fr.maxcom.os.storage

Class Volume

java.lang.Object

fr.maxcom.os.storage.Volume

All Implemented Interfaces:

Comparable<Volume>

public class Volume
extends Object
implements Comparable<Volume>

A volume represents a Storage Unit, such as a USB device or a SdCard device.

Get the available volumes by calling VolumeManager.getVolumes()

Optionally, volumes can be given a label with a special convention: A file named .libmedia, located at the root folder, stores the label (as a UTF-8 string). Some operations (check, write, delete) are available to manage this file in an application.

Since:

3.1 - Is not backwards compatible and supersedes previous versions.

Field Summary

Fields

Modifier and Type	Field and Description
String	description A free field, available for your convenience.
static String	EMULATED_STORAGE The type returned by getType() if the volume is emulated from a directory.
static String	STORAGE The type returned by getType() if the volume is really based on a Storage Provider.

Method Summary

Modifier and Type	Method and Description
int	compareTo(Volume o) Compares two volumes.
boolean	deleteLabelFile() Deletes the label file.
boolean	forget() Releases the authorization once granted by the user to access this volume.
String	getLabel() Returns the label of the volume.
String	getName() Returns the name of the volume.
DocumentFile	getRoot() Returns the root entry of the volume.
String	getType() Returns the type of storage unit.
boolean	hasLabelFile() Tells if a label file exists.
boolean	isForgettable() Tells whether the volume is issued from a previous authorization of the user.
String	toString() Returns a default string representation of the volume.
boolean	writeLabelFile(String label) Writes a new label in the label file, creating the file if necessary.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

description

public String description

A free field, available for your convenience.

STORAGE

public static final String STORAGE

The type returned by getType() if the volume is really based on a Storage Provider.

See Also:

Constant Field Values

EMULATED_STORAGE

public static final String EMULATED_STORAGE

The type returned by getType() if the volume is emulated from a directory.

See Also:

VolumeManager.addEmulatedStorageContainer(String), Constant Field Values

Method Detail

getRoot

public DocumentFile getRoot()

Returns the root entry of the volume.

Returns:

The root entry.

getName

public String getName()

Returns the name of the volume.

• In case of a direct file access capability (including the Emulation mode), it is the name of the root directory.
• In the case of Storage Access Framework, it is the display name.

Returns:

The name.

getLabel

public String getLabel()

Returns the label of the volume. The label is searched in the following sources, in priority order:

• The optional label file, and if not empty.
• In the case of a real storage unit, the possible hardware label (unlikely made available if not Android TV).
• The name of the volume.

Returns:

The label.

getType

public String getType()

Returns the type of storage unit.

Returns:

The type, as one of the constants defined in this class.

isForgettable

public boolean isForgettable()

Tells whether the volume is issued from a previous authorization of the user. Only meaningful with Storage Access Framework.

Returns:

true if the volume can be forgotten.

See Also:

forget()

hasLabelFile

public boolean hasLabelFile()

Tells if a label file exists.

Returns:

true if the file exists.

writeLabelFile

public boolean writeLabelFile(String label)

Writes a new label in the label file, creating the file if necessary.

Parameters:

label - The new contents.

Returns:

true if the operation succeeded.

deleteLabelFile

public boolean deleteLabelFile()

Deletes the label file.

Returns:

true if the operation succeeded.

forget

public boolean forget()

Releases the authorization once granted by the user to access this volume. Only meaningful with Storage Access Framework.

Returns:

true if the operation succeeded.

See Also:

isForgettable()

toString

public String toString()

Returns a default string representation of the volume. This is just the string returned by the getLabel() method.

Overrides:

toString in class Object

Returns:

The string form of this volume.

compareTo

public int compareTo(Volume o)

Compares two volumes. This method is mainly dedicated to VolumeManager to avoid the creation of duplicate volumes.

Specified by:

compareTo in interface Comparable<Volume>

Parameters:

o - The other volume to be compared to this volume.

Returns:

Zero if the volumes point to the same storage unit, or the lexicographical comparison of their labels (but a value less than zero in the special case where these labels are identical).