public
class
Environment
extends Object
java.lang.Object | |
↳ | android.os.Environment |
Provides access to environment variables.
Constants | |
---|---|
String |
MEDIA_BAD_REMOVAL
Storage state if the media was removed before it was unmounted. |
String |
MEDIA_CHECKING
Storage state if the media is present and being disk-checked. |
String |
MEDIA_EJECTING
Storage state if the media is in the process of being ejected. |
String |
MEDIA_MOUNTED
Storage state if the media is present and mounted at its mount point with read/write access. |
String |
MEDIA_MOUNTED_READ_ONLY
Storage state if the media is present and mounted at its mount point with read-only access. |
String |
MEDIA_NOFS
Storage state if the media is present but is blank or is using an unsupported filesystem. |
String |
MEDIA_REMOVED
Storage state if the media is not present. |
String |
MEDIA_SHARED
Storage state if the media is present not mounted, and shared via USB mass storage. |
String |
MEDIA_UNKNOWN
Unknown storage state, such as when a path isn't backed by known storage media. |
String |
MEDIA_UNMOUNTABLE
Storage state if the media is present but cannot be mounted. |
String |
MEDIA_UNMOUNTED
Storage state if the media is present but not mounted. |
Fields | |
---|---|
public
static
String |
DIRECTORY_ALARMS
Standard directory in which to place any audio files that should be in the list of alarms that the user can select (not as regular music). |
public
static
String |
DIRECTORY_DCIM
The traditional location for pictures and videos when mounting the device as a camera. |
public
static
String |
DIRECTORY_DOCUMENTS
Standard directory in which to place documents that have been created by the user. |
public
static
String |
DIRECTORY_DOWNLOADS
Standard directory in which to place files that have been downloaded by the user. |
public
static
String |
DIRECTORY_MOVIES
Standard directory in which to place movies that are available to the user. |
public
static
String |
DIRECTORY_MUSIC
Standard directory in which to place any audio files that should be in the regular list of music for the user. |
public
static
String |
DIRECTORY_NOTIFICATIONS
Standard directory in which to place any audio files that should be in the list of notifications that the user can select (not as regular music). |
public
static
String |
DIRECTORY_PICTURES
Standard directory in which to place pictures that are available to the user. |
public
static
String |
DIRECTORY_PODCASTS
Standard directory in which to place any audio files that should be in the list of podcasts that the user can select (not as regular music). |
public
static
String |
DIRECTORY_RINGTONES
Standard directory in which to place any audio files that should be in the list of ringtones that the user can select (not as regular music). |
Public constructors | |
---|---|
Environment()
|
Public methods | |
---|---|
static
File
|
getDataDirectory()
Return the user data directory. |
static
File
|
getDownloadCacheDirectory()
Return the download/cache content directory. |
static
File
|
getExternalStorageDirectory()
Return the primary shared/external storage directory. |
static
File
|
getExternalStoragePublicDirectory(String type)
Get a top-level shared/external storage directory for placing files of a particular type. |
static
String
|
getExternalStorageState()
Returns the current state of the primary shared/external storage media. |
static
String
|
getExternalStorageState(File path)
Returns the current state of the shared/external storage media at the given path. |
static
File
|
getRootDirectory()
Return root of the "system" partition holding the core Android OS. |
static
String
|
getStorageState(File path)
This method was deprecated
in API level 21.
use |
static
boolean
|
isExternalStorageEmulated()
Returns whether the primary shared/external storage media is emulated. |
static
boolean
|
isExternalStorageEmulated(File path)
Returns whether the shared/external storage media at the given path is emulated. |
static
boolean
|
isExternalStorageRemovable()
Returns whether the primary shared/external storage media is physically removable. |
static
boolean
|
isExternalStorageRemovable(File path)
Returns whether the shared/external storage media at the given path is physically removable. |
Inherited methods | |
---|---|
From
class
java.lang.Object
|
String MEDIA_BAD_REMOVAL
Storage state if the media was removed before it was unmounted.
See also:
Constant Value: "bad_removal"
String MEDIA_CHECKING
Storage state if the media is present and being disk-checked.
See also:
Constant Value: "checking"
String MEDIA_EJECTING
Storage state if the media is in the process of being ejected.
