# LocusId
Added in[API level 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
Summary:[Inherited Constants](https://developer.android.com/reference/android/content/LocusId#inhconstants)\|[Fields](https://developer.android.com/reference/android/content/LocusId#lfields)\|[Ctors](https://developer.android.com/reference/android/content/LocusId#pubctors)\|[Methods](https://developer.android.com/reference/android/content/LocusId#pubmethods)\|[Inherited Methods](https://developer.android.com/reference/android/content/LocusId#inhmethods)
# LocusId
*** ** * ** ***
[Kotlin](https://developer.android.com/reference/kotlin/android/content/LocusId "View this page in Kotlin")\|Java
`
public
final
class
LocusId
`
`
extends `[Object](https://developer.android.com/reference/java/lang/Object)`
``
implements
`[Parcelable](https://developer.android.com/reference/android/os/Parcelable)`
`
|---|-------------------------|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | 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/android/os/Build.VERSION_CODES#Q)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:
LocusId chatId = new LocusId("Chat_A_B");
And then you should use that`chatId`by:
- Setting it in the chat notification (through[Notification.Builder.setLocusId(chatId)](https://developer.android.com/reference/android/app/Notification.Builder#setLocusId(android.content.LocusId))).
- Setting it into the[ShortcutInfo](https://developer.android.com/reference/android/content/pm/ShortcutInfo)(through[ShortcutInfo.Builder.setLocusId(chatId)](https://developer.android.com/reference/android/content/pm/ShortcutInfo.Builder#setLocusId(android.content.LocusId))), if you provide a launcher shortcut for that chat conversation.
- Associating it with the[ContentCaptureContext](https://developer.android.com/reference/android/view/contentcapture/ContentCaptureContext)of the root view of the chat conversation activity (through[View.getContentCaptureSession()](https://developer.android.com/reference/android/view/View#getContentCaptureSession()), then[new ContentCaptureContext.Builder(chatId).build()](https://developer.android.com/reference/android/view/contentcapture/ContentCaptureContext.Builder)and[ContentCaptureSession.setContentCaptureContext(android.view.contentcapture.ContentCaptureContext)](https://developer.android.com/reference/android/view/contentcapture/ContentCaptureSession#setContentCaptureContext(android.view.contentcapture.ContentCaptureContext))- see[ContentCaptureManager](https://developer.android.com/reference/android/view/contentcapture/ContentCaptureManager)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/android/content/Intent#ACTION_VIEW_LOCUS)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/android/view/contentcapture/ContentCaptureManager)for more details.
## Summary
| ### Inherited constants |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| From interface[android.os.Parcelable](https://developer.android.com/reference/android/os/Parcelable) |-------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `int` | [CONTENTS_FILE_DESCRIPTOR](https://developer.android.com/reference/android/os/Parcelable#CONTENTS_FILE_DESCRIPTOR) Descriptor bit used with[describeContents()](https://developer.android.com/reference/android/os/Parcelable#describeContents()): indicates that the Parcelable object's flattened representation includes a file descriptor. | | `int` | [PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE) Flag for use with[writeToParcel(Parcel, int)](https://developer.android.com/reference/android/os/Parcelable#writeToParcel(android.os.Parcel,%20int)): 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)`". | |
| ### Fields ||
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------|
| ` public static final `[Creator](https://developer.android.com/reference/android/os/Parcelable.Creator)`<`[LocusId](https://developer.android.com/reference/android/content/LocusId)`>` | [CREATOR](https://developer.android.com/reference/android/content/LocusId#CREATOR)
|
| ### Public constructors ||
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---|
| ` `[LocusId](https://developer.android.com/reference/android/content/LocusId#LocusId(java.lang.String))`(`[String](https://developer.android.com/reference/java/lang/String)` id) ` Default constructor. |
| ### Public methods ||
|-----------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| ` int` | ` `[describeContents](https://developer.android.com/reference/android/content/LocusId#describeContents())`() ` Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. |
| ` boolean` | ` `[equals](https://developer.android.com/reference/android/content/LocusId#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` obj) ` Indicates whether some other object is "equal to" this one. |
| ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[getId](https://developer.android.com/reference/android/content/LocusId#getId())`() ` Gets the canonical`id`associated with the locus. |
| ` int` | ` `[hashCode](https://developer.android.com/reference/android/content/LocusId#hashCode())`() ` Returns a hash code value for the object. |
| ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[toString](https://developer.android.com/reference/android/content/LocusId#toString())`() ` Returns a string representation of the object. |
| ` void` | ` `[writeToParcel](https://developer.android.com/reference/android/content/LocusId#writeToParcel(android.os.Parcel,%20int))`(`[Parcel](https://developer.android.com/reference/android/os/Parcel)` parcel, int flags) ` Flatten this object in to a Parcel. |
| ### Inherited methods |
|-----------------------|---|
