Parcel

Kotlin |Java

class Parcel

kotlin.Any
↳	android.os.Parcel

Container for a message (data and object references) that can be sent through an IBinder. A Parcel can contain both flattened data that will be unflattened on the other side of the IPC (using the various methods here for writing specific types, or the general Parcelable interface), and references to live IBinder objects that will result in the other side receiving a proxy IBinder connected with the original IBinder in the Parcel.

Parcel is not a general-purpose serialization mechanism. This class (and the corresponding Parcelable API for placing arbitrary objects into a Parcel) is designed as a high-performance IPC transport. As such, it is not appropriate to place any Parcel data in to persistent storage: changes in the underlying implementation of any of the data in the Parcel can render older data unreadable.

The bulk of the Parcel API revolves around reading and writing data of various types. There are six major classes of such functions available.

Primitives

The most basic data functions are for writing and reading primitive data types: writeByte, readByte, writeDouble, readDouble, writeFloat, readFloat, writeInt, readInt, writeLong, readLong, writeString, readString. Most other data operations are built on top of these. The given data is written and read using the endianess of the host CPU.

Primitive Arrays

There are a variety of methods for reading and writing raw arrays of primitive objects, which generally result in writing a 4-byte length followed by the primitive data items. The methods for reading can either read the data into an existing array, or create and return a new array. These available types are:

writeBooleanArray(boolean[]), readBooleanArray(boolean[]), createBooleanArray()
writeByteArray(byte[]), writeByteArray(byte[],int,int), readByteArray(byte[]), createByteArray()
writeCharArray(char[]), readCharArray(char[]), createCharArray()
writeDoubleArray(double[]), readDoubleArray(double[]), createDoubleArray()
writeFloatArray(float[]), readFloatArray(float[]), createFloatArray()
writeIntArray(int[]), readIntArray(int[]), createIntArray()
writeLongArray(long[]), readLongArray(long[]), createLongArray()
writeStringArray(java.lang.String[]), readStringArray(java.lang.String[]), createStringArray().
writeSparseBooleanArray(android.util.SparseBooleanArray), readSparseBooleanArray().

Parcelables

The Parcelable protocol provides an extremely efficient (but low-level) protocol for objects to write and read themselves from Parcels. You can use the direct methods writeParcelable(android.os.Parcelable,int) and readParcelable(java.lang.ClassLoader) or writeParcelableArray and readParcelableArray(java.lang.ClassLoader) to write or read. These methods write both the class type and its data to the Parcel, allowing that class to be reconstructed from the appropriate class loader when later reading.

There are also some methods that provide a more efficient way to work with Parcelables: writeTypedObject, writeTypedArray, writeTypedList, readTypedObject, createTypedArray and createTypedArrayList. These methods do not write the class information of the original object: instead, the caller of the read function must know what type to expect and pass in the appropriate Parcelable.Creator instead to properly construct the new object and read its data. (To more efficient write and read a single Parcelable object that is not null, you can directly call Parcelable#writeToParcel and Parcelable.Creator#createFromParcel yourself.)

Bundles

A special type-safe container, called Bundle, is available for key/value maps of heterogeneous values. This has many optimizations for improved performance when reading and writing data, and its type-safe API avoids difficult to debug type errors when finally marshalling the data contents into a Parcel. The methods to use are writeBundle(android.os.Bundle), readBundle(), and readBundle(java.lang.ClassLoader).

Active Objects

An unusual feature of Parcel is the ability to read and write active objects. For these objects the actual contents of the object is not written, rather a special token referencing the object is written. When reading the object back from the Parcel, you do not get a new instance of the object, but rather a handle that operates on the exact same object that was originally written. There are two forms of active objects available.

Binder objects are a core facility of Android's general cross-process communication system. The IBinder interface describes an abstract protocol with a Binder object. Any such interface can be written in to a Parcel, and upon reading you will receive either the original object implementing that interface or a special proxy implementation that communicates calls back to the original object. The methods to use are writeStrongBinder(android.os.IBinder), writeStrongInterface(android.os.IInterface), readStrongBinder(), writeBinderArray(android.os.IBinder[]), readBinderArray(android.os.IBinder[]), createBinderArray(), writeBinderList(java.util.List), readBinderList(java.util.List), createBinderArrayList().

