MessageParcel

java.lang.Object
- ohos.utils.Parcel
- - ohos.rpc.MessageParcel

```
public class MessageParcel
extends Parcel
```
Inherits from the Parcel class and provides methods for managing MessageParcel objects.
This class provides methods for reading and writing objects, interface tokens, file descriptors, and big data.

从以下版本开始:

1

方法概要

所有方法静态方法实例方法具体方法
限定符和类型	方法	说明
`static void`	`closeFileDescriptor(FileDescriptor descriptor)`	Disables a file descriptor in `MessageParcel`.
`boolean`	`containFileDescriptors()`	Checks whether this `MessageParcel` object contains file descriptors.
`static MessageParcel`	`create()`	Creates a `MessageParcel` object.
`static MessageParcel`	`create(long object)`	Creates a `MessageParcel` object with a given pointer.
`IRemoteObject[]`	`createRemoteObjectArray()`	Creates an array of `IRemoteObject` objects.
`List<IRemoteObject>`	`createRemoteObjectList()`	Creates a list of `IRemoteObject` objects.
`static int`	`detachFd(FileDescriptor fileDescriptor)`	Detaches the native fd from FileDescriptor.
`static FileDescriptor`	`dupFileDescriptor(FileDescriptor descriptor)`	Obtains a new file descriptor which is a duplication of an existing file descriptor.
`protected void`	`finalize()`	Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`int`	`getDataVersion()`	return data version from the `MessageParcel` object.
`static int`	`getFd(FileDescriptor fileDescriptor)`	Reads an native fd from FileDescriptor
`static FileDescriptor`	`getFdFromDatagramSocket(DatagramSocket datagramSocket)`	Reads an FileDescriptor from DatagramSocket
`int`	`getRawDataCapacity()`	Obtains the maximum amount of raw data a `MessageParcel` can hold.
`static MessageParcel`	`obtain()`	Creates a `MessageParcel` object.
`static MessageParcel`	`obtain(long object)`	Obtains a `MessageParcel` object with a given pointer.
`Ashmem`	`readAshmem()`	Reads an `Ashmem` object from this `MessageParcel`.
`void`	`readException()`	Reads an exception from the `MessageParcel`.
`FileDescriptor`	`readFileDescriptor()`	Reads a file descriptor from `MessageParcel`.
`String`	`readInterfaceToken()`	Reads an interface token from `MessageParcel`.
`byte[]`	`readRawData(int size)`	Reads raw data from `MessageParcel`.
`IRemoteObject`	`readRemoteObject()`	Reads a remote object from `MessageParcel`.
`void`	`readRemoteObjectArray(IRemoteObject[] objects)`	Reads an array of `IRemoteObject` objects from the `MessageParcel`.
`void`	`readRemoteObjectList(List<IRemoteObject> objects)`	Reads a list of `IRemoteObject` objects from the `MessageParcel`.
`void`	`reclaim()`	Adds a `MessageParcel` object to the cache pool.
`void`	`updateDataVersion(IRemoteObject object)`	update a remote object data version to the `MessageParcel` object.
`boolean`	`writeAshmem(Ashmem ashmem)`	Writes a specified `Ashmem` object to this `MessageParcel`.
`void`	`writeException(Exception exception)`	Writes an exception to the `MessageParcel`.
`boolean`	`writeFileDescriptor(FileDescriptor descriptor)`	Serializes a file descriptor and writes it to `MessageParcel`.
`boolean`	`writeInterfaceToken(String token)`	Writes an interface token to the `MessageParcel` object.
`void`	`writeNoException()`	Writes no exception to the `MessageParcel`.
`boolean`	`writeRawData(byte[] rawData, int size)`	Writes raw data to be sent to a remote process to a `MessageParcel` object.
`boolean`	`writeRemoteObject(IRemoteObject object)`	Serializes a remote object and writes it to the `MessageParcel` object.
`boolean`	`writeRemoteObjectArray(IRemoteObject[] objects)`	Writes an array of `IRemoteObject` objects to the `MessageParcel`.
`boolean`	`writeRemoteObjectList(List<IRemoteObject> objects)`	Writes a list of `IRemoteObject` objects to the `MessageParcel`.

