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Android APIs
public class

ParcelFileDescriptor

extends Object
implements Parcelable Closeable
java.lang.Object
   ↳ android.os.ParcelFileDescriptor

Class Overview

The FileDescriptor returned by readFileDescriptor(), allowing you to close it when done with it.

Summary

Nested Classes
class ParcelFileDescriptor.AutoCloseInputStream An InputStream you can create on a ParcelFileDescriptor, which will take care of calling ParcelFileDescriptor.close() for you when the stream is closed. 
class ParcelFileDescriptor.AutoCloseOutputStream An OutputStream you can create on a ParcelFileDescriptor, which will take care of calling ParcelFileDescriptor.close() for you when the stream is closed. 
Constants
int MODE_APPEND For use with open(File, int): append to end of file while writing.
int MODE_CREATE For use with open(File, int): create the file if it doesn't already exist.
int MODE_READ_ONLY For use with open(File, int): open the file with read-only access.
int MODE_READ_WRITE For use with open(File, int): open the file with read and write access.
int MODE_TRUNCATE For use with open(File, int): erase contents of file when opening.
int MODE_WORLD_READABLE For use with open(File, int): if MODE_CREATE has been supplied and this file doesn't already exist, then create the file with permissions such that any application can read it.
int MODE_WORLD_WRITEABLE For use with open(File, int): if MODE_CREATE has been supplied and this file doesn't already exist, then create the file with permissions such that any application can write it.
int MODE_WRITE_ONLY For use with open(File, int): open the file with write-only access.
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Inherited Constants
From interface android.os.Parcelable
Fields
public static final Creator<ParcelFileDescriptor> CREATOR
Public Constructors
ParcelFileDescriptor(ParcelFileDescriptor descriptor)
Public Methods
static ParcelFileDescriptor adoptFd(int fd)
Take ownership of a raw native fd in to a new ParcelFileDescriptor.
void close()
Close the ParcelFileDescriptor.
static ParcelFileDescriptor[] createPipe()
Create two ParcelFileDescriptors structured as a data pipe.
int describeContents()
Describe the kinds of special objects contained in this Parcelable's marshalled representation.
int detachFd()
Return the native fd int for this ParcelFileDescriptor and detach it from the object here.
ParcelFileDescriptor dup()
Create a new ParcelFileDescriptor that is a dup of the existing FileDescriptor.
static ParcelFileDescriptor dup(FileDescriptor orig)
Create a new ParcelFileDescriptor that is a dup of an existing FileDescriptor.
static ParcelFileDescriptor fromDatagramSocket(DatagramSocket datagramSocket)
Create a new ParcelFileDescriptor from the specified DatagramSocket.
static ParcelFileDescriptor fromFd(int fd)
Create a new ParcelFileDescriptor from a raw native fd.
static ParcelFileDescriptor fromSocket(Socket socket)
Create a new ParcelFileDescriptor from the specified Socket.
int getFd()
Return the native fd int for this ParcelFileDescriptor.
FileDescriptor getFileDescriptor()
Retrieve the actual FileDescriptor associated with this object.
long getStatSize()
Return the total size of the file representing this fd, as determined by stat().
static ParcelFileDescriptor open(File file, int mode)
Create a new ParcelFileDescriptor accessing a given file.
String toString()
Returns a string containing a concise, human-readable description of this object.
void writeToParcel(Parcel out, int flags)
Flatten this object in to a Parcel. If PARCELABLE_WRITE_RETURN_VALUE is set in flags, the file descriptor will be closed after a copy is written to the Parcel.
Protected Methods
void finalize()
Invoked when the garbage collector has detected that this instance is no longer reachable.
[Expand]
Inherited Methods
From class java.lang.Object
From interface android.os.Parcelable
From interface java.io.Closeable

Constants

public static final int MODE_APPEND

Since: API Level 3

For use with open(File, int): append to end of file while writing.

Constant Value: 33554432 (0x02000000)

public static final int MODE_CREATE

Since: API Level 1

For use with open(File, int): create the file if it doesn't already exist.

Constant Value: 134217728 (0x08000000)

public static final int MODE_READ_ONLY

Since: API Level 1

For use with open(File, int): open the file with read-only access.

Constant Value: 268435456 (0x10000000)

public static final int MODE_READ_WRITE

Since: API Level 1

For use with open(File, int): open the file with read and write access.

Constant Value: 805306368 (0x30000000)

public static final int MODE_TRUNCATE

Since: API Level 1

For use with open(File, int): erase contents of file when opening.

Constant Value: 67108864 (0x04000000)

public static final int MODE_WORLD_READABLE

Since: API Level 1

For use with open(File, int): if MODE_CREATE has been supplied and this file doesn't already exist, then create the file with permissions such that any application can read it.

Constant Value: 1 (0x00000001)

public static final int MODE_WORLD_WRITEABLE

Since: API Level 1

For use with open(File, int): if MODE_CREATE has been supplied and this file doesn't already exist, then create the file with permissions such that any application can write it.

Constant Value: 2 (0x00000002)

public static final int MODE_WRITE_ONLY

Since: API Level 1

For use with open(File, int): open the file with write-only access.

Constant Value: 536870912 (0x20000000)

Fields

public static final Creator<ParcelFileDescriptor> CREATOR

Since: API Level 1

Public Constructors

public ParcelFileDescriptor (ParcelFileDescriptor descriptor)

Since: API Level 1

Public Methods

public static ParcelFileDescriptor adoptFd (int fd)

Since: API Level 13

Take ownership of a raw native fd in to a new ParcelFileDescriptor. The returned ParcelFileDescriptor now owns the given fd, and will be responsible for closing it. You must not close the fd yourself.