FileDescriptor objects, representing raw Linux file descriptor identifiers, can be written and ParcelFileDescriptor objects returned to operate on the original file descriptor. The returned file descriptor is a dup of the original file descriptor: the object and fd is different, but operating on the same underlying file stream, with the same position, etc. The methods to use are writeFileDescriptor(java.io.FileDescriptor), readFileDescriptor().

Untyped Containers

A final class of methods are for writing and reading standard Java containers of arbitrary types. These all revolve around the writeValue(java.lang.Object) and readValue(java.lang.ClassLoader) methods which define the types of objects allowed. The container methods are writeArray(java.lang.Object[]), readArray(java.lang.ClassLoader), writeList(java.util.List), readList(java.util.List,java.lang.ClassLoader), readArrayList(java.lang.ClassLoader), writeMap(java.util.Map), readMap(java.util.Map,java.lang.ClassLoader), writeSparseArray(android.util.SparseArray), readSparseArray(java.lang.ClassLoader).

Summary

Public methods
Unit	`appendFrom(parcel: Parcel!, offset: Int, length: Int)`
Array<IBinder!>?	`createBinderArray()`
ArrayList<IBinder!>?	`createBinderArrayList()` Read and return a new ArrayList containing IBinder objects from the parcel that was written with `writeBinderList` at the current dataPosition().
BooleanArray?	`createBooleanArray()`
ByteArray?	`createByteArray()` Read and return a byte[] object from the parcel.
CharArray?	`createCharArray()`
DoubleArray?	`createDoubleArray()`
FloatArray?	`createFloatArray()`
IntArray?	`createIntArray()`
LongArray?	`createLongArray()`
Array<String!>?	`createStringArray()`
ArrayList<String!>?	`createStringArrayList()` Read and return a new ArrayList containing String objects from the parcel that was written with `writeStringList` at the current dataPosition().
Array<T>?	`createTypedArray(c: Parcelable.Creator<T>)` Read and return a new array containing a particular object type from the parcel at the current dataPosition().
ArrayList<T>?	`createTypedArrayList(c: Parcelable.Creator<T>)` Read and return a new ArrayList containing a particular object type from the parcel that was written with `writeTypedList` at the current dataPosition().
ArrayMap<String!, T>?	`createTypedArrayMap(creator: Parcelable.Creator<T>)` Read into a new `ArrayMap` with string keys items containing a particular object type that were written with `writeTypedArrayMap(android.util.ArrayMap,int)` at the current dataPosition().
SparseArray<T>?	`createTypedSparseArray(creator: Parcelable.Creator<T>)` Read into a new `SparseArray` items containing a particular object type that were written with `writeTypedSparseArray(android.util.SparseArray,int)` at the current dataPosition().
Int	`dataAvail()` Returns the amount of data remaining to be read from the parcel.
Int	`dataCapacity()` Returns the total amount of space in the parcel.
Int	`dataPosition()` Returns the current position in the parcel data.
Int	`dataSize()` Returns the total amount of data contained in the parcel.
Unit	`enforceInterface(interfaceName: String!)`
Boolean	`hasFileDescriptors()` Report whether the parcel contains any marshalled file descriptors.
ByteArray!	`marshall()` Returns the raw bytes of the parcel.
static Parcel	`obtain()` Retrieve a new Parcel object from the pool.
Array<Any!>?	`readArray(loader: ClassLoader?)` Read and return a new Object array from the parcel at the current dataPosition().
ArrayList<Any!>?	`readArrayList(loader: ClassLoader?)` Read and return a new ArrayList object from the parcel at the current dataPosition().
Unit	`readBinderArray(val: Array<IBinder!>)`
Unit	`readBinderList(list: MutableList<IBinder!>)` Read into the given List items IBinder objects that were written with `writeBinderList` at the current dataPosition().
Boolean	`readBoolean()` Read a boolean value from the parcel at the current dataPosition().
Unit	`readBooleanArray(val: BooleanArray)`
Bundle?	`readBundle()` Read and return a new Bundle object from the parcel at the current dataPosition().
Bundle?	`readBundle(loader: ClassLoader?)` Read and return a new Bundle object from the parcel at the current dataPosition(), using the given class loader to initialize the class loader of the Bundle for later retrieval of Parcelable objects.
Byte	`readByte()` Read a byte value from the parcel at the current dataPosition().
Unit	`readByteArray(val: ByteArray)` Read a byte[] object from the parcel and copy it into the given byte array.
Unit	`readCharArray(val: CharArray)`