从类继承的方法 java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

从类继承的方法 ohos.utils.Parcel
addAppClassLoader, appendFrom, createSequenceable, createSequenceable, createSequenceableArray, flushBuffer, getBytes, getCapacity, getReadableBytes, getReadPosition, getSize, getWritableBytes, getWritePosition, readBoolean, readBooleanArray, readBooleanArray, readByte, readByteArray, readByteArray, readChar, readCharArray, readCharArray, readDouble, readDoubleArray, readDoubleArray, readFloat, readFloatArray, readFloatArray, readInt, readIntArray, readIntArray, readList, readLong, readLongArray, readLongArray, readMap, readPacMapEx, readParcelableEx, readPlainArray, readPlainBooleanArray, readSequenceable, readSequenceableArray, readSequenceableList, readSequenceableMap, readSerializable, readShort, readShortArray, readShortArray, readString, readStringArray, readStringArray, readStringList, readValue, rewindRead, rewindWrite, setCapacity, setSize, writeBoolean, writeBooleanArray, writeByte, writeByteArray, writeBytes, writeChar, writeCharArray, writeDouble, writeDoubleArray, writeFloat, writeFloatArray, writeInt, writeIntArray, writeList, writeLong, writeLongArray, writeMap, writeMap, writePacMapEx, writeParcelableEx, writePlainArray, writePlainBooleanArray, writeSequenceable, writeSequenceableArray, writeSequenceableList, writeSequenceableMap, writeSerializable, writeShort, writeShortArray, writeString, writeStringArray, writeStringList, writeTypedSequenceable, writeTypedSequenceableArray, writeValue

- 方法详细资料
  - obtain
```
public static final MessageParcel obtain()
```
    Creates a MessageParcel object.
    
    返回:
    
    Returns the created MessageParcel object.
    
    从以下版本开始:
    
    1
  - create
```
public static final MessageParcel create()
```
    Creates a MessageParcel object.
    
    返回:
    
    Returns the created MessageParcel object.
    
    从以下版本开始:
    
    3
  - finalize
```
protected void finalize()
                 throws Throwable
```
    从类复制的说明: Object
    
    Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.
    The general contract of finalize is that it is invoked if and when the Java™ virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.
    The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.
    The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.
    After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.
    The finalize method is never invoked more than once by a Java virtual machine for any given object.
    Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.
    
    覆盖:
    
    finalize 在类中 Parcel
    
    抛出:
    
    Throwable - the Exception raised by this method
    
    另请参阅:
    
    WeakReference, PhantomReference
  - obtain
```
public static MessageParcel obtain(long object)
```
    Obtains a MessageParcel object with a given pointer.
    
    参数:
    
    object - Indicates the address of a MessageParcel.
    
    返回:
    
    Returns the MessageParcel object with the specified index if it is found in cache pool; returns a new MessageParcel object with the specified index if not found.
    
    从以下版本开始:
    
    1
  - create
```
public static MessageParcel create(long object)
```
    Creates a MessageParcel object with a given pointer.
    
    参数:
    
    object - Indicates the address of a MessageParcel.
    
    返回:
    
    Returns the MessageParcel object with the given pointer if it is found in cache pool; returns a new MessageParcel object with the given pointer if not found.
    
    从以下版本开始:
    
    3
  - reclaim
```
public final void reclaim()
```
    Adds a MessageParcel object to the cache pool.
    This method is used to clear a MessageParcel object that is no longer used.
    
    覆盖:
    
    reclaim 在类中 Parcel
    
    从以下版本开始:
    
    1
  - updateDataVersion
```
public void updateDataVersion(IRemoteObject object)
```
    update a remote object data version to the MessageParcel object.
    
    参数:
    
    object - Indicates the remote object and its data version written to MessageParcel.
    
    从以下版本开始:
    
    5
  - getDataVersion
```
public int getDataVersion()
```
    return data version from the MessageParcel object.
    
    返回:
    
    Returns data version from MessageParcel.
    
    从以下版本开始:
    
    5
  - writeRemoteObject
```
public boolean writeRemoteObject(IRemoteObject object)
```
    Serializes a remote object and writes it to the MessageParcel object.
    
