect())`()` Enable I/O operations to the tag from this[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)object. | | abstract[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#)! | [getTag](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#getTag())`()` Get the[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#)object backing this[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)object. | | abstract[Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | [isConnected](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#isConnected())`()` Helper to indicate if I/O operations should be possible. | ## Public methods ### close Added in[API level 10](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` abstract fun close(): Unit ``` Disable I/O operations to the tag from this[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)object, and release resources. Also causes all blocked I/O operations on other thread to be canceled and return with[IOException](https://developer.android.com/reference/kotlin/java/io/IOException.html#). Requires the[android.Manifest.permission#NFC](https://developer.android.com/reference/kotlin/android/Manifest.permission.html#NFC:kotlin.String)permission. | Exceptions || |-------------------------------|--------------------------------------------------------------| | `java.lang.Exception` | if this resource cannot be closed | | `java.io.IOException` | if an I/O error occurs | | `java.lang.SecurityException` | if the tag object is reused after the tag has left the field | **See Also** - ### connect Added in[API level 10](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` abstract fun connect(): Unit ``` Enable I/O operations to the tag from this[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)object. May cause RF activity and may block. Must not be called from the main application thread. A blocked call will be canceled with[IOException](https://developer.android.com/reference/kotlin/java/io/IOException.html#)by calling #close from another thread. Only one[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)object can be connected to a[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#)at a time. Applications must call #close when I/O operations are complete. Requires the[android.Manifest.permission#NFC](https://developer.android.com/reference/kotlin/android/Manifest.permission.html#NFC:kotlin.String)permission. | Exceptions || |-------------------------------|--------------------------------------------------------------| | `TagLostException` | if the tag leaves the field | | `java.io.IOException` | if there is an I/O failure, or connect is canceled | | `java.lang.SecurityException` | if the tag object is reused after the tag has left the field | **See Also** ### getTag Added in[API level 10](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` abstract fun getTag(): Tag! ``` Get the[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#)object backing this[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)object. | Return || |------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#)! | the[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#)backing this[TagTechnology](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#)object. | ### isConnected Added in[API level 10](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` abstract fun isConnected(): Boolean ``` Helper to indicate if I/O operations should be possible. Returns true if[connect](https://developer.android.com/reference/kotlin/android/nfc/tech/TagTechnology#connect())has completed, and #close has not been called, and the[Tag](https://developer.android.com/reference/kotlin/android/nfc/Tag.html#)is not known to be out of range. Does not cause RF activity, and does not block. | Return || |------------------------------------------------------------------------------------|-------------------------------------------| | [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | true if I/O operations should be possible |