Parameters
fd The native fd that the ParcelFileDescriptor should adopt.
Returns
  • Returns a new ParcelFileDescriptor holding a FileDescriptor for the given fd.

public void close ()

Since: API Level 1

Close the ParcelFileDescriptor. This implementation closes the underlying OS resources allocated to represent this stream.

Throws
IOException If an error occurs attempting to close this ParcelFileDescriptor.

public static ParcelFileDescriptor[] createPipe ()

Since: API Level 9

Create two ParcelFileDescriptors structured as a data pipe. The first ParcelFileDescriptor in the returned array is the read side; the second is the write side.

Throws
IOException

public int describeContents ()

Since: API Level 1

Describe the kinds of special objects contained in this Parcelable's marshalled representation.

Returns
  • a bitmask indicating the set of special object types marshalled by the Parcelable.

public int detachFd ()

Since: API Level 12

Return the native fd int for this ParcelFileDescriptor and detach it from the object here. You are now responsible for closing the fd in native code.

public ParcelFileDescriptor dup ()

Since: API Level 14

Create a new ParcelFileDescriptor that is a dup of the existing FileDescriptor. This obeys standard POSIX semantics, where the new file descriptor shared state such as file position with the original file descriptor.

Throws
IOException

public static ParcelFileDescriptor dup (FileDescriptor orig)

Since: API Level 13

Create a new ParcelFileDescriptor that is a dup of an existing FileDescriptor. This obeys standard POSIX semantics, where the new file descriptor shared state such as file position with the original file descriptor.

Throws
IOException

public static ParcelFileDescriptor fromDatagramSocket (DatagramSocket datagramSocket)

Since: API Level 14

Create a new ParcelFileDescriptor from the specified DatagramSocket.

Parameters
datagramSocket The DatagramSocket whose FileDescriptor is used to create a new ParcelFileDescriptor.
Returns
  • A new ParcelFileDescriptor with the FileDescriptor of the specified DatagramSocket.

public static ParcelFileDescriptor fromFd (int fd)

Since: API Level 13

Create a new ParcelFileDescriptor from a raw native fd. The new ParcelFileDescriptor holds a dup of the original fd passed in here, so you must still close that fd as well as the new ParcelFileDescriptor.

Parameters
fd The native fd that the ParcelFileDescriptor should dup.
Returns
  • Returns a new ParcelFileDescriptor holding a FileDescriptor for a dup of the given fd.
Throws
IOException

public static ParcelFileDescriptor fromSocket (Socket socket)

Since: API Level 1

Create a new ParcelFileDescriptor from the specified Socket. The new ParcelFileDescriptor holds a dup of the original FileDescriptor in the Socket, so you must still close the Socket as well as the new ParcelFileDescriptor.

Parameters
socket The Socket whose FileDescriptor is used to create a new ParcelFileDescriptor.
Returns
  • A new ParcelFileDescriptor with the FileDescriptor of the specified Socket.

public int getFd ()

Since: API Level 12

Return the native fd int for this ParcelFileDescriptor. The ParcelFileDescriptor still owns the fd, and it still must be closed through this API.

public FileDescriptor getFileDescriptor ()

Since: API Level 1

Retrieve the actual FileDescriptor associated with this object.

Returns
  • Returns the FileDescriptor associated with this object.

public long getStatSize ()

Since: API Level 3

Return the total size of the file representing this fd, as determined by stat(). Returns -1 if the fd is not a file.

public static ParcelFileDescriptor open (File file, int mode)

Since: API Level 1

Create a new ParcelFileDescriptor accessing a given file.

Parameters
file The file to be opened.
mode The desired access mode, must be one of MODE_READ_ONLY, MODE_WRITE_ONLY, or MODE_READ_WRITE; may also be any combination of MODE_CREATE, MODE_TRUNCATE, MODE_WORLD_READABLE, and MODE_WORLD_WRITEABLE.
Returns
  • Returns a new ParcelFileDescriptor pointing to the given file.
Throws
FileNotFoundException Throws FileNotFoundException if the given file does not exist or can not be opened with the requested mode.

public String toString ()

Since: API Level 1

Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression:

   getClass().getName() + '@' + Integer.toHexString(hashCode())

See Writing a useful toString method if you intend implementing your own toString method.

Returns
  • a printable representation of this object.

public void writeToParcel (Parcel out, int flags)

Since: API Level 1

Flatten this object in to a Parcel. If PARCELABLE_WRITE_RETURN_VALUE is set in flags, the file descriptor will be closed after a copy is written to the Parcel.

Parameters
out The Parcel in which the object should be written.
flags Additional flags about how the object should be written. May be 0 or PARCELABLE_WRITE_RETURN_VALUE.

Protected Methods

protected void finalize ()

Since: API Level 1

Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.

Note that objects that override finalize are significantly more expensive than objects that don't. Finalizers may be run a long time after the object is no longer reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup. Note also that finalizers are run on a single VM-wide finalizer thread, so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary for a class that has a native peer and needs to call a native method to destroy that peer. Even then, it's better to provide an explicit close method (and implement Closeable), and insist that callers manually dispose of instances. This works well for something like files, but less well for something like a BigInteger where typical calling code would have to deal with lots of temporaries. Unfortunately, code that creates lots of temporaries is the worst kind of code from the point of view of the single finalizer thread.

If you must use finalizers, consider at least providing your own ReferenceQueue and having your own thread process that queue.

Unlike constructors, finalizers are not automatically chained. You are responsible for calling super.finalize() yourself.

Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.

Throws
Throwable