# LocusId

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

# LocusId

*** ** * ** ***

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

```
class LocusId : Parcelable
```

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

An identifier for an unique state (locus) in the application. Should be stable across reboots and backup / restore.

Locus is a new concept introduced on[Android Q](https://developer.android.com/reference/kotlin/android/os/Build.VERSION_CODES.html#Q:kotlin.Int)and it lets the intelligence service provided by the Android System to correlate state between different subsystems such as content capture, shortcuts, and notifications.

For example, if your app provides an activity representing a chat between 2 users (say`A`and`B`, this chat state could be represented by:  

```kotlin
<code>
  LocusId chatId = new LocusId("Chat_A_B");
  </code>
```

And then you should use that`chatId`by:

- Setting it in the chat notification (through[Notification.Builder.setLocusId(chatId)](https://developer.android.com/reference/kotlin/android/app/Notification.Builder.html#setLocusId(android.content.LocusId))).
- Setting it into the[android.content.pm.ShortcutInfo](https://developer.android.com/reference/kotlin/android/content/pm/ShortcutInfo)(through[ShortcutInfo.Builder.setLocusId(chatId)](https://developer.android.com/reference/kotlin/android/content/pm/ShortcutInfo.Builder#setLocusId(android.content.LocusId))), if you provide a launcher shortcut for that chat conversation.
- Associating it with the[android.view.contentcapture.ContentCaptureContext](https://developer.android.com/reference/kotlin/android/view/contentcapture/ContentCaptureContext.html#)of the root view of the chat conversation activity (through[android.view.View#getContentCaptureSession()](https://developer.android.com/reference/kotlin/android/view/View.html#getContentCaptureSession()), then[new ContentCaptureContext.Builder(chatId).build()](https://developer.android.com/reference/kotlin/android/view/contentcapture/ContentCaptureContext.Builder.html#)and[android.view.contentcapture.ContentCaptureSession#setContentCaptureContext( * android.view.contentcapture.ContentCaptureContext)](https://developer.android.com/reference/kotlin/android/view/contentcapture/ContentCaptureSession.html#setContentCaptureContext(android.view.contentcapture.ContentCaptureContext))- see[ContentCaptureManager](https://developer.android.com/reference/kotlin/android/view/contentcapture/ContentCaptureManager.html#)for more info about content capture).
- Configuring your app to launch the chat conversation through the[Intent.ACTION_VIEW_LOCUS](https://developer.android.com/reference/kotlin/android/content/Intent#ACTION_VIEW_LOCUS:kotlin.String)intent.

NOTE: The LocusId is only used by an on-device intelligence service provided by the Android System, see[ContentCaptureManager](https://developer.android.com/reference/kotlin/android/view/contentcapture/ContentCaptureManager.html#)for more details.

## Summary

| Inherited constants ||
|---|---|
| From class[Parcelable](https://developer.android.com/reference/kotlin/android/os/Parcelable.html#) |----------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html) | [CONTENTS_FILE_DESCRIPTOR](https://developer.android.com/reference/kotlin/android/os/Parcelable.html#CONTENTS_FILE_DESCRIPTOR:kotlin.Int) <br /> Descriptor bit used with[describeContents()](https://developer.android.com/reference/kotlin/android/os/Parcelable.html#describeContents()): indicates that the Parcelable object's flattened representation includes a file descriptor. <br />                                                                                                                                                                                                        | | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html) | [PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/kotlin/android/os/Parcelable.html#PARCELABLE_WRITE_RETURN_VALUE:kotlin.Int) <br /> Flag for use with[writeToParcel](https://developer.android.com/reference/kotlin/android/os/Parcelable.html#writeToParcel(android.os.Parcel,%20kotlin.Int)): the object being written is a return value, that is the result of a function such as "`Parcelable someFunction()`", "`void someFunction(out Parcelable)`", or "`void someFunction(inout Parcelable)`". Some implementations may want to release resources at this point. <br /> | ||

