DocumentFile


abstract class DocumentFile


Representation of a document backed by either a android.provider.DocumentsProvider or a raw file on disk. This is a utility class designed to emulate the traditional File interface. It offers a simplified view of a tree of documents, but it has substantial overhead. For optimal performance and a richer feature set, use the android.provider.DocumentsContract methods and constants directly.

There are several differences between documents and traditional files:

  • Documents express their display name and MIME type as separate fields, instead of relying on file extensions. Some documents providers may still choose to append extensions to their display names, but that's an implementation detail.
  • A single document may appear as the child of multiple directories, so it doesn't inherently know who its parent is. That is, documents don't have a strong notion of path. You can easily traverse a tree of documents from parent to child, but not from child to parent.
  • Each document has a unique identifier within that provider. This identifier is an opaque implementation detail of the provider, and as such it must not be parsed.

Before using this class, first consider if you really need access to an entire subtree of documents. The principle of least privilege dictates that you should only ask for access to documents you really need. If you only need the user to pick a single file, use ACTION_OPEN_DOCUMENT or ACTION_GET_CONTENT. If you want to let the user pick multiple files, add EXTRA_ALLOW_MULTIPLE. If you only need the user to save a single file, use ACTION_CREATE_DOCUMENT. If you use these APIs, you can pass the resulting getData into fromSingleUri to work with that document.

If you really do need full access to an entire subtree of documents, start by launching ACTION_OPEN_DOCUMENT_TREE to let the user pick a directory. Then pass the resulting getData into fromTreeUri to start working with the user selected tree.

As you navigate the tree of DocumentFile instances, you can always use getUri to obtain the Uri representing the underlying document for that object, for use with openInputStream, etc.

To simplify your code on devices running KITKAT or earlier, you can use fromFile which emulates the behavior of a android.provider.DocumentsProvider.

Summary

Public functions

abstract Boolean

Indicates whether the current context is allowed to read from this file.

abstract Boolean

Indicates whether the current context is allowed to write to this file.

abstract DocumentFile?
createDirectory(displayName: String)

Create a new directory as a direct child of this directory.

abstract DocumentFile?
createFile(mimeType: String, displayName: String)

Create a new document as a direct child of this directory.

abstract Boolean

Deletes this file.

abstract Boolean

Returns a boolean indicating whether this file can be found.

DocumentFile?
findFile(displayName: String)

Search through listFiles for the first document matching the given display name.

java-static DocumentFile
fromFile(file: File)

Create a DocumentFile representing the filesystem tree rooted at the given File.

java-static DocumentFile?
fromSingleUri(context: Context, singleUri: Uri)

Create a DocumentFile representing the single document at the given Uri.

java-static DocumentFile?
fromTreeUri(context: Context, treeUri: Uri)

Create a DocumentFile representing the document tree rooted at the given Uri.

abstract String?

Return the display name of this document.

DocumentFile?

Return the parent file of this document.

abstract String?

Return the MIME type of this document.

abstract Uri

Return a Uri for the underlying document represented by this file.

abstract Boolean

Indicates if this file represents a directory.

java-static Boolean
isDocumentUri(context: Context, uri: Uri?)

Test if given Uri is backed by a android.provider.DocumentsProvider.

abstract Boolean

Indicates if this file represents a file.

abstract Boolean

Indicates if this file represents a virtual document.

abstract Long

Returns the time when this file was last modified, measured in milliseconds since January 1st, 1970, midnight.

abstract Long

Returns the length of this file in bytes.

abstract Array<DocumentFile!>

Returns an array of files contained in the directory represented by this file.

abstract Boolean
renameTo(displayName: String)

Renames this file to displayName.

Public functions

canRead

Added in 1.0.0
abstract fun canRead(): Boolean

Indicates whether the current context is allowed to read from this file.

Returns
Boolean

true if this file can be read, false otherwise.

canWrite

Added in 1.0.0
abstract fun canWrite(): Boolean

Indicates whether the current context is allowed to write to this file.

Returns
Boolean

true if this file can be written, false otherwise.

createDirectory

Added in 1.0.0
abstract fun createDirectory(displayName: String): DocumentFile?

Create a new directory as a direct child of this directory.

Parameters
displayName: String

name of new directory

Returns
DocumentFile?

file representing newly created directory, or null if failed

Throws
java.lang.UnsupportedOperationException

when working with a single document created from fromSingleUri.

See also
createDocument

createFile

Added in 1.0.0
abstract fun createFile(mimeType: String, displayName: String): DocumentFile?

Create a new document as a direct child of this directory.

Parameters
mimeType: String

MIME type of new document, such as image/png or audio/flac

displayName: String

name of new document, without any file extension appended; the underlying provider may choose to append the extension

Returns
DocumentFile?

file representing newly created document, or null if failed

Throws
java.lang.UnsupportedOperationException

when working with a single document created from fromSingleUri.

