public class ParcelFileDescriptor
extends Object
implements Parcelable, Closeable
java.lang.Object | |
↳ | android.os.ParcelFileDescriptor |
The FileDescriptor returned by readFileDescriptor()
, allowing you to close it when done with it.
Nested classes |
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class |
ParcelFileDescriptor.AutoCloseInputStream An InputStream you can create on a ParcelFileDescriptor, which will take care of calling |
class |
ParcelFileDescriptor.AutoCloseOutputStream An OutputStream you can create on a ParcelFileDescriptor, which will take care of calling |
class |
ParcelFileDescriptor.FileDescriptorDetachedException Exception that indicates that the file descriptor was detached. |
interface |
ParcelFileDescriptor.OnCloseListener Callback indicating that a ParcelFileDescriptor has been closed. |
Constants |
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int |
MODE_APPEND For use with |
int |
MODE_CREATE For use with |
int |
MODE_READ_ONLY For use with |
int |
MODE_READ_WRITE For use with |
int |
MODE_TRUNCATE For use with |
int |
MODE_WORLD_READABLE This constant was deprecated in API level 19. Creating world-readable files is very dangerous, and likely to cause security holes in applications. It is strongly discouraged; instead, applications should use more formal mechanism for interactions such as |
int |
MODE_WORLD_WRITEABLE This constant was deprecated in API level 19. Creating world-writable files is very dangerous, and likely to cause security holes in applications. It is strongly discouraged; instead, applications should use more formal mechanism for interactions such as |
int |
MODE_WRITE_ONLY For use with |
Inherited constants |
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![]() android.os.Parcelable
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Fields |
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public static final Creator<ParcelFileDescriptor> |
CREATOR
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Public constructors |
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ParcelFileDescriptor(ParcelFileDescriptor wrapped) Create a new ParcelFileDescriptor wrapped around another descriptor. |
Public methods |
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static ParcelFileDescriptor |
adoptFd(int fd) Take ownership of a raw native fd in to a new ParcelFileDescriptor. |
boolean |
canDetectErrors() Indicates if this ParcelFileDescriptor can communicate and detect remote errors/crashes. |
void |
checkError() Detect and throw if the other end of a pipe or socket pair encountered an error or crashed. |
void |
close() Close the ParcelFileDescriptor. |
void |
closeWithError(String msg) Close the ParcelFileDescriptor, informing any peer that an error occurred while processing. |
static ParcelFileDescriptor[] |
createPipe() Create two ParcelFileDescriptors structured as a data pipe. |
static ParcelFileDescriptor[] |
createReliablePipe() Create two ParcelFileDescriptors structured as a data pipe. |
static ParcelFileDescriptor[] |
createReliableSocketPair() Create two ParcelFileDescriptors structured as a pair of sockets connected to each other. |
static ParcelFileDescriptor[] |
createSocketPair() Create two ParcelFileDescriptors structured as a pair of sockets connected to each other. |
int |
describeContents() Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. |
int |
detachFd() Return the native fd int for this ParcelFileDescriptor and detach it from the object here. |
static ParcelFileDescriptor |
dup(FileDescriptor orig) Create a new ParcelFileDescriptor that is a dup of an existing FileDescriptor. |
ParcelFileDescriptor |
dup() Create a new ParcelFileDescriptor that is a dup of the 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 |
static ParcelFileDescriptor |
open(File file, int mode) Create a new ParcelFileDescriptor accessing a given file. |
static ParcelFileDescriptor |
open(File file, int mode, Handler handler, ParcelFileDescriptor.OnCloseListener listener) Create a new ParcelFileDescriptor accessing a given file. |
static int |
parseMode(String mode) Converts a string representing a file mode, such as "rw", into a bitmask suitable for use with |
String |
toString() Returns a string representation of the object. |
void |
writeToParcel(Parcel out, int flags) Flatten this object in to a Parcel. If |
Protected methods |
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void |
finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. |
Inherited methods |
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![]() java.lang.Object
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![]() android.os.Parcelable
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![]() java.io.Closeable
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![]() java.lang.AutoCloseable
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int MODE_APPEND
For use with open(File, int)
: append to end of file while writing.