Double	`readDouble()` Read a double precision floating point value from the parcel at the current dataPosition().
Unit	`readDoubleArray(val: DoubleArray)`
Unit	`readException()` Special function for reading an exception result from the header of a parcel, to be used after receiving the result of a transaction.
Unit	`readException(code: Int, msg: String!)` Throw an exception with the given message.
ParcelFileDescriptor!	`readFileDescriptor()` Read a FileDescriptor from the parcel at the current dataPosition().
Float	`readFloat()` Read a floating point value from the parcel at the current dataPosition().
Unit	`readFloatArray(val: FloatArray)`
HashMap<Any!, Any!>?	`readHashMap(loader: ClassLoader?)` Please use `readBundle(java.lang.ClassLoader)` instead (whose data must have been written with `writeBundle`.
Int	`readInt()` Read an integer value from the parcel at the current dataPosition().
Unit	`readIntArray(val: IntArray)`
Unit	`readList(outVal: MutableList<Any?>, loader: ClassLoader?)` Read into an existing List object from the parcel at the current dataPosition(), using the given class loader to load any enclosed Parcelables.
Long	`readLong()` Read a long integer value from the parcel at the current dataPosition().
Unit	`readLongArray(val: LongArray)`
Unit	`readMap(outVal: MutableMap<Any?, Any?>, loader: ClassLoader?)` Please use `readBundle(java.lang.ClassLoader)` instead (whose data must have been written with `writeBundle`.
T?	`readParcelable(loader: ClassLoader?)` Read and return a new Parcelable from the parcel.
Array<Parcelable!>?	`readParcelableArray(loader: ClassLoader?)` Read and return a new Parcelable array from the parcel.
Parcelable.Creator<*>?	`readParcelableCreator(loader: ClassLoader?)` Read and return a Parcelable.
MutableList<T>	`readParcelableList(list: MutableList<T>, cl: ClassLoader?)` Read the list of `Parcelable` objects at the current data position into the given `list`.
PersistableBundle?	`readPersistableBundle()` Read and return a new Bundle object from the parcel at the current dataPosition().
PersistableBundle?	`readPersistableBundle(loader: ClassLoader?)` Read and return a new Bundle object from the parcel at the current dataPosition(), using the given class loader to initialize the class loader of the Bundle for later retrieval of Parcelable objects.
Serializable?	`readSerializable()` Read and return a new Serializable object from the parcel.
Size	`readSize()` Read a Size from the parcel at the current dataPosition().
SizeF	`readSizeF()` Read a SizeF from the parcel at the current dataPosition().
SparseArray<T>?	`readSparseArray(loader: ClassLoader?)` Read and return a new SparseArray object from the parcel at the current dataPosition().
SparseBooleanArray?	`readSparseBooleanArray()` Read and return a new SparseBooleanArray object from the parcel at the current dataPosition().
String?	`readString()` Read a string value from the parcel at the current dataPosition().
Unit	`readStringArray(val: Array<String!>)`
Unit	`readStringList(list: MutableList<String!>)` Read into the given List items String objects that were written with `writeStringList` at the current dataPosition().
IBinder!	`readStrongBinder()` Read an object from the parcel at the current dataPosition().
Unit	`readTypedArray(val: Array<T>, c: Parcelable.Creator<T>)`
Unit	`readTypedList(list: MutableList<T>, c: Parcelable.Creator<T>)` Read into the given List items containing a particular object type that were written with `writeTypedList` at the current dataPosition().
T?	`readTypedObject(c: Parcelable.Creator<T>)` Read and return a typed Parcelable object from a parcel.
Any?	`readValue(loader: ClassLoader?)` Read a typed object from a parcel.
Unit	`recycle()` Put a Parcel object back into the pool.
Unit	`setDataCapacity(size: Int)` Change the capacity (current available space) of the parcel.
Unit	`setDataPosition(pos: Int)` Move the current read/write position in the parcel.
Unit	`setDataSize(size: Int)` Change the amount of data in the parcel.
Unit	`unmarshall(data: ByteArray, offset: Int, length: Int)` Set the bytes in data to be the raw bytes of this Parcel.
Unit	`writeArray(val: Array<Any!>?)` Flatten an Object array into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeBinderArray(val: Array<IBinder!>?)`
Unit	`writeBinderList(val: MutableList<IBinder!>?)` Flatten a List containing IBinder objects into the parcel, at the current dataPosition() and growing dataCapacity() if needed.
Unit	`writeBoolean(val: Boolean)` Write a boolean value into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeBooleanArray(val: BooleanArray?)`