    参数:
    
    object - Indicates the remote object to be serialized and written to MessageParcel.
    
    返回:
    
    Returns true if the operation succeeds; returns false otherwise.
    
    从以下版本开始:
    
    1
  - readRemoteObject
```
public IRemoteObject readRemoteObject()
```
    Reads a remote object from MessageParcel.
    This method is used to deserialize a MessageParcel object to generate an IRemoteObject.
    Remote objects are read in the sequence they were written to MessageParcel.
    
    返回:
    
    Returns the IRemoteObject.
    
    从以下版本开始:
    
    1
  - writeInterfaceToken
```
public boolean writeInterfaceToken(String token)
```
    Writes an interface token to the MessageParcel object.
    
    参数:
    
    token - Indicates the interface token.
    
    返回:
    
    Returns true if the operation succeeds; returns false otherwise.
    
    从以下版本开始:
    
    1
  - readInterfaceToken
```
public String readInterfaceToken()
```
    Reads an interface token from MessageParcel.
    Interface tokens are read in the sequence they were written to MessageParcel.
    
    返回:
    
    Returns the interface token.
    
    从以下版本开始:
    
    1
  - writeFileDescriptor
```
public boolean writeFileDescriptor(FileDescriptor descriptor)
```
    Serializes a file descriptor and writes it to MessageParcel.
    In the current version, this method does not apply to cross-device communication.
    
    参数:
    
    descriptor - Indicates the file descriptor.
    
    返回:
    
    Returns true if the operation succeeds; returns false otherwise.
    
    从以下版本开始:
    
    1
  - readFileDescriptor
```
public FileDescriptor readFileDescriptor()
```
    Reads a file descriptor from MessageParcel.
    File descriptors are read in the sequence they were written to MessageParcel.
    In the current version, this method does not apply to cross-device communication.
    
    返回:
    
    Returns the file descriptor.
    
    从以下版本开始:
    
    1
  - writeRawData
```
public boolean writeRawData(byte[] rawData,
                            int size)
```
    Writes raw data to be sent to a remote process to a MessageParcel object.
    If the remote process runs on the current device, the raw data is transmitted through the shared memory. If the remote process runs on the peer device, the raw data is transmitted through a cross-device channel such as a socket.
    Only a group of raw data can be written to each MessageParcel. In cross-device case, raw data can only be sent sequentially.
    
    参数:
    
    rawData - Indicates the raw data to be sent to the remote process. A maximum of 128 Mb raw data can be sent through IPC, and the maximum is 128 Mb - 64byte in RPC case. If the data size is greater than maximum, false will be returned. You must manage the lifecycle of data memory by yourself.
    
    size - Indicates the size of the raw data to be sent.
    
    返回:
    
    Returns true if the operation succeeds; returns false otherwise.
    
    从以下版本开始:
    
    1
  - readRawData
```
public byte[] readRawData(int size)
```
    Reads raw data from MessageParcel.
    The size of the raw data to be read must be the same as that of the raw data written to MessageParcel.
    Raw data is read in the sequence it was written to MessageParcel.
    
    参数:
    
    size - Indicates the size of the raw data to be read.
    
    返回:
    
    Returns the raw data (in bytes). The lifecycle of the data memory must be the same as that of the MessageParcel object.
    
    从以下版本开始:
    
    1
  - getRawDataCapacity
```
public int getRawDataCapacity()
```
    Obtains the maximum amount of raw data a MessageParcel can hold.
    
    返回:
    
    Returns the maximum amount of raw data a MessageParcel can hold, that is, 128 Mb.
    
    从以下版本开始:
    
    1
  - closeFileDescriptor
```
public static void closeFileDescriptor(FileDescriptor descriptor)
```
    Disables a file descriptor in MessageParcel.
    In the current version, this method does not apply to cross-device communication.
    
    参数:
    
    descriptor - Indicates the file descriptor to be disabled.
    
