public final class StorageVolume
extends Object
implements Parcelable
java.lang.Object | |
↳ | android.os.storage.StorageVolume |
Information about a shared/external storage volume for a specific user.
A device always has one (and one only) primary storage volume, but it could have extra volumes, like SD cards and USB drives. This object represents the logical view of a storage volume for a specific user: different users might have different views for the same physical volume (for example, if the volume is a built-in emulated storage).
The storage volume is not necessarily mounted, applications should use getState()
to verify its state.
Applications willing to read or write to this storage volume needs to get a permission from the user first, which can be achieved in the following ways:
DIRECTORY_PICTURES
), they can use the createAccessIntent(String)
. This is the recommend way, since it provides a simpler API and narrows the access to the given directory (and its descendants). ACTION_OPEN_DOCUMENT
and ACTION_OPEN_DOCUMENT_TREE
, although these APIs do not guarantee the user will select this specific volume. READ_EXTERNAL_STORAGE
and WRITE_EXTERNAL_STORAGE
permissions respectively, with the latter including the former. This approach is discouraged, since users may be hesitant to grant broad access to all files contained on a storage device. It can be obtained through getStorageVolumes()
and getPrimaryStorageVolume()
and also as an extra in some broadcasts (see EXTRA_STORAGE_VOLUME
).
See getExternalStorageDirectory()
for more info about shared/external storage semantics.
Constants |
|
---|---|
String |
EXTRA_STORAGE_VOLUME Name of the |
Inherited constants |
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![]() android.os.Parcelable
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Fields |
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public static final Creator<StorageVolume> |
CREATOR
|
Public methods |
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Intent |
createAccessIntent(String directoryName) Builds an intent to give access to a standard storage directory or entire volume after obtaining the user's approval. |
int |
describeContents() Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. |
boolean |
equals(Object obj) Indicates whether some other object is "equal to" this one. |
String |
getDescription(Context context) Returns a user-visible description of the volume. |
String |
getState() Returns the current state of the volume. |
String |
getUuid() Gets the volume UUID, if any. |
int |
hashCode() Returns a hash code value for the object. |
boolean |
isEmulated() Returns true if the volume is emulated. |
boolean |
isPrimary() Returns true if the volume is the primary shared/external storage, which is the volume backed by |
boolean |
isRemovable() Returns true if the volume is removable. |
String |
toString() Returns a string representation of the object. |
void |
writeToParcel(Parcel parcel, int flags) Flatten this object in to a Parcel. |
Inherited methods |
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![]() java.lang.Object
|
|
![]() android.os.Parcelable
|
String EXTRA_STORAGE_VOLUME
Name of the Parcelable
extra in the ACTION_MEDIA_REMOVED
, ACTION_MEDIA_UNMOUNTED
, ACTION_MEDIA_CHECKING
, ACTION_MEDIA_NOFS
, ACTION_MEDIA_MOUNTED
, ACTION_MEDIA_SHARED
, ACTION_MEDIA_BAD_REMOVAL
, ACTION_MEDIA_UNMOUNTABLE
, and ACTION_MEDIA_EJECT
broadcast that contains a StorageVolume
.
Constant Value: "android.os.storage.extra.STORAGE_VOLUME"
Intent createAccessIntent (String directoryName)
Builds an intent to give access to a standard storage directory or entire volume after obtaining the user's approval.
When invoked, the system will ask the user to grant access to the requested directory (and its descendants). The result of the request will be returned to the activity through the onActivityResult
method.
To gain access to descendants (child, grandchild, etc) documents, use buildDocumentUriUsingTree(Uri, String)
, or buildChildDocumentsUriUsingTree(Uri, String)
with the returned URI.
If your application only needs to store internal data, consider using Context.getExternalFilesDirs
, getExternalCacheDirs()
, or getExternalMediaDirs()
, which require no permissions to read or write.
Access to the entire volume is only available for non-primary volumes (for the primary volume, apps can use the READ_EXTERNAL_STORAGE
and WRITE_EXTERNAL_STORAGE
permissions) and should be used with caution, since users are more likely to deny access when asked for entire volume access rather than specific directories.
Parameters | |
---|---|
directoryName |
String : must be one of DIRECTORY_MUSIC , DIRECTORY_PODCASTS , DIRECTORY_RINGTONES , DIRECTORY_ALARMS , DIRECTORY_NOTIFICATIONS , DIRECTORY_PICTURES , DIRECTORY_MOVIES , DIRECTORY_DOWNLOADS , DIRECTORY_DCIM , or DIRECTORY_DOCUMENTS , or {code null} to request access to the entire volume. |
Returns | |
---|---|
Intent |
intent to request access, or null if the requested directory is invalid for that volume. |
See also:
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 | |
---|---|
int |
a bitmask indicating the set of special object types marshaled by this Parcelable object instance. |
boolean equals (Object obj)
Indicates whether some other object is "equal to" this one.
The equals
method implements an equivalence relation on non-null object references:
x
, x.equals(x)
should return true
. x
and y
, x.equals(y)
should return true
if and only if y.equals(x)
returns true
. x
, y
, and z
, if x.equals(y)
returns true
and y.equals(z)
returns true
, then x.equals(z)
should return true
. x
and y
, multiple invocations of x.equals(y)
consistently return true
or consistently return false
, provided no information used in equals
comparisons on the objects is modified. x
, x.equals(null)
should return false
. The equals
method for class Object
implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x
and y
, this method returns true
if and only if x
and y
refer to the same object (x == y
has the value true
).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the general contract for the hashCode
method, which states that equal objects must have equal hash codes.
Parameters | |
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obj |
Object : the reference object with which to compare. |
Returns | |
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boolean |
true if this object is the same as the obj argument; false otherwise. |
String getDescription (Context context)
Returns a user-visible description of the volume.
Parameters | |
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context |
Context
|
Returns | |
---|---|
String |
the volume description |
String getState ()
Returns the current state of the volume.
Returns | |
---|---|
String |
one of MEDIA_UNKNOWN , MEDIA_REMOVED , MEDIA_UNMOUNTED , MEDIA_CHECKING , MEDIA_NOFS , MEDIA_MOUNTED , MEDIA_MOUNTED_READ_ONLY , MEDIA_SHARED , MEDIA_BAD_REMOVAL , or MEDIA_UNMOUNTABLE . |
int hashCode ()
Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap
.
The general contract of hashCode
is:
hashCode
method must consistently return the same integer, provided no information used in equals
comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. equals(Object)
method, then calling the hashCode
method on each of the two objects must produce the same integer result. equals(java.lang.Object)
method, then calling the hashCode
method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables. As much as is reasonably practical, the hashCode method defined by class Object
does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)
Returns | |
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int |
a hash code value for this object. |
boolean isEmulated ()
Returns true if the volume is emulated.
Returns | |
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boolean |
is removable |
boolean isPrimary ()
Returns true if the volume is the primary shared/external storage, which is the volume backed by getExternalStorageDirectory()
.
Returns | |
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boolean |
boolean isRemovable ()
Returns true if the volume is removable.
Returns | |
---|---|
boolean |
is removable |
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 parcel, int flags)
Flatten this object in to a Parcel.
Parameters | |
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parcel |
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 . |