See also
createDocument

delete

Added in 1.0.0
abstract fun delete(): Boolean

Deletes this file.

Note that this method does not throw IOException on failure. Callers must check the return value.

Returns
Boolean

true if this file was deleted, false otherwise.

See also
deleteDocument

exists

Added in 1.0.0
abstract fun exists(): Boolean

Returns a boolean indicating whether this file can be found.

Returns
Boolean

true if this file exists, false otherwise.

findFile

Added in 1.0.0
fun findFile(displayName: String): DocumentFile?

Search through listFiles for the first document matching the given display name. Returns null when no matching document is found.

Throws
java.lang.UnsupportedOperationException

when working with a single document created from fromSingleUri.

fromFile

Added in 1.0.0
java-static fun fromFile(file: File): DocumentFile

Create a DocumentFile representing the filesystem tree rooted at the given File. This doesn't give you any additional access to the underlying files beyond what your app already has.

getUri will return file:// Uris for files explored through this tree.

fromSingleUri

Added in 1.0.0
java-static fun fromSingleUri(context: Context, singleUri: Uri): DocumentFile?

Create a DocumentFile representing the single document at the given Uri. This is only useful on devices running KITKAT or later, and will return null when called on earlier platform versions.

Parameters
singleUri: Uri

the getData from a successful ACTION_OPEN_DOCUMENT or ACTION_CREATE_DOCUMENT request.

fromTreeUri

Added in 1.0.0
java-static fun fromTreeUri(context: Context, treeUri: Uri): DocumentFile?

Create a DocumentFile representing the document tree rooted at the given Uri. This is only useful on devices running LOLLIPOP or later, and will return null when called on earlier platform versions.

Parameters
treeUri: Uri

the getData from a successful ACTION_OPEN_DOCUMENT_TREE request.

getName

Added in 1.0.0
abstract fun getName(): String?

Return the display name of this document.

getParentFile

Added in 1.0.0
fun getParentFile(): DocumentFile?

Return the parent file of this document. Only defined inside of the user-selected tree; you can never escape above the top of the tree.

The underlying android.provider.DocumentsProvider only defines a forward mapping from parent to child, so the reverse mapping of child to parent offered here is purely a convenience method, and it may be incorrect if the underlying tree structure changes.

getType

Added in 1.0.0
abstract fun getType(): String?

Return the MIME type of this document.

See also
COLUMN_MIME_TYPE

getUri

Added in 1.0.0
abstract fun getUri(): Uri

Return a Uri for the underlying document represented by this file. This can be used with other platform APIs to manipulate or share the underlying content. You can use isDocumentUri to test if the returned Uri is backed by a android.provider.DocumentsProvider.

isDirectory

Added in 1.0.0
abstract fun isDirectory(): Boolean

Indicates if this file represents a directory.

Returns
Boolean

true if this file is a directory, false otherwise.

See also
MIME_TYPE_DIR

isDocumentUri

Added in 1.0.0
java-static fun isDocumentUri(context: Context, uri: Uri?): Boolean

Test if given Uri is backed by a android.provider.DocumentsProvider.

isFile

Added in 1.0.0
abstract fun isFile(): Boolean

Indicates if this file represents a file.

Returns
Boolean

true if this file is a file, false otherwise.

See also
COLUMN_MIME_TYPE

isVirtual

Added in 1.0.0
abstract fun isVirtual(): Boolean

Indicates if this file represents a virtual document.

Returns
Boolean

true if this file is a virtual document.

lastModified

Added in 1.0.0
abstract fun lastModified(): Long

Returns the time when this file was last modified, measured in milliseconds since January 1st, 1970, midnight. Returns 0 if the file does not exist, or if the modified time is unknown.

Returns
Long

the time when this file was last modified.

length

Added in 1.0.0
abstract fun length(): Long

Returns the length of this file in bytes. Returns 0 if the file does not exist, or if the length is unknown. The result for a directory is not defined.

Returns
Long

the number of bytes in this file.

See also
COLUMN_SIZE

listFiles

Added in 1.0.0
abstract fun listFiles(): Array<DocumentFile!>

Returns an array of files contained in the directory represented by this file.

Returns
Array<DocumentFile!>

an array of files.

Throws
java.lang.UnsupportedOperationException

when working with a single document created from fromSingleUri.

renameTo

Added in 1.0.0
abstract fun renameTo(displayName: String): Boolean

Renames this file to displayName.

Note that this method does not throw IOException on failure. Callers must check the return value.

Some providers may need to create a new document to reflect the rename, potentially with a different MIME type, so getUri and getType may change to reflect the rename.

When renaming a directory, children previously enumerated through listFiles may no longer be valid.

Parameters
displayName: String

the new display name.

Returns
Boolean

true on success.

Throws
java.lang.UnsupportedOperationException

when working with a single document created from fromSingleUri.

See also
renameDocument