|                                                                                                     Public constructors                                                                                                      ||
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|
| [LocusId](https://developer.android.com/reference/kotlin/android/content/LocusId#LocusId(kotlin.String))`(`id:` `[String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)`)` Default constructor. |

|                                                                                                                                                                                                      Public methods                                                                                                                                                                                                      ||
|------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html)         | [describeContents](https://developer.android.com/reference/kotlin/android/content/LocusId#describeContents())`()` <br />                                                                                                                                                                                                             |
| [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | [equals](https://developer.android.com/reference/kotlin/android/content/LocusId#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)   | [getId](https://developer.android.com/reference/kotlin/android/content/LocusId#getId())`()` Gets the canonical`id`associated with the locus.                                                                                                                                                                                         |
| [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html)         | [hashCode](https://developer.android.com/reference/kotlin/android/content/LocusId#hashCode())`()` <br />                                                                                                                                                                                                                             |
| [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html)   | [toString](https://developer.android.com/reference/kotlin/android/content/LocusId#toString())`()` <br />                                                                                                                                                                                                                             |
| [Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html)       | [writeToParcel](https://developer.android.com/reference/kotlin/android/content/LocusId#writeToParcel(android.os.Parcel,%20kotlin.Int))`(`parcel:` `[Parcel](https://developer.android.com/reference/kotlin/android/os/Parcel.html#)`, `flags:` `[Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html)`)` <br /> |

|                                                                                                                                                              Properties                                                                                                                                                               ||
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------|
| static[Parcelable.Creator](https://developer.android.com/reference/kotlin/android/os/Parcelable.Creator.html#)\<[LocusId](https://developer.android.com/reference/kotlin/android/content/LocusId#)!\> | [CREATOR](https://developer.android.com/reference/kotlin/android/content/LocusId#CREATOR:android.os.Parcelable.Creator) <br /> |

## Public constructors

### LocusId

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

```
LocusId(id: String)
```

Default constructor.

|                                                     Parameters                                                     ||
|------|--------------------------------------------------------------------------------------------------------------|
| `id` | [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html):This value cannot be`null`. |

|                           Exceptions                           ||
|--------------------------------------|--------------------------|
| `java.lang.IllegalArgumentException` | if`id`is empty or`null`. |

## Public methods

### describeContents

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

```
fun describeContents(): Int
```

|                                                                                                                                                                               Return                                                                                                                                                                               ||
|----------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html) | a bitmask indicating the set of special object types marshaled by this Parcelable object instance. Value is either`0`or[android.os.Parcelable#CONTENTS_FILE_DESCRIPTOR](https://developer.android.com/reference/kotlin/android/os/Parcelable.html#CONTENTS_FILE_DESCRIPTOR:kotlin.Int) |

### equals

Added in[API level 29](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` | This value may be`null`. |

|                                                                           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. |

### getId

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

```
fun getId(): String
```

Gets the canonical`id`associated with the locus.

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

### hashCode

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

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

|                                                     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 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels)  

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

|                                                          Return                                                          ||
|----------------------------------------------------------------------------------|----------------------------------------|
| [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html) | a string representation of the object. |

### writeToParcel

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

```
fun writeToParcel(
    parcel: Parcel, 
    flags: Int
): Unit
```

|                                                                                                                                                                                                                                                                                     Parameters                                                                                                                                                                                                                                                                                     ||
|---------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `dest`  | The Parcel in which the object should be written. This value cannot be`null`.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| `flags` | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html):Additional flags about how the object should be written. May be 0 or[PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/kotlin/android/os/Parcelable.html#PARCELABLE_WRITE_RETURN_VALUE:kotlin.Int). Value is either`0`or a combination of[android.os.Parcelable#PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/kotlin/android/os/Parcelable.html#PARCELABLE_WRITE_RETURN_VALUE:kotlin.Int), and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES |

## Properties

### CREATOR

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

```
static val CREATOR: Parcelable.Creator<LocusId!>
```