    从以下版本开始:
    
    1
  - dupFileDescriptor
```
public static FileDescriptor dupFileDescriptor(FileDescriptor descriptor)
```
    Obtains a new file descriptor which is a duplication of an existing file descriptor.
    The status of the new file descriptor is the same as that of the existing one.
    Calling this method does not close the input file descriptor. You are responsible for closing the returned new file descriptor.
    In the current version, this method does not apply to cross-device communication.
    
    参数:
    
    descriptor - Indicates an existing file descriptor.
    
    返回:
    
    Returns the new file descriptor.
    
    从以下版本开始:
    
    1
  - containFileDescriptors
```
public boolean containFileDescriptors()
```
    Checks whether this MessageParcel object contains file descriptors.
    After the writeFileDescriptor or writeRawData method is called, the MessageParcel object will contain file descriptors.
    
    返回:
    
    Returns true if this MessageParcel object contains file descriptors; returns false otherwise.
    
    从以下版本开始:
    
    4
  - createRemoteObjectArray
```
public IRemoteObject[] createRemoteObjectArray()
```
    Creates an array of IRemoteObject objects.
    This method is used to read IRemoteObject objects from the MessageParcel and create an array of IRemoteObject objects.
    
    返回:
    
    Returns the array of IRemoteObject objects. The lifecycle of the array is up to your application.
    
    从以下版本开始:
    
    3
  - createRemoteObjectList
```
public List<IRemoteObject> createRemoteObjectList()
```
    Creates a list of IRemoteObject objects.
    This method is used to read IRemoteObject objects from the MessageParcel and create a list of IRemoteObject objects.
    
    返回:
    
    Returns the list of IRemoteObject objects. The lifecycle of the list is up to your application.
    
    从以下版本开始:
    
    3
  - writeRemoteObjectArray
```
public boolean writeRemoteObjectArray(IRemoteObject[] objects)
```
    Writes an array of IRemoteObject objects to the MessageParcel.
    You can use the createRemoteObjectArray() or readRemoteObjectArray(ohos.rpc.IRemoteObject[]) method to read the array of IRemoteObject objects from the MessageParcel.
    
    参数:
    
    objects - Indicates the array of IRemoteObject objects to write to the MessageParcel.
    
    返回:
    
    Returns true if the array of IRemoteObject objects is successfully written to the MessageParcel; returns false if objects is null or the array fails to be written to the MessageParcel.
    
    从以下版本开始:
    
    3
  - writeRemoteObjectList
```
public boolean writeRemoteObjectList(List<IRemoteObject> objects)
```
    Writes a list of IRemoteObject objects to the MessageParcel.
    You can use the createRemoteObjectList() or readRemoteObjectList(java.util.List<ohos.rpc.IRemoteObject>) method to read the list of IRemoteObject objects from the MessageParcel.
    
    参数:
    
    objects - Indicates the list of IRemoteObject objects to write to the MessageParcel.
    
    返回:
    
    Returns true if the list of IRemoteObject objects is successfully written to the MessageParcel; returns false if objects is null or the list fails to be written to the MessageParcel.
    
    从以下版本开始:
    
    3
  - readRemoteObjectArray
```
public void readRemoteObjectArray(IRemoteObject[] objects)
```
    Reads an array of IRemoteObject objects from the MessageParcel.
    When using this method, your application needs to pass the array of IRemoteObject objects it wants to read from the MessageParcel.
    
    参数:
    
    objects - Indicates the array of IRemoteObject objects your application wants to read from the MessageParcel. If the length of this array is not equal to the number of IRemoteObject objects actually read from the MessageParcel, the array of IRemoteObject objects passed by your application will be returned.
    
    从以下版本开始:
    
    3
  - readRemoteObjectList
```
public void readRemoteObjectList(List<IRemoteObject> objects)
```
    Reads a list of IRemoteObject objects from the MessageParcel.
    When using this method, your application needs to pass the list of IRemoteObject objects it wants to read from the MessageParcel.
    
    参数:
    
    objects - Indicates the list of IRemoteObject objects your application wants to read from the MessageParcel. No matter whether the length of this list is greater or less than the number of IRemoteObject objects actually read from the MessageParcel, a list of the IRemoteObject objects actually read from the MessageParcel will be returned.
    