Unit	`writeBundle(val: Bundle?)` Flatten a Bundle into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeByte(val: Byte)` Write a byte value into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeByteArray(b: ByteArray?)` Write a byte array into the parcel at the current `dataPosition`, growing `dataCapacity` if needed.
Unit	`writeByteArray(b: ByteArray?, offset: Int, len: Int)` Write a byte array into the parcel at the current `dataPosition`, growing `dataCapacity` if needed.
Unit	`writeCharArray(val: CharArray?)`
Unit	`writeDouble(val: Double)` Write a double precision floating point value into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeDoubleArray(val: DoubleArray?)`
Unit	`writeException(e: Exception)` Special function for writing an exception result at the header of a parcel, to be used when returning an exception from a transaction.
Unit	`writeFileDescriptor(val: FileDescriptor)` Write a FileDescriptor into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeFloat(val: Float)` Write a floating point value into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeFloatArray(val: FloatArray?)`
Unit	`writeInt(val: Int)` Write an integer value into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeIntArray(val: IntArray?)`
Unit	`writeInterfaceToken(interfaceName: String!)` Store or read an IBinder interface token in the parcel at the current `dataPosition`.
Unit	`writeList(val: MutableList<Any?>?)` Flatten a List into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeLong(val: Long)` Write a long integer value into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeLongArray(val: LongArray?)`
Unit	`writeMap(val: MutableMap<Any?, Any?>?)` Please use `writeBundle` instead.
Unit	`writeNoException()` Special function for writing information at the front of the Parcel indicating that no exception occurred.
Unit	`writeParcelable(p: Parcelable?, parcelableFlags: Int)` Flatten the name of the class of the Parcelable and its contents into the parcel.
Unit	`writeParcelableArray(value: Array<T>?, parcelableFlags: Int)` Write a heterogeneous array of Parcelable objects into the Parcel.
Unit	`writeParcelableCreator(p: Parcelable)` Flatten the name of the class of the Parcelable into this Parcel.
Unit	`writeParcelableList(val: MutableList<T>?, flags: Int)` Flatten a `List` containing arbitrary `Parcelable` objects into this parcel at the current position.
Unit	`writePersistableBundle(val: PersistableBundle?)` Flatten a PersistableBundle into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeSerializable(s: Serializable?)` Write a generic serializable object in to a Parcel.
Unit	`writeSize(val: Size)` Flatten a Size into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeSizeF(val: SizeF)` Flatten a SizeF into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeSparseArray(val: SparseArray<T>?)` Flatten a generic SparseArray into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeSparseBooleanArray(val: SparseBooleanArray?)`
Unit	`writeString(val: String?)` Write a string value into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeStringArray(val: Array<String!>?)`
Unit	`writeStringList(val: MutableList<String!>?)` Flatten a List containing String objects into the parcel, at the current dataPosition() and growing dataCapacity() if needed.
Unit	`writeStrongBinder(val: IBinder!)` Write an object into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeStrongInterface(val: IInterface!)` Write an object into the parcel at the current dataPosition(), growing dataCapacity() if needed.
Unit	`writeTypedArray(val: Array<T>?, parcelableFlags: Int)` Flatten a homogeneous array containing a particular object type into the parcel, at the current dataPosition() and growing dataCapacity() if needed.
Unit	`writeTypedArrayMap(val: ArrayMap<String!, T>?, parcelableFlags: Int)` Flatten an `ArrayMap` with string keys containing a particular object type into the parcel at the current dataPosition() and growing dataCapacity() if needed.
Unit	`writeTypedList(val: MutableList<T>?)` Flatten a List containing a particular object type into the parcel, at the current dataPosition() and growing dataCapacity() if needed.
Unit	`writeTypedObject(val: T?, parcelableFlags: Int)` Flatten the Parcelable object into the parcel.
Unit	`writeTypedSparseArray(val: SparseArray<T>?, parcelableFlags: Int)` Flatten a `SparseArray` containing a particular object type into the parcel at the current dataPosition() and growing dataCapacity() if needed.
Unit	`writeValue(v: Any?)` Flatten a generic object in to a parcel.

