MemoryFile
open class MemoryFile
| kotlin.Any | |
| ↳ | android.os.MemoryFile |
MemoryFile is a wrapper for SharedMemory which can optionally be set to purgeable. Applications should generally prefer to use SharedMemory which offers more flexible access & control over the shared memory region than MemoryFile does. Purgeable files may have their contents reclaimed by the kernel in low memory conditions (only if allowPurging is set to true). After a file is purged, attempts to read or write the file will cause an IOException to be thrown.
Summary
| Public constructors | |
|---|---|
MemoryFile(name: String!, length: Int)Allocates a new ashmem region. |
|
| Public methods | |
|---|---|
| open Boolean |
allowPurging(allowPurging: Boolean)Enables or disables purging of the memory file. |
| open Unit |
close()Closes the memory file. |
| open InputStream! |
Creates a new InputStream for reading from the memory file. |
| open OutputStream! |
Creates a new OutputStream for writing to the memory file. |
| open Boolean |
Is memory file purging enabled? |
| open Int |
length()Returns the length of the memory file. |
| open Int |
Reads bytes from the memory file. |
| open Unit |
writeBytes(buffer: ByteArray!, srcOffset: Int, destOffset: Int, count: Int)Write bytes to the memory file. |
Public constructors
MemoryFile
MemoryFile(
name: String!,
length: Int)
Allocates a new ashmem region. The region is initially not purgable.
| Parameters | |
|---|---|
name |
String!: optional name for the file (can be null). |
length |
Int: of the memory file in bytes, must be positive. |
| Exceptions | |
|---|---|
java.io.IOException |
if the memory file could not be created. |
Public methods
allowPurging
open funallowPurging(allowPurging: Boolean): Boolean
Deprecated: Purgable is considered generally fragile and hard to use safely. Applications are recommend to instead use android.content.ComponentCallbacks2#onTrimMemory(int) to react to memory events and release shared memory regions as appropriate.
Enables or disables purging of the memory file.
| Parameters | |
|---|---|
allowPurging |
Boolean: true if the operating system can purge the contents of the file in low memory situations |
| Return | |
|---|---|
Boolean |
previous value of allowPurging |
close
open fun close(): Unit
Closes the memory file. If there are no other open references to the memory file, it will be deleted.
getInputStream
open fun getInputStream(): InputStream!
Creates a new InputStream for reading from the memory file.
| Return | |
|---|---|
InputStream! |
InputStream |
getOutputStream
open fun getOutputStream(): OutputStream!
Creates a new OutputStream for writing to the memory file.
| Return | |
|---|---|
OutputStream! |
OutputStream |
isPurgingAllowed
open funisPurgingAllowed(): Boolean
Deprecated: Purgable is considered generally fragile and hard to use safely. Applications are recommend to instead use android.content.ComponentCallbacks2#onTrimMemory(int) to react to memory events and release shared memory regions as appropriate.
Is memory file purging enabled?
| Return | |
|---|---|
Boolean |
true if the file may be purged. |
length
open fun length(): Int
Returns the length of the memory file.
| Return | |
|---|---|
Int |
file length. |
readBytes
open fun readBytes(
buffer: ByteArray!,
srcOffset: Int,
destOffset: Int,
count: Int
): Int
Reads bytes from the memory file. Will throw an IOException if the file has been purged.
| Parameters | |
|---|---|
buffer |
ByteArray!: byte array to read bytes into. |
srcOffset |
Int: offset into the memory file to read from. |
destOffset |
Int: offset into the byte array buffer to read into. |
count |
Int: number of bytes to read. |
| Return | |
|---|---|
Int |
number of bytes read. |
| Exceptions | |
|---|---|
java.io.IOException |
if the memory file has been purged or deactivated. |
writeBytes
open fun writeBytes(
buffer: ByteArray!,
srcOffset: Int,
destOffset: Int,
count: Int
): Unit
Write bytes to the memory file. Will throw an IOException if the file has been purged.
| Parameters | |
|---|---|
buffer |
ByteArray!: byte array to write bytes from. |
srcOffset |
Int: offset into the byte array buffer to write from. |
destOffset |
Int: offset into the memory file to write to. |
count |
Int: number of bytes to write. |
| Exceptions | |
|---|---|
java.io.IOException |
if the memory file has been purged or deactivated. |