| From class` `[java.lang.Object](https://developer.android.com/reference/java/lang/Object)` ` |--------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` `[Object](https://developer.android.com/reference/java/lang/Object) | ` `[clone](https://developer.android.com/reference/java/lang/Object#clone())`() ` Creates and returns a copy of this object. | | ` boolean` | ` `[equals](https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` `[finalize](https://developer.android.com/reference/java/lang/Object#finalize())`() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final `[Class](https://developer.android.com/reference/java/lang/Class)`` | ` `[getClass](https://developer.android.com/reference/java/lang/Object#getClass())`() ` Returns the runtime class of this`Object`. | | ` int` | ` `[hashCode](https://developer.android.com/reference/java/lang/Object#hashCode())`() ` Returns a hash code value for the object. | | ` final void` | ` `[notify](https://developer.android.com/reference/java/lang/Object#notify())`() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` `[notifyAll](https://developer.android.com/reference/java/lang/Object#notifyAll())`() ` Wakes up all threads that are waiting on this object's monitor. | | ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[toString](https://developer.android.com/reference/java/lang/Object#toString())`() ` Returns a string representation of the object. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait(long,%20int))`(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait(long))`(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait())`() ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*. | ||
| From interface` `[android.os.Parcelable](https://developer.android.com/reference/android/os/Parcelable)` ` |------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` abstract int` | ` `[describeContents](https://developer.android.com/reference/android/os/Parcelable#describeContents())`() ` Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. | | ` abstract void` | ` `[writeToParcel](https://developer.android.com/reference/android/os/Parcelable#writeToParcel(android.os.Parcel,%20int))`(`[Parcel](https://developer.android.com/reference/android/os/Parcel)` dest, int flags) ` Flatten this object in to a Parcel. | ||
## Fields
### CREATOR
Added in[API level 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static final Creator CREATOR
```
## Public constructors
### LocusId
Added in[API level 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public LocusId (String id)
```
Default constructor.
| Parameters ||
|------|----------------------------------------------|
| `id` | `String`: This value cannot be`null`.
|
| Throws ||
|--------------------------------------------------------------------------------------------------------|--------------------------|
| [IllegalArgumentException](https://developer.android.com/reference/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#ApiLevels)
```
public int describeContents ()
```
Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. For example, if the object will include a file descriptor in the output of[writeToParcel(android.os.Parcel, int)](https://developer.android.com/reference/android/os/Parcelable#writeToParcel(android.os.Parcel,%20int)), the return value of this method must include the[CONTENTS_FILE_DESCRIPTOR](https://developer.android.com/reference/android/os/Parcelable#CONTENTS_FILE_DESCRIPTOR)bit.
| Returns ||
|-------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `int` | a bitmask indicating the set of special object types marshaled by this Parcelable object instance. Value is either`0`or[CONTENTS_FILE_DESCRIPTOR](https://developer.android.com/reference/android/os/Parcelable#CONTENTS_FILE_DESCRIPTOR)
|
### equals
Added in[API level 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public boolean equals (Object obj)
```
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` | `Object`: This value may be`null`.
|
| Returns ||
|-----------|-------------------------------------------------------------------------------|
| `boolean` | `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#ApiLevels)
```
public String getId ()
```
Gets the canonical`id`associated with the locus.
| Returns ||
|--------------------------------------------------------------------|------------------------------------|
| [String](https://developer.android.com/reference/java/lang/String) | This value cannot be`null`.
|
### hashCode
Added in[API level 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public int hashCode ()
```
Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by[HashMap](https://developer.android.com/reference/java/util/HashMap).
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/java/lang/Object#equals(java.lang.Object))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/java/lang/Object#equals(java.lang.Object))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.
| Returns ||
|-------|-------------------------------------------|
| `int` | a hash code value for this object.
|
### toString
Added in[API level 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public String toString ()
```
Returns a string representation of the object.
| Returns ||
|--------------------------------------------------------------------|-----------------------------------------------|
| [String](https://developer.android.com/reference/java/lang/String) | a string representation of the object.
|
### writeToParcel
Added in[API level 29](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public void writeToParcel (Parcel parcel,
int flags)
```
Flatten this object in to a Parcel.
| Parameters ||
|----------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `parcel` | `Parcel`: The Parcel in which the object should be written. This value cannot be`null`.
|
| `flags` | `int`: Additional flags about how the object should be written. May be 0 or[Parcelable.PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE). Value is either`0`or a combination of[Parcelable.PARCELABLE_WRITE_RETURN_VALUE](https://developer.android.com/reference/android/os/Parcelable#PARCELABLE_WRITE_RETURN_VALUE), and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES
|