See also:
Constant Value: "ejecting"
String MEDIA_MOUNTED
Storage state if the media is present and mounted at its mount point with read/write access.
See also:
Constant Value: "mounted"
String MEDIA_MOUNTED_READ_ONLY
Storage state if the media is present and mounted at its mount point with read-only access.
See also:
Constant Value: "mounted_ro"
String MEDIA_NOFS
Storage state if the media is present but is blank or is using an unsupported filesystem.
See also:
Constant Value: "nofs"
String MEDIA_REMOVED
Storage state if the media is not present.
See also:
Constant Value: "removed"
String MEDIA_SHARED
Storage state if the media is present not mounted, and shared via USB mass storage.
See also:
Constant Value: "shared"
String MEDIA_UNKNOWN
Unknown storage state, such as when a path isn't backed by known storage media.
See also:
Constant Value: "unknown"
String MEDIA_UNMOUNTABLE
Storage state if the media is present but cannot be mounted. Typically this happens if the file system on the media is corrupted.
See also:
Constant Value: "unmountable"
String MEDIA_UNMOUNTED
Storage state if the media is present but not mounted.
See also:
Constant Value: "unmounted"
String DIRECTORY_ALARMS
Standard directory in which to place any audio files that should be
in the list of alarms that the user can select (not as regular
music).
This may be combined with DIRECTORY_MUSIC
,
DIRECTORY_PODCASTS
, DIRECTORY_NOTIFICATIONS
,
and DIRECTORY_RINGTONES
as a series
of directories to categories a particular audio file as more than one
type.
String DIRECTORY_DCIM
The traditional location for pictures and videos when mounting the device as a camera. Note that this is primarily a convention for the top-level public directory, as this convention makes no sense elsewhere.
String DIRECTORY_DOCUMENTS
Standard directory in which to place documents that have been created by the user.
String DIRECTORY_DOWNLOADS
Standard directory in which to place files that have been downloaded by the user. Note that this is primarily a convention for the top-level public directory, you are free to download files anywhere in your own private directories. Also note that though the constant here is named DIRECTORY_DOWNLOADS (plural), the actual file name is non-plural for backwards compatibility reasons.
String DIRECTORY_MOVIES
Standard directory in which to place movies that are available to the user. Note that this is primarily a convention for the top-level public directory, as the media scanner will find and collect movies in any directory.
String DIRECTORY_MUSIC
Standard directory in which to place any audio files that should be
in the regular list of music for the user.
This may be combined with
DIRECTORY_PODCASTS
, DIRECTORY_NOTIFICATIONS
,
DIRECTORY_ALARMS
, and DIRECTORY_RINGTONES
as a series
of directories to categories a particular audio file as more than one
type.
String DIRECTORY_NOTIFICATIONS
Standard directory in which to place any audio files that should be
in the list of notifications that the user can select (not as regular
music).
This may be combined with DIRECTORY_MUSIC
,
DIRECTORY_PODCASTS
,
DIRECTORY_ALARMS
, and DIRECTORY_RINGTONES
as a series
of directories to categories a particular audio file as more than one
type.
String DIRECTORY_PICTURES
Standard directory in which to place pictures that are available to the user. Note that this is primarily a convention for the top-level public directory, as the media scanner will find and collect pictures in any directory.
String DIRECTORY_PODCASTS
Standard directory in which to place any audio files that should be
in the list of podcasts that the user can select (not as regular
music).
This may be combined with DIRECTORY_MUSIC
,
DIRECTORY_NOTIFICATIONS
,
DIRECTORY_ALARMS
, and DIRECTORY_RINGTONES
as a series
of directories to categories a particular audio file as more than one
type.
String DIRECTORY_RINGTONES
Standard directory in which to place any audio files that should be
in the list of ringtones that the user can select (not as regular
music).
This may be combined with DIRECTORY_MUSIC
,
DIRECTORY_PODCASTS
, DIRECTORY_NOTIFICATIONS
, and
DIRECTORY_ALARMS
as a series
of directories to categories a particular audio file as more than one
type.
File getDataDirectory ()
Return the user data directory.