Constant Value: 33554432 (0x02000000)
int MODE_CREATE
For use with open(File, int)
: create the file if it doesn't already exist.
Constant Value: 134217728 (0x08000000)
int MODE_READ_ONLY
For use with open(File, int)
: open the file with read-only access.
Constant Value: 268435456 (0x10000000)
int MODE_READ_WRITE
For use with open(File, int)
: open the file with read and write access.
Constant Value: 805306368 (0x30000000)
int MODE_TRUNCATE
For use with open(File, int)
: erase contents of file when opening.
Constant Value: 67108864 (0x04000000)
int MODE_WORLD_READABLE
This constant was deprecated in API level 19.
Creating world-readable files is very dangerous, and likely to cause security holes in applications. It is strongly discouraged; instead, applications should use more formal mechanism for interactions such as ContentProvider
, BroadcastReceiver
, and Service
. There are no guarantees that this access mode will remain on a file, such as when it goes through a backup and restore.
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)
int MODE_WORLD_WRITEABLE
This constant was deprecated in API level 19.
Creating world-writable files is very dangerous, and likely to cause security holes in applications. It is strongly discouraged; instead, applications should use more formal mechanism for interactions such as ContentProvider
, BroadcastReceiver
, and Service
. There are no guarantees that this access mode will remain on a file, such as when it goes through a backup and restore.
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)
int MODE_WRITE_ONLY
For use with open(File, int)
: open the file with write-only access.
Constant Value: 536870912 (0x20000000)
ParcelFileDescriptor (ParcelFileDescriptor wrapped)
Create a new ParcelFileDescriptor wrapped around another descriptor. By default all method calls are delegated to the wrapped descriptor.
Parameters | |
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wrapped |
ParcelFileDescriptor
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ParcelFileDescriptor adoptFd (int fd)
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 | |
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fd |
int : The native fd that the ParcelFileDescriptor should adopt. |
Returns | |
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ParcelFileDescriptor |
Returns a new ParcelFileDescriptor holding a FileDescriptor for the given fd. |
boolean canDetectErrors ()
Indicates if this ParcelFileDescriptor can communicate and detect remote errors/crashes.
Returns | |
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boolean |
See also:
void checkError ()
Detect and throw if the other end of a pipe or socket pair encountered an error or crashed. This allows a reader to distinguish between a valid EOF and an error/crash.
If this ParcelFileDescriptor is unable to detect remote errors, it will return silently.
Throws | |
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IOException |
for normal errors. |
ParcelFileDescriptor.FileDescriptorDetachedException |
if the remote side called detachFd() . Once detached, the remote side is unable to communicate any errors through closeWithError(String) . |
See also:
void close ()
Close the ParcelFileDescriptor. This implementation closes the underlying OS resources allocated to represent this stream.
Throws | |
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IOException |
If an error occurs attempting to close this ParcelFileDescriptor. |
void closeWithError (String msg)
Close the ParcelFileDescriptor, informing any peer that an error occurred while processing. If the creator of this descriptor is not observing errors, it will close normally.
Parameters | |
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msg |
String : describing the error; must not be null. |
Throws | |
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IOException |
ParcelFileDescriptor[] createPipe ()
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.
Returns | |
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ParcelFileDescriptor[] |
Throws | |
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IOException |
ParcelFileDescriptor[] createReliablePipe ()
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.
The write end has the ability to deliver an error message through closeWithError(String)
which can be handled by the read end calling checkError()
, usually after detecting an EOF. This can also be used to detect remote crashes.
Returns | |
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ParcelFileDescriptor[] |
Throws | |
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IOException |
ParcelFileDescriptor[] createReliableSocketPair ()
Create two ParcelFileDescriptors structured as a pair of sockets connected to each other. The two sockets are indistinguishable.
Both ends have the ability to deliver an error message through closeWithError(String)
which can be detected by the other end calling checkError()
, usually after detecting an EOF. This can also be used to detect remote crashes.
Returns | |
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ParcelFileDescriptor[] |
Throws | |
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IOException |
ParcelFileDescriptor[] createSocketPair ()
Create two ParcelFileDescriptors structured as a pair of sockets connected to each other. The two sockets are indistinguishable.
