# CameraCharacteristics.Key

Added in[API level 21](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)

# Key

*** ** * ** ***

Kotlin\|[Java](https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.Key "View this page in Java")  

```
class Key<T : Any!>
```

|---|----------------------------------------------------------------------------------------------------------------------------------------------------------|
| [kotlin.Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html)                                                                           ||
| ↳ | [android.hardware.camera2.CameraCharacteristics.Key](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#) |

A`Key`is used to do camera characteristics field lookups with[CameraCharacteristics.get](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics#get(android.hardware.camera2.CameraCharacteristics.Key)).

For example, to get the stream configuration map:  

```kotlin
<code>
  StreamConfigurationMap map = cameraCharacteristics.get(
       CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
  </code>
```

<br />

To enumerate over all possible keys for[CameraCharacteristics](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics), see[CameraCharacteristics.getKeys()](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics#getKeys()).

## Summary

|                                                                                                                                                                                     Public constructors                                                                                                                                                                                     ||
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|
| [Key](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#Key(kotlin.String,%20java.lang.Class))`(`name:` `[String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)`, `type:` `[Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)<T>`)` Construct a new Key with a given name and type. |

|                                                                                                                                                                              Public methods                                                                                                                                                                              ||
|------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | [equals](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#equals(kotlin.Any))`(`other:` `[Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html)?`)` Indicates whether some other object is "equal to" this one. |
| [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)   | [getName](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#getName())`()` Return a camelCase, period separated name formatted like:`"root.section[.subsections].name"`.                                                             |
| [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html)         | [hashCode](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#hashCode())`()` Returns a hash code value for the object.                                                                                                               |
| [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)   | [toString](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#toString())`()` Return this[Key](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#)as a string representation.         |

## Public constructors

### Key

Added in[API level 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)  

```
Key(
    name: String, 
    type: Class<T>)
```

Construct a new Key with a given name and type.

Normally, applications should use the existing Key definitions in[CameraCharacteristics](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics), and not need to construct their own Key objects. However, they may be useful for testing purposes and for defining custom camera characteristics.

|                                                       Parameters                                                       ||
|--------|----------------------------------------------------------------------------------------------------------------|
| `name` | [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html):This value cannot be`null`.   |
| `type` | [Class](https://developer.android.com/reference/kotlin/java/lang/Class.html#)\<T\>:This value cannot be`null`. |

## Public methods

### equals

Added in[API level 21](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)  

```
fun equals(other: Any?): Boolean
```

Indicates whether some other object is "equal to" this one.

The`equals`method implements an equivalence relation on non-null object references:

- It is*reflexive* : for any non-null reference value`x`,`x.equals(x)`should return`true`.
- It is*symmetric* : for any non-null reference values`x`and`y`,`x.equals(y)`should return`true`if and only if`y.equals(x)`returns`true`.
- It is*transitive* : for any non-null reference values`x`,`y`, and`z`, if`x.equals(y)`returns`true`and`y.equals(z)`returns`true`, then`x.equals(z)`should return`true`.
- It is*consistent* : for any non-null reference values`x`and`y`, multiple invocations of`x.equals(y)`consistently return`true`or consistently return`false`, provided no information used in`equals`comparisons on the objects is modified.
- For any non-null reference value`x`,`x.equals(null)`should return`false`.

An equivalence relation partitions the elements it operates on into*equivalence classes*; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

|                     Parameters                     ||
|-------|---------------------------------------------|
| `obj` | the reference object with which to compare. |

|                                                                           Return                                                                           ||
|------------------------------------------------------------------------------------|------------------------------------------------------------------------|
| [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | `true`if this object is the same as the obj argument;`false`otherwise. |

### getName

Added in[API level 21](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)  

```
fun getName(): String
```

Return a camelCase, period separated name formatted like:`"root.section[.subsections].name"`.

Built-in keys exposed by the Android SDK are always prefixed with`"android."`; keys that are device/platform-specific are prefixed with`"com."`.

For example,`CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP`would have a name of`"android.scaler.streamConfigurationMap"`; whereas a device specific key might look like`"com.google.nexus.data.private"`.

|                                                                       Return                                                                        ||
|----------------------------------------------------------------------------------|-------------------------------------------------------------------|
| [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html) | String representation of the key name This value cannot be`null`. |

### hashCode

Added in[API level 21](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)  

```
fun hashCode(): Int
```

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by[java.util.HashMap](https://developer.android.com/reference/kotlin/java/util/HashMap.html#).

The general contract of`hashCode`is:

- Whenever it is invoked on the same object more than once during an execution of a Java application, the`hashCode`method must consistently return the same integer, provided no information used in`equals`comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
- If two objects are equal according to the[equals](https://developer.android.com/reference/kotlin/java/lang/Object.html#equals(kotlin.Any))method, then calling the`hashCode`method on each of the two objects must produce the same integer result.
- It is*not* required that if two objects are unequal according to the[equals](https://developer.android.com/reference/kotlin/java/lang/Object.html#equals(kotlin.Any))method, then calling the`hashCode`method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

|                                                     Return                                                     ||
|----------------------------------------------------------------------------|------------------------------------|
| [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html) | a hash code value for this object. |

### toString

Added in[API level 21](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)  

```
fun toString(): String
```

Return this[Key](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#)as a string representation.

`"CameraCharacteristics.Key(%s)"`, where`%s`represents the name of this key as returned by[getName](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#getName()).

|                                                                                                                     Return                                                                                                                     ||
|----------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html) | string representation of[Key](https://developer.android.com/reference/kotlin/android/hardware/camera2/CameraCharacteristics.Key#)This value cannot be`null`. |