    从以下版本开始:
    
    3
  - writeException
```
public void writeException(Exception exception)
```
    Writes an exception to the MessageParcel.
    Supported exceptions include SecurityException, IllegalArgumentException, NullPointerException, IllegalStateException, UnsupportedOperationException, IndexOutOfBoundsException, NegativeArraySizeException, ArrayStoreException, ClassCastException, and RemoteException. If any other exception is written to the MessageParcel, RuntimeException will be returned.
    This method is typically used when responding to a received packet.
    
    参数:
    
    exception - Indicates the exception to write to the MessageParcel.
    
    从以下版本开始:
    
    3
  - writeNoException
```
public void writeNoException()
```
    Writes no exception to the MessageParcel.
    
    从以下版本开始:
    
    3
  - readException
```
public void readException()
```
    Reads an exception from the MessageParcel.
    The exception read will be thrown.
    This method is typically used when reading a response packet.
    
    抛出:
    
    Exception - Throws the exception read from the MessageParcel. The exception can be SecurityException, IllegalArgumentException, NullPointerException, IllegalStateException, UnsupportedOperationException, IndexOutOfBoundsException, NegativeArraySizeException, ArrayStoreException, ClassCastException, or RemoteException.
    
    从以下版本开始:
    
    3
  - getFdFromDatagramSocket
```
public static FileDescriptor getFdFromDatagramSocket(DatagramSocket datagramSocket)
```
    Reads an FileDescriptor from DatagramSocket
    Creates a new file descriptor from the specified DatagramSocket. The new file descriptor holds the duplication of the original file descriptor in the DatagramSocket, so you are responsible for closing the returned new file descriptor.
    
    参数:
    
    datagramSocket - Indicates the DatagramSocket to get the FileDescriptor.
    
    返回:
    
    Returns a FileDescriptor.
    
    从以下版本开始:
    
    3
  - getFd
```
public static int getFd(FileDescriptor fileDescriptor)
```
    Reads an native fd from FileDescriptor
    
    参数:
    
    fileDescriptor - Indicates the FileDescriptor to get the fd.
    
    返回:
    
    Returns fd of the given FileDescriptor if it is not null; otherwise returns -1.
    
    从以下版本开始:
    
    3
  - detachFd
```
public static int detachFd(FileDescriptor fileDescriptor)
```
    Detaches the native fd from FileDescriptor.
    It is now your responsibility to turn off the native fd or fd leaks occur.
    You cannot call the method when the original creator of the descriptor expects to turn off the FileDescriptor itself.
    
    参数:
    
    fileDescriptor - FileDescriptor to detach fd.
    
    返回:
    
    Returns a fd if it is successfully detached from the given FileDescriptor; otherwise returns -1.
    
    从以下版本开始:
    
    3
  - writeAshmem
```
public boolean writeAshmem(Ashmem ashmem)
```
    Writes a specified Ashmem object to this MessageParcel.
    
    参数:
    
    ashmem - Indicates the Ashmem object to write to this MessageParcel.
    
    返回:
    
    Returns true if the Ashmem object is successfully written to this MessageParcel; returns false otherwise.
    
    从以下版本开始:
    
    4
  - readAshmem
```
public Ashmem readAshmem()
```
    Reads an Ashmem object from this MessageParcel.
    
    返回:
    
    Returns the Ashmem object.
    
    从以下版本开始:
    
    4

类 MessageParcel

方法概要

从类继承的方法 java.lang.Object

从类继承的方法 ohos.utils.Parcel

方法详细资料

obtain

create

finalize

obtain

create

reclaim

updateDataVersion

getDataVersion

writeRemoteObject

readRemoteObject

writeInterfaceToken

readInterfaceToken

writeFileDescriptor

readFileDescriptor

writeRawData

readRawData

getRawDataCapacity

closeFileDescriptor

dupFileDescriptor

containFileDescriptors

createRemoteObjectArray

createRemoteObjectList

writeRemoteObjectArray

writeRemoteObjectList

readRemoteObjectArray

readRemoteObjectList

writeException

writeNoException

readException

getFdFromDatagramSocket

getFd

detachFd

writeAshmem

readAshmem