Returns | |
---|---|
File |
File getDownloadCacheDirectory ()
Return the download/cache content directory.
Returns | |
---|---|
File |
File getExternalStorageDirectory ()
Return the primary shared/external storage directory. This directory may
not currently be accessible if it has been mounted by the user on their
computer, has been removed from the device, or some other problem has
happened. You can determine its current state with
getExternalStorageState()
.
Note: don't be confused by the word "external" here. This directory can better be thought as media/shared storage. It is a filesystem that can hold a relatively large amount of data and that is shared across all applications (does not enforce permissions). Traditionally this is an SD card, but it may also be implemented as built-in storage in a device that is distinct from the protected internal storage and can be mounted as a filesystem on a computer.
On devices with multiple users (as described by UserManager
),
each user has their own isolated shared storage. Applications only have
access to the shared storage for the user they're running as.
In devices with multiple shared/external storage directories, this
directory represents the primary storage that the user will interact
with. Access to secondary storage is available through
getExternalFilesDirs(String)
,
getExternalCacheDirs()
, and
getExternalMediaDirs()
.
Applications should not directly use this top-level directory, in order
to avoid polluting the user's root namespace. Any files that are private
to the application should be placed in a directory returned by
Context.getExternalFilesDir
, which the system will take care of deleting
if the application is uninstalled. Other shared files should be placed in
one of the directories returned by
getExternalStoragePublicDirectory(String)
.
Writing to this path requires the
WRITE_EXTERNAL_STORAGE
permission,
and starting in KITKAT
, read access requires the
READ_EXTERNAL_STORAGE
permission,
which is automatically granted if you hold the write permission.
Starting in KITKAT
, if your
application only needs to store internal data, consider using
getExternalFilesDir(String)
,
getExternalCacheDir()
, or
getExternalMediaDirs()
, which require no permissions to
read or write.
This path may change between platform versions, so applications should only persist relative paths.
Here is an example of typical code to monitor the state of external storage:
BroadcastReceiver mExternalStorageReceiver; boolean mExternalStorageAvailable = false; boolean mExternalStorageWriteable = false; void updateExternalStorageState() { String state = Environment.getExternalStorageState(); if (Environment.MEDIA_MOUNTED.equals(state)) { mExternalStorageAvailable = mExternalStorageWriteable = true; } else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) { mExternalStorageAvailable = true; mExternalStorageWriteable = false; } else { mExternalStorageAvailable = mExternalStorageWriteable = false; } handleExternalStorageState(mExternalStorageAvailable, mExternalStorageWriteable); } void startWatchingExternalStorage() { mExternalStorageReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { Log.i("test", "Storage: " + intent.getData()); updateExternalStorageState(); } }; IntentFilter filter = new IntentFilter(); filter.addAction(Intent.ACTION_MEDIA_MOUNTED); filter.addAction(Intent.ACTION_MEDIA_REMOVED); registerReceiver(mExternalStorageReceiver, filter); updateExternalStorageState(); } void stopWatchingExternalStorage() { unregisterReceiver(mExternalStorageReceiver); }
Returns | |
---|---|
File |
File getExternalStoragePublicDirectory (String type)
Get a top-level shared/external storage directory for placing files of a particular type. This is where the user will typically place and manage their own files, so you should be careful about what you put here to ensure you don't erase their files or get in the way of their own organization.
On devices with multiple users (as described by UserManager
),
each user has their own isolated shared storage. Applications only have
access to the shared storage for the user they're running as.