Protected methods
Unit	`finalize()`

Properties
static Parcelable.Creator<String!>!	`STRING_CREATOR`

Parameters
`code`	Int: Used to determine which exception class to throw.
`msg`	String!: The exception message.

Parameters
`outVal`	MutableList<Any?>: This value cannot be `null`.
`loader`	ClassLoader?: This value may be `null`.

Parameters
`outVal`	MutableMap<Any?, Any?>: This value cannot be `null`.
`loader`	ClassLoader?: This value may be `null`.

Parameters
`list`	MutableList<T>: This value cannot be `null`.
`cl`	ClassLoader?: This value may be `null`.

Parameters
`val`	Array<T>: This value cannot be `null`.
`c`	Parcelable.Creator<T>: This value cannot be `null`.

Parameters
`b`	ByteArray?: Bytes to place into the parcel. This value may be `null`.
`offset`	Int: Index of first byte to be written.
`len`	Int: Number of bytes to write.

Parameters
`p`	Parcelable?: The Parcelable object to be written. This value may be `null`.
`parcelableFlags`	Int: Contextual flags as per `Parcelable#writeToParcel(Parcel, int)`.

Parameters
`value`	Array<T>?: The array of objects to be written. This value may be `null`.
`parcelableFlags`	Int: Contextual flags as per `Parcelable#writeToParcel(Parcel, int)`.

Parameters
`val`	ArrayMap<String!, T>?: The map of objects to be written. This value may be `null`.
`parcelableFlags`	Int: The parcelable flags to use.

Parameters
`val`	T?: The Parcelable object to be written. This value may be `null`.
`parcelableFlags`	Int: Contextual flags as per `Parcelable#writeToParcel(Parcel, int)`.

Parameters
`val`	SparseArray<T>?: The list of objects to be written. This value may be `null`.
`parcelableFlags`	Int: The parcelable flags to use.

Parcel

Primitives

Primitive Arrays

Parcelables

Bundles

Active Objects

Untyped Containers

Summary

Public methods

appendFrom

createBinderArray

createBinderArrayList

createBooleanArray

createByteArray

createCharArray

createDoubleArray

createFloatArray

createIntArray

createLongArray

createStringArray

createStringArrayList

createTypedArray

createTypedArrayList

createTypedArrayMap

createTypedSparseArray

dataAvail

dataCapacity

dataPosition

dataSize

enforceInterface

hasFileDescriptors

marshall

obtain

readArray

readArrayList

readBinderArray

readBinderList

readBoolean

readBooleanArray

readBundle

readBundle

readByte

readByteArray

readCharArray

readDouble

readDoubleArray

readException

readException

readFileDescriptor

readFloat

readFloatArray

readHashMap

readInt

readIntArray

readList

readLong

readLongArray

readMap

readParcelable

readParcelableArray

readParcelableCreator

readParcelableList

readPersistableBundle

readPersistableBundle

readSerializable

readSize

readSizeF

readSparseArray

readSparseBooleanArray

readString

readStringArray

readStringList

readStrongBinder

readTypedArray

readTypedList

readTypedObject

readValue

recycle

setDataCapacity

setDataPosition