Android APIs
public class

Environment

extends Object
java.lang.Object
   ↳ android.os.Environment

Class Overview

Provides access to environment variables.

Summary

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_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 external storage directory.
static File getExternalStoragePublicDirectory(String type)
Get a top-level public external storage directory for placing files of a particular type.
static String getExternalStorageState()
Returns the current state of the primary "external" storage device.
static File getRootDirectory()
Gets the Android root directory.
static String getStorageState(File path)
Returns the current state of the storage device that provides the given path.
static boolean isExternalStorageEmulated()
Returns whether the device has an external storage device which is emulated.
static boolean isExternalStorageRemovable()
Returns whether the primary "external" storage device is removable.
[Expand]
Inherited Methods
From class java.lang.Object

Constants

public static final String MEDIA_BAD_REMOVAL

Added in API level 1

Storage state if the media was removed before it was unmounted.

Constant Value: "bad_removal"

public static final String MEDIA_CHECKING

Added in API level 3

Storage state if the media is present and being disk-checked.

Constant Value: "checking"

public static final String MEDIA_MOUNTED

Added in API level 1

Storage state if the media is present and mounted at its mount point with read/write access.

Constant Value: "mounted"

public static final String MEDIA_MOUNTED_READ_ONLY

Added in API level 1

Storage state if the media is present and mounted at its mount point with read-only access.

Constant Value: "mounted_ro"

public static final String MEDIA_NOFS

Added in API level 3

Storage state if the media is present but is blank or is using an unsupported filesystem.

Constant Value: "nofs"

public static final String MEDIA_REMOVED

Added in API level 1

Storage state if the media is not present.

Constant Value: "removed"

public static final String MEDIA_SHARED

Added in API level 1

Storage state if the media is present not mounted, and shared via USB mass storage.

Constant Value: "shared"

public static final String MEDIA_UNKNOWN

Added in API level 19

Unknown storage state, such as when a path isn't backed by known storage media.

Constant Value: "unknown"

public static final String MEDIA_UNMOUNTABLE

Added in API level 1

Storage state if the media is present but cannot be mounted. Typically this happens if the file system on the media is corrupted.

Constant Value: "unmountable"

public static final String MEDIA_UNMOUNTED

Added in API level 1

Storage state if the media is present but not mounted.

Constant Value: "unmounted"

Fields

public static String DIRECTORY_ALARMS

Added in API level 8

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.

public static String DIRECTORY_DCIM

Added in API level 8

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.

public static String DIRECTORY_DOCUMENTS

Added in API level 19

Standard directory in which to place documents that have been created by the user.

public static String DIRECTORY_DOWNLOADS

Added in API level 8

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.

public static String DIRECTORY_MOVIES

Added in API level 8

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.

public static String DIRECTORY_MUSIC

Added in API level 8

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.

public static String DIRECTORY_NOTIFICATIONS

Added in API level 8

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.

public static String DIRECTORY_PICTURES

Added in API level 8

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.

public static String DIRECTORY_PODCASTS

Added in API level 8

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.

public static String DIRECTORY_RINGTONES

Added in API level 8

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.

Public Constructors

public Environment ()

Added in API level 1

Public Methods

public static File getDataDirectory ()

Added in API level 1

Return the user data directory.

public static File getDownloadCacheDirectory ()

Added in API level 1

Return the download/cache content directory.

public static File getExternalStorageDirectory ()

Added in API level 1

Return the primary 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 external storage. Applications only have access to the external storage for the user they're running as.

In devices with multiple "external" storage directories, this directory represents the "primary" external storage that the user will interact with. Access to secondary storage is available through

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 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) or getExternalCacheDir(), 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);
}

public static File getExternalStoragePublicDirectory (String type)

Added in API level 8

Get a top-level public 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 external storage. Applications only have access to the external storage for the user they're running as.

Here is an example of typical code to manipulate a picture on the public external 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 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, or DIRECTORY_DCIM. May not be null.
Returns
  • 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().

public static String getExternalStorageState ()

Added in API level 1

public static File getRootDirectory ()

Added in API level 1

Gets the Android root directory.

public static String getStorageState (File path)

Added in API level 19

Returns the current state of the storage device that provides the given path.

public static boolean isExternalStorageEmulated ()

Added in API level 11

Returns whether the device has an external storage device which is emulated. If true, the device does not have real external storage, and the directory returned by getExternalStorageDirectory() will be allocated using a portion of the internal storage system.

Certain system services, such as the package manager, use this to determine where to install an application.

Emulated external storage may also be encrypted - see setStorageEncryption(android.content.ComponentName, boolean) for additional details.

public static boolean isExternalStorageRemovable ()

Added in API level 9

Returns whether the primary "external" storage device is removable. If true is returned, this device is for example an SD card that the user can remove. If false is returned, the storage is built into the device and can not be physically removed.

See getExternalStorageDirectory() for more information.