Here is an example of typical code to manipulate a picture on the public shared storage:
void createExternalStoragePublicPicture() { // Create a path where we will place our picture in the user's // public pictures directory. Note that you should be careful about // what you place here, since the user often manages these files. For // pictures and other media owned by the application, consider // Context.getExternalMediaDir(). File path = Environment.getExternalStoragePublicDirectory( Environment.DIRECTORY_PICTURES); File file = new File(path, "DemoPicture.jpg"); try { // Make sure the Pictures directory exists. path.mkdirs(); // Very simple code to copy a picture from the application's // resource into the external file. Note that this code does // no error checking, and assumes the picture is small (does not // try to copy it in chunks). Note that if external storage is // not currently mounted this will silently fail. InputStream is = getResources().openRawResource(R.drawable.balloons); OutputStream os = new FileOutputStream(file); byte[] data = new byte[is.available()]; is.read(data); os.write(data); is.close(); os.close(); // Tell the media scanner about the new file so that it is // immediately available to the user. MediaScannerConnection.scanFile(this, new String[] { file.toString() }, null, new MediaScannerConnection.OnScanCompletedListener() { public void onScanCompleted(String path, Uri uri) { Log.i("ExternalStorage", "Scanned " + path + ":"); Log.i("ExternalStorage", "-> uri=" + uri); } }); } catch (IOException e) { // Unable to create file, likely because external storage is // not currently mounted. Log.w("ExternalStorage", "Error writing " + file, e); } } void deleteExternalStoragePublicPicture() { // Create a path where we will place our picture in the user's // public pictures directory and delete the file. If external // storage is not currently mounted this will fail. File path = Environment.getExternalStoragePublicDirectory( Environment.DIRECTORY_PICTURES); File file = new File(path, "DemoPicture.jpg"); file.delete(); } boolean hasExternalStoragePublicPicture() { // Create a path where we will place our picture in the user's // public pictures directory and check if the file exists. If // external storage is not currently mounted this will think the // picture doesn't exist. File path = Environment.getExternalStoragePublicDirectory( Environment.DIRECTORY_PICTURES); File file = new File(path, "DemoPicture.jpg"); return file.exists(); }
Parameters | |
---|---|
type |
String :
The type of storage directory to return. Should be one of
DIRECTORY_MUSIC , DIRECTORY_PODCASTS ,
DIRECTORY_RINGTONES , DIRECTORY_ALARMS ,
DIRECTORY_NOTIFICATIONS , DIRECTORY_PICTURES ,
DIRECTORY_MOVIES , DIRECTORY_DOWNLOADS ,
DIRECTORY_DCIM , or DIRECTORY_DOCUMENTS . May not be null. |
Returns | |
---|---|
File |
Returns the File path for the directory. Note that this directory
may not yet exist, so you must make sure it exists before using
it such as with File.mkdirs() .
|
String getExternalStorageState ()
Returns the current state of the primary shared/external storage media.
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 .
|
See also:
String getExternalStorageState (File path)
Returns the current state of the shared/external storage media at the given path.
Parameters | |
---|---|
path |
File
|
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 .
|
File getRootDirectory ()
Return root of the "system" partition holding the core Android OS. Always present and mounted read-only.
Returns | |
---|---|
File |
String getStorageState (File path)
This method was deprecated
in API level 21.
use getExternalStorageState(File)
Parameters | |
---|---|
path |
File
|
Returns | |
---|---|
String |
boolean isExternalStorageEmulated ()
Returns whether the primary shared/external storage media is emulated.
The contents of emulated storage devices are backed by a private user
data partition, which means there is little benefit to apps storing data
here instead of the private directories returned by
getFilesDir()
, etc.
This returns true when emulated storage is backed by either internal storage or an adopted storage device.
Returns | |
---|---|
boolean |
boolean isExternalStorageEmulated (File path)
Returns whether the shared/external storage media at the given path is emulated.
The contents of emulated storage devices are backed by a private user
data partition, which means there is little benefit to apps storing data
here instead of the private directories returned by
getFilesDir()
, etc.
This returns true when emulated storage is backed by either internal storage or an adopted storage device.
Parameters | |
---|---|
path |
File
|
Returns | |
---|---|
boolean |
Throws | |
---|---|
IllegalArgumentException |
if the path is not a valid storage device. |
boolean isExternalStorageRemovable ()
Returns whether the primary shared/external storage media is physically removable.
Returns | |
---|---|
boolean |
true if the storage device can be removed (such as an SD card), or false if the storage device is built in and cannot be physically removed. |
boolean isExternalStorageRemovable (File path)
Returns whether the shared/external storage media at the given path is physically removable.
Parameters | |
---|---|
path |
File
|
Returns | |
---|---|
boolean |
true if the storage device can be removed (such as an SD card), or false if the storage device is built in and cannot be physically removed. |
Throws | |
---|---|
IllegalArgumentException |
if the path is not a valid storage device. |