Messenger

Kotlin |Java

class Messenger : Parcelable

kotlin.Any
↳	android.os.Messenger

Reference to a Handler, which others can use to send messages to it. This allows for the implementation of message-based communication across processes, by creating a Messenger pointing to a Handler in one process, and handing that Messenger to another process.

Note: the implementation underneath is just a simple wrapper around a Binder that is used to perform the communication. This means semantically you should treat it as such: this class does not impact process lifecycle management (you must be using some higher-level component to tell the system that your process needs to continue running), the connection will break if your process goes away for any reason, etc.

Summary

Inherited constants

From class Parcelable

Int

CONTENTS_FILE_DESCRIPTOR

Descriptor bit used with describeContents(): indicates that the Parcelable object's flattened representation includes a file descriptor.

Int

PARCELABLE_WRITE_RETURN_VALUE

Flag for use with writeToParcel: 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.

Public constructors
`Messenger(target: Handler!)` Create a new Messenger pointing to the given Handler.
`Messenger(target: IBinder!)` Create a Messenger from a raw IBinder, which had previously been retrieved with `getBinder`.

Public methods
Int	`describeContents()`
Boolean	`equals(other: Any?)` Comparison operator on two Messenger objects, such that true is returned then they both point to the same Handler.
IBinder!	`getBinder()` Retrieve the IBinder that this Messenger is using to communicate with its associated Handler.
Int	`hashCode()`
static Messenger!	`readMessengerOrNullFromParcel(in: Parcel!)` Convenience function for reading either a Messenger or null pointer from a Parcel.
Unit	`send(message: Message!)` Send a Message to this Messenger's Handler.
static Unit	`writeMessengerOrNullToParcel(messenger: Messenger!, out: Parcel!)` Convenience function for writing either a Messenger or null pointer to a Parcel.
Unit	`writeToParcel(out: Parcel, flags: Int)`

Properties
static Parcelable.Creator<Messenger!>	`CREATOR`

Public constructors

Messenger

Added in API level 1

Messenger(target: Handler!)

Create a new Messenger pointing to the given Handler. Any Message objects sent through this Messenger will appear in the Handler as if Handler.sendMessage(Message) had been called directly.

Parameters
`target`	Handler!: The Handler that will receive sent messages.

Messenger

Added in API level 1

Messenger(target: IBinder!)

Create a Messenger from a raw IBinder, which had previously been retrieved with getBinder.

Parameters
`target`	IBinder!: The IBinder this Messenger should communicate with.

Public methods

describeContents

Added in API level 1

fun describeContents(): Int

Return
`Int`	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`

equals

Added in API level 1

fun equals(other: Any?): Boolean

Comparison operator on two Messenger objects, such that true is returned then they both point to the same Handler.

Parameters
`obj`	the reference object with which to compare.
`otherObj`	This value may be `null`.

Return
`Boolean`	`true` if this object is the same as the obj argument; `false` otherwise.

getBinder

Added in API level 1

fun getBinder(): IBinder!

Retrieve the IBinder that this Messenger is using to communicate with its associated Handler.

Return
`IBinder!`	Returns the IBinder backing this Messenger.

hashCode

Added in API level 1

fun hashCode(): Int

Return
`Int`	a hash code value for this object.

readMessengerOrNullFromParcel

Added in API level 1

static fun readMessengerOrNullFromParcel(in: Parcel!): Messenger!

Convenience function for reading either a Messenger or null pointer from a Parcel. You must have previously written the Messenger with writeMessengerOrNullToParcel.

Parameters
`in`	Parcel!: The Parcel containing the written Messenger.

Return
`Messenger!`	Returns the Messenger read from the Parcel, or null if null had been written.

send

Added in API level 1

fun send(message: Message!): Unit

Send a Message to this Messenger's Handler.

Parameters
`message`	Message!: The Message to send. Usually retrieved through `Message.obtain()`.

Exceptions
`android.os.RemoteException`	Throws DeadObjectException if the target Handler no longer exists.

writeMessengerOrNullToParcel

Added in API level 1

static fun writeMessengerOrNullToParcel(
    messenger: Messenger!, 
    out: Parcel!
): Unit

Convenience function for writing either a Messenger or null pointer to a Parcel. You must use this with readMessengerOrNullFromParcel for later reading it.

Parameters
`messenger`	Messenger!: The Messenger to write, or null.
`out`	Parcel!: Where to write the Messenger.

writeToParcel

Added in API level 1

fun writeToParcel(
    out: Parcel, 
    flags: Int
): Unit

Parameters
`dest`	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_WRITE_RETURN_VALUE`. Value is either `0` or a combination of `android.os.Parcelable#PARCELABLE_WRITE_RETURN_VALUE`, and android.os.Parcelable.PARCELABLE_ELIDE_DUPLICATES

Properties

CREATOR

Added in API level 1

static val CREATOR: Parcelable.Creator<Messenger!>