Returns | |
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ParcelFileDescriptor[] |
Throws | |
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IOException |
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(Parcel, int)
, the return value of this method must include the CONTENTS_FILE_DESCRIPTOR
bit.
Returns | |
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int |
a bitmask indicating the set of special object types marshaled by this Parcelable object instance. |
int detachFd ()
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.
You should not detach when the original creator of the descriptor is expecting a reliable signal through close()
or closeWithError(String)
.
Returns | |
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int |
See also:
ParcelFileDescriptor dup (FileDescriptor orig)
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.
Parameters | |
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orig |
FileDescriptor
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Returns | |
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ParcelFileDescriptor |
Throws | |
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IOException |
ParcelFileDescriptor dup ()
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.
Returns | |
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ParcelFileDescriptor |
Throws | |
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IOException |
ParcelFileDescriptor fromDatagramSocket (DatagramSocket datagramSocket)
Create a new ParcelFileDescriptor from the specified DatagramSocket.
Parameters | |
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datagramSocket |
DatagramSocket : The DatagramSocket whose FileDescriptor is used to create a new ParcelFileDescriptor. |
Returns | |
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ParcelFileDescriptor |
A new ParcelFileDescriptor with the FileDescriptor of the specified DatagramSocket. |
ParcelFileDescriptor fromFd (int fd)
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 | |
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fd |
int : The native fd that the ParcelFileDescriptor should dup. |
Returns | |
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ParcelFileDescriptor |
Returns a new ParcelFileDescriptor holding a FileDescriptor for a dup of the given fd. |
Throws | |
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IOException |
ParcelFileDescriptor fromSocket (Socket socket)
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 | |
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socket |
Socket : The Socket whose FileDescriptor is used to create a new ParcelFileDescriptor. |
Returns | |
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ParcelFileDescriptor |
A new ParcelFileDescriptor with the FileDescriptor of the specified Socket. |
int getFd ()
Return the native fd int for this ParcelFileDescriptor. The ParcelFileDescriptor still owns the fd, and it still must be closed through this API.
Returns | |
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int |
FileDescriptor getFileDescriptor ()
Retrieve the actual FileDescriptor associated with this object.
Returns | |
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FileDescriptor |
Returns the FileDescriptor associated with this object. |
long getStatSize ()
Return the total size of the file representing this fd, as determined by stat()
. Returns -1 if the fd is not a file.
Returns | |
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long |
ParcelFileDescriptor open (File file, int mode)
Create a new ParcelFileDescriptor accessing a given file.
Parameters | |
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file |
File : The file to be opened. |
mode |
int : 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 | |
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ParcelFileDescriptor |
a new ParcelFileDescriptor pointing to the given file. |
Throws | |
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FileNotFoundException |
if the given file does not exist or can not be opened with the requested mode. |
See also:
ParcelFileDescriptor open (File file, int mode, Handler handler, ParcelFileDescriptor.OnCloseListener listener)
Create a new ParcelFileDescriptor accessing a given file.
Parameters | |
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file |
File : The file to be opened. |
mode |
int : 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 . |
handler |
Handler : to call listener from; must not be null. |
listener |
ParcelFileDescriptor.OnCloseListener : to be invoked when the returned descriptor has been closed; must not be null. |
Returns | |
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ParcelFileDescriptor |
a new ParcelFileDescriptor pointing to the given file. |
Throws | |
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FileNotFoundException |
if the given file does not exist or can not be opened with the requested mode. |
IOException |
See also:
int parseMode (String mode)
Converts a string representing a file mode, such as "rw", into a bitmask suitable for use with open(File, int)
.
Parameters | |
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mode |
String : The string representation of the file mode. |
Returns | |
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int |
A bitmask representing the given file mode. |
Throws | |
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IllegalArgumentException |
if the given string does not match a known file mode. |
String toString ()
Returns a string representation of the object. In general, the toString
method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.
The toString
method for class Object
returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@
', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
Returns | |
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String |
a string representation of the 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.
Parameters | |
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out |
Parcel : The Parcel in which the object should be written. |
flags |
int : Additional flags about how the object should be written. May be 0 or PARCELABLE_WRITE_RETURN_VALUE . |
void finalize ()
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 JavaTM 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.
Throws | |
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Throwable |